CA2581740A1 - Coin discrimination apparatus and method - Google Patents

Abstract

A coin discrimination apparatus and method is provided. Coins, preferably after cleaning, e.g. using a trommel, are singulated by a coin pickup assembly configured to reduce jamming. A coin rail assists in providing separation between coins as they travel past a sensor. The sensor provides an oscillating electromagnetic field generated on a single sensing core. The oscillating electromagnetic field is composed of one or more frequency components. The electromagnetic field interacts with a coin, and these interactions are monitored and used to classify the coin according to its physical properties. All frequency components of the magnetic field are phase-locked to a common reference frequency. The phase relationships between the various frequencies are fixed, and the interaction of each frequency component with the coin can be accurately determined without the need for complicated electrical filters.

Description

COIN DISCRIMINATION APPARATUS AND METHOD

The present invcotion relates to an apparatus and method for sensing coins and other small discrete objects, and in particular to an apparatus which may be used in coin counting or handling.
BACKGROUND INFORMATION
A number of devices are interxkd to identify afld/or discriminate coins or other small discxete objects.
One example is coin counting or handling devices, (such as those described in U.S. Patent Application 0805,539, now U.S. Patent 5564546, and its continuation application S.N.
08/689 826, 08/237,486, now U.S. Patent 5620079 and its continuation serial number, 08/834,952, filed April 7, 1997 , and 08/431,070, now U.S. patents 5,799,767 and 5,746,299. Other exampies include vending machines, gaming devices surb as slot madtioes, bus or subway coin or token "fare boxes,' and the like.
Preferably, for such purposes, the sensors provide infocmation which can be used to discriminate coins from uon-coin objects and/or which can discriminate among different coin denominations snd/or diseriminate coins of one country from those of another.
Previous coin handling devices, and sensors therein, however, have suffered from a number of deficiencies. Many previous seaLsocs have resdted in an undesirably large propoction of diserimuiation etrors.
At least in some cases this is believed to arise Irm an undesirably small sigoal to noise ratio in the sensor oippA Aocordingly, it would be usefW to pmvide ooia discrimination sensas having improved sigaal to noise ratio.
Many previous coin handling deviccs, and associated sensors, were configured to receive only one coin at a time, such as a typical vending machine which receives a single coin at a time thmugb a coin slot.
These devices typically present an easier coin handling and sensing enviromnent because there is a lower expectatiaa for coin tlvoughput, an avoidance of the deposit of foreign material, an avoidance of small inter-coin spacing (or coin overlap), and because the slot naturally defines maximum coin diameter and thickness.
Coin hendlezs afld sensors that might be operable for a one-at-a-time win environment may not be satisfactory for aa envirooment in which a mass or pluraGty of coins can be received in a single location, all at once (such as a tray for receiving a mass of coins, poured into the tray &om, e.g., a coin jar). Accordingly it would be useful to provide a eoin handlet and/or sensor which, alQwugh it might be successfully employed in a one-coin-at-a-time eavironment, can also function satisfact ily in a device which receives a mass of coins.
Msny pcevious sensas and associated ciwauiv}r used for coia disairnination were confiigured to sense characteristics or parameters of coins (or other objects) so as to provide data relating to an average value for a coin as a whola Such sensors and circnitry were not able to provide information specific to certain regions or levels of the coin (such as core nataial vs. cladding material). In some cuzrencies, two or more denaminatioos may have average characteristics which are so similar that it is difficult to distinguish the coins.
For example, it is dit}'icult to distinguish U.S. dimes from pre-1982 U.S.
pennies, based only on average di$'erences, the main physical difference being the difference in cladding (or absence thereof). In some previous devices, inductive coin testing is used to detect the e8'ect of a coin on an alternating electromagnetic 8eld produced by a coil, and specifically the coin's effect upon the coil's impodanee, e.g.
related to one or more of the coin's diameter, thiekness, conductivity and permeability. In general, when

2 an altemating electromagnetic field is provided to such a coil, the field will penetrate a coin to an extent that decaeases with increasing frequency. Properties near the surface of a coin have a greater e$'ect on a higher fivquency field, and interior material have a lesser effect. Because certain coins, such as the United States tm and twenty-five oeat coins, are laminated, this frequency dependency can be of use in coin discrimination, but, it is believed, has not previously been used in this manner..
Accordingly, it would further be useful to provide a device which can provide information relating to different regions of coins or other objects.
Although there are a number of parameters which, at least theoretically, can be useful in discriminating coins and small objects (such as size, including diameter and thickness), mass, density, conductivily, magnetic permeability, homogeneity or lack thereof (snc,h as cladded or plated coins), and tbe like, niany pnevious sensors were configured to detect only a single one of such paramete,rs. In embodimeats in which only a single parameter is used, discrimination among coins and other small objects was often inaccnrate, yielding both misidentification of a coin denomination (false positives), and failure to recognize a coin cknomination (false negatives). In some cases, two coins which are different may be identified as the same coin because a parameter which could serve to disariminate betweea the coins (such as presence or absence of plating, magnetic non-magnetic character of the coin, etc.) is not detected by the sensor. Thus, using suah sansacs, when it is desired to use several parameters to disaimuiate coins and other objects, it his been necessary to provide a plurality of sensors (if such sensors are available), typically one sensar for each parameter to be detected. Multiplying the number of sensors in a device increases the cost of fabricating, designing, maintaining and repairing sach apparatus. Futthamore, previous devices typic.ally required that multiple sensors be spaced apart, usually along a linear track which the coins foDow, and often the spacing must be relatively far apart in order to properly correlate sequuntial data fmm two sensors with a particular coin (and avoid attn'buting data 5nm the two sensors to a single coin when the data was related, in faet, to two diffaent coins). This spacing increases the pbysical size reqairements for such a device, and may lead to an apparatus which is relatively slow sinee the path which the eoins are required to traverse is longer.
Furthermore, when two or more sensors each output a single parameter, it is typically difficult or impossble to base discximination on the relationship or profile of one parameter to a second parameter for a given coin, because of the difficulty in knowing which point in a first parameter profile caresponds to which point m a second parameter profile. If there are multiple sensors spaced along the coin path, the software for coin discrimination becomes more complicated, since it is necessary to keep track of when a coin passes by the various sensors. Timing is affected, e.&, by speed variations in the coins as they move along the coin path, such as rolling down a rail.
Even in cases where a single coro is used for two different frequencies or parameters, many previous devices take measurements at two different times, typically as the coin moves through different locations, in order to measure several different parameters. For example, in some devices, a core is arranged with two spaced-apart poles with a first messurement taken at a first time and location when a coin is adjaoeat a first pole, and a second measurtment taken at a second, later time, when the coin has moved substantially toward the second pole. It is believed that, in general, providing two or more different measurement locations or times, in order to measure two or more parameters, or in order to use two or more frequencies, leads to

3 urdesirable loss of coin throughput, occupies undesirably extended space and requires relatively complicated cin,vits and/or algcxithnis (e.g. to match up sensor outputs as a particular coin moves to different measurement locations).
Some sensors relate to the electrical or magaetic properties of the coin or other object, and may involve creation of an electromagnetic field for application to the coin. With many previous sensors, the interaotion of generated magnetic flux with the coin was too low to permit the desired efficiency and accuracy of coin disorimination, and resulted in an insufficient signal-to-noise ratio.
Many previous coin handling devices and sensors had characteristics which were undesirable, especially whea the devices were for use by untrained users. Such previous devices had insaflicient acxuracy, short service life, had an undesirably high potential for causing user injuries, were difficult to use, requiring training or extensive instruction, failed, too oflen, to return unprocessed coins to the user, took too long to process eoia4, had an undesirably low throughput, were susceptible to frequent jamming, which could not be cleared without human intervention, oftea requiring intervention by trained persoonel, could handle only a naciow range of coin types, or denominations, were overly sensitive to wet or sticky coins or foreign or non-coin objects, either malfimctianing or plaeing the foreign objects in the coin bins, rejected an undesirably high poctien of good coins, required fiequent and/or complicated set-up, calibration or maintenance, requirod too large a volume or footprint, were overly-sensitive to temperature variations, were undesirabty loud, were hard to upgrade or retrofit to benefit from new technologies or ideas, and/or were difficult or expensive to design and manufacture Accordingly, it would be advantageous to provide a coin handler and/or sensor device having improved discrimination and accuracy, reduced costs or space requirements, which is faster than previous devices, easier or less expensive to design, cooshuct, use and maintain, and/or results in improved sigoal-to-noise ratio.

SUMMARY OF THE INVENTION
The present imreation provides a device for processing and/or discriminating coins or other objects, suah as discriminating among a plurality of coins or other objects received all at once, in a mass or pile, from the user, wit.h the coia4 or objeets being of many diffeneat sizes, types or deaominations. The device has a high degree of automation and high toleianoe for foreign objects and less-than-piistine objects (such as wet, sticky, coated, bent or misshapen coins), so that the device can be readily used by members of the general public, requiring little, if any, training or instruction and little or no human manipulation or intervention, other than inputting the mass of coins.
According to one embodiment of the invention, after input and, preferably, cleaning, coins are singulated and move past a sensor for discrimination, counting and/or sorting.
In general, coin slowing or adhesion is reduced by avoiding avoiding extensive flat regions in surfaces which contact coins (such as making sucb surfaoes curved, quilted or dimpled). Coin paths are configured to flare or widen in the direction of coin travel to avoid jamming.

4 A singulating coin pickup avsembly is preferably provided with two or more concentricalty-mounted disks, one ofwlich includes an integrated exit ledge. Movable paddles flex to avoid oreating or exacerbating jams and deflect over the coin exit ledge. Vertically stacked coins tip backwards into a recess and slide over suppo~ting coins to facilitate singulatioa At the end of a transaction, coins are forced along the coin path by a rake, and debris is removed througb a trap door. Coins exiting the coin pickup assembly are tipped away from the faee-support rail to minimiz.e friction.
Aarording to one embodiment of the present invention, a sensor is provided in which nearly all the magaaio Sdd produced by the coil interac:ts with the eoin providing a relatively intense electroosagnetic 5eld in the regian traversed by a coin or otha' objeet. Preferably, the xceor can be used to obtain information o0 two diffierent parameters of a coin or other object In one embodiment, a single seasar provides infeamation indicative of both size, (diameter) and conductivity. In one embodiment, the sensor includes a core, such as a ferrite or other magnetically penneable matarial, in a curved (e.&, taroid or half-tamid) shape wlrich defines a gap. The coin being sensed moves through the vicinity of the gap, ia one embodiment, through the gap. In one embodkont, the ceae is shaped to roduoe sensitivity of the sensor to slight deviatieos in the locatian af the coin withitt the gap (bounce or wobble). As a coin or the object passes througb the field in the vicanitsr af ihe gap, data rPlating to coin pareme<eca we sensed, such as changes in inductatwe (from which the diameter af the object or coin, or portions thereof, can be derived), and the quality factor (Q factor), related to the aQwunt cf eaergy dissipated (fram which caoductivity of the object or coin, ar poctim theteol; can be obtained).
In one embodimeot, data relating to candudance of the coin (or portions thereof) as a firoctioa of diameter are analyz.ed (e.& by comparing with conductanoe-diameter data for known coins) in order to discriminate the sensed coins. Preferably, the detection procedure uses several thresholds or window parameters to provide bigh recognition acmsacy.
According to one aspect of the inventioo, a coin discrimination apparatus and method is provided in which an oscillating eketcornagnetic field is generated on a single sensing core. The oscillating elechntnagnetic field is omVosed of cee or more frequency components The electromagaetic field interacts with a coin, and tlxae interactions are nwniwred and uaed to classify the coin accarding to its physical properties. All frequeney components of the magoetic field an phase-locked to a common refereace 5equeocy. TLe phase rdatioa4hips between the various $reqaeocies are locked in order to avoid intafereace between $~equeneies and with any neighboring cores or seosors and to facilitate accurate determination of the interaotion of each freqoeeoy component with the coin.
In me embodiment, low and high fieqeency coils on the core form a part of oscillator circuits. The eircuits are configured to maintain oscillatim of the signal tLrough the coils at a substantially cansvot frequency, even as the effective inductance of the coil changes (e.g. in response to passage of a coin). The amount of change in other components of the circuit needed to o$set the change in inductance (and thus maintain the frequency at a substantially constant value) is a measure of the magnitude of the ebange in the inductance caused by the passage of the coin, and indicative of coin diameter.

In additiea to providing infonnation related to coin diameter, the sensor can also be used to provide infosnation related to coin conductance, preferably substantially simultaneously with providing the diameter iuformatioa As a coin moves past the coil, there will be an amount of energy loss and the amplitude of the signal in the coil will change in a manner related to the conductance of the coin (or portions thereof). For a

5 given effective diameter of the coin, the energy loss in the eddy cucrents will be inversely related to the conductivity of the coin material penehated by the magaetic field.
Preferably, the ooin pickup assembly and sensor regions are configured for easy access for cleaning and maiakeoance, such as by providing a sensor block which slides away from the coin path and can be re-positioned without recahbrabaa In one embodiament, the diverber assembly is hinged to pernut it to be tipped outward for access. Preferably, coins which stray from the coin path are deflected, e.g. via a ramped sensor housing andlor bypass chutes, to a customer return area.
Coins which are recognized and properly positioned or spaced are deflected ot of the defaalt (gavity-fed) ooin path into an aoeptaooe bin or trolley. Any coins or otha objects which are not thus actively accepted travel along a default path to the cudomer return area. Preferably, information is seased wbi.ch permits an estima6e af ooin velocity and/ar acceleration so that the deflector mechanism can be tinmed to deDkd coins even though diFaent coins may be traveliog at different velocities (e.
g. owing to stickiness or adhesion).
In eoe embodiment, each object is individually aoalymd to detamine if it is a coin that should be accepted (Le. is recognized as an acceptable coin denomination), and, if so, if it is possible to properly defleet the coin (e.g it is sufficiently spaced fran adjaout coins). By requiring that active steps be taken to accept a coin (i.e.
by malong the defauk pah the '4qecC path), it is more likely that all aeoepbed objects will in fact be members of an acceptable class, and will be accurately conntod.

BHIEF DESC1tIPTION OF THE DRAWINGS
Fig. IA depicts a coinliandling appaatus that may be used in connection with an embodiment of the present invention;
Fib 1B depicts a coin handling apparatus according to an embodiment of the present invention;
Fig. 2A is a fivnt elevational view of a seasor and adjacent coin, according to an embodiment of the present invention;
Figs. 2B and 2C are peaspechve views of seosocs and coin transport rail aoeocding to embodiments of the present invention;
Fig 2D depicts a two-core configuration according to an embodiment of the present invention;
Fig. 3 is a$aot elevatienal view of a sat9or and adjaceat coin, aceording to another embodimeat of the present invention;
Fig. 4 is a top plan view of the sensor of Fig. 3;
Fig. 5 is a block diagram of a disiximination device according to an embodime,nt of the preseat invention.
Fig. 6 is a block diagram of a discrimination device according to an embodiment of the present invention;

6 Fig. 7 depicts various signals that occur in the circuit of Figs. 8A-C;
Fig 8A-8D are block and schematic diagrams of a circuit which may be used in connection with an embodiment of the present invention;
Fig. 9 depicts an example of output signals of a type output by the circuit of Figs. 8A-D as a coin passes the sensor, Figs l0A and lOB depict standard data and tolerance regions of a type that may be used for discrinunating coins on the basis of data output by sensors of the present invention;
Fig. 11 is a block diagram of a discrimination device, according to an embodiment of the presmt invention;
Fig. l lA is a block diagram of a two-core discrimination device, acoording to an embodiment of the presentinvention;
Fig. 12 is a schematic and block diagram of a discrimination advice according to an embodiment of the present invention;
Fig. 13 depicts use of in-phase and delayed amplitude data for coin discriminating according to one embodiment;
Fig. 14 depicts use of in-phase and delayed amplitude data for coin discriminating according to another embodimeat;
Figa 15A and 15B am finnt elevational and top plan views of a sensor, coin path and coin, according to an embodiment of the present invention;
Figs. 16A and 16B are graphs showing D output from high and low frequency sensors, respectively, for eight copper and aluminum disks of various diameters, according to an embodiment of the present iavention;
Fig.17 is a perspective view of a coin pickup assembly, rail, sensor and chute system, according to an embodiment of the present invention;
Fig. 18 is an exploded view of the system of Fig. 17;
Fig 19 depicts the system of Fig. 17 with the front portion pivoted;
Fig 20 is a cross-sectional view taken along line 20-20 of Fig. 17;
Fig. 21 is a&ont elevational view of the ooin rail portion of Fig. 17;
Fig. 22 is a perspective view of the system of Fig. 17, showing an example of coin locations;
Figs 23A tbrough 23G are cross sectional views taken along lines 23A-23A
through 23G-23G, respectively, of Fig. 21;
Fig 24 is a cross sectional view taken along line 24-24 of Fig 22;
Fig. 25 is a rear elevational view of the system of Fig. 17;
Fig. 25A is a partial view carresponding to Fig. 25, but showing the rake in the downstream position;
Figs. 26 and 26A are cross-sectional views taken along lines 26-26 and 26A-26A
of Figs. 25 and 25A;
Fig. 26 is a top plan view of a portion of the system of Fig 17, showing a rail rake;

F

7 Figs. 27A and 27B are front and rear perspective views of a sensor and sensor board according to an embodiment of the present invention;
Figs. 28A-281 are front, elevational and top views of sensor cores according to embodiments of the present invention;
Fig 29 is a block diagram of functional components of a sensor board, according to an embodiment of the present invention;
Fig. 30 is a graph of an example of sensor signals according to an embodiment of the present invention;
Fig. 31 is a schematic diagram of a sensor board, according to an embodiment of the present invention;
Fig. 32 is a block diagram of hardware for a coin disorimination device, acxording to an embodiment of the presentinvention;
Fig. 33 is a graph of a hypothetical example of sensor signals, according to an embodiment of the presentinvention;
Fig. 34 is a flow chart of a coin signature calculation process, according to an embodiment of the presentinvention;
Fig. 35 is a state diagram for a coin discrimination prooess according to an embodiment of the present invention;
Fig. 36 is a state diagram for a categorization process according to an embodiment of the present invention;
Fig.37 is a block diagram for a categorization process according to an embodiment of the present invention;
Fig. 38 is a state diagram of a Direct Memory Access process according to an embodiment of the present invention;
Fig. 39 is a timing diagram of a Direct Memory Access process according to an embodiment of the presentinvention;
Fig. 40 is a flowchart showing a coin discrimination process, according to an embodiment of the presentinvention;
Fig. 41 is a block diagram showing components of a coin discrimination system according to an embodiment of the present invention;
Fig. 42 is a flowchart showing a leading and trailing gap verification procedure;
Fig. 43 is a partial perspective view showing a coin return path according to an embodiment of the present invention;
Fig. 43A is a partial perspective view showing the diverter cover in a closed or normal position, according to an embodiment of the present invention Fig. 44 is a partial perspective view, similar to the view of fig 43, but with the diverter cover in an open configuration;
Fig. 45 is a partial rear perspective view corresponding to Fig. 43;

8 Fig. 46 is a partial perspective view coiresponding to Fig. 44 but with the sensor retracted;
Fig. 47 is a partial rear perspective view corresponding to Fig. 45, but with the sensor retracted;
Fig. 48 is a partial perspective view showing the relative position of a trommel according to an embodiment of the present invention;
Fig. 49 is a paitial petspective view corresponding to Fig. 48 but with the trommel tilted downward;
Fig. 50 is a partial perspective view cmespcoding to Fig. 49 but with the trommel partially retracted from the cradle;
Fig. 51 is a partial top plan view showing a trommel according to an embodimeat of the present invention;
Fig. 52 is a partial rear elevational view showing a tranmel release mechanism, according to an embodiment of the present invention;
Fig. 53 is a peispective view of a trommel with endcaps and cradle according to an embodiment of the present invention;
Fig. 54 is a paspective, partially exploded view of a trornmel cradle according to an embodimeat of the present invention;
Figs. 55A-C are block diagrams depicting signal generation and use according to embodimentt of the presentinvention;
Fig. 55D is a block diagram depicting use of a sensor cwreat response to a square wave voltage; and Figs 56A-H are side views of sensor shapes according to embodiments of the present inventioa DETAILED DESCRIPTION OF THE PREFERRED EMBODIIKENTS
The sensor and associated apparatus described herein can be used in connection with a number of devices and pucposes. One device is illustrated in Fig 1 A. In this device, coins are placed into a tray 120, and fed to a sensor regicn 123 via a first ramp 230 and coin pickup assembly 280.
In the sensor region 123, data is collec,ted by which coms are discriminated from non-coin objects, and different denominations or countries of coins are disaiminated. The data collected 'ut the sensor area 123 is used by the computer at 290 to control movement of coins along a seoond ramp 125 in such a way as to route the coins into one of a plurality of bins 210. The computer may output infonnation such as the total value of the coins placed into the tray, via a printer 270, screen 130, or the like. In the depicted embodiment, the conveyance apparatus 230, 280 which is upstream of the sensor region 123 provides the coins to the sensor area 123 serially, one at a time.
The embodiment depicted in Fig 1B generally includes a coin counting/sorting portion 12 and a coupaoJvoirher dispensing portions 14a,b. In the depicted embodiment, the coin counting portion 12 includes an input tray 16, a voucher dispet>sing region 18, a coin return region 22, and customer 1/O devices, including a keyboard 24, additional keys 26, a speaker 28 and a video screen 32. The apparatus can include various indicia, signs, displays, advertisement and the like on its external surfaces.
A power cord 34 provides power to the mechanism as described below.
Preferably, when the doots 36a, 36b are in the open position as shown, most or all of the components ane accessible for cleaning and/or maintenance. In the depicted embodiment, a voucher printer 23 (Fig. 41)

9 is mounted on the inside of the door 36a. A number of printers can be used for this purpose. In one embodiment, a model KLDS0503 printer, available from Axioh is used. Tlu right-hand portion of the cabinet includes the coupon feeder 42 for dispensing, e.g., pre-printed manufacturer coupon sheets through a chute 44 to a coupon hopper on the outside portion of the door 36b. A cocnputer46, in the depicted embodiment, is posilioned at the top of the right hand portion of the cabinet in order to provide a relatively clean, location for the computer. An 1/O board 48 is positioned adjacent the sheet feeder 42.
The general coin path for the etabodiment depicted in Fig I B is from the input tray 16, down first and second chutes to a tromme152, to a coin pickup assembly 54, along a coin rail 56 and past a sensor 58. If, based an sensor data, it is detetminad that the coin can and should be accepted, a controllable deflector door 62 is activated to divert coins ftnm their gravitational path to coin tubes 64a, b for defivery to coin troUeys 66a, b. If it has not been determined that a coin can and should be accepted, the door 62 is not activated and coins (or other objects) continue down their gravitational or default path to a reject chute 68 for delivery to a customer-accessible reject or return box 22.
Devices that may be used in connection with the input tray are described in U.S. S.N. 08/255,539.
now U.S. Patent 5564546, 08l237,486, now U.S. Patent 5620079, supra.
Devices that may be used in connection with the coin trolleys 66a, 66b are described in S.N.
08/883,776, for COIN BIN WITH LOCKING LID, Devices that may be used in connection with the coin chutes and the tromme152 are described in PCTlUS97/03136 Feb 28, 1997 and its parent provisional application U.S.S.N.
60/012 964.
In one embodiment, depicted in Figs. 51 and 53, the trommel cage 5 112 is configured to facilitate removal, e.g. for cleaning or maintenance purposes or the like. In the embodiment depicted in Figs 48 - 54, trommel removal can be accomplished with only one hand, particularly by pressing buttan 5212 (Figs 52 and 54)which moves socket 5414 (Fig F4) out of engagetnent with cradle pin 5414 (Fig 54) permitting the czadle 5416 which beats the trommel cage (as shown in Fig.
53) to pivot downward 5312 (Fig 53) from the position 4812 shown in Fig. 48 to the position 4912 shown in Fig. 49. The cradle 5416 inchdes a telescoping section 5418a,b for pe,rmitting the trommel cage to be further retracted to the position 5012 shown in fig 50 where it can be easily lifled from the cradle.
Briefly, and as described more thoroughly below and in the above-noted appiicationa, a user is provided with instruetions such as on computer screen 32. The user places a mass of coins, typically of a plurality of denaninations (typically aooompanied by dirt or other non-coin objects and/or foreign or otherwise non-aceeptable coins) in the input tray 16. The user is prompted to push a button to inform the machine that the user wishes to have coins discriminated. Thereupon, the computer causes an input gatc 17 (Fig. 41) to open and iDusninates a signal to prompt the user to begin feeding coins The gate may be controlled to open or close for a number of purposes, such as in response to sensing of a jam, sensing of load in the trommel or coin pickup assembly, and the like. In one embodiment, sipal devices such as LEDs can provide a user with an indication of whether the gate is open or closed (or otherwise to prompt the user to feed or discontinue feeding coins or other objects). ABhough instrvctions to feed or discontinue may be provided on the computer scroen 32, indicator ligbts (although involving additional wiring and attendant difficulties) are believed useful since users often are watching the throat of the chute, rather than the computer screen, during the feeding of coins or other objects. When the gate is open, a motor 19 (Fig. 41) is activated to begin rotating the trommel assembly 52. The user moves coins over the peaked output edge 72 of the input tray 16, typically by lifting or pivoting the tray by handle 74, and/or manually feeding coins over the peak 72. The coins pass the gate 5 (typically set to prevent passage of more than a predetormined number of stacked coins, such as by defining an opening equal to about 3.5 times a typical coin thickness). Listructions on the screen 32 may be used to tell the user to continue or discontinue feeding coins, can relay the status of the machine, the anwunt counted thus far, provide encouragement or advertising messages and the like.
First and secaod chutes (not shown in Fig. IB) are positioned between the output edge 72 of the input

10 tray 16 and the input to the trommel 52. Preferably, the second chute provides a fimneling effect by having a greater width at its upstream edge than its downstream edge. Preferably, the coins cascade or "watafall"
whea passing &om the first chute to the second chute, e. g. to increase momentum and tumbling of the coins.
Preferably, some or all af the surfaces that contact the coin along the coin path, including the chutes, have no 8at region large enough for a coin to contact the surface over all or substantially all of one of the faces of the coin. Some surh surfaces are curved to achieve this result, such that coins make contact on, at most, two points of such surfaces. Other surfaces may have depressions or protrosions such as being provided with dimples, qniitiog or otber textiaes. Pieferably, the surface of the second chute is eonshveted such that it has a finite radius of curvature along any plane normal to its longitudinal axis, and preferably with such radii of curvature increasing in the direction of coin flow.
In one embodiment, the chutes are formed from injected molded plastic such as an acxtal resin e.g.
Delrin , available fimm E.L DuPont de Nemotus & Co., or a polyamide polymer, such as a nylon, and the like.
Other materials that can be used for the chute include metals, ceramics, fiberglass, reinforced matmials, epmes, oeramic-eoated or -manfa+oed materials and the like. The chutes may contain devices for performing additie al fiu-ctions such as stops or traps, e.g., for dealing with various types of elongate objects.
The trommel 52, in the depicted embodiment is a perforated-wall, square cross-section, rotatably mounted container. Preferably, dimples protrude slightly into the interior region of the trommel to avoid adhesiea and!oc reduce friction between eoias and the interior surface of the trommel. The trommel is rotated I
about its longitudinal axis. Preferably, operation of the device is monitored, such as by monitoring current draw for the trommel motor using a cutrent sensor 21. A sudden increase or spike in current draw may be considered indicative of an undesirable load and/or jam of the trommel. The system may be configured in various ways to respond to such a sensed jam such as by turning off the trommel motor to stop attempted trommel rotation and/or reversing the motor, or altering motor direction periodically, to attempt to clear the jam. In one embodimeat, when a jam or undesirable load is seosed, coin feed is stopped or discouraged, e.g., by closing the gate and/or illuminating a"stop feed" indicator. As the trommel motor 19 rotates the trommel, one or more vanes protruding into the inteaior of the trommel assist in providing coin-li8ing/&ee-fall and moving the coins in a direction towards the output region. Objects smaller than the smallest acceptable coin (about 17.5 mm, in one embodiment) pass tluough the perforated wall as the coins tumble. In one embodiment, the holes have a diameter of about 0.61 inches (about 1.55 cm) to prevent passage of U.S. dimes. An output

11 chute directs the (at least partially) cleaned coins exiting the trommel towards the coin pickup assembly 54.
The depicted horizontal disposition of the trommel, which relies on vanes rather than trommel inclination for longitudinal coin movements, achieves a relatively small vectical space requiremant for the troauuel.
Prdaably the trommel is mounted in such a way that it may be easily reawved andlor opeaed or disassembled for cleaning and maintenance, as described, e.g., in PCT Application US97103136, supra.
As dcpictcd in Fig. 17, coin pickup assembly 54 includes a hopper 1702 for receiving coins output from the tromme152. The hopper 1702 may be made at relatively low cost such as by vacuum forming. In one embodiment, the hopper 1702 is formed of a plastic material, anch as polyethylene, backed with sound-absorbing foam for reducing noise. Preferably, the hopper (or other components along the coin path) are eoofigumd to avoid slow-up, jams or other difficulties, such as may otherwise result parliculady from wet or sticky coins. Without being bound by any theory, it is believed that polyethylene is useful to reduce coin sticking. Thus, it may be desirable to include a mechanical or other transducer for prvviding energy, in nspmse to a sensed jam, slow-up or other abnornality. One configuration for providing energy is described in U.S. patent 5,746,299. In one embodiment, slow or atuck coips ane aufamelically provided with kinetic mergy ln one embodimatt, vibrational or other kiaetic energy is imparted by pulsing, alteraating, reversing or otherwise activating the hopper motor.
Other feateres which may be provided for the hopper include stwping to ravide a curvature sufficient to avoid face-to-face contact between ooins and the hopper surfaco and/or providing ssface texture (such as embossing, dimpiing, faceting, quiltiog, ridging or ribbing) on the bopper interior surface. The hopper 1702 preferably has an amount of fleability, rather than being rigid, which reduces the occutrance of jsms and assists in clearing jams since coins are not forced against a solid, unyielding surfaee.
As deaen'bed below, the eoios move into an aanular coin path defined, an the outside, by the edge of a cirailar:ecess 1802 (Fig 18) and, oe the inside, by a ledge 1804 facmod on a rail disk 1806. The coins are moved along the aemalar path by paddks 1704a, b, c, d for delivery to the coia rail 56.
A circuit board 1744 for providing certain control functions, as described below, is preferably moudod an the generally aooesstble 5eet surface of the chassis 1864. An electromagnetic interferenoe (EMi) safety shield 1746 nocmally cavers the cincuit board 1744 and swings open on hinges 1748a,b for easy savice acce.ss.
In the embodicnent depicted in Fig. 17 and l S. the coin rai156 and the recess 1808 for the disks are formed as a single piece or block, such as the depicted base plate 1810. In one embodiment, the base plate 1810 is formed fmm high density polyethylene (I!=IDPE) and the recess 1808 and coin rat7 56, as well as the various openinga depicted, are focmed by machining a sheet or block of HDPE.
HDPE is a useful material because, among other reasons, components may be mounted using self-tapping socews, reducing maaufactnring costs. Fmlhantane, use of a non-metallic back plate is prefered in order to avoid interference with the sensor. In one embodimmt, electrically conductive HDPE may be u9ed, e.g. to dissipate sWic electricity.
The base plate 1810 is mounted on a chassis 1864 which is positioned within the cabinet (Fig. IB) such that the base plate 1810 is disposed at an angle 1866 with respect to vertical 1868 of between about 0

12 and about 45 , preferably between about 0 and about 15 , more preferably about 20 . Preferably, the diverter cover 1811 is pivotally coupled to the baseplate 1810, e. g. by hinges 1872a, 1872b, so that the diverter cover 1811 may be easily pivoted forward (Fig. 19), e.g. for cleaning and maintenance.
A rotating main disk 1812 is eonfigiaed fac tight (small clearance) fit against the edge 1802 of reeess 1808. Finger holes 1813a, b, c, d facilitate removal of the disk for cleaning or maintenance. Relatively loose (large clearance) fit is provided between disk holes 1814a, b, c, d and hub pins 1816a, b, c, d and between om" opening 1818 and motoa hub 1820. The loose fit of the holes and the tight fit of the edge of disk 1812 assist in reducing debris entrapment and motor jams. Because the main disk is received in recess 1802, it is frae to flex and/or tilt, to some degree, e.g. in order to react to coin jams.
A statieoary rail disk 1806 is positioned adjacent the main disk 1812 and has a central opening 1824 fitling loosely with respect to the motar hub 1820. ]n rne enbodiment, the rail disk is foimed of gcaphite-filled phenolic.
The ledge 1804 defined by the rail disk 1806 is preferably configured so that the annular coin path flares or widens in the direction of coin travel such that spacing between the ledge and the recess edge near the bottom or begimting of the coin path (at the eight o'clock position 1876) is smaller (such as about 0.25 inches, or about 6 mm smaller) than the corresponding distance 1827 at the twelve o'clock position 1828. In one embodiment, the rail disk 1806 (and motor 2032) are mounted at a slight angle to the plane farmed by the attaehment edge 2042 of ihe hopper 1702 such that, along the coin path, the coin channel generally increases in depth (i.e. in a direction perpendicular to the face of the rail disk).
As th,e coins travel counterclockwise from approximately a 12:00 position 1828 of the rail disk, the ledge is thea ea8er substautially linew along a patian 1834 ( Fig. 19) extending to the periphery of the rail disk 1806 and ending adjacent the coin backplate 56 and rail tip 1836. A tab-like protrusion 1838 is engaged by rail tip 1836, hokling the rail disk 1806 in position The rail disk is believed to be more easily manufactured and constructed than previous designs, such as those using a coin knife.
Furthermore, the present design avoids the problem, often found with a coin knife, in which the tip of the knife was susceptible to prying outward by debris accumulated behind the tip of the coin knife.
A tension disk 1838 is positioned adjacent the rail disk. The tension disk 1838 is mounted on the motor hub 1820 via ceatral opaiing 1842 aQd threaded disk knob 1844. As the knob 1844 is tightened, spring fmgers 1846a, b, c, d apply force to keep the disks 1838, 1806, 1812 tightly together, reducing spaces or cracks in which debris could othewise become entrapped. Preferably, the knob 1844 can be easily removed by luald, petmitting removal of all the disks 1812,1806, 1838 (e.g., for maintenance or cleaning) without the need for tools.
In one embodimart, the tension disk 1838 and main disk 1812 are formed of stainless steel while the rail disk 1806 is fomned of a diffei+ont material such as gaphite-filled phenolic, which is believed to be helpful in reducing galling. The depicted ooin disc configuration, using the described materials, can be manufactured relatively easily and inexpensively, compared to previous devices. Paddles 1704a, b, c, d are pivotally mounted on tension disk pins 1848a, b, c, d so as to permit the paddles to pivot in directions 1852a, 1852b parallel to the tension disk plane 1838. Such pivoting is useful in reducing the creation or exacerbation of coin

13 jams since mns a other items which are stopped along the coin path will cause the paddles to flex, or to pivot acaaid pins 1848a, b, c, d, rather than requiring the paddles to continue applying full motor-induced force on the stopped onins or other objocts. Springs 1854a, b, c, d resist the pivoting 1852a, 1852b, urging the paddles to a position oriented radially outward, in the absence of resistance e.g.
from a stopped coin or other objeet.
Preferably, sharp or itregular surfaces which may stop or entrap coins are avoided. Thus, covers 1856a, b, c, d are placed over the springs 1854a, b, c, d and conically-shaped washers 1858a, b, c, d protect the pivot pins 1848a, b, c, d In a similar spirit, the edge of the tension disk 1862 is angled or chamfered to avoid coins hanging on a disk edge, potentially causingjin&
As depicted in Fig. 25, a number of canpeoetds are mounted on the rear surface of the chassis 1864.
A motor, sueh es moded 2032 drives the rotation of disks 1812, 1838 via motor drive hub 1820. An actuator such as solenoid 2014 controls movement of the trap door 1872 (described below). A sensor assembly, including sensor printed circuit board (PCB) 2512 is slidably mamted in a shield 2514.
The lower edge of the recess 1808 is formed by a separate piece 1872 which is mounted to act as a trap door. The trap door 1872 is configured to be moved rearwardly 2012 (Fig.
20) by actuator 2014 to a position 2016 to enable debris to fall into debris cup 2018. Solenoid 2014 is actuated under control of a micaooonholler as descn'bed below. Preferably, the trap door 1872 retracts substantially no fiuiher than the front edge of the coin rail disk, to avoid catching, which could lead to a failure of the trap door to close.
Preferably, a sensor switch provides a signal to the microcontroller indicating whether the trap door has completely shnt. Preferably the trap door is resiliently held in the closed position in such a manner that it can be manually opened if desired.
Coins which fall into the hopper 1702 from the trommel 52 are directed by the curvature of the hopper towands the 6:00 position 1877 (Fig. 19) of the annular coin path. In general, coins traveling over the downward-turning edge 2024 of the hopper 1702 are tipped onto edge and, pattiaAy owing to the backward inclination 1866 of the apparatus, tend to fall into the annular space 1801.
Coins which are not positioned in the space 1801 with their faces adjacent the surface of the rail disk (such as coins that may be tipped outward 2026a or may be perpendicular to the rail disk 2026b) will be struck by the paddle 1704 as it rotates, agitating the coins and ewentually ean=tly pasitioning coins in the annular space 1801 with their faces adjacent the face 1801 of the annular space defined by the rail disk 1806. It is believed that the shape of the paddle head 2028a, 2028c, in pacticular the ramded shape of the radially outmost portion 2206 of the head, assists in agitating or striking coins in such a manner that they will assume the desired position.
Once coins are positioned along the annular path, the leading edge of the paddle heads 2028 eontact the trailing edge of the coins, forcing them along the coin path, e.g. as depicted in Fig. 17. Preferably each paddle can move a plurality of coins, such as up to about 10 coins. The coins are thus eventually forced to travel onto and along the linear portion 1834 of the rail disk ledge 1804 and are pushed onto the coin rail tip 1836. Some previous devices were provided with an exit gate for coins exiting the coin pickup assembly which, in some cases, was susceptible to jamming. Aocading to an embodiment of the present invention, such jamming is eliminated because no coin pickup assembly exit gate is provided.

14 As the paddle heads 2028 contiaue to move along the circular path, they contact the linear portion 1834 (Fig. 19) of the ledge 1804 and flex axially outward 2032, facilitated by a tapered shape of the radially inward portion of the paddle pad 2028 to ride over (i.e. in front of) a portion 1884 of the rail disk. In one embodimeat, openings or holes 1708 are provided in this portion to reduce frictional drag and to receive e.g.
trapped debris, which is thus cleared from the aonular coin path.
As seen in Fig. 21, tla: ledge 1804 as defined by the rail disk 1806 is displaced upwardly 2102 with respect to the ledge 2104 of the ooin rail tip 1836. The distance 2102 may be, for example, about 0.1 inclm (about 2.5 mtn). The diffeteace in height 2102 assists in gravitationally moving coins from the rail disk ledge 1804 over the upper portion of the "V" gap (described below) and onto the ledge of coin rail tip 1836.
The terminal point 2105 of the rail disk ladge is laterally spaced a distance 2107 from the initial edge of the oornn rad ledge 2104 to de6ne a "V" gap therebetween. This gap, which extends a certain dLstancx 2109 circumferentially, as seen in Fig. 21, receives debris which may be swept along by the coin paddles. The odsience of the gap 2107, and its placement, exteuding below the rail ledge, by providing a place for debris swept up by the paddles, avoids a problem found in certain previous devices in which debris tended to acraamilate where a disk region met a linear region, sometimes accumulating to the point of creating a bump or obstruction which could cause coins to hop or fly off the ledge or rail.
The coin rai156 fimctions tn reeeive coins output by the coin pickup assembly 54, and "nsporis the coins in a singulated (one-at-a-time) fashion past the sensor 58 to the diverting door 62. Singulation and separatioa of coins is of pmticular use in eannection with the described sensor, although other types of senaors may also bene6t from coia singulation and spacing. In general, coias are delivered to the coin rai156 rolling or sliding on their edge or rim along the rail ledge 2104. The face of the coins as they slide or roll down the coin rail are supported, during a portion of their travel, by rails or stringers 2106a, b, c. The stringers are positioned (Fig 23A), respectively, at heights 2108a, b, c (with respect to the height of the ledge 2104) to provide support suitable for the range of coin sizes to be handled while providing a relatively small ares or region of contact between the coin face and the stringers. Although some previous devices provide for flat-tapped or rounded-profile rails or ridges, the present invention provides ridges or stringers which at least in the second portion, 2121 b, have a triangular or peaked profile. This is believed to be easier to manufaetue (such as by machining into the baseplate 1810) and also maintains relatively small area of contact with the coin face despite stringer wear.
The positien and shape of the stringers and the width of the rail 2104 are selected depending on the range of coin sizEs to be haodled by the device. In one embodiment, which is able to handle U.S. coins in the size range between a U.S. dime and a U.S. half-dollar, the ledge 2104 has a depth 2111 (from the backplate 2114) of about 0.09 inches (about 2.3 mm). The top stringer 2106a is positioned at a height 2108a (above the ledge 2104), of about 0.825 inches (about 20 mm), (the tniddle stringer 2106b is positioned at a height 2108b of about 0.49 inches (about 12.4 mm), and the bottom stringer 2106c is positioned at a height of about 0.175 inches (about 4.4 mm). ln one embodiment, the stringers are about 0.8 inches (about 2 mm) wide 2109 (Fig. 23C) and protnule about 0.05 inches (about 1.3 mm) 2112 above the back plate 2114 of the coin raiL

As seen in Fig. 22, as the coins enter the coin rail 56, the coins are typically horizontally singulated, i.e., coins are in single file, albeit possibly adjacent or touching one another. The singulated configuration of the coins can be contrasted with coins which are horizontally partially overlapped 2202a,b as shown in Fig.
22A. Fig. 22A also illustrates a situation in which some coins are stacked on top of one another vertically 5 2202c, d A number of features of the coin rail 56 contribute to changing the coins from the bunched confipration to a singulated, and eventually separated, series of coins by the time they move past the seasar 58. One such feature is a cut-out or reeess 2116 provided in or adjacent the top portion of the rail along a first portion of its extent. As seen in Fig. 24, when coins which are vertically stacked such as coins 2202c, b, illuscated in Fig. 22, reach the cut-out partion 2116, the top coin, aided by the inclination 1866 of the rail, tips 10 backward 2402 an amount sufficient that it will tend to slide forward 2404 in frant of the lower coin 2202, falling into the hopper extension 2204 which is positioned beneath the cut-out region 2116, and sliding back into the main portion of the hopper 1702 to be conveyed back on to the coin rail.
Another feature contributing to singWation is the change in inclination of the coin rail from a 5rst portian 2121 a which is inclined, with respect to a heuizontal plane 2124 at an angle 2126 of about 0 to about

15 30 , preferably about 0 to about 15 and more preferably about 100, to a second portion 2121b which is inclined with respect to a horizental plane 2124 by an angle 2128 of about 30 to about 60 , preferably between about 40 aod about 50 and more preferably about 45 . Preferably, the coin path in the transitional regian 2121 c between the first portion 2121 a and second portion 2121 b is smoothly curved, as shown. ln one embodiment, the radius of curvature of the ledge 2104 in the transition region 2121c is about 1.5 inch (about 3.8 cm).
One feature of singulating coins, according to the depicted embodiment, is to primarily use gravitational forces for this purpose. Use of gravity force is believed to, in general, reduce system cost and complexity. This is aooomplished by con6guring the rail so that a given coin, as it approaches and then enters the seeond portion 2121b, will be gravitationaqy accelerated while the next ("following") coin, on a shallower slope, is being accelerated to a much smaller degree, thus allowing the first coin to move away fim the following coin, creating a space therebetween and effectively producing a gap between the singulated coins.
Thereafter, the following coin moves into the region where it is, in turn, accelerated away from the successive coin. As a coin moves frnm the first regien 2121a toward and into the second region 2121 b, the change in rail inclination 2126, 2318 (Fig. 21) causes the coin to accelerate, while the following coins, which are still positioned in the first region 2121 a, have a relatively lower velocity.
In one embodiment, acceleration of a coin as it moves into the second rail region 2121b is also enhanced by placement of a short, relatively tall auxiliary stringer 2132 generally in the transition region 2121c. The awdliary stringer 2132 projects outwardly fmn the back surface 2114 of the coin rail, a distance 2134 (Fig. 23B) greater than the distance 2112 of projection of the normal stringers 2106a, b, c. Thus, as a coin moves into the transition region 2121c, the auxiliary stringer 2132 tips the coin top outward 2392, away from caatact with the normal stringers 2106a, b, c so that it tends to "fly"
(roll or slide on its edge or rim along the coin rail ledge 2104 without contact with the normal stringers 2106a, b, c) and, for at least a time period following movement past the auxiliary stringer 2132, continues to contact the coin rail only along the ledge

16 2104, further minimizing or reducing friction aW allowing the coin to accelerate along the second region 2121 b of the cain rail. ln one embodiment, the coin-contact portion of the stringers in the first portion 2121 a are somewhat flattened (Fig. 23A) to increase friction and exaggerate the difference in coin acceleration between the first section 2121 a and the second section 2121 b, where the stringer profiles are more pointed, such as being substantially peaked (Fig. 23C).
Another feahue of the coin rail contributing to acceleration is the provision of one or more free-fall regicos where coins will normally be out of contact with the stringers and thus will contact, at most, only the ledge portion 2104 of the rail. hi the depicted embodicnent, a fitst free-fall region is provided at the area 2136a wherein the auxiliary stringer 2132 terminates. As noted above, coins in this region will tend to contact the coin rail only along the ledge 2104. Another free-fall region occurs just downstream of the upstream edge 2342 of the door 62. As seen in Fig. 23E, the door 62 is preferably positioned a distance 2344 (such as about 0.02 inches, about 0.5 mm) from the surface 2114 of the rail region. This setback 2344, combined with the taminatlon of the stringes 2106, pruvides a free-fall region adjacent the door 62. If desired, another free-fall region can be provided downsheam &om the door 62, e.g., where the reject coin path 1921 meets the (preferably embossed) surface of the reject chute or reject chute entrance which may be set back a distance such as about 1/8 inch (about 3 mm).
Another fnao-fall regicn may be de6ned near the location 2103 where coins exit the disks 1812,1806 and enter the rai156, e.g., by positioning the disk 1812 to have its front surface in a plane slightly forward (e.g., about 0.3 inches, or about 7.5 mm) of the plane defined by rail stringers 2106. This free-fall region is useful not only to assist the transition from the disk onto tlx rail but makes it more likely that coins which may be slowod or atopped on the rail near the end of a hmactian will be positioned downstream of the ratract position (Fig. 21) of the rake 2152 such that when the rake operates (as described below), it is more likely to push sknved or stopped coins down the rail than to knock such coins off the rail.
Providing periods of coin flying refixes fricticn, cantributes to ooin acceleration and also reduces variation in coin velocity since sticky or wet coins behave similariy to pristine coins when both are in a flying mode.
Producing periods of flying is believed to be particularly useful in maintaiuting a desimd aooeleratiom and velocity of coins which may be wet or sticky.
The sensor 58 is pasitioned a dLtanoe 2304 (Fig. 23D) away from the surface of the stringers 2106a, b, c su&cient to accommodate passage of the thickest coin to be handled Although cmtain prefen-ed sensm, and tbeir use, are desaibed mao thoroughly below, it is passible to use featuc+es of the present invention with other types of sensors which may be positioned in another fashion such as embedded in the coin rail 56.
The leading surfaoe al'the sensor housing is preferably ramped 2306 such that eoins or other objects which do not travel into the space 2304 (such as coins or other objects which are too large or have moved partially off the coin path) will be defleoted by the ramp 2306 onto a bypass chute 1722 (Fig. 17), having a deflector plane 1724 and a trough 1726 for delivery to the coin retutn or reject chute 68 where they may be returned to the user. The sensor housing also performs a spacer function, tending to hold any jams at least a minimum distance fran the sensar cae, preferably suffiaently far that the sensor reading is not affected (which could cause misdetec6on). If desired, the sensor housing can be configured such that jams may be permitted within the sensing range of the sensor (e.g., to assist in detecting jam occurrence).

17 In the depicted configuration, the sensor 58 is configured so that it can be moved to a position 2142 away from the coin rai156, for cleaning or maintenance, such as by sliding along slot 2144. Preferably, the device is cmsbmted with an interfetmice fit so that the sensor 58 may be moved out of position only when the diverter cover 1811 has been pivoted forward 1902 (Fig. 19) and such that the diverter cover 1811 may not be repositioned 1904 to its operating configuration until the sensor 2142 has been properly positioned in its apaaGng location (Fig. 21). In another embadin-ent, depicted in Figs 43 - 47, closing the diverter cover 1811 before the saL9or 2142 has been properly positioned, is prevented by interference with a pin 4312 (rather than interfen:oee with the sensor itself, which could result in impact and/or damage to the sensor). In the depicted embodiment, the pin 4312 is registered with a hole 4313 in the diverter cover 1811 when the sensor 2412 is in the unretracted position shown in Fig. 43. Fig 44 shows the configuration with the diverter cover 1811 open. With the divetta cover 1811 in the open position, the sensor 2142 can be moved from the unretracted position (Figs 43, 44) to the retracted position (Fig 46), eg. For purposes of cleaning, mainte,nance and the like.
Fig. 45 is a rear view showing the bottom edge 4511 of the sensor assembly protniding ffom under a sensor cover 4512. In the depicted embodiment, when the sensor is retracted the bottom edge 4511 moves from the position shawn in fig 45 to the position shown in fig 47. (Although Fig 47 shows the cover 4512 moving with the sensoc, it is also possible to configure the cover 4512 to be stationary while the sensor 2142 is retraoted) To avoid accidentally leaving the sensor in the retracted position when the cleaning and maintenance operations are completed, as the sensor is retracted, the bottom edge 4511 moves a pin 4515, projecting reaiwardly from a rotatably-mount,ed disk 4517. Movement of the pin 45] 5 causes the disk 4517 to rotate 4519, against the urging of spring 4521, catrying the pin 4312 to the position shown in fig 46, out of registration with the hole 4313. When thus moved, the pin 4312 is positioned such that, if an attempt is made to close 4612 the diverter cover 1811 while the sensor is retracted (Fig. 46) the rear surface of the diverter cover 1811 will strike the pin 4312, preventing closm-c of the cover 1811. By sliding the sensor to its unretracted position (Fig. 44) the spring 4521 rotates the disk 4517 to return the pin 4312 to the position depicted in Fig. 44, registered with the hole 4313, permitting closure of the cover 1811. Preferably, the sensar apparatus is camfigiued so that it will seat reliably and accurately in a desired position with respect to the coin rail such as by engagement of a retention clip 2704 (Fig. 21). Such seating, preferably combined with a relativety high tolerance for positional variations of coins with respect to the sensor (described below), means that the sensor may be moved to the maintenance position 2142 and returned to the operating position repeatedly, without requiring recalibration of the device.
As noted above, in the depicted embodiment, a door 62 is used to selectively deflect coins or other objects so the coins ultimately travel to either an acceptable-object or coin bin or trolley, or a reject chute 68.
In the embodiment depicted in Fig. 43, a coin return ramp 4312 extends from the coin return region 1921, through the opening 1813 of the diverter cover 1811 and extends a distance 4314 outward and above the initial partion of the onin return chute 68. Thus, coins which are not deflected by the door 62 travel down the ramp 4312 and fly off the end 4316 of the ramp in a "ski jump" fashion before landing on the coin return chute surfaoe 68. Even though preferably, coin contact surfaces such as the ramp 4312 and coin retum chute 68 are embossed or otherwise reduce facial contact with coins, providing the "sla jump" flying region fiuther

18 reduces potential for slowing or adhesion of coins (or other objects) as they travel down the return chute towards the customer return box.
Preferably the device is configured such that activafion of the door deflects coins to an acceptable coin bin and non-activation allows a coin to move along a default path to the reject chute 68. Such "actuate-to-aooept" teolmique not only avoids accnmulation of debris in the exit bins but improves accuracy by accepting only coins that are recognized and, fudher, provides a configuration which is believed supetior during power failure situations. The actuate-to-accept appmach also has the advantage that the actuation mechaoism will be opecating on an object of laawn charactetistics (e.g. known diameter, which may be used, e.g. in connection with determining velocity and/or acceleration, or kaown mass, which may be used, e.g for adjustment of forces, such as deflection forces). This affords the opportunity to adjust, e.g. the timing, duration and/or strength of the deflection to the speed and/or mass of the coin. In a system in which items to be rejected are actively deflected, it would be neoessary to actuate the deflection mechanism with respect to an object which may be unrecognized or have unknown characteristics.
Although in one embodiment the door 62 is separately actuated for each acceptable coin (thus reducing solenoid 2306 duty cycle and heat generation), it would also be possible to configure a device in which, when there are one or two or more sequential accepted coins, the door 62 is maintained in its flexed position continuously until the next non-accepted coin (or other object) approaches the door 62.
An embodiment for control and timing of the door 62 deflection will be described more thoroughly below. In the depicted embodiment, the door 62 is deflected by activation of a solenoid 2306. The door 62, in one embodiment, is made of a hard resilient material, such as 301 fiill hard stainless steel which may be provided in a chanael shape as shown. In one embodiment, the back surface of the coin-contact region of the door 2308a is substantially covcred with a sound-leadening material 2334 such as a foam tape (available &om 3M Co[npany). Ptr,Baably the foam tape has a hole 2335 adjacent the region where the solenoid 2306 strikes the door 62.
In one embodiment, the door 62 is not hinged but moves outwardly from its rest position (Fig. 23E) to its deflected position (Fig. 23F) by bending or flexing, rather than pivoting. Door 62, being formed of a resilient material, will then deflect back 2312 to its rest position once the solenoid 2306 is no longer activated.
By relying on resiliency of an unhinged door for a return motion, there is no need to provide a door return spring. Furthermore, the resiliency of the door, in general, provides a force greater than the solenoid spring return force normally provided with a solenoid, so that the door 62 wiIl force the solenoid back to its rest position (Fig. 23E) (after cessation of the activation pulse), more quickly than would have been possible if relyitng only an the force of the solemid return spring. As a result, the effective cycle time for the solenoid/door system is reduced. In one embodiment, a solenoid is used which has a normal cycle time of about 24 milliseconds but which is able to achieve a cycle time of about 10 milliseconds when the resilient-door-closing feature is used for solenoid return, as described. In one embodiment, a solenoid is used which is rated at 12 volts but is activated using a 24-volt pulse.
In some situations, particularly at the end of a coin discrimination cycle or transaction, one or more coins, especially wet or sticky coins, may reside on the first portion 2121 a of the rail such that they will not

19 spontaneously (or will only slowly) move toward the sensor 58. Thus, it may be desirable to include a mechanical or other transducer for providing energy, in response to a sensed jam, slow-up or other abnormality. One configuration for providing energy is described in U.S.
patent 5,746,299, incorporated hereir- by refereuce. According to aae anbodiment for providing energy, a coin rake 2152, noimally retracted into a rake slot 2154 (Fig. 23A), may be activated to extend outward 2156 from the slot 2154 and move lengthwise 2156 down the slot 2154 to push slow or stapped ooins down the coin path, such as onto the second portion 2121 b of the coin rail, or off the rail to be captured by the hopper extension 2204. An embodiment for timing and control of the rake is described more thoroughly below. In one embodiment, rake movement is achieved by activating a rake motor 2502 (Fig. 19) coupled to a link arm 2504 (Fig. 25). This link 2504 is movably rnounted to the reas patian of the chassis 1864 by a pin and slot system 2506a,b, 2507a,b. A plate section 2509 of the link 2504 is coupled via slot 2511 to an eccenttic pin of motor 2502. A slot 2513 of the link arm 2504 engages a rear portion of the rake 2152. Activation of the motor 2502 rotates eccenhic pin 2515 and causes link 2504 to move longitodinally 2517. A slot 2513 of the link arm 2504, forces the rake 2152 to move 2519 along the incliaed slot 2154 toward a doamsfream position 2510 ( Fig. 26A). The fuaction of causing the rake to protrude or extend outward 2156 from the slot 2154 can be achieved in a number of fashions. In one embodiment, the link arm 2504 is shaped so that when the rake is positioned down the slot 2154, the rake 2152 is urged outwwdly 2156 bu the shape ol'the resilient link arm 2504. As the rake is moved upstnm 2525 toward the normal operating location, a cam follower formed on the free end 2527 of the link arm is urged rearwardty by a cam 2529 cartying the rake 2152 with it, rearwardly to the retracted position (Fig.
23A, Fig. 26).
Preferably, the rake positian is sensed ar maniwred, such as by sensing the position of the rake motor 2502, in order to ensure proper rake operatioa Pceferably the system will detect (e. g. via activity sensor 1754) if the coin rake lmocked coins off the rail or, via coin sensor 58, if the coin rake pushed coins down the coin rail to move past the seasor 58. In aoe embodimeat if activatien of the coin rake results in coins being knocked off the rail or moved down the rail, the coin rake will be activated at least a second time and the system may be configured to output a message iadicating that the system should be cleaned or requires maintenance.
Between the time that a coin passes beneath the sensor 58 and the time it reaches the deflection door 62 (typically a period of about 30 milliseconds), control apparatus and software (described below) determine whdher the coin shaWd be diverted by the door 62. In general, it is preferred to make the time delay between sensing an object and deflecting the object (i.e., to make the distance between the sensor and the deflection door) as sbort as possible while still allowing sufficient time for the recognition and categorization processes to operate. The time requirements will be at least partially depeodent on the speed of the processor which is used In general, it is possible to shorten the delay by employing a higher-speed processor, albeit at increased expense. Shortening the path between the sensor and the deflector not only reduces the physical size of the device but also reduces the possbility that a coin or other object may become stuck or stray fran- the coin path after detection and before disposition (potentially resulting in errors, e.g.
of a type in a coin is "credited" but not directed to a coin bin). Furthermore, shortening the separation reduces the chance that a faster following coin will "catch up" with a previous slow or sticky coin between the sensor and the deflector door. Shortening the separation additionally reduces the opportunity for coin acceleration or velocity to change to a significant degree between the sensor 58 and the door 62. Since the door, in one embodiment, is controlled based on velocity or acceleration measured or (calculated using data measured) at the sensor, a larger separation (and consequently larger rail length with potential variations is, e.g. friction) between the sensor 58 and the door 5 62 increases the potential for the measured or calculated coin velocity or acceleration to be in eiTor (or misleading).
Because the coin deflector requires a certain minimum cycle time (i.e., the time from activation of the solenoid until the door has returned to a rest state and is capable of being reactivated), it is impossible to suooessfully defled two ooias which are too clase together. Aceocdingly, when the systeas determines that two 10 coins are too close together (e.g. by detecting saccessive "irail" tiinm which are less than a minimum period apart), the system will refrain 5nm activating the deflector door upon passage of one or both such coins, thus allowing one ar both such coins to follaw the default path to the reject chute, despite the fact that the coins may have been both sucxessfully recognized as acceptable coins.
If a coin is to be diveated, whea it reaohes the door 62, solenoid 2306 is activated. Typically, because 15 of the step 2136b and/or other flying-inducing features, by the time a coin reaches door 62 it will be spaced a short distance 2307 (such as 0.08 inches, or about 2 mm) above the door plane 62 and the door, as it is deflected to its activated position (Fig. 23F), will meet the flying coin and knock the coin in an outward direction 2323 to the common entrance 1728 of acceptable-coin tubes 64a, 64b.
Preferably all coin contaot surfaces of the return chute and coin tube are provided with a surface texdm such as an embossed surfacx

20 which will reduce friction and/or adhesion. Additiooally, such surfaces may be provided with a sonnd-deadenmg material and/or a kinetic energy-absorbing material (to help direot coins accurately into the accxpt bins).
In one embodirneat, the timiug of deflertkn of the door 62 is c=,antrolled to increase the likelihood that the door will strike the coin as desired in such a fasbion as to divert it to entrance to the coin tubes 1728. The preferred striking position may be selected empirically, if desired, and may depend, at least partially, on the diameter and mass of the coins and the coin mix eTac.~ted in the machine as well as the size and charactecistics of the door 62. In one embodiment, the machine is configured to, on average, strike the coin when the leading edge of the coin is apprommately 3 mm upstream ("upstream" indicating a direction opposite the direction of coin flow 2332) of the downstream edge 2334 of the actuator door 62 (Fig.
23E). In one embodiment, this strike position is the preferred position regardless of the diameter of the coin.
Preferably, there is a gap between coins as they stream past the door 62. The prefeired gap between adjaoent coins which have diffelent destinations (i.e., when adjacent coins include an accepted ooin and a not-accepted coin) depends on whether the accepted coin is before or after the non-accepted coin (in which the "accepted coid' is a coin which will be diverted by the door and the not-accepted coin will travel past the door without being diverted). The gap behind a not-accepted coin (or other object) which reaches the door 62 before an accepted coin is refened to herein as a "leading gap". The gap behind an accepted coin is referred to herein as a"trailing gap". In one embodiment, the prefen-ed leading gap is described by the following equation:
GAPi.w. - AdftA.IW + En:or... + a (1)

21 where:
A" represents the change in the actual inter-ooin gap from the time the coins pass the sensor 58 to the time when the coins reach the door 62 (approximately 3 mm);
Error.,. represents the distance error due to compansation uncataiaties, assuming leading gap worst conditions of maximum initial velocity and a frictionless rail (approximately 6 mm);
and a represents the dimension from the downstream edge of the actuator door 2334 to the leading edge of the coin at the preferred strike position (approximately 3 mm).
The prefated minimiun leading gap of approximately 12 mm applies when a non-accepted coin (or other object) precedes an accepted coin. In the coaunon case of a string of consecutive accepted coins, this oonstraint need not be enforced atter the first coin in the stream.
ln one embodiment, the prefemeld trailing gap is described by the following equation:
GAPtr= = Ad,,,,., + Ad.,-. + Error,;. + b - a - Do,..; (2) where:
Ad,.,,,,,i represents the change in actual inter-coin gap between the sensor 58 and the door 62 (approximately 2 mm);
Adõ,. represents the distance the coins travel during the time the actuator door is extended (approximately 5 mm);
Error.,iõ. represents the errar due to compensation uncertainties, assuming trailing gap worst eonditions of zero initial velocity and a sticky or high-friction rail (approxmately 6 mm);
b represents the length 2336 of the door 62; sad D.represents the diameter of the accepted coin (in the worst case for a common U.S. coin mix, 17.5 mm).
This results in a preferred minimum trailing gap of 5.2 mm.
A process for vaifying the edAeace of preferred leading and trailing gaps, in appropriate situations, and/or selecting or oontrolling the activatien of the door 62 to strike coins at the preferred position, is described below.
In the depicted embodiment, the region of the common entrance 1728 (Fig. 17) is provided with a flapper movable from a first position 1732a which guides the coins into the first coin tube 64a for delivery, altimately, to a first coin bolley 66a, to a second position 1732b for deflection to the second coin tube 64b for delive,ry to the secrnd coin trolley 66b. In one embodiment, the flapper 1732 is made of plastic to reduce noise and the tendenc.y to bind during operation. A solenoid actuator 1734, via link atm 1736, is used to move the flapper between the positions 1732a, 1732b, e.g. in response to control signals from a microcontroller (described below). The flapper 1732 may also be rapidly cycled between its extreme positions to self-clean material finm the mec6anism. In one embadiment, such self-cleaning is performed after each transaction. In one embodiment, coin detectors such as paired LEDs and optical detectors 1738a, b output signals to the micromotroller wtscwver passage of a coin is detected. These signals may be used for various puwposes such as verifying that a coin deflected by the door 62 is delivered to a coin tube, verifying that the flapper 1732 is

22 in the coirect position, and detecting coin tube blockages sach as may result from backup of coins from an over-filled coin bin. Thus, the sensor 1738a, 1738b at the end of each tube, each provides data used for perfortning two or moro functions, such as verifying accepted-coin delivety, verifying flapper placement, and verifying and detecting coin bin overfill.
As best seen in Figs. 27A and 27B, the sensor 58 is preferably directly mounted on the sensor PCB
2512 and communicates, electrically, therewith via a header 2702 with leads 2704 soldered onto the board 2512. Providing the sensor and the sensor board as a single integrated unit reduces manufacturing costs and eliminates cabling and associated signal noise. The sensor 58 is made of a core 2802 (Figs. 28A, 28B) with a low-Erequency 2804 and high &equency 2806 windings on the core. Polarity of the windings should be obsmved so that they are properly synchroniz.ed Providing a winding in a reverse direction can cause signal cancellation The core 2802, in the depicted embodimeat, is generally U-shaped with a lower annular, semicircular, rectangular cross-sectioned partion 2808 and an upper portion defining two spsced-apart legs 2812a, 2812b. The com 2802, in the depicted embodiment, has a thiclmess 2814 of less than about 0.5 inches, preferably about 0.2 inches (about 5 mm), a height 2816 of about 2.09 inches (about 53 mm) and a width 2818 of about 1.44 inches (about 3.65 cm) although other dimensioas can also be used, such as a thiclmess greater than about 0.5 inches.
Because the sensor 58 is preferably relatively thin, 2814, the magnetic field is relatively tightly focusad'm the longitudinal (sbvamwise) directioa As a result, the coin or other object must be relatively close to the sensor before the coin will have significaut effect on sensor output.
For this reason, it is possible to provide relatively close spacing of coins without substantial risk of undesirable influence of a leading or following coin on sensor output.
The facing surfaces 2822a, b of the legs 2812a, b are, in the depicted embodimeat, substantially parallel and planar and are spaeed apart a distaooe 2824 of about 0.3 inches (about 8 mm). The interior facing mrfaoes 2822a, b have a height at least equal to the width of the coin rai12826, such as about 1.3 inches (about 33 mm). With the sensor positieoed as depicted in Fig. 21 in the operating configuration, the upper leg 2812a of the rnre is spaoed from tbE lower leg 2812b of the core (see Fig. 23D) by the inter-face gap 2824 to define a spaoe 2304 for coin passage through the inter-leg gap. The core 2802 may be viewed as having the shape of a gapped tomroid with extended legs 2812a, 2812b with parallel faces 2822a, b. In one embodimeat, the legs 2812a,b are substantially parallel. In another embodiment, the legs 2812a,b are slightly inclined with respect to one another to define a tapered gap. Without wishing to be bound by any theory, it is believed that, as depicted in Fig. 28E, extended faces which are inclined to define a gap which slightly tapers 2832 (taper exaggerated, for at least some embodiments in Fig. 28E) vertically downward yields somewhat greater sensitivity near the rail (where the majority of the coins or other items will be located) but is relatively insensitive to the vertica12828 or horizontal 2832 position of coins therein (so as to provide useful data iegardless of modaate coin boimce and/or wobble) as a coin passes through the gap 2824. In the embodiment ofFig. 28F, the extended faces taper in the opposite vertical direction 2834.
The faces may be configured at an angle 2836a,b,c to the lateral axis 2838 of the sansor, as depicted in Figs. 280, H, and I. By selecting the

23 angle(s) 2836 ABC used, or otherwise selecting the shapes of the sensor faces, other tapered spaces between the legs can be provided. It is also possible to provide for changes in inter-leg spacing as a function of the distance along the longitudinal axis 2858 including changes which are non-linear, such as providing curved, angled, dog-legged or similar sensor face configarstions.
In the depicted embodiment, the faces 2822a,b extend 2816 across the entire path width 2133, to sense all metallic objects that move along the path in the region of the sensor. It is also possible to provide face extents which are larger or smaller than the path width, such as equal to the diameter of the largest acceptable coin.
It is believed that providing a core with a larger gap (i.e. with more air volume) is partially responsible for decreasing the sensitivity to coin misalignments but tends to result in a somewhat lower magnetic sensitivity and an increase in cross-talk. In one embadiment, the sensor can provide reliable sensor ouqxA despite a vertical displacement ("bounce") of about 0.1 inch (about 2.5 mm) or more, and a sideways (away from the stringers) displacement or "wobble" of up to 0.0 15 inches (about 0.4 mm).
In the depicted embodiment the low frequency winding 2804 is positioned at the bottom of the semicireular portion 2808 and the high frequency winding is positioned on each leg 2806a, b of the semicar,~ulat portion. In one embodiment the low ffequcnc.y winding is configured to have an inductance (in the driving and detection eircuitry described below) of about 4.0 millihearys and the higb fiequency winding 2806a, b to have an inductance of about 40 microhenrys. These inductance values are aleasared in the low frequency winding with the high frequency winding open and measured ia the high frequency winding with the low 5+equ c.y winding shorted together. The signals on the windings are provided to printed cincuit board via leads 2704.
In the embodiment of Fig. 28C, the low frequeacy winding 2842 crosses over itself whereas in the embodiment of Fig. 28D, a single eontinuous winding 2844 is provided without cross-over or multiple layers, which is believed to imptm the consistency and repeatability of sensor performance. Without wishing to be boand by any theory, this is believed to be due at least partially to increasing the self-resonant feequency of the low-frequency winding.
In the embodiment al'Fig. 28C, the high &eqaency windings 2846 are positioned about midway up the bigbt 2846 e~the sumar. In the embodiment of Fig. 28D, the high freqnency windings 2852 are positioned farther towards the gapped end 2854 and, in the depicted embodiment, at a non-orthogonal angle 2856 with respe~..~t to the langiddinal axis 2858 of the sensor. The position of the high &+equency winding shown in Fig.
28D is believed to provide improved coupling 8rom the high fivquency windings to the coin and less imdesu-able eoupling between the high frequency and the low frequency windings. Fuwther, it is believed that by demvasing the number of turns for the high frequency winding, a resultant decresse in the winding-to-coin leakage inductance improves coin coupling (while maintaining the high frequency winding indnctance, as described above) and further improves high frequency performance of the sensor.
In addition to the toroid or torus-shaped sensors (Figs 2A, 2B), extended-leg sensors (Figs. 28A-I) and other depicted and described sensor shapes, other shapes for the magnetic core can be provided, such as a G-shape(5612, Fig. 56A), a C-shape (5614, Fig 56B), a triangular shape (5618, Fig 56D), a square shape

24 (5616, Fig. 56C), a rectangular shape(5622, Fig 56E), a polygonal shape(5624, Fig 56F), a circular shape (214, Fig 2A), a V-shape (5626 Fig 56G), and an oval or elliptical shape(5628, Fig. 56H, sections or portie s thereof and the like. It is believed that alternative magnetic core shapes can be advantageously considered, despite effects such shape changes may have on sensor performance, at least partially because other shapes may be found to be more cost-effective to produce.
Although the depicted embodiments provide a sensor with a single magnetic core as a unitary piece, it is possible to canfigure a sensor with two spaced apart components such as providing the signal-generating magnetic means on one side of a coin and a signal-receiving magnetic means on the other side of a coin (as the coin moves past the center). It is believed, however, that such a multipart sensor will present alignment requirements and may prove to be relatively expensive or provide less uniform or reliable performance.
Fig. 29 depicts the major functional components of the sensor PCB 2512. In general, the sensor or transducer 58 provides a portion of a phase looked loop which is maintained at a substantially constant frequency. Thus, the low frequency coil leads are provided to a low frequency PLL 2902a and the high frequency leads are provided to high frequency sensor PLL 2902b.
Fig. 40 provides an overview of a typical transaction. The transaction begins when a user presses a"go" or stait button 4012. In response, the system opens the gate, and begins the trmnmel and coin pickup assembly disk motors 4014. As coins begin passing through the system, a sensor (not shown) is used to determine if the hopper is in an overfill condition, in whieh ease the gate is closed 4018. The system is continuously monitonad for current peaks in the motors 4022 e.g. using current sensors 21, 4121 (Fig. 41) so that corrective action such as reversing either or both of the motors for dejamming purposes 4024 can be impleme,nted.
During normal counting operations, the system will sense that coins are streaming past the sensor 4026. The system is able to detamine 4028 whether ooins are being sent to the reject chute or the coin trolley.
In the latter case, the system proceeds normally if the sensor in the coin tube outputs an intermittent or flickering signal. However, if the coin tube sensor is stuck on or off, indicating a jam upstream or downstream (such as an overfilled bin), operations are sospeaded 4036.
In one embodiment, the flow of coins through the system is managed and/or balanced. As shown in Fig 41, coin flow can be managed by, e.g., controlling any or all of the state of the gate 17, state or speed of the trommel motor 19 and/or state or speed of the coin pickup assembly motor 2032 e.g. to optimize or othawi.se control the amount of coins residing in the trommel and/or coin pickup assembly. For example, if a sen9or 1754 indicates that the coin pickup assembly 54 has become full, the mierocontroller 3202 can tum off the trommel to stop feeding the coin pickup assembly. In one embodiment, a sensor 4112, coupled to or adjacent the trommel 52, senses the amount (and/or type) of debris faIIing out of the trommal during a particular transaction or time period and, in response, the microcontroller 3202 causes the coin pickup assembly motor 2032 to nm in a different speed and/or movement pattem (e.g. to accommodate a particularly dirty batch of coins), possibly at the expense of a reduction in throughput.

When the coin sensor 58 (and associated cnvitry md software) are used to measure or calculate coin speed, this infonna6on may be used not only to control the deflector door 62 as described herein, but to output an indieation of a need for maintenanx. Fa example as coin speeds decxease, a message (oc series of messages) to that effect may be sent to the host computer 46 so that it can request preventive maintenance, 5 potentially thereby avoiding ajam that might halt a transaction.
Once the system senses that coins are no longer streaming past the sensor, if desired a sensor may be used to detecmine whether coins are present e.g. near the bottom of the hopper 4042. If coins are still pmsent, the motors continue operating 4044 uatil coins are no longer detected near the bottom of the hopper.
Once no more coins are detected near the bottom of the hopper 4046, the system determines that the 10 tmsaaron is oampkta. The system will then aaivate the coin rake, and, if eoins are sensed to mave past the coin sensor 58 or into the hopper, the counting cycle is preferably repeated Otheiwise, the traasaction will be ooasidand finished 4028, and tbe system will cycle the trap door and output e.g. a vouohet of a type which may be exchanged for goods, services or cash.
The coin sensor phase locked loop (PLL), which includes the sensor or transducer 58, maintains a 15 ca-stant fraquency and responds to the piesence of a coin in the gap 2824 by a change in the oscillator signal amplitude and a change in the PLL error voltage. The phase locked loop shown in the depicted embodiment requires no adjusimentg and typically settks in abwt 200 micxuaeoondg. TU
systam is self-stasting,ad begias aacillating and locks phase automatically. It is also possible to provide frequencies or signals for application to a sensor without using a phase loclc. The winding sigaals (2 each for high frequency and low frequepcy 20 channels) are conditioned 2904 as described below and sent to an analog-to-digital (AN) oonvdtm 2906.
The A/D canveiter samples and digitius the analog signais and passes the information to the microconhollar 3202 (Fig. 32) on the Control Printed Circuit Board Assembly (PCBA) (desedbed below) for finther manipulation to identify coins.

AlthUugh 1n ane embodlnleffi tlle slgl8l or sig<lals pPOvlded to the sensor are mibsNafially shnO80ldal,

25 it is also possible to use configurations in which non-sinusoidal signals are provided to the sensor, such as (filtered or unfiltered) substantially square wave, pulse, triangle, or similar periodic signals. Such non-sinusmdal signals, in addition to o$ering system cost savings, for sonie configurations, also typically include vawus hatmmica A hommio-rich siggml, snch as a square wave signal is believod to be affected differently for different coins, e.g., due to the interrelationships of the various hacmonics' phases and amplitudes. For example, in one embodiment, as depicted in Fig. 55D, applicatien of a square wave voltage to a sensor winding may resWt in a hannonio-rich eucreat flowing through the sensor winding 4552.
The sensor curreat can be analyzod as depictad 4552 or various components or bandwidths of the seasor current can be separated, e.g., using filters 4554a,b,c for analysis by, e.g., a micxnproxssor 4556 as descnbed herein. In this way, it is possible to use one signal applied to a sensor coil in connection with two or more signal detecting means for distinguishing one coin from another. If desired, each signai detecting means can be used to provide infamation on one aspect of a coin's electrical properties. Altetnatively, it is poss~ble to obtain information on differeat aspects of a eoin's elecxrical properties by providing different signals 4542a,b,c, applying diBerent

26 wave forms, frequencies, and the like 4544a,b,c to a coin, for detection by sensors 4546a,b,c as depicted in Fig. 55C.
Although a phase locked loop (PI.L) approach to providing one or more constant frequencies is depicted in Fig. 29, other approaches can be used for achieving a relationship between a first and a second frequency. For example, as depicted in Fig. 55A, if a first frequency is provided 4512, a frequency divider 4514 can be used to provide a socmd &equency 4516 in a known and stable relatieaiship to the first 8roquency.
In the embodiment of Fig. 55B, if a first frequency is provided 4522, a xoond frequency, 4524 may be obtained by using a mixer 4526 to combine the first frequency 4522 with a third frequency 4528, as will be clear to those who have skill in the art after understanding the present disclosure.
One approach provides a plurality of signals for distinguishing coin types (e.g., a different signal "toned" for each anticipated or acceptable coin type. It is believed tlus approach may provide relatively high accuracy but may involve additional cost compared to providing a reduced number of sigaals.
Retimiing to the configuratiea of Fig. 29, as a coin passes through the transducer 58, the amplitude af the PLL emor voltage 2909 ab (sometimes referred to herein as a "D" sigaal) and the amplitude of the PLL
sinusoidal osoillator signal (aometimm refeaed to as a "Q" signal) decrease.
The PLL eirar voltage is filtered and eonditiened for canversion to digital data. T6e oscillator signal is filtered, demodulated, then conditioned for canversian to digital data. Sinoe theae signals are generated by two PLL
circuits (high and low frequency), fous signals result as the "signature" for identifying coins. Two of the signals (LF-D, I.F-Q) are indicative of low-frequency, coin charactoristics, and the remaining two signals (I3F-D, I-IF-Q) are indicative of high-frequency coin eharacteristics. Figure 30 shows a four ehannel oscilloscope plot of the change in the four signals (LF-D 3002, I.F-Q 3004, HF-D 3006, and I-iF-Q 3008) as a coin passes the sensor. Infoimation about the coin is represented in the shape, timing and amplitude of the signal changes in the four sigaals. The Control PCBA, which receives a digitized data representation of these signals, performs a discrimination algorithm to categorize a coin and detennine its speed through the transducer, as descnbed below.
The coin sensor phase locked loop, according to one embodiment, consists of a voltage controlled osciIlator, a phase comparator, amplifier/filter for the phase comparator output, and a reference clock. The two Pld.'s operate at 200 KHz and 2.0 MHZ, with their reference clocks symchronized. The phase relationship between the two clock signals 3101 a, b is maintained by using a divided-down clock rather than two independent dock sota ces 3102. The 2 MHZ clock output 3 101 a is also used as the master clock for the A/D
converter 2906. -As a coin passes through the transdac.c's slot, there is a change in the magnetic circuit's reluetance.
Tbis is seen by circuitry as a decrease in the inductance value and resiilts in a corresponding decrease in the amplitude of the PLL error voltage, providing a first coin-identifying factor.
The passing coin also causes a decrease in the amplitude of the sinusoidal oscillator waveform, depending on its composition, e. g. due to an eddy current loss, and this is measared to provide a secand coin-identifying factor.
Tbe topology of the oscillators 2902a, b relies on a 180 degree phase shift for feedback to its drive cinWtry and is classified as a Colpitts oscillator. The Colpitts oscillator is a symmetric topology and allows the oscillator to be isolated from ground. Drive for the oscillator is provided by a high speed comparator

27 3104s, b. The cxxnparata has a fast propagation to minimize distortion due to phase delay, low input cument to miuizniae loss, and cansins stable while operating in its linear region. In the depicted embodiment, the plus and niinus taminals of the inductocs go directly to a high-speed comparator which autobiases the comparator so that signals convert quickly and are less susxptibk to osciAation and so that there is no need to bias the comparator to a central voltage level. By tying the plus snd niinus terminals of the induetor to the plus and miaus tecminals of the comparator, the crossing of the teaninals' voltage at any arbitrary point in the voltage spectnnn will cause a switch in the comparator output voltage so that it is autobiasing. This achieves a moce nearly even (50%) duty cycle.
The output al'the comparator drives the oscillatar ahrough reaistaas 3106a, b.
The ampGtude of the oscillating signal varies and is correlated to the change in "Q" of the tuned eircuit Without wishing to be bouod by any thmy, this change is beGeved to be due to change in eddy cumnt when a coin passes through the transducer gap. Resistors 3108 a, b, c, d work with the input capacitance of the comparator 3104a, b to provide filtering of unwanted high frequau,y signal camponents.
Voltage control of the oscillator frequency is provided by way of the varactas 3112a, b. c, d, which act as voltage oont<oUed capaeftm (or tuning diodes). These varaetors change the capacitive components of the ascillator. Use of two varactas maintsins balanced capacitance on each leg of wind'wgs 2804, 2806. It is also possible to provide for tuning without using varaotore such as by using variable indactanoe. As the raverse diode voltage increases, capacitance decreases. Thus by changing the Voltage Controlled Oscillator (VCO) input voltage in aooortonee with the change in inductance due to the presence of a coin, the frcquea.y afaseMation can be maintained. This VCO input voltage is the signal used to indicate chango of indudaooe in this circuit.
The phau/fteqoaY.y de0xtor 3114a, b perfacaos catain control fimetioos in this eircuit. It ootnparea the output &equency of the comparator 3106a, b to a syncbroaized reference clock signal and has an output that varies as the two signals divrrge. 1'he output stage of the device amplifies and filters this phase compuatQ autput si oal. This aenplified and filtered output provides the VCO
oDntrol signal used to indicate change of inductance in this circuit.
In addition, ft depicted device has an output 31 I6a, b whieh, when appropriately conditioned, can be used to determine whethar the PLL is "in lock". In one embodiment, a lock-fail signal is sent to the microprocessor on the Control PCBA as an error indication, and an LED is provided to indicate when both bigh and low frequency PLL are in a locked state.
Hecause the sensor 58 reoeives eaaatation at two frequencies through two coils wrapped on the same fetrite oace, there is a potential far the coupling of signals which may realt in undesired ampGwde modulatian on the individual signals that are being monitored. Filters 2912a, b remove the undesired spectral component whik maiataining the desired signal, prior to amplitude meamrement. In this way, the measured amplitude of each signal is not iafluenoed by an indepeadent cbange in the amplitude of the other oscillator circuit sigaals.
The filtered output signals are level-shifted to center them at 3.0 VDC in order to control the measurement of the signal amplitude by downstream circuitry.

28 ln tbe depicted aabodimeat, the active highpass and lowpasa filters are implemented as Sallen-ICey Butterworth two-pole filter circuits 2916a, b. DC offset adjustment of the output sigaals is aeoomplished by using a buffered voltage divider as a reference. Input buffers 2914a, b are provided to minimize losses of the oscillator cirouit by maintaiaing a high iaput impedance to the filter stage.
The lowpass filter 2916a is desigaed to provide more than 30dB of attenuadon at 2 MHZ whfle maintaiaing integrity of the 200KHz signal, with le,a4 thst 0.5dB of loss at that frequency. The cutoff frequency is 355IQ-Iz Fi'ighpasa filtering of the output fran the lowpass filter is provided 2918a with a cutoff frequmcy of 20IQ3z Tying to a DC refaeaoe 2922a provides an adjusted output that centers the 200KH2 sigaal at 3.0 VDC, This output offset adjustment is desired for subsecryent amplitude messuremmt.
The highpass filter 2916b is designed to provide more than 30dB of attenuation at 200KHz while maintaining integrity of the 2.0 MHZ signal, with less that 0.5 dB of loss at that frequeniy. The cutoff frequetu.=y is 1.125MHz.
Aanplitude measuvaut af the sinu9~ooidal oacillator wavefmm is accomplished by demodulating the signal with a negative peak detecting circuit, and mearming the difference between this value and the DC
refwcaoe voltage at which the sinusoidal sigaal is centered. This comparison meavxcwAnt is then scaled to utiTrrt a signifieaot prntion of the A/D couvetter's input range. The input to the eircuit is a filtered sinusoidal signal centsaed at a known DC reference voltaga output of the highpass or lowpass active filter.
The input signal is demodulated by a closed-loop diode peak detector circuit The time constant of the network, e.g. 20 msec, is long compared to the period of the sinusoidal input, but sheat when eomparod to the time elapsed as a coia passes through the sea,sor. This relatiaoabip allows the peak detector to react quickly to a change in amplitude causcd by a coin event. The cireuit is implemented as a negative peak detectar ratha than a positive peak detector because the crnnparator is more predictable in its ability to drive the sigoal to gnomd thaa to drive it high. Comparatas 3126a, b, such as model LT 1016CS8, available $nm Linear Teohnology, provide a high slew rate and maintain stabiGty while in the linear region. The analog closed-loop peak detector avoids the poten6al phase mor problems that filter-stage phase lag and dynamic PLL phase shifTs might create for a sample-and-hold implementatioa, and eliminates the need for a sampling clock.
The negative peak datecbor output is oamparod to the DC refereace voltage, thea scaled and filtered, by using an op amp 3124a, b implemented as a difference amplifier. The difference amp is configured to subtract the negative peak from the DC refereace and multiply the difference by a scaling factor. In one embodimeat, fa the low frequency channel, the scaling factor is 4.02, aod the high fiequency ohannel soales the output by 5.1 1. The output of the differenoe amplifier has a lowpass filta on the feedbaolc with acomer $equeney at apprordmafely 160 Hz In the depicted embodiment, there is a snubber at the output to 51ter high frequency transients caused by switching in the AJD converter.
The error voltage meaauement, scaling, ead filtering circu-t 3128a, b is designed to subtract 3.0 VDC from the PLL errar voltage and amplify the rasultiag difference by a factor of 1.4. The PLL etror voltage ia1xR signal will be in the 3.0-6.0 VDC range, and in order to maximize the use of the A/D converter's input range, the offset voltage is subtracted and the signal is amplified.

29 The input sigaal is pre-$ltered with a lowpass corner frequency of 174 Hz, and the output is filtered in the feedback loop, with a cut-offfrequency 340Hz. A filter at the output filters high frequency transients caused by switching in the A/D converter.
In an interface cirouit, 2922 data and eentrol sgnals are pulled up and pass through senes termination resistors. In addition, the data signals DATA-DATA15 are buffered by bi-directional registers. These bidirectional buffers isolate the A/D converter from direct connection to the data bus and associated interconnect cabling.
The A/D converter 2906 is a single supply, 8-channel, 12-bit sampling converter (such as model AD7859AP available from Analog Devixs). The A/D transactions are directiy controlled by the microprocessor on the Control PCBA.
Aa ovr=view of eanttoi pe ovided for vatious hardware components is depieted in Fig. 32. In Fig. 32, the ooimd hardwm is generally divided into the coin sensor hardware 3204 and the coia transpart hardware 3206. A mmber of aspects of hardware 3204, 3206 are controlled via a microcontroller 3202 which may be auy of a ntenber of microcantedlas In one emboditnent,lvlodel AM186ES, available fran Advanoed Miaro I S Devices, is provided.
The microcontroller 3202 communicates with and is, to some degree, contcolled by, the host eoarWukr 46. Ihe host camp6er 46 cau be any of a number of oanpnters. In one embodiment, caaqmuer 46 is a oomputer employing an Intel 486 or Pentium processor or equivalent. The host computer 46 aad microcontroller 3202 communicate over serial line 3208 via respective serial ports 3212, 3214. The microcontrollec 3202, in the depictod e.mbodimeat, has a second serial port 3216 which may be used for pinposes such as debugging, field savice 3218 and the like.
Duriag normal opaation, prograamning and data for the microcontroller are stored ia memory which may ioclude aamal random access memory (RAM) 3222, nan-volatile random access memory such as flash memory, static memory and the like 3224, and read-only memory 3226 which may include programmable and/or electronically erasable programmable read-only memory (EEPRONI). In one embodimeot, micxoproeessor firmware can be downloaded from a remote location via the host computer.
Applicatioos soltwere 3228 for controlling operation of the host computer 46 may be stored in, e.g., hard disk memory, nonvolatile RAM memos}+ aad the lika.
Although a number of items are described as being implamented in soflware, in gemal it is also possible 1o provide a hardwue implmwntitien sirh as by using bard wired control logic and/oc an application spoci8c integrated cireuit (ASIC).
An input/output (I!O) intefface on the microeontroller 3232 facilitates ceaomunicatien such as bus coumnunication, dira4l/O, intemipt reqoasts and/or diroet memory access (DMA) requests. Since, as described more thoroughly below, DMA is used for much of the sensor commutrications, the coin seusor ciraiitry ineludes DMA logic accuitcy 3234 as well as circuitry for status and cmtrol signats 3236. Although, in the desenled embodimeat, only a single sensor is provided for coin sensing, it is possible to configure an operable device having additional sensas 3238.

In addition to the motors 2502, 2032, vwleiroids 2014,1734, 2306 and seasors 1738,1754 described above in comimfion with coin transpoM oontrolling latches, gates and drivers of a type that will be undestood by those of skill in the art, a$er understaading the present inventioq are provided 3242.
A method for deriving, from the four sensor sigaals (Fig. 30) a sd of values or a"signatiue"
5 indiCative of a coin which has passed the sensor, is descnbed in connection with the graphs of Fig. 33 which show a hypothetical example of the four signals LFD 3302, LFQ 3304, IIFD 3306 and HFQ 3308 during a period of time in wbich a coin passes through the anna of the sensor. Units of Fig. 33 are arbitrary siuoe Fig.
33 is used to illustrate the pcinciples behind this embodictmt. A baseGae value 3312, 3314, 3316, 3318 is associated with each of the sensor signals, repneseatiag a value equal to the average or mean value for that 10 signal when no coins are adjaoent the sensor. Although, in the depicted embodiment, the LFD signal is usod to define a window of time 3322 during which the minimum values for each of the fonc signals 3302, 3304, 3306, 3308 will be deteminod and other threshold-crossing events, (at least in part becaese this signai typically has the shwpest peak), it would be possible to use other signals to de6ne any or all of the various crossing events, or it may be possible to define the window separately for each signal.
15 In the depicted embodinueat, the base line value 3312 associated with tbe LFD sigoa13302 is used to de6ne a desoeat threshold 3324 (equal to the LFD baseline 3312 minus a predefned descmt offset 3326, and a predefined gap threshold 3328 equal to the LFD baseline 3312 minus a gap offset 3332).
In one embodiment, the system will remain in an idle loop 3402 (Fig. 34) until the system is platxd in a ready status (as descxibed below) 3404. Once the system is in ready status, it is ready to respood to 20 passage of a ooin past tbe seato~
In the depicted embodiment, the begianing of a coin passage past the seasor is signaled by the I.FD
sigoa13302 booomiag less 4212 than the desoent thre.shold 3324 (3406) which, in the embodimaat of Fig. 33, oocaas at time t, 3336. Wl= this event occurs 3338, a number of values are iaitialized or stored 3408. The status is set to a value indicating that the window 3322 is open 4214. Both the "peak" time value and the 25 "lead" time value are set equal to the clock value, i.e., equal to t, 3336.
Four variables LFDMIN 3342, LFQMN 3344, HEDMIN 3346 and IHFQMIN 3348, are used to hold a value indicating the minimum sigoal values, for each of the signals 3302, 3304, 3306, 3308, thus-fer achdeved during tbe window 3322 snd thug am initialized at tbe T, vehies for each of the variables 3302, 3304, 3306, 3308. Ia the illustration of Fig. 33, the running minimum values 3342, 3344, 3346, 3348 are depicted as dotted lines, slightly offset vertically

30 downward for clarity.
During the tiroe that the windotiv is open 3322, the minimum-holding variables LFD1uIIN, LFQIvI1N, HFDMINI and HFQ1bIIN will be updated, as needed, to reflect ihe minimum value thus-far achieved. In the depictad embodiment, the four values are updated serially and cyclically, once every clock signal. Updating af values can be distributed in a diffeient fashion if it is desired, for example, to provide greater time resolWim for some variables than for others. It is believed that, by over sampling specific channels, reoognition and aomacy can be iaVtoved. As the LFD valae is being tested and, if neoessary, updated, a value for an ascent tlmeabold 3336 (which will be used to define the end of the window 3322, as desaibed below) is calculated

31 or updated 3414. The value for the asoent thresbold 3336 is calcWated or updated as a value equal to the current value for LFDMIN 3342 plus a predefined ascent hysteresis 3352.
Whenever the LFD1vIIP1 value 3342 must be updated (i.e., when the value of LFD
descends below the previously-stored minimum value 3412), the "peakõ time value is also updated by being made equal to the cturent clock value. In this way, at the end 4226 of ahe window 3322, the "peak" variabk wiIl hold a value indicating the time at which LFD 3302 reached its mini,mum value within the window 3322.
As a coin passes through the acros of a sensor, the foar signal values 3302, 3304, 3306, 3308 will, in general, reach a mininniun value and then begin once more to ascend toward the baselme value 3312,3314, 3316, 3318. In the depicted embodiment, the window 3322 is declared "closed"
when the LFD value 3302 raises to a poiat that it equals the caurent value for the ascent value tbresIwld 3336. Ia the illostration of Fig.
33, this event 3354 oaaus at time T3 3356. Upon detection 3418 of this event, the cmtent value for the clock (i.e., the value indicating time T3) is stored in the "frail" variable. Thus, at this point, three times have been stored in three variables: "lead" holds a value indicating time T, i.e., the time at which the window was opened; "peak' holds a value indicating time T2, i.e., the minimum value for variable LFD 3302; and variable "trail" holds a value indicating time T3, i.e., the time when the wiudow 3322 was closed.
The otber pation of the sigoature for the coin which was just detected (in addition to the threa time variables) are values indicating the miaimum achievod, within the window 3332, for each of the variabks 3302, 3304, 3306, 3308. These values are calculated 3422 by subtracting the minimum values at time T3 3342, 3344, 3346, 3348 from the respective baseline values 3312, 3314, 3316, 3318 to yield four diffe=iooe or delta values, ALFD 3362, ALFQ 3364, AI-1FD 3366 and M1F'Q 3368. Providing output wbich is relative to the baseline value for each signal is usefnl in avoiding sc,asitivity to temperature changes.
Although, at time t, 3356, aA the values required for the coin sigaature have been obtaiuied, in the depicted embodiment, the system is not yet placed in a"ready" state. This is becaux it is desired to assuee that tbam is at least a miniaamd gap betwem the coin which was just detected and any foilowing coin. It is also desirable to maintain at least a minimum distance or gap from any precoding coin. In general, it is believed useful to provide at least some spaciag between ooins for accurate sensor reading, since coins which are touching can result ia oldy cirrent passmg between coins. Maintaining a minimum gap as coina move toward the door 62 is useful in making sune that door 62 wili striiae the coin at the desired tirre and locatiae. Striking too soon or too late may result in detiecting an aooepted coin other than into the acceptance bin, degrading system acxvracy.
lafatmffiicn gathend by the samor 58 may also be used in connection with assuring the existenoe of a prefefred miaimum gap betwecn coins. In this way, if coins are too closely spaced, one or more coins which might otherwise be an accepted coin, will not be deflected (and will not be "countod" as an accepted coin).
Similarly, in one embodiment, a coin having an aooeleratio less than a threshold (such as less than half a maximum aoceleration) will not be accepted.
Accadingly, in order to assure an adequate leading gap, the system is not placed in a"ready" state u4til the LFD signa13302 has reached a value equal to the gap threshold 3328.
Aftcr the system verifies 3424

32 that this eveot 3372 has occurred, the status is set equal to "reedy " 3326 and the system teturns to an idle state 3401 to await passage of the next coin.
To pravide for a minimun p~efemed tsailing gap, in one embodiment, the software monitors the LFD
sigoal 3302 for a shost time atta the asoaoding hystacais criterion has been satisfied 4236. If the sigoal has moved su8'iciently back towards the baseline 3312 (tneasured either with respect to the baseline or with respect to the peak) after a predetmtnined time period, then an adequate trailing gap exists and the door, if the coin is an accepted coin, will be actuated 4244. If the trailing gap is not achieved, die actuation puln is canceled 4244, and normally the coin will be returned to the user. In all cases, software thresholds are preferably calibrated using the smallest coins (e.g., a U.S. dime in the case of a U.S. coin mix).
Because the oaauraioe afevents such as the erossing of thresholds 3338, 3354, 3372 are only tested at discrete time intervals 3411 e, 3411b, 3411 c, 3411 d, in most eases the event will not be detected until some time atta it has ooaaned. For exmVle, it may happen that, with regard to the ascent-crossing event 3354, the pn.wioos event-test at time T4 3374 occm before the enossing event 3354 and the next event-test oocm at time T5, a period of time 3378 aiter the crossing event 3354. Accordingly, in one embodiment, once a test l5 detetmitm that a cxossing event haa oaan+eci, uotetpoiation such as linear intapolatien, spline-fit intapoldion or the like, is used to provide a more axasate estimate of the achual titne of the event 3354.
As noted above, by time t, 3356, all the values required for the coin signature have been obtained.
Also, by time t,, the information which can be used for calculating the time at which the door 62 should be activated (assuming the coin is identified as an accepted coin) is available.
Because the distance from the sensw to the door is constant and lcnown, the amotmt of time required for a ooin to travel to the prefemcd position with respect to the door can be calciilated exaetly if the aceeleration of the coin along the rail is Imown(and constant) and a velocity, such as the velocity at the sensor is lmowa Aecording to one method, aoodaation is cakailated by eompriOg tltie velocity of the coin as it moves past the seflsor 58 with the velocity af the ooin as it passes over the "knee" in the traosition region 2121C. In one embodinoeat, the initial "9mee"
velocity is asanned to be a single value for all coins, in one case, 0.5 meters/secoasd. Knowing the velocity at two lacatieos (the lmee 2121 C and the sensor location 58) and lawwing the disiance fram the 1mee 2121 C to the sensor location 58, the acceleration experienced by the coin can be calculated. Based on this ealculated aooelaation, it is then posstble to calculate how long it will be, cantinaing at that aoceleratiazi, before the coin is positioned at the preferred location over the actuator. This system essentially operates on a principle of asaaning an initial velocity and using mcommements of the sensor to altimatoly calculate how fiiction (or other factors such as surface tension) affects the acceleration being experienced by each coin. Another approach migbt be u9ad in w}rich an effec6ve ticbon was assumod as aconsunt value and the data gathered at the sensor was u9od to calculate the initial ('9mee") velocxty In any oase, tbe calailatien af the time when the cain wiIl reach the preferred position can be expected to have some amount of error (i.e., difference between calealated position and adual position at the door activation time). The error can arise from a number of factors including departures from the assumption regarding the lmee velocity, non-constant values for fiiction along the rail, and the like. In one embodiment it has bera foiatd that, using the described pnooe"e, and for the depicted and desaribed desiga, the worst-case

33 ereor oocurs with the smallest coin (e.g., amount 17.5 mm in diameter) and amounts to approximately 6 mm in either dkeetim It is belicwed thd, in at least some eaviroemeuts, an error window of 6 mm is tolerable (i.e., results in a relatively low rate of misdirecting coins or other objects).
In order to implement this procedure, data obtained at the sensor 58 is used to caloulate a velocity.
According to one scheme, time t, 3336 is taken as the time when the coin first enters the sensor and time t, (the "peW time) is taken as the tune when the coin is centered on the sensor, and thus has traveled a distance apptrnamately equal to a coin radius. Because, once the coin has been recognizcd (e.g as described below in eaenection with Figs. 36 and 37), the radius of the coin is Jcnown (e.g. using a look-up table), it is possible to calculate veloeity as radius divided by the difference (t,-t,).
Tbe pracedure illustrated in Figs. 33 and 34 is an example of one embodiment of a detection prooess 3502. As som in Fig. 35, a munber of piocesses, in addition to detection, should be performed between the time data is obtained by the sensor 58 and the time a coin reaches the door 62. In general, processes can be easisidered as being either recognition processes 3504 relating to identifying and locating objects which pass the sensor, and disposition processes 3506, relating to sending coins to desired destinations. Once the detection pcncess has examined the stream of sensor readings and has generated signatores cam.sponding to the coin (or othx object) passing the sansor, the sigoatures are passed 4228 to a categoriz.ation process 3508.
This process exsmine.s the sigoatitm received from the detection process 3502 and determines, if possible, what coin or object has passed the sensor. Refeiring to Fig. 32, the recognition and disposition processcs 3504, 3506 are preferably perfeimed by the microcontroller 3202.
Fig. 36 provides an ilhobadan eiane embodiment of a ca2egorization process. As shown in Fig. 36, in one embodmomt a cah'bratian mode may be pwvided in which a plurality of known types of coins are placed in the machiae and these coins are usod to define maximum and minimum LFD, LFQ, HFD and HFQ values for that particular category or denomination of coia In one embodiment, timing parameters are also established and stored during the calibration process. According to the embodiment of Fig. 36, if the system is undergoing calibration 3602, the system does not attempt to recognize or categorize the coins and, by caavention, the coins used for calibratie are categorized as "unrecognized"
3604.
As illustratod in Fig. 37, in one embodiment, a coin sigoature 3702 is used to categoriu an objeet by performing a camparison for each of a number of differeat potratial oategaries, starting with the first category 3606 and stapping to each next category 3608 until a match is found 3612 or all categories are exhausted 3614 without finding a match 3616, in which case the coin is categorized 4220 as unrecogaiz.ad 3604. During each test far a match 3618, each of the four signal peaks 3362, 3364, 3366, 3368 is compared, (successively for each category 3704a, 3704b, 3704n) with minimum and maximum ("floor" and "ceiling=') vahies defining a"window" for each sigaature component 3712a, 3712b, 3714a, b, 3716a, b, 3718a, b. A
match is daolared 3612 far a given category only if all four comiponents of the signaturc 3362, 3364, 3366, and 3368 fall within the crnregponding window for a partieular category 3704a, b, c, n.
In the embodinnent of Fig. 36, the system may be configured to end the categorization process 3622 wheaem the first category 3624 resulting in a nuteb has been found, or to continue 3626 until all n categories

34 have been tested. In nomal operation, the first mode 3624 will typically be used. It is believed the latter mode will be useful prinoipally for research and development purpcees.
The resalts of the categorization 3508 are stored in a category buffer 3512 and are provided to the relegator pmcess 3514. The diffemoe betwece categotization and relegation relates, in part, to the difference between a coin category and a coin denomination. Not all coins of a given dena oination will have similar structure, and thus two coins of the same denomination may have substantially diff'ereat signatures. For example, pennies minted before 1982 have a stsucture (copper core) substantially different 6nm that of pennies minted afler that date (zm cone). Some paevioas devices have attempted to de6ne a coia disaiminatiea based oa eoin deaamnination, which would thus require a device which recogoizes two pb,ysically different types of penny as a single category.
According to one embodiment, coins or other objeots are discriminated not necessarily on the basis of deuominatiee but an the basis of coin categories (ia which a single denomination may have two or mae cate aries). T7ros, aow[ding to one embodianent, peonies minted before 1982 and pennies minted after 1982 beleog to two different coin categories 3704. This use of categories, based on physical characteristics of eoins (or other objects), rather than attempting to define on the basis of denominations, is advantageous since it is believed tlwt this approach leads to better disaimination accuracy. In partieolar, by defining separabe eategorics e.g. for pre-1982 and post-1982 pennies, it becomes easier to discriminate all pennies &nrn other objects, whereas if an attempt was made to define a singie category embracing both types of pennies, it is belmed that the reoognition windows or aht+esholds would have to be so broadly defined that there would be a substantial risk of mis-discrimination. By providing a system in which coin categories rather tlum coin denominations are recognized, coin destinations may be easily oonSgured and changed.
Farthermore, in addition to improving discximinatim accuracy, the preaaot invention provides an opparhmity to count coins and mt coins or other objects on a basis other than denomination. For example, if desiied, the dCvice could be ooofig+aed to place "real silver" coins in a separste coin bin so that the maobine operator caa benefit from their potentially greater value.
Once a relegator prooess 3514 receives informafion fram a categary buffer regarding the cxtegory of a coin (or other object), the relegator ouVuts a destiaatiea indieatar, coiresponding to that coin, to a destination buffer 3516. Tbe data from the destination buffer is provided to a director process 3518 whose fimction is to provide appropriate control agnals at the appropriate time in order to send the coin to a desired destination, e.g. to provide signals causing the de8xtar door to aotivate at the proper time if the coin is destined for an acceptance bin. In the embodiment of Fig. 25, the director procedure outputs information ngarding the action to be taken and the time when it is to be taken to a control schedule process 3522 which gencmtes a eontsol bit image 3524 provided to microprocessor output potts 3526 for traosmisaion to the coin transpcxt hardware 3206.
In one embodiment, the solenoid is controlled in such a manner as to not only control the time at which the door is activated 4234, 4244 but also the amoamt of force to be used (such as the stcvngth and/or duration of the soleomd activatien Volts). In one embodiment, the amount of force is varied depending on the mass of the coin, which can be detwmined, e.g., &om a look-up table, based on recognition of the coin category.
Preferably, information from the destination buffer 3516 is also provided to a counter 3528 which tetains a tally of at least the number of coins of each denomination sent to the coin bins. If desired, a namba 5 of camteis can be provided so that the system can keep track not only of each coin denomination, but of each coin category and/ar, which coin bin the coin was destined for.
In ge,noral, the flow of data depicted in Fig. 35 represarts a narrowing bandwidth in which a relatively ]arge amount af data is provided fnan the AJD convecta:r which is used by the detector 3502 to output a smaller amamt of deta (as the coin signature), ultimately restilting in a single cotmtx incxement 3528. According to 10 aoe embodiment of the present invention, the system is configured to use the most rapid and efficient means of infamation trmmsfer for those information or sigual paths which have the greatest volume or bandwidfh requirements. Accordingly, in one embodiment, a direat memory access (DMA) prooedure is used in comwtion with transferring sensor data from the converter 2906 to the nric7ocontroller reading buffer 3500.
As depicted in Fig. 38, a two-channel DMA controller (providing channels DMAO
and DMAI ) is 15 used 3802. Tn the depicted embodiment, one of the DMA channels is used for uploading the program from one of the serial ports to memosy. Aitear this operatian is compkted, both DMA
chmnels are used in implemmting the DMA transfer. DMAO is used to write centroller data 3804 to the A-to-D oo verter 2906, via a control register image buffer 3806. This operation selects the analog channel for the next read, atarts the conversion and sets up the next read for the A-to-D eonverter output data register. DMAI t6en reads the 20 output data register 3808. DIvtAO will tbea write to the controller register 3806 and DMAI wiII read the nact analog channel and so forth.
In the preferred embodiment, the DMA interface does not limit the abiGty of the so8ware to indepmdently read or write to the A-to-D convrita. It is possible, however, that writing to the control register of the A-to-D converter in the middle of a DMA transfer may cause the wrong channel to be read.
25 Prefmnbly the DMA process takes advautege of tbe DMA channels to configure a multiple word table in memay with the desired A-to-D cootroller register data Preferably the table length (number of words in the table) is configurable, permitting a balance to be struck between reducing miorocontroller overhead (by usiog a longer table), and reducing memory requirements (by using a shorter table). The DMA process sets up DIufAO for writiog these wotds to a fixed UO address. Next, DMAI is set up for readiog the same namber 30 of words from the same I/O address to a data buffer in nwmory. DMAI is preferably set up to interrupt the pnooessor when all words have been read 3812. Preferably hardware DMA decoder logic controls the timing betweea DMAO and DMAI.
Fig. 39 depicts timing for DMA tsansfer acooad'mg to an embodiment of the present invention. In this anbodimwt, a PIO pin wiU be used to enable or disable the timar output 3902.
ffthe timer enable sigoal 3904

35 is low, the hardware will block the timer output 3902 and conversions can only be started by setting the start conversion bit in the control register of the A-to-D oonverttt 3906. ffthe timer enable signal 3904 is high, the A/D conversions start at the rising edge of the timer output 3902, and write cycles will be allowed only atter the following edge oftbe timer output 3902 with read cycles only being allowed after the busy signal 3912

36 goes low while the timer output signa13902 is high. The described design provides great flexibility with relatively small over}md. There is a single intemWt (DMA intemipt) event once the buffer is filled with data from the A-to-D converter are read and put into memory. Preferably, software can be configured to change the DMA configuratieai to read any or all aoalog channels, do multiple reads in some channels, read the chawids in any order and the like. Preferably, the A-to-D converter is directly linked to the mioropr~or by a 16-bit data bus. The microprocessor is able to read or write to the A-to-D converter bus interfax port as a single input or output inshuction to a fixed 1/O address. Data flow between the A-to-D converter and the mia+opmcessor is controlled by the busy 3912, chip seleot, read 3914 and write 3908 signals. A conversion clock 3902 and clock enable 3904 sigoals provide control and flexibility over the A-to-D eonve.rsion rate Another embodiment of a gapped torroid seaaor, and its use, is depicted in Figs 2A through 16B.
As depicted in Fig 2A, a sensor, 212 includes a care 214 having a generally eurved shape and defining a gap 216, having a first width 218. In the depicted embodiment, the curved oore is a tocroidal section. Although "tonnidal iacbndes a locus de5ned by rotating a ehole about a non-interseoting eoplanar line, as used herein, ahe term "torroidal" generaliy mesos a shape whicb 'ta caaved or otherwiae non-linear. Examples iocLude a ring shape, a U shape, a V shape or a polygon. In the depicted embodiment both the major crow section (af the shape as a whole) and the minar cxnss section (of the generating form) have a eiroular shape. However, other major and mina aoss-sactienal shapes can be used, iacluding ellipticai or oval shapes, partial ellipses, ovals a circies (such as a semi-circular shape), polygonal shspes (such as a regular or iiregular hexagoo/actagon, ete.), and the like.
The core 214 may be made from a number of materials provided that the material is capable of providing a substantial magnetic field in the gap 216. In one embodiment, the me 214 consists o& or inclndes, a ferrite material, such as farmed by fusing faric oxide with another material such as a earbooate hydroxide or allcaline metal ehionde, a ceramic feirite, and the like. 1f the core is driven by an altcnatmg can-ent, the material chosen for the core of the inductor, should be nonnal-loss or low-loss at the freqnenc,~y of oscillation such that the "no-coin" Q of the LC circuit is substantially higher than the Q of the LC circuit with a coin adjacent the sensor. This ratio detewnine.s, in pact, the signal-to-noise ratio for the coin's eonductivity aneasaement. The lower the losses in the car+e and the winding, the gmter the change in eddy cutent lossm whea the coin is placed in or passes by the gap, and thus the gt+eatet the sensitivity of the device.
In the depicted embod'ameot, a conductive wire 220 is wound about a portion of the core 214 so as to form an inductive device. Althougb Fig. 2A depicts a single coil, in some embodiments, two or more coils may be used, e.g. as described below. ln the depicted embodiment, the coin er other object to be dis<ximinated is positiaoed in the vicinity of the gap (in the depicted embodiment, within the gap 216). Thus, in the depicted embodiment the gap width 218 is somewhat larger than the thickness 222 of the thickest coin to be seused by the sensor 212, to allow for mis-aligmnent, movement, defmmity, or dirtiness of the coin. Preferably, the gap 216 is as small as possible, consisteM with practicai passage of the coin.
In one embodiment, the gap is about 4 mm.
Fig. 2B depicts a sensor 212', positioned with respect to a eoin conveying rai1232, such that, as the coin 224 moves down the rai1234, the rail guides the coin 214 through the gap 216 of the sensor 212'.

37 Although Fig. 2B depicts the coin 214 traveling in a vertical (on-edge) orientation, the device could be eao8guced so that the coin 224 travels in other orientations, such as in a lateral (horizontal) configuration or angles therebetwecn. One of the advantages of the present invention is the ability to increase speed of coin movement (and thus throughput) sinee coin discrimination can be performed rapidly. This feature is patiicularly important in the present invention since coins which move very rapidly down a eoin rail have a tendency to "fly" or move partially and/or momentacily away from the rail. The present invention can be eon6gtu,ad soch that the sensor is relatively insensitive to such departures from the expected or nominal coin position. Thus, the present invention contributea to the ability to achieve rapid coin movement not only by providiag rapid ooin disaiuninatian but insensitivity to coin "flying."
Although Fig. 2B depicts a configuration in which the coin 224 moves down tha rail 232 in respon,e to gravity, coin movement can be achieved by other tn~ovuerad or powered means such as a conveyor belt. Although passage of the coin through the gap 216 is depicted, in another embodiment the coin passes across, but not through the gap (e.g. as depieted with regard to the embodiment of Fig. 4).
Fig. 3 depicts a seceod configuration of a sensor, in which the gap 316, rather than being fonarod by oppased faees 242a, 242b, of the core 214 is, instead, formed between opposed edges of spaced-apart plates (or "pole pieoes") 344a, 344b, which are empled to the cae 314. In this oonf'iguration, the core 314 is a half-torus. The plates 344a, 344b, may be coupled to a torroid in a number of fashions, such as by using an adl>mwe, cement or glue, a press6t, spot welding, or brazting, riveting, screwing, and the like. Altbough the embodhnent depicted in Fig. 3 shows the plates 344a, 344b attached to the toiroid 314, it is also possible for the plates and torroid to be formed integrally. As seat in Fig. 4, the plates 344a, 344b, may have half-oval sbapes, but a nurnber af other shepes are posale, including semi-circular, square, rectangular, polygonal, and the like. In the embodimeat of Figs. 3 sod 4, the field-oonceahating effect of ferite can be used to pioduae a very locel'rzed field for interaaron with a coin, thus reducing or eliminating the effect of a touehing neighbac coin. The embodiment adFigs. 3 and 4 caa also be coofigured to be relatively insnnsitive to the offects of coin "flying" and thus contribute to the ability to provide rapid coin movement and incxease coin throughput.
Although the paeentage of the magnetic 6cld which is affected by the presence of a coin will typically be less in the caofiguratien of Figs. 3 and 4, than in the configuration of Fig. 2, satisfactory results can be obtained if the fidd ehaoges we sOmently Urge to yield a eoosistently high signal-to-noise indication of coin parameters.
Prefaably the gap 316 is sufficiently sinall to produce the desired magnetic field intensity in or adjaceat to the coin, in order to expose the coin to an intease field as it passes by and/or through the gap 316. In the embodiment of Fig. 4, the length of the gap 402 is large enough so that coins with different diameters cover different proportices of the gap.
The embodiment of Fig. 3 and 4 is believed to be particularly usefW in situations in which it is difficult or impossible to provide access to both faces of a coin at the same time. For example, if the coin is being canvryed an me of its faces ratlur than on an od e (e.g., being conveyred on a conveyor belt or a vacuum belt).
Furthermore, in the embodiment of Figs. 3 and 4, the gap 316 does not need to be wide enough to aocarunodate the thiclmess of tbs eoin and can be made quite narrow such that the magnetic Seld to which the coin is exposed is also relatively narrow. This configuration can be useful in avoiding an adjacent or

38 "EoucW coin situation since, even if coins are touching, the magaetic field to which the coins are exposed will be too narrow to substantially influence more than one cein at a time (daring most of a coin's passage past the sensor).
When an electrical potential or voltage is applied to the coil 220, a magoetic field is creatod in the vicinity of the gap 216, 316 (i.e. created in and near the gap 216,316). The interaction of the coin or other object with such a magnetic field (or lack thereof) yields data which provides iaformation about parameters of the coin or object which can be used for discrimination, e. g. as descn'bed more thoroughly below.
In one embodiment, current in the form of a variable or alternating current (AC) is supplied to the coil 220. Although the fona of the eaareat naay be substantially sinusoidal as osed herein "AC" is meant to include any variable (non-constant) wave foim, including ramp, sawtooth, square waves, and complex waves such as wave fatm4 which are the sum or two or more sinusoidal waves. Bocause of the conSguradon of the sea9or, and the positiooal relationsbip of the coin or object to the gap, the coin can be eaqxOSed to a significant magnetic field, whieh can be significantly affected by the presence of the coia. The sm9or can be used to detect these changes in the elecuomagnetic 5eld, as the coin passes over or through the gap, preferably in such as way as to provide data indicative of at least two differeat parameters of the coin or objcd, ln aoe embodiment, a parameter such as the size or diameter of the coin or objeot is indicaied by a chan8e in inductance, due to the passage of the coin, and the conductivity of the coin or object is (inve:gcly) related to the energy loss (which may be indicated by the quality factor or "Q.0) Figs. 15A and 15B depirt an embodiment which provides a capability for capacitive sensing, e.g, for detocting or eomp sating for coin re)ief andMc flying. In the embodiment of Figs. 1 SA and I SB, a coin 224 is eoostrained to move alaog a subsfanbally liaar coin path 1502 defined by a rail device such as a polystynate rail 1504. At least a portion of the coin path is adjacent a two-layer shucom having an upper layer whieh is subatatdially non-e)ecxrically conducting 1506 sucb as fibetglass and a second layer 1508 which is substantially conductive such as eopper. The two-layer shvoture 1506, 1508 can be canveaiently provided by ordittary circuit board material 1509 such as 1/23 inch thick circuit board material with the fiberglass side contacting the coin as depicted. In the depicted embodimient, a rectangular window is foimed in the copper cladding or laya 1508 to aooommodate zectangular feaite plates 1512a,1512b which are coupled to faces 1514a,1514b of the ferrite torroid coro 1516. A conductive structure such as a oopper plate or shield 1518 is positioned within the gap 1520 formed betwaen the fenite plates 1512s, 1512b. The sbield is useful for inarasing the flmt intmuting with the oaia Without wishing to be bound by any tbeory, it is believed that such a shield 1518 has the effect of foming the flux to go around the shield and therefae to bulge out more into the coin path in the vicinity of the gap 1520 which is believed to provide mote flux interacting with the coin than without the shield (for a better signal-to-noise ratio). The shield 1518 can also be used as one side of a capacitive stnsor, with the other side being the copper backingJground plane 1508 of the circuit board structur+e 1509.
Capacitive changes sensed between the shield 1518 and the ground plane 1508 are believed to be related to the reiief of the coin adjacent the gap 1520 and the distance to the coin.
In the embodiment of Fig. 5, the output of signal 512 is related to change in inductsnce, and thus to coin diameter which is termed "D." The configuration of Fig. 6 rmilts in the output of a signa1612 which

39 is related to Q and thus to conductivity, termed, in Fig. 6, "Q." Although the D signal is not purely proportional to diameter (beiag at least somewhat influenced by the value of Q) and Q is not strictly and linearly proportional to conductance (being somewhat influenced by coin diameter) there is a sufficient relationship between signal D 512 and coin diametor and between signal Q 612 and ceoductanoe that these sigoaK when properly analyzed, can serve as a basis for coin discrimination.
Without wishing to be bound by any theory, it is believed that the interaction between Q and D is substantially predictable and is substantially linear over the range of interest for a coin-countusg devicx Many methods aud/or devices can be used for analyzing the signals 512, 612, including visual inspection of an oscilloscope trace or graph (e.& as shown in Fig. 9), automatic analysis using a digital or analog circuit and/or a computing device such as a microprocessor-based oomputer and/or using a digital sigaal pavoesor (DSP). Wlun it is desired to uge a codnputer, it is uxful to provide signals 512 and 612 (or modify those sigoals) so as to have a voltage range and/or other parametexs compatible with input to a computer. In one embodiment, siguais 512 and 612 will be voltage signals notrnally lying within the range 0 to +5 volts.
Ia some caves, it is desiced to separately obtain information about coin parameta's for the interior or eore portion of the eoin and the exteria or skin pattieo, patticutarly in eases where some or all of the coins to be discximmated may be dadded, plated or eoatod ooins. For example, in some cases it may be that the most efficient and reliable way to disoriminate between two types of coins is to determine the presenae or absence of daddiiog or plating, or compare a skin or core pwameter with a cenespooding sldn or core pacammeter of a lnmn coin. In one embodimeat, difforr.nt frequeacies are used to probe different depths in the thidcness of the onin. This method is effactive because, in terms of the iateractioa betweea a coin and a magnetic field, the frequency af a variable mapetic field defines a"skin depth," which is the effective depth of the portion of the coin or otha object which interacts with the variable magnetic field. Thus, in this embodiment, a fitst fivqucaq is provided which is relatively low to provide for a larger skin depth, and thus inUeraction with the core of the coin or other object, and a seeood, higher &equax.y is provided, high rayough to resalt in a skin depth substantially less than the thicamess of the coin. In tbis way, ratber than a single sensor providing two perametes, the sensor is able to provide four parameters: c4ore conductivity, cladding or coating conduotivity, eore diameta-, aad cladding a oflating diametar (although it is aaticipaUod that, in many instanees, the core and cladelieg diamoe6rts will be similsr). Prefaably, the low-freqaonc,y skin depth is greater than the thiclrness of the plating or lamination, and the high frequency skin depth is less than, or about equal to, the plating or lamination thicimess (or the range of lamioation de,pths, for the anticipated ooin population). Thus the $equency which is ehossn depends on the characteristics of the coins or other objects expeeted to be input.
In one embodiment, the low frequency is between about 50 KF-lz and about 500 ICHz, preferably about 200 K14z and the high frequency is between about 0.5 MHZ and about 10 MHZ, preferably about 2 ME1Z.
In some sitoatieos, it may be necessary to provide a first driving sigaal frequency commponent in order to ao}rieve a second, ddmwt froquamy seasor signal component In particular, it is found that if the seagw 212 (Fig. 2) is first driven at the bigh frequeak,y using high &equency coi1242 aad then the low frequency signal 220 is added, addiog the low frequetuy signal will affect the frequency of the high frequency sigaa1242. Thus, the high frequency driving signal may need to be adjusted to drive at a nominal frequency which is differeat tiom the desired high frequency of the seasm such that when the low frequency is added, the high frequency is periurbed into the desired value by the addition of the low frequmwy.
Multiple hequei,cies can be provided in a number af ways. In one embodiment, a single continuous wave 5 form 702 (Fig. 7), which is the sum of two (or more) sinusoidal or periodic waveforms having diffeneot Ercquencies 704, 706, is pmvided to dw seisor. As depioted in Fig. 2C, a sensor 214 is preferably configurod with two different coils to be driven at two diffaut frequencies. It is beGeved that, generally, the presence af a secand eod can wxdesaably affect the inductance of the fust coil, at the frequency of operation of the first coil CieaaWly, the number of tutns of the first cal may be oorrvspOadingly adjusoed so that the first eoil lus 10 t6e deaired inductance. In the embodiment of Fig. 2C, the sensor core 214 is wound in a lower portion with a Srst ooil 220 for driving with a low frequency signa1706 and is wound in a second region by a seeond coil 242 for driving at a higher frequency 704. In the depicted embodiment, the high frequency eoi1742 has a smalier number af tucag and uses a larger gange wire than the firat coil 220.
1n the depicted embodiment, the high fiequency coi1242 is spaced 242a, 242b from the first eoi1220 and is positiened closa to the gap 216.
15 Pnavidmg some separation 242a, 242b is believed to help reduce the effect one coil has oa the inductanoe of the other and may somewhat reduce direct coupling between the low freqnaa,y and high freqoency sigoals.
As can be seen from Fig 7, the phase relationship of the high frequency signa1704 and low freqveascy signa1706 will affect the particular sbape of the compos;te wave form 702.
Signals 702 and 704 represent voltage at the tenninals of the high and low $r,qnenc,y coils, 220, 242. If the phase relatiooship is not 20 eoatrollod, or at 1ea9t knawn, adput signals indiatmg, for example, amplitude and/or Q in the oscillator eircuit as the oain passes the sensor may be such that it is diffienlt to determine how much of the change in amplitude or Q of the signal results Erom tbe passage of the coin and b.ow much is attributable to the phase relationahip of the two sigoals 704 and 706 in the particular cycle being analyzed.
Accordingly, in one eanbodiment, tiu:
phases of the low and high signals 704, 706 are conbolletl such that sampling points along the composite 25 signa1702 (described below) are taken at the same phase for both the low and high signals 704, 706. A
nLxnber of ways of assuring We desired phase relationship can be used including genorating both signals 704, 706 fiam a eommoa neference source (such as a erystal oscillatar) and/or using a phase locked loop (PLL) to control the phase relationship of the signals 704, 706. By using a phase locked loop, the wave shape of the eomposite sigrw1702 wiA be the same dnring any cycle (i.e., during any low fi+cqoenoy cycle), or at least wiu 30 chan8e only very slowly and thus it is possible to detamine the sampling points (described below) based on, e.g., a pre-defined position or phase within the (low frequeney) cycle rather than based on deteeting characteristics of the wave form 702.
Figs. 8A - 8D depict circuitry which can be used for driving the sensor of Fig. 2C and obtaining sigoals useful in coin discrimination. The low frequency and high frequency coils 220, 242, form portions of a low 35 fnquenc,y and high freqaency phase locked loop, respectively 802a, 802b.
Details of the clock circuits 808 are shawn in Fig. SD. Tlbe details of the high frequency phese locked loop are depicted in Fig. 8B and, the low fi+eqaeacy phase loc.laed loop 802a may be ideatical to thst shown in Fig. 8B
except that some components may be lxovided with ddm+eat values, ag., as discussed below. The output from the phase locked loop is provided to filtaa, 804, shown in greatar detail in Fig. 8C. The ramainder of the components af Fig. 8A are geacrelly directed to providing refereaoa andlor sampling pnlse.s or signals for purposea described more fully bolow.
The aystal oscillata circuit 806 (Fig 8D) provides a refemm Svquaicy 808 inpA
to the clock pin af a cmder 810 sudi as a Jobosan "divide by 10" omakc Tbe ooimter awpuss a high frepzoc,y rdcrraoe signal 812 and vatimoutputs Q0-Q9 define 10 differeat phase poaiticoa with respect to the refermce sigoa1812 In tbe depicxed anbodiment, two af t6ese p6ase powtian pulses 816a, 816b at+e provided tothe high 5equany phaee locked loop 802bEorpiapoees desrnbed be]ow. A sec.mcl cadar 810' neoeive.w its clock ialxrt firom the tefimoe sigoa1812 and auo#s a low Eneqmcy refaeace sigua181Z a4d fitst and sooond low fifreqiaiq sscoph puisea 816s! 816b~ whio6 ere u9ed in a fashion malogou to the u9e cf tbe lugh finqmq pulses 816a and 816b dGwcribod below.
Tbe highk"my phase lockad loop circuit 802b, dopided in Fig. SB, oaoquoa five main sodioos. The eae oeciUaOor 822 pmvides a driving sipal for the ltigb fioqueacy ca11242. The positive a4d negat ive peak samplaa 824 sample peak and trough voltagcs of the ooi1242 which am pcovided to an ouqM eiccuit 826 for autputting tbe high fieqmnc,y Q o>dpki sigoa1612 The high &"xOcy refaenoe signa1812 is eoavated to a tfiengk wave by a triaogle wave gmerator828. 1be triangle wave is used, in a feahian disoussad below, by a sampling phase detectac 832 forproviding an inlxt to a diffetcaoe aaWlifier 834 which ogpuis an enar sigoa1512, which is provided ro tbe oscillator 822 (to, maintain the fixquency and phare afthe oscillator substantially oaostw-t) and provides the high ftequwcy D oalptrt signe1512.
Ltiwfiequas,y phase lodced bop cirait 802a is similas to that depicted in Fig.
8B ewoept for the value of eataiu oompooarts wlrich ae diffmant in acdcr b pmvide appnopriate low frequwcy raspoose. la the high fneqoeacy circait of Fig. 8B, an fiducta 836 and capacitor 838 ace pwvided to filtw out low flnq=cy, e.g. b avoid duty ftequeac.y cycling fhe oa pmatar 842 (wluch hav a low ficqucncy counpooant).
This is usefiil to avoid driving low froquency aad lrighfic*eoc,y in dz same oecillatoc 822. As seen in Fig. 813, the indueta and capacitor have vahm reepectivdy, af 82 miaiohenys sod 82 pioafasads 'llr cmycqonding eaupoowts in the law 5quw.y circuit 802A
have vaha% respectively, of aoe miarohenry and 0.1 micanfarads, naspective]y (if surh a filter is provided at all). In lrigh 5equaxy tria* wave 8eneaataa, capacafar 844 is shnwn with a value of 82 piodarads whik the omespondbng cmVanent in the low frequency cinait 802a has a value of 0.001 miaofatads.
Caa.suderiog the circuit of Fig. 813 in someuvhat goeater detail, it is desired to ptovida the o cxllatar 822 in sirh aEasirim that the fi+aqnawy t+eaoaios sebstantially caostaot, despite chemges in inxkxta4ce al'the cod 242 (such asmayarisefi+ampassageofa winpaat tbe scnsor). In arder to achim this goal, the oscillatar 822 isprovidod with a voltage coaWWble capacatar (or vacactor diode) 844 such t44 as tbe iodudanae af t6e coil 242 chenges, t6e capacitanoe afdr varadar diode 844 is adjusted, u4ing the enur signa1512 to compto-sate, so as to maintain the LC
neoneotfi+eqamc.y abdmbally ooWmt la the oonfigucaticn al'Fig. 8B, the capacAmwe ddwnrining the neooant fieqiuncy is a fuidion af bolhthevatactor d'iode capacitanee and the capacitaocc od'Sxed capacita M. Pneferably, capacitor 846 and varactor diode 844 are selected so that the control voltage 512 caa we the greater part af the dy>awm raage of the varacta diode a+id yet the eontsol vdtage 512 caneins ia a preferred range such as 0-5 volts (uwful Bor aOiting drtatly to a eotz>puIa} Op amp 852 is a zero gain buffer amplifier (impedance isolatar) whose output provides ene r4xt to camparator 842 which acts as a had limiter aad has reletively high gaia 1he hffid-limitad (squae wave) aVrt of oomparatar 842 is provided, aaoss a high value resi.stac 844 to drive thc coi1242.

Tbe high vahwaf ihe resiatanoe 844 is wlxfed such that neafly all the volta e of the aqaazc wave is broppod aanas @us trsisiar and thus the resulbng vdta e on tbe o00 242 is a fiax6an of its Q. In manauffy, a sine wave oecOlatian m ft LC c=it is earanated to a castant amplitude square wave sigi-at dnving the LC circuit so that the amplitude of the oecillafina in tbe LC caocuit ate directly a oowe of the Q of the caeaut ln ocderto abtaia a measune of the amp]itude aif tbe volta e, it is neoessary to sample We vrolta8e at a peek aM a bough of ibe sigal. In tlie embodimelt afFig. 8B, Sret aad 9ooaod suvrtches 854e, 854b prnvide smmpla+ of the voltage value at tirim daGamined by the bigh frequeacy puL9es 816a, 816b.
Ia ane embodbootthe timing is detacmisied anpaioally by aelectietig diffarnt outputs 814 fian the camter 810. As soon in Fig 8A, iLe (eanpinically sdected) outpuo imed for the high fiequeaay aram may be dffermt fiam ftae used for the low 5vqueaa.y oinaat, e.g, b== of diffau%delays in the two ahuib and tho libe. Switches 854 aod capacitas 855 fann a sample and bdd caam farsm;li-gpeekaal trough vololCa and drae vdtages are providod to dfixential asnpliSer 856 whoee output 612 is thm pcopatioaal to the amplitude of the sigal in the LC ciraiit aod, aooocdingly is invosely pupatianl to Q(and tbnm]atad to oanductanoe of the eoin). Beceuse the pha9e locked loopa yor dhe law aud higb &rqnatiy eigoaL4 are loclced to a common reBa+cuce, the phase selatiaosbip bdween the two &rqucncy oomponmta ishaed, and anq ioAmfamoe batwcea the two Aeqxncies will be canamm mode (ar nariy su), a~noe the wave fam will stay neariy the samo 8nai cycle tD e)cle, aod tbe ommwa mode wmponent w01 be subtrac,ted aut by die diffenedial amplifier 856.
In addition to providing an outiwt 612 which is rela0od to coin candtctanoe, the sasne circarit 802b also peovides an cwtpuc 512 related to coin diameter. In the anboaimear ofFig. 8B, the high rrequaic.y aiaaneta 4nat F1FD 512 is a si8nal wbich kdic0sthe msoid~de afthe oona4ian Ibat must be appfiod to vaackr diode 8441o oomect for eban es in inhxtanoe of the ao0 242 as the coin passes the sca9or.
Fig. 7 illushrates sipels which play amie mddermoing widfia cwecfion to the vmcWrdiode 844 is noodod if t1ne iasbeen no chmge in Ihe aail inductance 242, the roaaast fiweacy of the oedlleta' 822 will ranain aubstaotially aroatmt and wffl hatne a sabefa4tialiy omstantpba9e ~ wi~h tcypectto tLe high frequeney ce,fa+eatioe signa1812. Thus, in the abseooe d'Ihe passap oia ooin past the sensar (or any odier disdabance of the inductance of the ca1242) Uie squQe wave afpnt ipa1843 will have a phase which oomespaods to the phase of the refereaoe sigpa1812 such tLat at the time deach edge 712a, 712b, 712c af do asca7ia0or aqueio wave sipal 843, tbe re.8naoe stpal 812 will be in a pbasie midway between the wave peak and wave iiagb. Any deparhr+e fram this aaoditian indicatea there has baea a cbmgo inthe reaonast 8iuqamcy af the eacallatnr 822 (and ooa9equent plLse shift) witch needs to be oatecWd. In @o cmbo&ncnt cf Fig. SB, in adcr lo dalrct and earoct such depattmm tlye refaraoe sigoa1812 is oonvertad, via hiangle wave genaraGar 828, to a hiaogle wave 862 having the same phase as the tela+enoe spa1812. Tbis ttiaogle wave 862 is provided to an amiag switch 864 which samples the triangle wave 862 at times detaminod by pulxa gmaaped in response to edges of the aecffiator square wave signal 843, output over line 866. The sampled aignals am hold by copacitar 868. As can be 9aen fivm Fig 7, if thae hag boea no chaage in the fivqneaxy or phase relationsbip of the o ctillator signa1843, at the times of the square wave odges 712a, 712b, 712c, the value afthe squsawave sipa1862 will be half way betweea ihe peak value and the ho* valuc.
Tn the depicled embodimeN, Ibe tcien&wave 862 is oon6gured to have an asnplitude equal to the diffaeace betweea VCC (typically 5 volts) a4d giwnd potegiaL T6us, diffeaeace amplifier 834 is eon6gawad to oompane the saarpie vahms &om Ihe hiangle wave 862 with an"alf of VCC 872. If ihe sampled values fi am the kiangle wave 862 a<e half way betwecn gcMod potarial and VCC. 8tie output 512 $+om canpasator 834 will be zam and thu4 tht= will be no ertnr signal-induced cban8e to the capecitanoe cf varectar diode 844. 1-lowever, if the sampled values finm the triangle wave 862 a+e nd halfway between ground pot tial and VCC, differame ampliSer 834 wi11 oatput a voita e on lina 512 wLich is adkient to adjust the capacitance cfvasactcr diode 844 in an ammmt and direcaion needed to corinct the ca9ooad fiequau.y of the ceA 822 to maintain the fi+ecluenc,y at the desu+ed substantially caostet-t valua. Tbug sipa1512 ia a measae oftbemapitude of the ciwo8es in 16e effoctive ioductooe a~the ooi1242, e.g, arisng from pam e of a coin past the sensor. As shawn in Fig. 8A, ootputs 612, 512 from the high frequeacy PLL cmvit as well as oameypooding ariputs 61Z 512' Erom the 1ow fiiequeacy PLI, are }xovidod to filucs 804. Tlre depicted filtas 804 an lov pass Ehrs eoo5gimed far naa9a iejadiea The paas bands for the 5ltera 804 are pra!'arebly selecLed to pravide desirable sipal to noise ratio cheracteriatic for the outpR siBnals 882a, 882b, 882a', 882b'. For example, the bandwidth which is provided for the filtets 804 may depend apon the spaed at which coins pasa the smsom aod sinv7arfaetaa.
ln one embodimat, the ou4put signals 884 882b, 882a', 882b' at+e prrovidad to a oomputa for oain discximinatiaa or otha aoalysis. Befoc+e desaz'bing axamp1es of such analysis, it is bdioved asm'td to doscxibe the typical pca6k.w e[the oufput sigwls 882a, 882b, 882a', 882b'. Fig 9 is a paph depicting ibe oaqwt agnsla, ag., as fitymigbt appoarif$rolptt sigule wae c)isplayed on a propaly coaSgured oecilloecape. 1n the iUu.9tratian afFig 9, the values of the high as-d low fnoquawy Q sipala 882a, 882a' and the high and bw fi"umcq D aiguals 882b, 882b' bavevabrs (depictadmthe kSofthe graph a(Fig 9) piior to gassa e ef a coin paat the aaoor, wbicb cheo8e as iadkded mFig. 9 as the ooin moves tawaod the seasrx, aod is adjaceirt or eaitmed witbin the gap af the sonsar at time T,, nehaning to substantially the original vahies as the ooin moves away from the am.9or at time T2.
The aignela 882a, 882b, 882a', 882b' can be u9od 'm a rnanber af fa9hians to dmactaciae eoios a aiha djeds as desated below. Th megrihude cf chmW 902a, 902a' of tba low freqaeac,y and higb fitquaicy D value.s as the oau-pasees the aasir and tbe absolute values 904, 904' of the low and high $equeiwy Q si sala 882a', 882a, respcWvely, at the tiaoe t, when the coin or otbw objed is awat nearly aligned with the seauac (as datinmined ag., bybe tim aftbe bcal mLxmnm in the D signals 882b, 882b) am useU in characteiizing coins. Both the law aod }riglifnxgimqr Q values sae uaeU fae discaimmation. Leooimted eoiag show ssgmfieaut ddkreaeas in tha Q rading far bw va high fi+eque .y. The law and high firoq=,y "D" vahxa am also asd'W
for disaiaw>atian. It has bedi fiotrod that same af aIl aflhse values are, at least fa aame coin popdstiens, stAcientiy chwactaistic af variaus coin deaominatiions that ooins can be discximioated with high aocu[acy.
In one anbodanat, values 902a, 902a', 904,904' aoe obtaiood for a large number afooins so as to define staodad vahrs charadaistie of each eoia deaomittetiea Fip. l0A and 10B depict high and low 5apzac,y Q and D daRa f+or diffiav~t U S. ooaos. Tho values fa the data points in Figx IOA
aod l OB are in acbitmy units. A number of Seafim ofihe data are appaeent &om Figs. IOA and IOB. Firsit, it is mted thet the Q, D data points for ddk+ait denominatiaos of coins ase chnEaed in the sease tbat a givm Q, D data poiat far a ooiu ttnds to be eloea tfl data points for the seme deaaminatien coin thm for a different dencmination coin.
Seoond, it is noted that the rdativoe position of the denaminetiaos for the low &equency data (Fig. lOB) are differcnt fiom tbe relative poaitions for conespood.g denominstions in the bigh &equency gtaph Fig.10A

One mathod of using standud refaeooe data a[the type depicted ia Figs. IOA aM
l OB to ddca-ine ffie dantn~n of an iadmown coin is to define Q, D regions on each oftbe high fitqumcy and low fi+aqueac.y graphs in the vicinity of the data points. For example, in Figa. IOA and l OB, regions 1002a - 1002e, 1002a'- 1002e' ane depidod as neduiggider ateas efloaupssmg the data poinRa. Aooording to aae embodiment, whea low fiequanq and high fi-equency Q and D data ara imqnd to the oonopnter 'vt respaose to the ooin movuig past the samor, the high fi+aqumgr Q D vahrs for@e udmawn aom ae oampanad to each d'the regians 1002a -1002e of the high 5eqomc,~y gaph andthe 1owAWawyQD deQa is oacpffedto each of the tegions 1002a' -1002e' af the low $equmay graph Fig. I OB. If the imimawn coin lies wituin the predefined regi(xn oomapaading tn the aame denomioatian for each afthe 1wo graphsFig lOAFig. IOB, the ooin is iodieatad as having that dmominatiao. 1f tha Q, D data fdh alside thongiotB 1002a -1002e.1002a' -1002e' on the two graphs or if the data point a[the nnlmown coin or objed falls inaide uegiaa caiesponding bo afist denoroinatien with a high fraloeacy graph birt a diffaeat denomaaation with low 8roqoawy graph, t6e coin or other object is iidicatod as not oarrespooding to atry of the denaminatioa+ defined in the gaphs ofFigs. IOA and IOB.
As will be appareat finm the above divcussiao, the aror rate that will owa ia regud to sueh aa a4alysis wiU pa6elly depend on te siae af Ihecegioos 1002a -1002e,1002a' -1002e which we defned Regiaos vwhich are too lmp will tead to sesult in an aoaoceptably large mumber of falae positives (ie., idmtifying ahe coin as being a pactiwlar d aminebaa when it is tnt) wh& definiog nqions which are too snall will result ia an imoooeptably larpe number of false negatives (i.e., failing to identify a legi6mate coin deaomioation). Ttau, the size and shape of t6e vaiiout n*ns may be defioed or a4u4ted, ag enVirioallyr, to aehieve emor rates whidt ate no pedw Wan desioed enarrales. In one embodimet, the wiodows 2002a - 2002e, 2002s! - 2002e haw a sFee md sbape deknmined on de besis e[a statisticel aaalysis aithe Q, D values for a slmdand or sample coin population, such as being equal to 2 or 3 standam+d deviations fram the num Q, D values for lawwn coins. The sim atd alWe ol'the negms 1002a -1002e,1002a' -1002e' may be diff+ervut from one aodha, i.e., diffa+xt far diffmat denoroinatiaos a4d/or diffeawt far the law fi~equawy and hig~ fiequeoc.y ~ph~ Futhamom the size aed 9hape af the vegiow maybe adfix0ed dTaxWgm die amtiapdod coin pepnlatian (e.g., in regioag neaf natiaaal baaders, regions may need to be de!'mod so as to discznminate faeigm coins, evea at the cost af raising the false negative enor rate wherre.as such adjushnent of tUe size or shape of the regians may not be neoessary at locatiaos in the interior ol'a oamtry where fa[riga coins may be nela4vdy rane).
If demed, the oompft can be ooofiguted to obtain siatialics regarding the Q D
values af the coins vwhirh are discriminated by the device in the ficId. This data can be asafW to detect cheoges, e.g., dangrs hi the coin popul8tion owtiaoe, or chnges in the avasge Q, D valuea such as may reaiilt fram aging or vvear al'the sen.9as or otlw oampaneats Such infatmatian may be used to adjust the sofi.wace or hmdwace, perfam maintenanoe on the devise and the Llw. In one embodimeat, the apparatav iu which the eon dieaiminatian davice is used may be pmvidad with a oommmicakian device such as a nuodem 25 (Fig. 41) and may be configured to pamit ft defiai6on of the regians 1002a - 1002e, 1002a' - 1002e or odier data or softwae to be modified remotely (i.e., to be dewnbaded 6o a field site &an a oenhal site). In andlrr embodinoeat, the device is cotfigurod to autamabcaUy adjust the de5nitions of the ngions 1002a -1002e,1002a' -1002e in neqon,qe to ongoing statiatical analysis of the Q, D
data I'or cdas wbich ate discrimufetod usiog the devioe, to provide a type af self cablration far the eoin disaiaoinetar.

In light of the above description, a number advantages of the present invention can be seen.
Fmbodiments od'the present invention can provide a device with iixxeased accuracy aad secvice life, ease and safety of use, requiring Gttle or no training and Gttle or no instruction, which reliably returns uaprocessed coins to the user, rapidly processes coins, has a high throughput, a reduced incidence of jamming, in which some or 5 all jams can be reliably cleared without human intervention, which has reduced need for intervention by trained personnel, can handle a broad range of coin types, or denominations, can handk wet or sticky coins or faeign or nam-coin objocts, has reduced incidaice of malfnnctioning or placing foreign objects in the coin bins, has reduced incidence of rejecting good coins, has simplified and/or reduced requirements for set-up, cslibration or maiatenance, has relatively smaII volume or footprint rcquirements, is toleraut of temperature 10 variatioos, is relatively quiet, and/or enhanced ease of upgrading or retrofitting.
In one embodiment, the apparatus achievos singulation of a randomly-oriented mass of coins with rechuoad jamning and high throughput. In one embodiment, coins are effectively separated fran one another prict to seosing and/or defleotion. In one enbodiment, deflection parameters, such as force and/or timing of de8oction can be adjusted to take into account characteristics of eoins or other objects, such as mass, speed, 15 and/or aeceleration, to assist in accuracy of ooin handiing. In one embodiment, slow or stuck coina are autamatically moved (such as by a pin or rake), or otharwise provided with kinetic energy. In one embodianent items including those which are not rocogaized as valuable, acceptable or desirable coins or other objects are allowed to follow a non-diverted, default path (preferably, under the force of gravity), whik at least some raoogoiaed snd/or awepted coins are diverded from the default path to move such items into an acxxptanoe bia 20 or other location.
In one embodiment, the device provides for ease of applicatien (e.g. multiple meas<uemouts done simultaoeously andlor at one kioalion), inaea9ed pafamnoe, such as improved throughput and reduced jams (that prematurely end transactions and risk losing coins), more accurate discrimination, and reduced cost and/a size. One or more torroidal cores can be used for sensing properties of coins or other objects passing 25 througli a magnetic field, ccrated in or adjaoent a gap in the torroid, thus allowing coins, disks, spherical, round a other objects, to be measiuod for their physical, dimensiond, or metallic properties (preferably two or more propaties, in a single pass over or through one sensor). The device facilitates rapid coin movement and high throug*t. The device provides for better discxiaunation among coins and other objects than many previous devices, particularly with respect to U.S. dimes and penaies, while requiring fewer sensors andlor a smaller 30 sensor region to achieve this result. Preferably, multipie paramebas of a coin are measiued substantially siandtaneansly and with the coin looatad in the same position, e.g., multiple sensors are co-located at a position on the coin path, such as on a rail. In a number of cases, components are provided which produce more than one function, in order to reduce part count and maintenance. For example, certain sensors, as described below, are used for sensing two or more items and/or provide data which are used for two or more functions.
35 Coin handling apparatns having a lower cost of design, fabrication, shipping, maintenance or repair can be achieved. In one embodiment, a single sensor exposes a coin to two different elechrnnagnetic frequencies substan6ally simultaneously, and substantially without the need to move the coin to achieve the desired two-fiequenc,y meamemrot. In this context, "substantiaiy' means that, while there may be some minor depariure ftm simWtaneaty or minur coin movement dtuing the esposure to two diferent frequencies, the departure from siuwltancity or movemeat is not so great as to interfere with certain purposes of the invention such as reducing spaoe reqmmmts, increasing coin throughput and the like, as compared to previous devices. For example, preferably, during detection of the results of exposure to the two frequencies, a coin will move less thaa a diameter of the largest-diameter coin to be detected, more preferably less than about 3/4 a largest-coin diameter and even more preferably less than about 1/2 of a coin diameter.
The present invention makes possible improved discrimination, lower cost, simpler circuit implementation, smaller size, and caae of use in a praGical system.
Preferably, all parameters needed to identify a eoin are obtained at the saw time and with the coin in the saax physical location, so software and other discrimination algorithms are simplified.
Other door configurations than those depicted can be used. The door 62 may have a laminated struotbue, such as two steel or other sheets coupled by, e.&. adhesive foam tape.
A number of variations and modifications of the invention can be used. It is possible to use saau aspects of the itnnntion without using ottters. For example, the desciibed techniques and devices for providing multiple &cgxmm at a single seoor location can be advantageously employed without necessarily using the seasor geometiy depicled. It is passible to uw tbe desenbod torroid-core sensors, while using analysis, devices or tehniques diBaent from those described herein and vice versa. It is possible to use the saisor and or ooin rail eonfiguration described herein without using the described coin pickup assembly. For example it is possible to use the sensor described herein in coooaxion with the coin pickup assembly described in S.N.
08/883,655, for POSITIVE DRIVE COIN DISCRIMINATING APPARATUS AND METHOD, aad incarporated hetin by reference. It is possible to use aspects of the singulatioa aad/or discximination po+tioa of the apparatus without using a tromanel. Although the invention has been described in the tsmtext of a machine whicb recxives a phrality of coins ia a mass, a number of features of the invention can be used in cocutoctioa with devices which receive coin9 one at a time, such as through a coin slot.
Although the sensors have been descn'bed in connection with the coin eoamting or handling device, sensors can also be used in connection with coin activated devixs, such as vending machines, telephanes, gaming devices, and the like. In addition to using information about discriminated coins for outputting a priated var.ha, the information can be used in connection with making elechvnic limds traosfen, e.g. to the bank aocamt of the user (e. g. in accardaum with infamation read from a bank card, credit eard or the Ue) and/or to an account of a third party, such as the rdail location where the apparatus is plac,ed, to a utiGty company, to a govenvnent agency, such as the U.S. Postal Savice, or to a charitable, non-profit or political organization (e.g. as described in U.S. application Serial Number 08/852.328.
filed May 7, 1997 for ponation Transaction method and apparatus. . In addition to discriminating among coins, devices can be used for discrinrinating and/or quality control on other devices such as far small, disexete metallic parts such as ball bearings, bolts and the Wce. Although the depicted embodiments show a single seflsor, it is possible to provide adjacent or spaced multiple sensors (e.g., to detect one or more properties or parauetets at ddkreat sidn depths). The sensacs of the present invention can be cambked with other seosors, Irnowo in the ast such as optioal sas9as, ma4s sensors, and the like. In ffie depicted embodiment, the coin 242 is positioned on both a fu~st side 244a of the gap and a second side 244b of the gap. It is believed that as the can 224 moves down the rail 232, it will be typically positioned very close to the seeond portion 244b of the coil 242. If it is found that this close positioning results in an undesirably high sensitivity of the sensor inductance to the coin position (e.g. an undesirably large variation in inductance when coins "fly" or are othawise somwahet spaced $om the back wall efthe rail 232), it may be desirable to place the high frequency coil 242 only on the second pactieu 244a (Fig. 2C) which is believed to be normally somewhat farther spaced from the coin 242 and thus less sensitive to coin positional variations. The gap may be fonned between opposed faces of a torroid section, or formed botween the opposed aod spaood edges of two plates, coupled (such as by ad4emon) to faces of a sectieu of a twroid In either ooofigaration, a single continuous non-litxat cae has first and second ends, with a gap thavbetwrea.
Although it is poasible Vi provide a sensor in which the core is driven by a direct current, preferably, the core is driven by an alternating or varying currwt In one embodiment two or more frequeacies are used. Preferably, to reduce the number of sensors in the devic,es, both frequencies drive a single com. In this way, a first frequency can be selected to obtain pacameteis relating to the care of a coin and a second frequency selected to obtain parameters relating to the skin region of tk coin, e.g., to characte:'rce plated or lamiuated coias. One difficulty in using two or more &equencies on a single core is the poteatial for interference. In one embodiment, to avoid such interference both frequencies are phase locked to a single reference frequency. In one approach, the sensor forms an fiducter af anL-C oseffiator, whose freqo oy is maintained by a Phase-Locked Loop (PI I.) to deflue an earor sigoal (related to Q) and amplitude which change as the coin moves past the sensor.
As seea in Figs. 2A, 2B, 3 and 4, the depicted sensor includes a coil which will provide a ceRain amamt cfinductanee or iaductive reactance in a eircuit to which it is conuected. The effective inductanee of the eoil will change as, e.g a ooin maves adjaoeat or thtough the gap and tlus ehange of inductanoe can be used to at least partially clsmactaiae the coin. Without wishing to be boumd by any tlreory, it is believed the coin or other object affects induetance in the following maoner. As the coin moves by or across the gap, the AC
magnetic field lines are altesod. If the freqnenoy of the varying magnetic field is suTiciently high to define a "slon depUi" which is less than about the thicJnrss of Oe e04 no fieW lines will go through the coia as the coin moves aaoss or thtough the gap. As the coin is moved acrosa or into the gap, the inductance of a coil wound on the core decreases, because the magnetic field of the direet, shoit path is canceled (e.g., by eddy currents flowing in the coin). Since, under these conditions no flux goes through any coin having any substantial caaductivity, the decrease in inductance due to the presence of the coin is primarily a funetiea of the surface area (and thus diameter) of the coin.
A relatively straightforward approach would be to use the coil as an inductor in a resonant circuit such as an LC oscillator circuit and detect changes in the resooant frequency of the circuit as the coin moved past or through the gap. Although this approach has bew fouad to be operable and to provide infoemation which may be used to sense certain characteristics of the coin (such as its diameter) a more preferred embodiment is shown, in general form, in Fig. 5 and is described in greater detail below.

In the embodiment of Fig. 5, a phase detector 506 compares a signal indicative of the frequency in the oscilletoc 508 with a refec+enee frequency 510 and outputs an error signa1512 which controls a frequemey-vmying emVmait af the oscallator 514 (such as a variable capacitor). The magnitude of the ecror signal 512 is an indication of the magnitude of the ohange in the effective inductance of the coi1502. The detoction con6guration sliawn in Fig. 5 is thus capable of detecting changes in inductance (related to the coin diameter) while maintaining the frequency of the oseillator substantially constant.
Providing a substantially constont frequency is useful because, among other reasons, the sensor will be less affected by interferiag clectoompefic fields than a smsoc that albwa the fraqneocy to shiit would be.
It wi11 also be easier to prevent iaiwanted elecUnmagwtic radiation from the sensor, since filtering or shielding would be provided only with respect to one frequency as opposed to a range of frequeaeies.
Without wishing to be bamd by any thaory, it is believed that the presence of the coin affects eaergy loss, as indicated by the Q factor in the following maoner. As noted above, as the coin moves past or ahrough the gap, eddy currents flow causing an enerU loss, which is related to both the amplitude of the cmrent and the resistance af the coin. The amplitude af the cuncnt is substantially independent of coin ceudoctivity (since the noagoitude of the current is always enough to cancel the msgnetic field that is prevented by the presence of the coin). Therefae, for a given effocdve diametar of the coin, the energy loss in the addy currents wiill be iaversely related to the conductivity of the coin. The nelatioaship can be complicated by such faotors as the skin depth, which affects the area of eucrent flow with the skia depth being related to conductivity.
Ihus, for a eoi1502 driven at a first, e.g. simmidal, f&cqmncy, the amplitude can be detttimined by using timing signals 602 (Fig. 6) to sample the voltage at a time kaown to comeVond to the peak voltage in the cycle, using a first sampler 606 and sampling at a secand point in the cycle lmown to correspond to the trough using a second sampler 608. The sampled (and held) pealc and trough voltages can be provided to a diffaential amplifier 610, the ouqxrt of which 612 is related to the conductance. More precisely speaking, the output 612 will represeat the Q of the circuit. In general, Q is a measure of the amount of energy loss in an oscillata: In a paffectoscillatar arcuit, thene would be no energy loss (once starbod, the circuit wonid oscillate forever) and tbe Q value would be in8nite. In a real circuit, the amplitude of oscillations will diminish and Q
is a*eae+m of the rate at which the amplitude diminishes. In another embodimeat, data relating to changes in frequency as a fimation of changes in Qwe analyzed (or correlated with data iadicative of this fuactional relationship for various types of coias or other objects).
In one emboditnczit, the ioveatieo imvotves cambining two or more 5equencies on one core by phase-locldng aII the fivquawies to the same reference. Because the freqnencies are phase-locked to each other, the interfereace effect of one frequency on the others becomes a common-mode signal, which is removed, e.g., with a differential amplifier.
In one embodimart, a coin disaimination apparatus and method is provided in which an oscillating ekchumagae4c field is generated on a single sensing core. The oscillating electromagnetic field is composed uf ooc ar moce fnquexwy components. The electromagnetic field interacts with a coin, and these interactions are monitored and used to classify the coin according to its physical properties. All frequency components of the magnetic field are phase-locked to a common reference frequency. The phase relationships between the various fivquenoies are fix~ed, and the interaction of each frequency component with the coin can be accurately detamined without the need for canplicated electrieal filters or special geometric shaping of the sensing core.
In one embodime,nt, a swsor having a core, preferably ferrite, which is curved (or otherwise non-linear), such as in a U-shape or in the shape of a section of a torus, and defining a gap, is provided with a wire winding for aa'tation and!ar detedion. The sensor can be used for simultaneously obtaining data relating to two or more pmamctesa of a coin or other abject, such as size and conductivity of the object. Two or more frequencies can be used to sense core and/or cladding properties.
In the embodiment dcpicted in Figs. 8A-8C, the apparahis can be eoashvcted using pacts whieb a+e all caarently readily available and ielatively low oost As will be appannt to those af slrill in the art, otber cimuits may be eonfigued for pafaming fimctioas usefid in dLvriminating coins using the seasor of Figa 2-4. Same emboditrarAs may be uvebul to sded eeitVacsstts to mioimiae the effects of Omnperadne, drift, eta. In some situatieos, patticulm~ highvoluae sh>etions, sane ar all af the dmuritry may be provided in an integrated fa$tmn such as being piovidod an an application specific integrated cin~uit (ASIC). In some embodimatts it may be desirable to switch t6e re]atfNernles af the sqowe wave 843 and triangle wave 862. For cxample, rather tban obtaining a sample pulse based on a square wave signa1843, a circWt could be used which would provide a puLge nefa+eaoe that would go directly to the analog switch (without noadiag an edge dotoot). The squane wave waM be used to goneraie a tsiangularwave.
The phase lodced loop ertaats desmbed above use very high (theocdically in6nite) DC gain sueh as about 100 dB ormne m theload~ac,ic path, so as to maintam a very small phase eiror.
In some sitaetieaa this may Iead to c)itsmilly in acdieving phase lock up, upon initiating the oircuits and thus it may be desirable to t+elax, somewhat, the small phase ernor requinanmts in oniar to achieMe initial phase lock up nmam neadily.
Al@nugh the embodinat of Figs. 8A-8C provides for two finquenciea, it is possible to design a deteetor using thcre or more froqoencies, e.g. to pmvide for better oan di.9aiminatieo.
Additianelly, ratber fhan pmvid;ng two ar mam diserete fiequmxies, the apparatus eould be eanfigimed to swaep ar "chhp" dffmgh afivqjency range. In one embodimant, in order to aohieve swept .6eqowCy data it would be useSiil to pwvide an eaatretaely rapid 5+equeac.y sweep (so that ihe eom does not move a large dLtmm dwing the time ttquaed for ihe freqoaicy to sweep) or to maintain the coin statiaoary during the firquetwy sweep.
In same embodbeeats in plaoe af or in addition to aoalyzing values obtained at a single time (t, Fig. 9) to dmacteriae coins or athtr objacts, it may be u9aiid mue deft fram a variety af difirmt times to develop a Q vs. t pofile or D va t profile (where t represents time) for defocted objects. For exampk, it is believed that larFger ooins sUCh as quartets, tend to m.siilt in a Q vs. t pinSle which is flatler, oompa+od b a D vs. t proft than the prafile for $nallQ ooina h is belicved thet some, mostly symmnetrio, wavefoims have dips in the ariddle due to an "annalar" type eaamwhaetbe Q eftbe imerradiu4ofthe eom is diAreat from the Q of tbe outcx annulis. It is believod that, in some cases, btmps on the leading and trailing edges of tbe Q wavefoans may be relatod to the rim of the coin ar the thiclmesa ef plating or laminatian near the rim of the ooia In some embodicnents the oul{ag data is mffimced by relatively small-scale eoin dboutmutes such as plating thiclamor siaface relief. In some cincumstanoes it is believed thet sarface relief iofamatiaa can be used, c.g, to distinguish the face of the ooin, (to distinguish "heads" from "tails") to distinguish old coins firamm new coins of the same denominatioa and the like. In aQder to prevent rotational orientation of the coin fnmi interfaing with proper surface relief analysis, it is preferable to coratruct seosocs to provide data which is averagad over amular regions such as a ca&aUy sym<uetrio sanar a aeray of sensm configumd to pmvide data averaged in aanu]ar zegioa4 centcred on the coin face eentex.
5 Although Fig. 5 depicts oae fashion of obtaining a signal related to Q, odxr circuits can also be used In the embodiment depicted in Fig. 5, a sinusoidal voltage is applied to the sensor coi1220, e.g., using an oscillator 1102. The wavefam afthe ctarent in the ooi1220, will be affected by the pnesece of a coin or other object adjacent the gap 216, 316, as described above. DifferaN phase components of the resiilting cuareot wave fam can be, used to obtain data related to inductence and Q respectively.
In the depicted embodimeot, 10 the cutrent in the coil 220 is decmposed into at least two components, a first componeat which is in-phase with the output of the oscillator 1102, and a secand component which is delayed by 90 degrees, with respeat to the ouilnrt of the a cillatar 1102. =1bese cwVonents can be obtained using phase-sensitive amplifiars 1104, 1106 sueh as a phase locked loop device and, as needed, a phase shift or delay device of a type well known in the art. The in-phase component is related to Q, and the 90 degree lagging component is related to 15 inductanoe. In one embodiment, the output from the phase discriminators 1104, 1106, is digitized by an analog-to-digital converter 1108, and processed by a microprooessor 1110. In one implementation of this technique, meLwuesnents are takea at meey fivquenaes. Each frequency drives a resistor oounected to the coil.
Tbe other end af the eoil is grnnuoded. For each fiequency, there is a dedicated "receiver" that detoets the I and Q signals. Alteiaatively, it is posdble to aaalyze all frequencies simultaneously by emplcrying, e.g., a fast 20 Fourier transform (FFT) in the micxoprocessor. In another embodiment, it is possible to use an impedance analym to read the Q (or "loss taugent") and inductanoe of a coil.
In another embodiment, depicted in Fig. 12, infoimation regarding the coin parameters is obtained by using the seasor 1212 as an indaotor in an LC oscillator 1202. A number of types of LC oseillatois can be used as will be apparent to those of skill in the art, after unde:*andieg the present disclosure. Although a 25 transistar 1204 has been depicted, other amplifieas such as op amps, can be used in different configurations.
In the depicted embodiuaeat, the seasar 1212 has been depicted as an inriuetor, since pm,moe of a coin in the vicinity of the sensor gap will affect the induetanex. Sincx the resonant frequency of the oscillator 1202 is related to the effective indaotauce (frequency varies aa (1/LCr): as the diameter of the coin inereases, the Erequency of the osoillator increases. The amplitude of the AC in the resonant LC eircuit, is affected by the 30 conductivity af objects in the vicinity of the sausor gap. The frequency is detected by frequency detector 1205, and by amplitude detector 1206, using well known electronics teohniques with the results preferably beiag digitized 1208, and processed by micropmce9sar 1210. In one embodiment the oseillation loop is completed by amplifying the voltage, using a hard-limiting amplifier (square wave output), which drives a resistor.
Changes in the magoitade of the indnctance caused the oscillator's frequency to ehange. As the diameter of 35 the Oest coin inaeaaes, the 5"aaic,y of the oscillator increases. As the conductivity of the test coin decreases, the amplitude of the AC voltage and the tuaed circuit goes down. By having a hard-limiter, and having a current limiting mmstet that is much Iarger than the resonant impodanoe of the tunod c'tt cuit, the amplitude of the signal at the resonant circuit substantially accurately indicates, in inverse relationship, the Q of the conductor.
Although one momer of analyzing D and Q signals using a micmpioceasor is described above, a vprooessor can use the data in a number of other ways. Although it would be possible to use focmulas or statistical regressions to calculate or obtain the numerical values for diameter (e.g., in inches) and/a canductivity (ag., in mhos), it is oa-tanplatod Wat a 8cquwt use of the present invention will be in caonection with a coin covnter or handler, which is intended to 1) discaiminate coins from non-coin objects, 2) discriminate domestic from foreign coins and/or 3) discriminate one coin denomination from another.
Aecordingly, in one embodimeat, the micYopeocessor oompares the diameter-indicating data, and conductivity-inificitting data, with staodatrl data indicative af eoududivity and diameter for various lanown eoins. Although it woiild be possible to use the microprooessor to convert detected data to standard diameter and caiducdvity values or units (such as inc}xs or mbos), and compare with data which is stored ia memory in standard values or units, the conversion step can be avoided by staring in memory, data eharactmistic of various coins in the same values or units as the data reoeived by the microprocessor. For example, whea the detector of Fig. 5 aad/or 6 outputs values in the range of e.g., 0 to +5 volts, the standard data charaoteristic of various lcnown coins can be oonvated, prior to storage, to a scale of 0 to 5, and stored in that form so that the comparison can be made directly, without an additional step of canversion.
Although in one embodiment it is possible to use data from a single point in time, such as when the coin is acntaed on the gap 216, (as indicatad, e.g., by a relative maximum, or minimum, in a signal), in aaother embodiment a plurality of values or a eontinuous sigaal of the values obtained as the coin moves past or through the gap 216 is preferably used.
An example of a single poiot af oompansan for each of the in-phase aod dela}rod detector, is depicted in Fig. 13. In this figure, standard date (stored in the computer), indicates the avarage andJor acceptance or tolerance range of in-phase amplitudes (indicative of conductivity), which has been found to be asaociat.ed with U.S. penoies, nickels, dime.s and quar4xs, resnectively 1302. Data is also stored, indicating the average and/or aeeeptancx or tolerance range of values output by the 90 degree delayed amplitude detector 406 (indicative of diematec) associated with the same coins 1304. preferably, the emelope or tolerance is sufficiently broad to lessea the aecu<nanee of false negative results, (which can arise, e.g., &om worn, misshapen, or dirty coins, elecUronic noise, and the like), but sufficiently narrow to avoid false positive results, and to avoid or reduce substantial overlap of the envelopes of two or more curves (ia order to pmvide for discrimination between demmina>ieas). Although, in the figures, the data stared in the computer is shown in graphical feam, for the sake of clarity of disclosure, typically the data will be stored in digital form in a memory, in a manner well known in the computer art. In the embodiment in which only a single value is used for discrimination, the digitized single in-phase amplitude value, which is detected for a particular coin (in this example, a value of 3.5) (soaled to a range of 0 to 5 and digitizod), is compared to the standard in-phase data, and the vah:e of 3.5 is found (using programming techniques known in the art) to be consistent with either a quarter or a dime 1308. Similarly, the 90-degree delayed amplitude value which is detected for this same coin 1310 (in this example, a value of 1.0), is compared to the standard in-phase data, and the value of 1.0 is fouad to be consistent with either a penny or a dime 1312. Thus, although each test by itself wouid yield ambiguous residts, since the single detoctor provides iefocmation on two parameters (one related to conductivity and me related to diameter), the disefimination can be made unambiguously since there is only one denomination (dime) 1314 wbich is consistent with both the conductivity data and the diameter data.
As noted, rather than using single-point companisons, it is possible to use multiple data points (or a continuars c,urve) geaetated as the coin moves past or through the gap 216, 316. Profiles of data of this type can be used in several different ways. In the example of Fig. 14, a plurality of known deaominations of coins are sent through the disoriminatiag device in order to accumulate standard data profiles for each of the denaminatiana 1402a, b, c, d,1404a, b, c, d These represent the average ehange in output from the in-phase amplitude deteatoc 1104 and a 90-deg+ee delay detector for (shown on the vertical axes) 1403 and aocxptaoce rao cs or toleraocea 1405 as the coins move past the dewor over a period of time, (shown on the hori;ontel axis). In order to discriminate an imlmown coin or other object, the object is passed through or across tha defedot and each of the in-phase amplitude detectar 1104 and 90-degrx delayed amplitude detector 1106, respectively, produce a curve or profile 1406,1410, respectively. ln the embodiment depicted in Fig. 8, the in-phase pmfile 1406 8coetated as a coin passes the detedor 212, is compared to the various staudard profiles for different coins 1402a, 1402b, 1402c, 1402d. Comparism can be made in a number of ways. In one embodiment, the data is scaled so that a horizootal axis between initial and fmal threshold values 1406a equals a standacd time, far better matcbing with the standa<d values 1402a through 1402d The profile shown in 1406 is then compared with standard proSles stored ia menmory 1402a through 1402d, to determine whether the deteoted ptofile is within the aooeptabk eavelopes defaned in any of the curves 1402a through 1402d. Another method is to calculate a closeness of fit parameter using well kaown curve-fitting teahniques, and selecx a deaominatim or several deaomiaations, which most closely fit the sensed profile 1406. Still another method is to select a phaglity of points at predetecmined (sealed) intervals aioog the time axis 1406a (1408a, b, c, d) and compare these valoes with eomespanding time points for each of the denaminsfions. In this case, only the standard values and tolerances or envelapes at such predetermined times needs to be stored in the computer memary. Using any or all these methods, the comparison of the seosed data 1406, with the stored standard data 1402a threugh 1402d indicates, in this example, that the in-phase sensed data is most in accord with stsudavd data bor quacteis ar dimes 1409. A similar comparisaa of the 90-degree delayed data 1410 to stored sfandatd 90-depree delayed data (1404a through 1404d), indicates that the sensed coin was either a penny or a dime. As before, using both these results, it is possible to determine that the coin was a dime 1404.
In am embodimeat, tho in-pbase and out-of-phase data are correlat.ed to provide a table or graph of in-phase amplitude versus 90-degree delayed amplitude for the sensed coin (similar to the Q versus D data depicted in Figs l0A and l OB), which can then be coznpared with standard in-phase versus delayed profiles obtained for various coin denominatioas in a maaner similar to that discu.ssed above in conaeotion with Figs l0A and IOB.
Although coia acceptance regions are depicted (Figs. 10A, lOB) as rectangular, they may have any shspe.

In both the configuration of Fig. 2 and the canfiguration of Figs. 3 and 4, the presence of the coin affeots the magnetic field. It is believed tbat in some cases, eddy currents flowing in the coin, result in a smaller inductance as the coin diameter is larger, and also result in a lower Q of the inductor, as the canductivity of the coin is lower. As a result, data obtaiaed from either the sensor of Figs. 2A and 213, ar the sensor of Figa 3 aod 4, can be gathered and analyzed by the apparatus.
depicted in Figs. 5 ard 6, even though tbe detected changes in the oonfigaration of Figs. 3 and 4 will typically be smaller than the ohanges detected in the configuration of Figs. 2A and 2B.
Althougb oertain sensor shapes have been desaibed herein, the techniques disclosed for applymg multiple Bequencies on a single core could be applied to and of a number of sensor shapes, or other means of forming an inductor to subject a coin to an alternating magnetic field.
Although an embodiment deacribed above provides two AC frequencws to a singk sceser core at the same time, other approaches are possibla One approach is a time division approach, in which diffemt fi+eqomcies are genaated during different, small time periods, as the coin moves past the sensor. This approach presents the diffiailty of aontrolling the oscillator in a"time-slice" fashion, and correlating time periods with Aequencies for adueving the desrted analysis. Another potential problem with time-multiplexing is the inhetent time it takes to accurately meawe Q in a resonant circuit. The higber the Q, the leoger it takes for tha oecillator's amplitade to setale to a stable value. This will limit the rate of switcbing and ultimately tba eoin tlnougbpat. In another embodiment; two separate sensor eores (1142 a,b Fig 11 A) can be provided, each with its own windiag 1144a, b and each driven at a different fi equency 1146a, b. This approach has not only the advantage of reducing or avoiding harmonic interference, but provides the opporUmity of optimizuzg the eooe mataials or ahape to piovido the best results at the frequency for which that cm is desigaed. When two or more frequencies are used, analysis of the data can be similar to that described above, with diffa+ent seta of standwd or refermce data being provided for each frequency. In one embodimeat, maltiple cores, such as the two cores 1142a, b of Fig 11 A, along the coin path 1148 are driven by different frequeneies 1146a,b that are phaso-locked 1152a, b to the same referanee 1154, such as a crystal or other refecence oscillator. In ane embodimeat, the eecallators 1154a, b that provide the co+e driving ficquencies 1146a,b are phase-locked by varactor tuning (e.g as described above) the oscillatars 1154a, b using the sensing iaduetor 1154 a, b as part of the frequenc.y determimation In me embodianeat, a sensor includes first and secood femte cores, each substantially in the shape of a eoction of a torus 282a, b (Fig. 2D), said first core defining a first gap 284a, and said second core defioning a secmd gap 284b, said cores poaitioned with said gaps aligaed 286 so that a coin eceveyed by said counting device will move through said first and second gaps; at least first and seewd coils 288a, b of conductive material wound about a first portion of each of said first and second cores, respectivelyr, an osciliator 292 a coupled to said first eoi1288a configured to provide mrent defining at least a first frequmcy da6ning a~rcst sldn depth less then said cladding didamss and wherein, when a coin is conveyed past said first gap 282a, the sigaal in said coil undergoes at least a first change in inductance and a change in the quality factor of said inductor; an oscillator 292b coupled to said second coil 288b configured to provide curreat de5ning_at least a second frequency defining a second skin depth greater than said first skin depth wherein.

when said coin is conveyed past said second gap 284b, the signal in said coil undergoee at least a second chsnge in induatance and a semnd change in the quality factac aI'said indaetor; and a proeessoc 294 configured to receive data indicative of said first aed secand changes in induetance and changes in quality factor to penmit separate characterizatian of said eladding and said core.
In anMher anbodiment, carrent provided to the coil is a substsntially constant or DC cwrent This configuration is useful for deteoting magnetic (ferromagoetic) v. non-magnetic coins. As the coin moves thcough or past the gap, thene will be eddy current effects, as well as pameability effeots. As discussed above.
these effeots esu be used to obtain, e.g., infacmation regarding eonductivity, such as core cauductivity. T6us, in this ooofiguratiaa such a sensor ean provide not only inforn-ation about the fenaima aetic or non magnetic nature of the coin, but also regarding the conductivity. Such a eonfigm-atien can be combined with a higb-frequency (skin efflect) excitation of the cam and, uxx thm would be no low-fivqnency (and thus no low fi+eqmey hatmonics) inmfere=problems would beavoided. It is also poasible to use two (or more) corea, one driven with DC, and another with AC. The DC-driven sensor provides atwtber parameter for discrimination (permeability). PermeabiGty meamement can be usefel in, for example, discrvminatiog between U.S. oaios and oatsin 6omgo coins or slugs. Preferably, computer proassing ia performed in order to renove "speed effacts.=
Although the inventien has been described by way of a prCfen-ed embodiment and c,mtsin veriatie s and modifications, other variations and modifications can also be used, the invention being defined by the following claims.

Claims (12)

1. A coin-handling apparatus comprising:
a first region for receiving a plurality of coins of a plurality of denominations in random orientation;
means for singulating at least some of said plurality of coins and transporting along a path toward at least a first sensing location;
at least a first sensor for receiving at least a first driving signal, for driving said sensor and providing sensor output, said sensor output including at least a first signal, said output being indicative of at least a first low-frequency coin characteristic and a second high-frequency coin characteristic;
circuitry coupled to said at least first sensor for receiving at least said sensor output and outputting at least a second signal indicative of whether a sensed object is an acceptable coin.

2. An apparatus as claimed in claim 1 wherein said driving signal is selected from the group consisting of:
a sinusoidal signal;
a triangle signal;
a sawtooth signal;
a pulse signal; and a squarewave signal.

3. An apparatus, as claimed in claim 1 further comprising means for providing a second sensor driving signal in a predefined relationship with said first driving signal.

4. An apparatus as claimed in claim 3 wherein said means for providing a second sensor driving signal in a predefined relationship with said first driving signal is selected from the group consisting of:
a phase locked loop circuit;
a frequency divider circuit; and means for combining first and second frequencies.

5. An apparatus as claimed in claim 1 further comprising means for separating at least first and second components of said sensor output.

6. An apparatus as claimed in claim 5 wherein said means for separating comprises at least first and second filters.

7. Apparatus as claimed in claim 1 wherein said sensor includes a magnetic core and first and second windings and wherein said first driving signal provides a signal at a first frequency to said first winding and further comprising means for providing a second driving signal, at a second frequency to said second winding.

8. Apparatus for sensing coins moving along a coin path comprising:
magnetic core means adjacent said coin path;
winding means coupled to said magnetic core means;
means for providing at least a first signal with a first frequency to said winding means;

means for tuning said means for providing; and means for using said winding means for frequency determination.

9. Apparatus as claimed in claim 8 wherein said means for tuning is selected from the group consisting of a varactor and a variable inductor.

10. Coin-handling apparatus comprising:
an input tray for receiving a plurality of coins of a plurality of denominations in random orientations;
means for transporting coins from said input tray to a coin pickup device;
said coin pickup device having a hopper for receiving coins in a random orientation and at least a first rail for delivering coins at an exit region of said first rail, with said coins in a substantially coplanar attitude and in single file;
at least a first sensor, spaced from said exit region, for providing at least a first signal indicative of at least a first coin characteristic;
means for providing kinetic energy to said hopper to assist in movement of sticky coins.

11. Apparatus as claimed in claim 10 wherein said means for providing kinetic energy comprises means for providing vibration to said hopper.

12. Apparatus as claimed in claim 11 further comprising a motor for use in moving coins in said hopper and wherein said motor is controlled to provide said vibration.