GB2139387A - Sobriety interlock - Google Patents

Abstract

Vehicle engine disabling means for preventing use of the associated vehicle in the event that the driver is intoxicated by alcohol comprises a breath sampling means including a mouth-piece 136, a restrictor passage 144 within said mouthpiece and a tubular extension therefrom defining a cylindrical space containing a thermocouple 135 which senses the temperature of the breath downstream of the restrictor passage and gas sensor 14 for determining the concentration of alcohol; said disabling means further comprising an analog-to-digital converter for converting the respective outputs of the thermocouple and the gas sensor to equivalent digital values, a microprocessor connected to receive said digital values and programmed to test over a prescribed standard period the alcohol concentration in a breath sample which maintains a specific temperature consistent with a deep exhaled breath for the prescribed period and an ignition enabling means for enabling ignition only in the event that the test carried out by the microprocessor shows that the driver is not drunk. The microprocessor also has a waiting program for disabling the vehicle for a prescribed period in the event that a trial for ignition has failed due to drunkenness of the driver. <IMAGE>

Description

SPECIFICATION Sobriety interlock Description of the Prior Art Automobile driving by intoxicated persons is a serious problem responsible for thousands of accidental deaths and extensive property damage every year, yet despite various preventive efforts the problem has defied solution. Many schemes have been suggested to prevent drunks from driving, but because the schemes have all involved some driver inconvenience, none has gained widespread acceptance. Alcohol intoxication can be detected in various ways, all suffering from some drawback. A practical preventive test must be executed automatically without supervision.

Reaction time and dexterity test results such as disclosed in U.S. Patents 3,665,447 and 3,610,943 respectively depend on individual abilities, are only indirectly related to degree of intoxication, and are not always meaningful. Alcohol intoxication is directly measured in a driver's breath by U.S. Patent 3,186,508 by measuring the optical property change of a chemical solution which is bleached by reacting with alcohol fumes. This system requires an inconvenient frequent change of the solution. U.S. Patent 3,823,382 tests intoxication directly by an exothermic reaction of chemical granules with alcohol in a breath sample with a mercury thermostat to measure the amount of heat generated. The thermostat must be replaced after a failed test. U.S.Patent 4,093,945, tests intoxication by oxidizing any alcohol in a breath sample and measures the heat given off by a change in the electrical resistance of a sensor.

That system is relatively complex and expensive.

In short, prior art drunk-driving prevention devices generally can be evaded, are inaccurate, unreliable, tedious, inconvenient, or complex and prohibitively expensive. For these and other reasons, no drunk-driving prevention system has gained wide-spread acceptance. There remains, therefore, a real need for a convenient, reliable, and inexpensive sobriety interlock system.

SUMMARY OF THE INVENTION It is the principal object of this invention to provide an improved sobriety interlock which takes advantage of a microprocessor to achieve convenient, reliable, and economical control over operation of automobiles or other machinery by inebriated persons. The microprocessor is programmed to make more flexible and advantageous use of breath sensors than was previously known. The interlock requires only a simple connection to an electrical starter system and derives its power from the starter system. No chemicals are used and routine replacement of material is not required. The microprocessor first tests breath temperature, using a thermocouple, to guard against circumvention of the test.When the temperature test is passed, the breath alcohol concentration is measured based on the balance between adsorption and desorption of ethanol at the surface of a semiconductor sensor. The balance causes a measurable resistance change.

Responsive to the alcohol concentration, the microprocessor either: activates a steady green light and enables the ignition for a sober driver; activates a blinking yellow light and enables the ignition for a tipsy but not drunk driver; or activates a steady red light, disables the ignition, and imposes a programmed wait before allowing the test to be attempted again. The test may be repeated, after waiting each time until passed.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of the sobriety interlock 10 used with a controlled system 100; Figure 2 is a preferred embodiment of the invention showing details of circuits that may be used for the blocks in Fig. 1; Figures 3, 4, 5, 6, and 7 are examples of alternative circuits that may be used for the blocks in Fig. 1; Figure 8 is a side elevational view, partly broken away and in section, of the sobriety interlock, showing the mouthpiece attached to a housing containing the electronic circuitry of the invention; and Figure 9 is a view similar to Fig. 8 but enlarged to show the placement of a thermocouple relative to a breath port or orifice.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention, a sobriety interlock 10, may be inserted as in Fig. 1 into a system controller, to test a human operator for sobriety and to prevent system use until the test has been passed. For example, the invention may be used in the ignition system 78 (Fig. 2) of an automobile, or in other machinery that should not be operated by intoxicated persons. The sobriety interlock is installed in an automobile 100 by disconnecting line 98 between the key switch 97 and the solenoid in the starter system 99. The ends of disconnected line 98 are reconnected to the input 89 and to the output 96 of an ignition enable circuit 90 controlled by microprocessor 80 (Figs. 1 and 2), preferably Intel Model No. 8048.The interlock uses five volt power line 5 supplied by power supply 40 which is connected directly to the 1 2 volt car battery, not shown, allowing the interlock to operate regardless of whether key switch 97 is closed. In low temperatures, contaminants gradually absorb into, and bias the characteristics of, sensor 14 (Fig. 2), which is preferably Model No. TGS 812 made by the Figaro Engineering Co.

Continuous standby activation of heater coil 1 5 (Fig. 2) by heater driver 70 keeps alcohol sensor 14 free of contamination.

One begins the sobriety test by turning the key in ignition switch 97. Referring to Fig. 2, the current in line 89 passes through clipper 26 which clips spikes and smooths the voltage level to produce an "ignition on" signal on line 27. "Ignition on" signal 27 resets processor 80 and starts it on a routine such as the program in Appendix A, which works with an Intel 8048 as processor 80. First, a "heater on" signal is applied through line 71 to driver circuit 70 for several minutes to heat coil 15 and sensor 14 from standby to ready condition. Computer 80 may activate heater driver 70 by a 12 volt supply from line 41 alternated with, or instead of, 5 volt line 5 in order to heat sensor 14 faster. During the heat-up period, computer 80 blinks the three LEDs 85 in rotation.Each LED preferably has its cathode connected through a 220 ohm resistor to a computer I/O pin, and its anode connected to the 5 volt supply. Even when free of previous contamination, the sensitivity of alcohol sensor 14 is affected by temperature.

Heater coil 15 maintains the sensor at a known constant temperature to minimise the effect of ambient air temperature. Heater 15 is turned off by a low voltage on driver 70, which pulls the base of transistor 74 low and prevents it from turning on the transistor. A high voltage on driver 70 provides sufficient current through resistor 73 and the base and emitter of transistor 74 for the transistor to conduct current to its grounded emitter from collector line 75, heater coil 15, and 5 volt supply 5 (or 12 volt supply 41). If alcohol sensor output line 16 were connected directly (not shown) to one of the computer input pins, the computer could measure the voltage drop across semiconductor sensor 14 to determine its resistance and thereby its temperature, indicating whether the sensor is ready.

When the sensor is heated and ready for a test, green LED 81 lights steadily. The prospective driver then breathes into port 1 2. To guard against circumvention of the sobriety interlock, a breath temperature sensor 20, preferably a type J monolithic thermocouple amplifier model AD954 by the Analog Devices Co., is used to measure the air temperature in breath port 1 2.

Temperature sensor 20 varies the voltage on line 22 according to the (breath) temperature at point 21 in breath port 12. To determine whether the temperature in port 12 is within a + 5'F range around normal 98 F human breath temperature, the line 22 test voltage is compared by temperature comparators 60 against a temperature floor reference 37 and a ceiling reference 39. The temperature references may be supplied through adjustable 5K ohm resistors 36 and 38 in a reference voltage supply circuit 30.

Fioor reference voltage 37, representing 95 F, is applied to the negative input terminal of comparator 67, and ceiling voltage 39, representing 105"F, is applied to the positive input of comparator 69. The temperature test voltage 22 is applied through respective resistors 23 and 24, both preferably 12K ohms, to the positive input of floor comparator 67, and to the negative input of comparator 69. Temperature voltages 22 above the floor and below the ceiling cause both comparators 67 and 69 to act as sources of current flowing out through resistor 65, preferably 9.1K ohms, to supply voltage line 5. This results in greater than 5 volts on "Temp OK?" line 68, which acts as a "wired AND" gate providing input to pin C28 of computer 80.

Although the temperature indication voltage on line 22 will always satisfy at least one of the comparisons and that comparator will raise the voltage on line 68, if the line 22 voltage does not also satisfy the other comparison, that other comparator will act as a sink and pull the line 68 voltage below the signal threshold of computer input pin C29. When "Temp OK" line 68 has remained high for the programmed number of seconds, LED display 85 changes from steady green to all three blinking in unison while the alcohol level is tested for about 1.5 seconds.

Rather than using comparators 50 and 60, voltage reference supply 30, and their output lines, A-D converter 25 may be used to supply digitized values of temperature 22 and alcohol 16. Computer 8Q is thus self-calibrating and would then compare against values stored internally.

The proportion of alcohol present in the breath is measured by gas sensor 1 3. Sensor 13 includes a tin dioxide semiconductor 14 whose resistance is changed by absorption and desorption of ethanol according to the gaseous concentration at the sensor surface (as well as the resistance being changed by temperature). The sensor output voltage on line 16 indicates the ethanol concentration. Current flowing to ground through resistors 1 7 and 19, preferably 1.5K ohms and 6.8K ohms respectively, reduces the voltage from line 16 to a lower voltage in line 18.

Empirical tests have determined that the breath of a person having a blood alcohol level of 0.05% (tipsy, but not considered legally impaired) will cause the sensor 14 to produce 3.1 volts on line 18. Testing a person having a 0.10% blood alcohol level will produce 1.9 volts on line 1 8. Reference voltage supply circuit 30 provides alcohol reference voltages 33 and 35, equal to these levels, derived through variable resistors 32 and 34 by which the references may be calibrated. Comparator 55 compres the alcohol level voltage on line 1 8 against the 0.05% (lower) standard on line 35, produces a current in its output line 56 through resistor 57 according to the outcome of the comparison.An alcohol level less than low reference 35 causes comparator 55 to act as a current sink, reducing the voltage in line 56 to less than 5 volts.

Conversely, a test result voltage 1 8 greater than low reference 35 causes comparator 55 to act as a current source raising the voltage in line 56 above 5 volts.

Comparator 53 operates similarly to cause a current through preferably 9.2K ohm resistor 52 and produce less than 5 volts in line 54 for alcohol test results less than the high reference in line 33, and more than 5 volts in line 54 for test results greater than reference line 33.

Microprocessor 80 uses the temperature verification signal 68 and the alcohol level comparison results 54 and 56 to decide whether the sobriety test has been passed. An alcohol level below 0.05% activates the green LED continuously, and a high voltage "OK to Drive" signal output on line 88 preferably through a 1 K ohm resistor 47. A high signal on line 88 to the base of transistor 91, preferably a 2N4401, and preferably current from the 5 volt supply through a 10K ohm resistor 48, cause the transistor to conduct current through its collector and a coil 92 in relay 93, preferably an AROMAT HBZE. Current flowing in coil 92 creates a magnetic field which attracts arms 94 towards contacts 95, completing the circuit around disconnected line 98.

A blood alcohol level between 0.05% and 0.10% provides a "tipsy" flashing yellow LED 82 which means that the vehicle should be driven with caution. A high "OK to Drive" signal enables relay 93.

If the blood alcohol level is above 0.10%, the breath test is failed and interlock 10 will not allow the car 100 to be started. "OK to Drive" line 88 is held low, and red LED 83 blinks. The key switch 97 must be turned off and back on again to bring computer 80 to a "power up condition and to restart the test. A four minute "long warm up" must be endured while heater 1 5 clears the sensor and hopefully the kidneys clear the blood, of alcohol contamination.

A preferred embodiment of the structure defining the mouthpiece and the support for the electronic circuitry of sobriety interlock 10 is shown in Figs. 8 and 9. This structure includes a housing 110 which is of a suitable material, such as rigid plastic, and which is rugged in construction. The housing is provided to contain and to protect the circuit boards and other electronic components contained therewithin against damage, such as in the event that the housing is dropped on a surface. One of the circuit boards 11 2 is shown in Fig. 8 within housing 110. A cable 114 having leads 11 6 extending outwardly therefrom connects the electronic circuitry with an external power source, such as the battery of a vehicle, and also connects the circuitry with the ignition system of the vehicle.

Housing 110 has a tubular neck 11 8 to which a tubular extension 1 20 is secured. Member 1 20 is rigid and can be formed from any suitable material, such as aluminum. For purposes of illustration, extension 1 20 includes a metallic member 121; such as of aluminum and a rigid plastic member 123 secured to and extending outwardly from one end of member 1 21. The outer surface of member 1 21 has annular ribs 1 22 thereon to help in dissipating heat absorbed in the member.

Sensor 14 is mounted in any suitable manner, such as by a press fit within member 1 21 near the outer open end thereof. Gas sensor 14 is adjacent to a number of spaced openings 1 24 through member 1 21 so that the space 1 26 adjacent to the outer face of gas sensor 14 communicates with the atmosphere to assist in cleaning the sensor as hereinafter described.

Member 1 23 contains a tubular, heat insulating element 1 30 typically of cork for shielding a portion of the breath temperature sensor 20 which is coupled by leads 1 32 to the circuitry in housing 110, leads 1 32 extending through member 1 20 as do a pair of leads (not shown) coupled with gas sensor 14. Such leads are connected to the circuitry contained in housing 110. Temperature sensor 20 includes a thermocouple 1 34 as shown in more detail in Fig. 9.

A mouthpiece member 1 36 is secured to the outer end of member 1 23 and has an outer end 1 38 over which the mouth is placed for blowing a breath sample into a mouthpiece member 136. An internal bore 140 in mouthpiece 136 contains a tubular element 142 having a fluid flow passage 144 therethrough, whereby the breath sample under pressure in a bore 140 can enter the space 146 containing thermocouple 1 34.

Thermocouple 1 34 is shown in its preferred location in Fig. 9 at the downstream end of passage 144. It can be seen from Fig. 9 that the thermocouple junction 1 35 is physically at the end of passage 144. The reason for this is that the thermocouple will be immediately sensitive to the temperature of the breath before the breath expands into space 146 and is thereby cooled.

Thermocouple 1 34 has a heating element 148 in heat exchange relationship thereto at a location spaced a short distance, such as .25 to .50 inch, from junction 135 as shown in Fig.

9. Heater 148 comprises a heating coil within a vacuum envelope 1 50 surrounding a portion of thermocouple 1 34. The purpose of heating coil 148 is to eliminate the tendency for sobriety interlock 10 to automatically turn itself on if the ambient temperature was about 98"F. To eliminate this problem, the heater 148 is placed in heat exchange relationship to the thermocouple, specifically to both wires thereof, to heat the thermocouple to a temperature above the 98" normal breath temperature.FOr example, it can be heated to 130"F and this is controlled by microprocessor 80 so that the temperature of the heated portion of the thermocouple remains at about 130 F. A small transistor can be switched on and off to regulate and stay at this temperature level, this heating being done by conduction to the junction 1 35 of the thermocouple. Thus, when a person blows into mouthpiece member 1 36 with the breath temperature at about 98"F, the thermocouple cools down from the 1 30'F temperature so that sobriety interlock 10 can then commence a valid test.

Another important feature of the structure shown in Figs. 8 and 9 is the use of passage 144 which typically has a diameter of .075" to .130". Thus, passage 144, which provides, in effect, a small orifice, forces a person to blow into the mouthpiece such that a slight air pressure is developed in the mouthpiece member. This forces the lips of the person to maintain an air seal about the mouthpiece member so as to prevent outside air from entering the breath sample directed into and through passage 144. Outside air would otherwise alter the results of the operation of sobriety interlock 10.

Passage 144, because it has a finite length, directs the breath flow onto the thermocouple junction 1 35 and then through extension 1 20 and onto gas sensor 14. To do this, a temperature of 95"F must be sensed by the thermocouple for a period of at least four seconds so that a deep lung breath sample is measured. Since openings 124 (Fig. 8) are provided in member 121, the gas sensor will be in free air which is essential for cleanup of the sensor. With the use of openings 124, it is possible to conduct a first test and have the sensor cleaned up in order to make a next test in less than 1 5 seconds.

Another feature of the present invention with respect to the cleanup of gas sensor 14 involves the use of a frequency (about 10 to 100 Hz) controlled voltage source applied to the sensor during the cleanup period. This frequency controlled voltage source is used instead of a steady voltage source to heat the sensor. Ordinarily, with a steady voltage, the cleanup period is about ten seconds as recommended by the manufacturer of the gas sensor. By using a frequency controlled, variable voltage source generated by microprocessor 80 to heat the sensor, this cleanup time is cut to less than five seconds. It is also possible to improve the accuracy of the gas sensor results. This is done by using the microprocessor 80 to check the level at which gas sensor 14 is cleaned up to, at the time a test is started.This starting point has a significant bearing on the results of an alcohol breath test. In the analog to digital version of sobriety interlock 10, compensation for any variation to starting point can be adjusted automatically by the microprocessor 88.

Details have been disclosed to illustrate the invention in a preferred embodiment of which adaptions and modifications within the spirit and scope of the invention will occur to those skilled in the art. The scope of the invention is limited only by the following claims.

The program can also contain in software an option such that, if a vehicle is not operated for 48 hours or other time period, the automatic cleaning cycle for the gas sensor is overridden to prevent the drain on the battery of the vehicle which supplies power to the circuitry Thus, the circuit shuts itself off. The only disadvantage of this is that cleaning of the gas sensor may take a minute when the vehicle is next operated rather than 10 seconds for normal operation.

A control program for use with interlock 11) is shown on the following pages.

REGISTER USAGE REGISTER BANK ZERD 7 6 5 4 3 2 1 # COUNTER USED BY LONGWARMUP AND GRACEWAIT UTILITY COUNTER USED BY PORGE, ETC COUNTER FOR "WAIT 1 SEC BUT ABORT IGN ON/OFF" ROUTINES USED TO SAVE A DURING CLOCK INTERRUPT OUTPUT VALUE TO SEND TO P1 OUTPUT VALUE TO SEND TO P2 ALC > .10#ALC > .05# # #ALC10 #ALC#5 #TEMPOK #IGN ON BREATH TEST RESULTS # INPUT STATUS TEGISTER BANK ONE 7 6 5 4 3 2 1 # RED # XELLOW # GREEN # RED #YELLOW # GREEN # CYCLE # BLINK BASIC LED PATTERN # COURRENT LED PATTERN # LED ACTIVITY DOWN COUNTER USED BY "TICK" TO CONTROL LED TIMING COUNTER USED BY "WAIT .01 SEC" COUNTER USED BY "WAIT .01 SEC" COUNTER USED BY "WAIT 1 SEC" ADDRESS INSTR SOURCE COMMENTS 000 E5 POWERON: SEL MB0 POWER ON COMES HERE 001 04 JMP POWERUP 002 20 003 93 RETR DUMMY INTERRUPT SERVER 007 64 JMP TICK CLOCK TICK SERVER 008 40 020 E5 POWERUP: SEL MB0 021 C5 SEL RB0 022 BD MOV R5,*OF 023 OF 024 BE MOV R6, #00 025 88 026 BF MOV R7,#00 027 00 # 028 23 MOV A,#7D 029 7D # 02A 62 MOV T,A 02B 55 STRT T 02C 25 EN TCNTI 02D 00 NOP 02E 00 NOP 02F 00 NOP 030 54 LONGWARMUP:CALL SETLCYCLE START LEDS CYCLING 031 00 # Q32 54 CALL HEATON TURN ON HEATER 033 18 034 B8 MOV R0,#F0 START 4 MINUTE TIMEOUT #35 F# 036 74 LWU1: CALL WAITSEC WAIT 1 SECOND 037 88 038 E8 DJNZ R#, LWU1 LOOP TILL 4 MINUTES UP 039 36 # 03A 00 NOP 03B 80 NOP 03C 00 NOP 03D 80 NOP 03E 00 NOP 03F 00 NOP 040 54 IGNOFF: CALL SETLCYCLE START LEDS CYCLIND 041 00 042 BD MOV R5,#EF 043 EF # 044 BE MOV R6,#00 046 00 # 046 54 CALL PURGE 047 40 # 048 00 NOP 049 88 NOP 04A FF MOV A,R7 04B 12 JB# IGNON 04C 60 04D 04 JMP IGNOW 04E 40 04F 8Q NOP 060 14 IGNON:CALL SHORTWARMUP 061 D0 # 062 54 CALL BLINKGRN 063 08 # 064 00 NOP ADDRESS INSTR SOURCE COMMENTS 065 00 NOP 066 34 CALL TESTBREATH 067 00 # 068 00 NOP 069 00 NOP 06A FF MOV A,R7 06B F2 JB7 DRUNK 06C A0 06D D2 JB6 TIPSY 06E 78 # 06F 00 NOP 07# 00 SOBER: NOP 071 00 NOP 072 54 CALL STEADYGRN 073 28 # 074 00 NOP 075 00 NOP 076 04 JMP DRIVE 077 80 # 078 00 TIPSY:NOP 079 00 NOP 07A 54 CALL BLINKYEL 07B 30 # 07C 88 NOP 07D 88 NOP 07E 88 NOP 07F 00 NOP 080 54 DRIVE: CALL HEATOFF 081 18 # 082 FE MOV A,R6 083 43 ORL A, #10 084 10 # 085 AE MOV R6,A 086 00 WAITIGNOFF: NOP 087 00 NOP 088 FF MOV A,R7 089 12 JB# WAITIGNOFF 08A 86 # 08B 04 JMP GRACE 08C B0 # 0A0 00 DRUNK: NOP 0A1 00 NOP 0A2 54 CALL BLINKRED 0A3 38 # 0A4 FF DRUNK1:MOV A, R7 0A5 12 JBO DRUNK1 0A6 A4 # 0A7 8A MOV R2,#0A 0A8 0A # 0A9 EA DJNZ R2,* OAA A9 QAB 04 JMP LONGWARMUP 0AC 30 0B0 FE GRACE: MOV A,R6 DISABLE STARTER 0B1 53 ANL A,#EF 0B2 EF # 083 AE MOV R6,A 084 54 CALL HEATON 0B5 10 # 0B6 B8 MOV R0,#F0 4-MINUTE GRACE PERIOD ADDRESS INSTR SOURCE COMMENTS 0B7 F0 0B8 74 GRACEWAIT:CALL WISBAION MORE WAITING 0B9 30 OBA FF MOV A,R7 OBB 12 JB0 DRIVE IF IGN ON, GO START CAR 0BC 80 0BD E8 DJNZ RO, GRACEWAIT OBE B8 OBF 04 JMP IGNOFF 0C0 40 # 0D0 54 SHORTWARMUP: CALL HEATON 0D1 10 # 0D2 B8 MOV R0,#20 0D3 20 # 0D4 FF SWULOOP: MOV A,R7 0D5 37 CPL A 0D6 12 JB0 SWUEXIT 0D7 DC # 0D8 74 CALL WISBAIO 0D9 20 # ODA E8 DJNZ RO, SWULOOP 0D8 D4 0DC 83 SWUEXIT: RET 100 00 TESTBREATH:NOP 101 00 NOP 102 00 NOP 103 00 NOP 104 FF MOV A,R7 105 53 ANL A,#0F 106 OF 107 AF MOV R7,A 108 00 NOP 109 00 NOP 10A 00 WAITSTABLE: MOV R2,#32 10B BA # 10C FF WSLOOP: MOVA,R7 10D 37 CPL A 10E 12 JB0 TBEXIT 10F 32 # 110 32 JB1 WAITSTABLE 111 0A # 112 74 CALL WAIT01 113 10 114 EA DJNZ R2, WSLOOP 115 0C # 116 00 NOP 117 00 NOP 118 BA MOV R2,#98 START ALCOHOL TEST 119 96 11A FF ALCLOOP:MOV A, R7 11B 37 CAL A 11C 12 JB0 TBEXIT 11D 32 11E 32 JB1 WAITSTABLE 11F 0A # 120 00 NOP 121 00 NOP 122 37 COL A 123 53 ANL A,#0C 124 0C # ADDRESS INSTR SOURCE COMMENTS 125 47 SWAPA 126 4F ORL A,R7 127 AF MOV R7,A 128 00 NOP 129 00 NOP 12A 74 CALL WAIT01 12B 10 # 12C EA DJNZ R2, ALCLOOP 12D 1A # 12E 00 NOP 12F 00 NOP 130 00 NOP 131 00 NOP 132 34 TBRET CALL BLINKALL 133 F8 134 74 CALL WISBAIO 135 20 # 136 74 CALLWISBAIO 137 20 138 88 NOP 139 00 NOP 13A 83 RET 1F8 D5 BLINKALL:SEL RB1 1F9 B8 MOV R0,#FD 1FA FD 1FB C5 SEL RB0 1FC 83 RET 200 D5 SETLCYCLE: SEL RB1 201 B8 MOV R0,#26 202 26 203 B9 MOV R1,#01 2o4 91 205 C5 SEL RB0 206 83 RET 208 D5 BLINKGRN: SEL RB1 209 B8 MOV R0,#25 28A 25 208 C5 SEL RB0 20C 83 RET 210 FD HEATON: MOV A, R5 211 43 ORL A,# 10 212 10 # 213 AD MOV R5,A 214 83 RET 218 FD HEATOFF: MOV A,R5 219 53 ANLA,*EF 21A EF 21B AD MOVR5,A 21C 83 RET 220 D5 LEDSOFF:SEL RB1 221 88 MOV R0,#0 222 00 # 223 C5 SEL RB0 224 83 RET 228 D5 STEADYGRN SEL RB1 ADDRESS INSTR SOURCE COMMENTS 229 B8 MOV R0,#24 22A 24 22B C5 SEL RB0 22C 83 RET 230 D5 BLINKYEL: SEL RB1 231 B8 MOV R0,#49 232 49 233 C5 SEL RB0 234 83 RET 238 D5 BLINKRED: SEL RB1 239 B8 MOV R0,#91 23A 91 23B C5 SEL RBO 23C 83 RET 240 00 PURGE: NOP 241 00 NOP 242 54 CALL HEATON 243 10 # 244 B8 MOV RO,&num;OS CYCLE 5 SECONDS ON 245 05 246 FF PONLOOP:MOV A,R7 247 12 JB0 PURGEXIT 248 58 249 74 CALL WISBAION 24A 30 24B E8 DJNZ RO,PONLOOP 24C 46 24D 54 CALL HEATOFF 24E 18 24F 88 MOV R0,#F0 250 F0 251 FF POFFLOOP: MOV A,R7 252 12 JB0 PURGEXIT 253 58 254 74 CALL WISBAION 255 30 256 E8 DJNZ R0, POFFLOOP 257 51 258 83 PURGEXIT: RET 300 D5 WAITISEC: SEL RB1 301 BF MOV R7,#64 302 64 # 303 C5 SEL RB0 304 74 WISECLOOP; CALL WAIT01SEC 305 10 # 306 D5 SEL RB1 307 EF DJNZ R7,WISECLOOP 308 O4 # 309 C5 SEL RB0 38A 83 RET 310 D5 WAIT01SEC:SEL RB1 311 BE MOV R6,#08 312 08 # 313 BD WOlSECLOOP: MOV R5,#FA 314 FA 315 ED DJNZ RT,* 316 15 317 EE DJNZ R6, WOISECLOOP ADDRESS INSTR SOURCE COMMENTS 318 13 319 C5 SEL RB0 31A 83 RET 320 88 WISBAIO: NOP 321 00 NOP 322 BB MOV R3,&num;64 323 64 324 74 WISBAIOLP: CALL WAIT01SEC 325 10 326 FF MOV A,R7 327 37 CPLA 328 12 JB0 WISBAIORET 329 2C 32A EB DJNZ R3,WISBAIOLP 32B 24 32C 83 WISBAIORET: RET 330 00 WISBAION: NOP 331 88 NOP 332 BB MOV R3,&num;64 333 64 334 74 WISBAIONLP: CALL WAIT01SEC 335 10 336 FF MOV A,R7 337 00 NOP 338 12 JB0 WISBAIONRET 339 3C 33A EB DJNZ R3,WISBAIONLP 338 34 33C 83 WISBAIONRET: RET 340 C5 TICK: SEL RB0 341 AC MOV R, A 342 FF MOV A,R7 343 53 ANL A,&num;FO 344 FO 345 AF MOV R7,A 346 09 IN A,PI 347 53 ANL A,#0F 348 OF 349 4F ORLA,R7 34A AF MOV R7,A 348 23 MOVA,&num;7D 34C 7D 34D 62 MOV T,A 34E FD MOV A,R5 34F 39 OUT P1,A 350 FE MOV A,R6 351 3A OUT P2,A 352 00 NOP 353 00 NOP 354 00 NOP 355 00 NOP 356 00 NOP 357 00 NOP 358 00 NOP 359 00 NOP 35A 00 NOP 358 88 NOP 35C 00 NOP 35D 00 NOP ADDRESS INSTR SOURCE COMMENTS 35E 00 NOP 35F 00 NOP 360 D5 DOLEDS:SEL RB1 361 E9 DJNZ R1,DONELEDS 362 98 363 F8 MOV A,R0 364 12 JB0 BLINK 365 72 366 32 JBLCYCLE 367 80 368 53 STEADY: ANL A,&num;E3 369 E3 36A A9 MOVR1,A 36B 77 RR A 36C 77 RR A 36D 77 RR A 36E 53 ANL A,#1C 36F 1C # 370 64 JMP SETLED 371 90 # 372 A9 BLINK:MOV R1,A 373 77 RR A 374 77 RR A 375 77 RR A 376 53 ANL A,#1C 377 1C # 378 D9 XRL A,R1 379 53 ANL A,#1C 37A 1C # 37B 64 JMP SETLED 37C 90 380 A9 CYCLE: MOVR1,A 381 E7 RLA 382 53 ANL A,&num;18 383 18 384 96 JNZ SETLED 385 90 386 23 MOV A,#04 387 04 # 388 64 JMP SETLED 389 90 390 A8 SETLED: MOV RO,A 391 F9 MOV A,R1 392 53 ANL A,#E3 393 E3 394 48 ORL A,R0 395 A8 MOV R0,A 396 B9 MOV R1,#0A 397 OA 398 C5 DONELEDS:SEL RB0 399 FD MOV A,R5 39A 43 ORL A,#E0 39B EO 39C AD MOV R5,A 39D FF MOV A,R7 39E 67 RRCA 39F E6 JNC DONETICK 3A0 00 NOP 3A1 00 NOP 3A2 88 NOP ADDRESS INSTR SOURCE COMMENTS 3A3 00 NOP 3A4 D5 SEL RB1 3A5 F8 MOV A,R0 3A6 C5 SEL RB0 3A7 53 ANL A,#1C 3A8 1C # 3A9 E7 RLA 3AA E7 RLA 3AB E7 RLA 3AC DD XRL A,R5 3AD AD MOV R5,A 3AE 88 NOP 3AF 88 NOP 380 FC DONETICK:MOV A,R4 3B1 93 RETR ******************* END OF PROGRAM *******************

SOBERLIZER PROGRAM FLOW CHART *************************************************************** ±---------+ # POWER ON # ±---------+ # ±---------+ @@@@@@@@@@@@ I START CLOCK I # 10 MS. TICK # ±------------+ # ±-------------------+ # SET L.E.D..CYCLING # ±-------------------+ ±--------------+ @@@@@@@@@@@@@@@@@ ITURN ON HEATERSI -------------------+ ±---------------------------# @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IWAIT 2 MINUTES TO HEAT UPI ±----------------------------+ # ±----------------------------+ IGNITION # WAIT TILL IGNITION ON # OFF--------- CYSLE HEATER OFF & ON # # # ±----------------------------+ # IGNITION ±----------------------------+ ON --------# SET GREEN L.E.D. FLASHING # ±----------------------------+ # ±--------------------------------+ # WAIT FOR TEMP. OK & STABLE # ±--------------------------------+ # ±--------------------------------+ # TEST ALCOHOL FOR 1 SEC. # # IF TEMPT. NOT OK, GO BACK TO # # PREVIOUS STEP SET ALL L.E.D. # I FLASHING FOR 1 SECOND I ±----------------------------------+ # ±----------------------------------+ I --- LCOHOL LEVEL---- I + + < .05 > .05 > .10 (.10 TO SOBER TO TIPSY TO DRUNK

TO SOBER TO TIPSY TO DRUNK # \ SOBER: # \ TIPSY: ±-------------------------------+ ±--------------------------+ # TURN GREEN L.E.D. ON STEADILY# # # START FLASHING YELLOW LED # ±-------------------------------+ ±--------------------------+ \ / ±------------------------+ # ENABLE STARIER # ±------------------------+ # ±----------------------------------+ # WAIT FOR IGNITION TO GO OFF # ±----------------------------------+ # ±-----------------------------------+ # WAIT 1 MINUTE, IF IGNITION TURNS # # BACK ON, GO BACK TO PREVIOUS STEP # ±-----------------------------------+ # ±--------------------------+ # TO IGNITION OFF # ±--------------------------+ ±--------------------------+ DRUNK---------## STEADY RED L.E.D. # ±--------------------------+ # ±--------------------------+ # WAIT FOR IGNITION OFF # ±--------------------------+ CLOCK (ONCE EVERY .01 SECOND ********************************* ±-----------------------------------+ #TEST ALL INPUTS & RECORD VALUES # ±-----------------------------------+ # ±---------------------------------------------+ # HAS ENOUGH TIME EIAPS ED TO CHANGE L.E.D.? #----NO----+ -----------------------------------------------+ # YES # # ±--------------------------------+ # #CHANGE L.E.D.STATE AS APPROPRIATE# # ±--------------------------------+ # # # ±-----------------+ # # IS IGNITION ON ? ##------------------------+ ±-----------------+ YES / \ NO ±----------------------+ ±--------------------------+ # ENASLE L.E.D.S # # DISABLE L.E.D.S. # ±----------------------+ ±--------------------------+ \ / ±------------------------+ # EXIT # ±------------------------+

Claims (27)

1. A sobriety interlock comprising: a power supply; a ground terminal; an "ignition on" input terminal; an "OK to drive" output terminal; means defining a breath receiving port; a temperature sensor adjacent and aligned with said port, said temperature sensor being connected to said power supply and said ground terminal and having a temperature output line for electrical signals generated in response to the temperature of a breath sample flowing through said port; a gas sensor adjacent to and aligned with said port, said gas sensor being connected to said power supply and said ground terminal and having an alcohol level output line for electrical signals generated in response to the alcohol level of a breath sample flowing through said port;; an analog-to-digital converter having a first input connected to the temperature sensor output line, a second input connected to the gas sensor output line, and a plurality of output lines for digital signals indicating the temperature and alcohol level of a breath sample flowing through the port; a microcomputer responsive to a signal at the "ignition on" terminal to read the digital signals on the converter output lines and to provide a signal at said "OK to Drive" terminal as a function of whether the alcohol level in a breath sample is different from a predetermined value, the computer having a plurality of gauge output lines for providing signals indicating computer operating states.

2. An interlock as in claim 1 further comprising: a clipper circuit connected to said "ignition on" terminal; an "ignition enable" circuit connected to said "OK to Drive" line; and wherein said clipper circuit is adapted to be connected to the key switch in a motorized vehicle, and said "ignition enable" circuit is adapted to be connected between the key switch and the starter solenoid in the vehicle.

3. An interlock as in claim 1 further comprising a heater drive circuit connected between said power supply and said gas sensor, said driver circuit being responsive to a signal from said computer to provide a current to said gas sensor, and wherein said gas sensor has a heating element powered by the heater drive.

4. An interlock as in claim 1 further comprising: a separate INDICATOR connected to each of the plurality of gauge output lines of the computer.

5. An interlock as in claim 1 wherein said analog to digital converter comprises: a voltage reference circuit connected between said power supply and said ground terminal and having separate output lines on which said reference circuit provides electrical signals indicative of each of: an alcohol high reference; an alcohol low reference; a breath temperature high reference; a breath temperature low reference; an alcohol comparator circuit connected to the alcohol sensor output line and having a first comparator connected to compare the alcohol sensor output to the alcohol high reference; a first alcohol output line to which the first comparator applies a signal indicative of the high comparison result; a second comparator connected to compare the alcohol sensor output to the alcohol low reference; and a second alcohol output line to which the second comparator applies a signal indicative of the low comparison result; a temperature comparator circuit connected to the temperature sensor output line and having a third comparator connected to compare the temperature sensor output to the temperature high reference; a fourth comparator connected to compare the temperature sensor output to the temperature low reference; and a temperature output line to which said temperature comparator applies a signal indicative of the temperature comparison results.

6. A sobriety interlock as set forth in claim 1, wherein said port defining means comprises a mouthpiece member having a fluid passage therein for receiving a breath sample, said temperature sensor being near the downstream end of said fluid passage.

7. A sobriety interlock as set forth in claim 6, wherein the temperature sensor includes a thermocouple having a junction near the downstream end of said fluid passage.

8. A sobriety interlock as set forth in claim 7, wherein the junction of the thermocouple is in the fluid passage at said downstream end thereof.

9. A sobreity interlock a set forth in claim 8, wherein the thermocouple has means spaced from the junction for heating the same so that the junction will be at a temperature different from the temperature of a normal breath sample passing through said fluid passage.

10. A sobriety interlock as set forth in claim 9, wherein said heating means includes a sealed envelope surrounding a portion of the thermocouple, and en electrically actuated heating device within the envelope in heat exchange relationship to the thermocouple.

11. A sobriety interlock as set forth in claim 9, wherein is included a heat insulating tubular member in surrounding relationship to said heating means.

1 2. A sobriety interlock as set forth in claim 6, wherein is included a tubular extension secured to the mouthpiece and extending outwardly therefrom, said temperature sensor extending through at least a portion of said extension, said gas sensor being in said extension downstream of the temperature sensor with reference to the direction of flow of a breath sample passing through the extension.

1 3. A sobriety interlock as set forth in claim 6, wherein is included a housing coupled to the outer end of the extension, said housing containing said converter and said microcomputer, said housing being of a size and weight to permit it to be hand-held as a person blows into the mouthpiece member to deliver a breath sample thereto.

14. A sobriety testing apparatus comprising: a support; an elongated, tubular mouthpiece mounted on the support and extending outwardly therefrom, said mouthpiece having a breath-receiving port; means defining a source of electrical power; a temperature sensor carried by the support adjacent to and aligned with said port, said temperature sensor being coupled with said power source and having a temperature output line for electrical signals generated thereby as a function of the temperature of a breath sample passing through said port; a gas sensor carried by the support adjacent to and aligned with said port, said gas sensor being coupled with said power source and having an alcohol level output line for electrical signals generated thereby as a function of the alcohol level of a breath sample passing through said port;; an analog-to-digital converter having a first input connected to the temperature sensor output line, a second input connected to the gas sensor output line, and a plurality of output lines for digital signals indicating the temperature and alcohol level of a breath sample passing through the port; and a microcomputer responsive to an input signal for reading the digital signals on the converter output lines and to provide an output signal indicative of whether the alcohol level in the breath sample passing through said portion is different from a predetermined level, the computer having a plurality of gauge output lines for providing signals indicating computer operating states.

1 5. An interlock as in claim 14, further comprising: a clipper circuit, an enable circuit, said clipper circuit adapted to be connected to a switch, and said enable circuit is adapted to be connected between the switch and another operable electrical component.

16. Apparatus as in claim 14, further comprising a heater drive circuit connected between said power source and said gas sensor, said drive circuit being responsive to a signal from said computer to provide a current to said gas sensor, and wherein said gas sensor has a heating element powered by the heater drive.

17. Apparatus as in claim 14, further comprising: a separate INDICATOR connected to each of the plurality gauge output lines of the computer.

1 8. Apparatus as in claim 14, wherein said analog to digital converter comprises; a voltage reference circuit connected to said power source and having separate output lines on which said reference circuit provides electrical signals indicative of each of: an alcohol high reference; an alcohol low reference; a breath temperature high reference; a breath temperature low reference; an alcohol comparator circuit connected to the alcohol sensor output line and having a first comparator connected to compare the alcohol sensor output to the alcohol high reference; a first alcohol output line to which the first comparator applies a signal indicative of the high comparison result; a second comparator connected to compare the alcohol sensor output to the alcohol low reference; and a second alcohol output line to which the second comparator applies a signal indicative of the low comparison result; a temperature comparator circuit connected to the temperature sensor output line and having a third comparator connected to compare the temperature sensor output to the temperature high reference; a fourth comparator connected to compare the temperature sensor output to the temperature low reference; and a temperature output line to which said temperature comparator applies a signal indicative of the temperature comparison results.

1 9. Apparatus as set forth in claim 14, wherein said mouthpiece has a fluid passage therein for receiving a breath sample, said temperature sensor being near the downstream end of said fluid passage.

20. Apparatus as set forth in claim 19, wherein the temperature sensor includes a thermocouple having a junction near the downstream end of said fluid passage.

21. Apparatus as set forth in claim 20, wherein the junction of the thermocouple is in the fluid passage at said downstream end thereof.

22. Apparatus as set forth in claim 21, wherein the thermocouple has means spaced from the junction for heating the same so that the junction will be at a temperature different from the temperature of a normal breath sample passing through said fluid passage.

23. Apparatus as set forth in claim 22, wherein said heating means includes a sealed envelope surrounding a portion of the thermocouple, and an electrically actuated heating device within the envelope in heat exchange relationship to the thermocouple.

24. Apparatus as set forth in claim 22, wherein is included a heat insulating tubular member in surrounding relationship to said heating means.

25. Apparatus as set forth in claim 19, wherein said support includes a tubular extension secured to the mouthpiece and extending outwardly therefrom, said temperature sensor extending at least a portion of said extension, said gas sensor being in said extension downstream of the temperature sensor with reference to the direction of flow of a breath sample passing through the extension.

26. A sobriety interlock as set forth in claim 19, wherein said support includes a housing coupled to the outer end of the extension, said housing containing said converter and said microcomputer, said housing being of a size and weight to permit it to be hand-held as a person blows into the mouthpiece member to deliver a breath sample thereto.

27. A sobriety interlock apparatus substantially as disclosed herein with reference to the accompanying drawings.