CN102389317A - Real-time keystroke-pressure acquisition system - Google Patents
Real-time keystroke-pressure acquisition system Download PDFInfo
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- CN102389317A CN102389317A CN2011101964119A CN201110196411A CN102389317A CN 102389317 A CN102389317 A CN 102389317A CN 2011101964119 A CN2011101964119 A CN 2011101964119A CN 201110196411 A CN201110196411 A CN 201110196411A CN 102389317 A CN102389317 A CN 102389317A
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Abstract
The invention provides a real-time keystroke-pressure acquisition system which is composed of a pressure sensor and an interface circuit, wherein the pressure sensor is connected with the interface circuit; the pressure sensor uses four foil gauges to constitute a Wheatstone full-bridge circuit, and carries out acquisition on pressures after resistance variation is converted into voltage variation; the pressure sensor is arranged at the bottom of a standard keyboard, and comprises a keycap and a rebound device; the interface circuit comprises an amplifier, a multi-channel check device, an analog-digital converter and a master controller; the analog-digital converter digitalizes gated analog signals; and the master controller is responsible for the control of a whole hardware circuit and the communication of a computer and takes 89SC52 as a master control unit, and a built-in serial port controller of the master controller can conveniently carry out communication with the computer. By using the system provided by the invention, a keystroke pressure can be acquired in real time under the condition of not changing a user interface; and because a normal keyboard is used as the user interface, a defect that the utilization of a special keyboard is easy to cause the change of keystroke habits of users is overcome, therefore, the system has a great significance for identity recognition.
Description
(1) technical field
The present invention relates to Signal Collection Technology, is exactly a kind of real-time keystroke pressure acquisition system specifically.
(2) background technology
The keystroke pressure acquisition system is based on a very important link of human body biological characteristics recognition system of keystroke characteristic, does not also occur general keystroke pressure acquisition system at present.All there is shortcoming separately in existing several kinds of keystroke pressure acquisition methods now.People such as Bo1duc have proposed a kind of method of measuring keystroke pressure.This method is based on presser sensor resistance.A varistor is installed in the keyboard bottom, embodies the variation of keystroke pressure through the variation of measuring resistance.But this method only uses a varistor to measure the pressure of whole keyboard, and this makes the installation site of varistor will influence the accuracy of measurement data.Concerning the different key of the quick resistive distance of tripping, the concordance of data can't guarantee.People such as Li Xiang have proposed the pressure sensitive keyboard that can gather pressure information.But from the data that they gathered, this keyboard is only gathered a force value in user's a keystroke process.This has lost much the crucial information of living things feature recognition undoubtedly, such as variation characteristic of pressure etc.Another kind of pressure acquisition keyboard has been proposed in other keystroke characteristic recognition system.This keyboard utilizes data collecting card to be connected with computer, and the pressure transducer on the keyboard is transferred to computer through data collecting card with pressure data.Though this method has high-resolution benefit, most of computers are not equipped with data collecting card, make this keyboard to be applied in the common computer.
(3) summary of the invention
The object of the present invention is to provide a kind of the change under the user interface situation, when keying in data, accurately gather the real-time keystroke pressure acquisition system of keystroke pressure in real time.
The objective of the invention is to realize like this: it is made up of pressure transducer and interface circuit, and pressure transducer connecting interface circuit, described pressure transducer use four foil gauges to form a Hui Sitong full-bridge circuit; The variation that changes in resistance is converted into voltage is gathered again, and pressure transducer is installed in the bottom of each button of QWERTY keyboard, comprises keycap and resilient mounting; Two dividing plates are set, and upper spacer has 12 holes, faces 12 pick offs; Two row's fixed supports are used for fixing pick off, and when the user pushes button, resilient mounting will be out of shape; The convexity of its bottom is touched the button of pressure transducer, and pressure is passed to pick off, unclamp button after; Resilient mounting restores to the original state, and keycap is lifted; Described interface circuit comprises amplifier, multichannel final election device, analog-digital converter and master controller, and amplifier connects multichannel final election device, multichannel final election device connection mode number converter, and analog-digital converter connects master controller; Wherein the effect of amplifier be amplify faint millivolt magnitude voltage signals extremely ± 5v; The selection of this numerical value is the input requirement according to ADC, adopts the instrument amplifier AD620 of low power consumption high-precision, and the effect of multichannel final election device is that a road in gating 12 road signals carry out digitized and handled; Two 8 tunnel analogue signal multiplexers are formed one 16 tunnel multiplex electronics; Satisfy the needs of 12 road signals, the effect of analog-digital converter is the analog signal digital with gating, so that main control unit is handled and is sent on the computer; That adopt is 8 analog-digital converter ADC0804; The control of the responsible whole hardware circuit of master controller reaches the work with compunication, adopts 89SC52 as main control unit, and its built-in serial ports controller can communicate with computer easily.
The present invention has realized when the user knocks keyboard sending simultaneously to computer the function of key and key force value, the data that the collection keyboard that the program on the computer of running on can be real-time sends.Final effect of the present invention is that the keypad of 12 buttons comprises 10 numeral keys, 1 acknowledgement key, 1 cancel key, and a capture program that runs on the computer.In user's a keystroke behavior, native system is gathered one of key, gathers 200 to 300 of force value, and each key and the force value sequence corresponding with it are saved on the hard disk.The present invention realizes one when the user keys in data under the situation that does not change user interface, accurately gather the system of keystroke pressure in real time.The present invention uses common keyboard as user interface, has overcome the shortcoming of using special keyboard to cause the user keystroke custom to change easily, and this is significant for identification.The present invention all installs a pressure transducer for each button, guarantees the accuracy of pressure acquisition.Through the design of interface circuit and capture program, the present invention has realized the keystroke pressure acquisition of real-time high-efficiency.
(4) description of drawings
Fig. 1 is a block diagram of the present invention;
Fig. 2 is a Hardware Design block diagram of the present invention;
Fig. 3 is the vertical view of button of the present invention and pick off mechanical connection;
Fig. 4 is the front view of button of the present invention and pick off mechanical connection;
Fig. 5 is a pressure transducer sketch map of the present invention;
Fig. 6 is an interface circuit block diagram of the present invention.
(5) specific embodiment
Below in conjunction with accompanying drawing the present invention is described further.
Embodiment 1: combine Fig. 3-Fig. 6, and a kind of real-time keystroke pressure acquisition system of the present invention, it is made up of pressure transducer and interface circuit, it is characterized in that: pressure transducer connecting interface circuit; Described pressure transducer uses four foil gauges to form a Hui Sitong full-bridge circuit, and the variation that changes in resistance is converted into voltage is gathered again, and pressure transducer is installed in the bottom of each button of QWERTY keyboard; Comprise keycap and resilient mounting, two dividing plates are set, upper spacer has 12 holes; Face 12 pick offs, two row's fixed supports are used for fixing pick off, when the user pushes button; Resilient mounting will be out of shape, and the convexity of its bottom is touched the button of pressure transducer, and pressure is passed to pick off; After unclamping button, resilient mounting restores to the original state, and keycap is lifted; Described interface circuit comprises amplifier, multichannel final election device, analog-digital converter and master controller, and amplifier connects multichannel final election device, multichannel final election device connection mode number converter, and analog-digital converter connects master controller; Wherein the effect of amplifier be amplify faint millivolt magnitude voltage signals extremely ± 5v; The selection of this numerical value is the input requirement according to ADC, adopts the instrument amplifier AD620 of low power consumption high-precision, and the effect of multichannel final election device is that a road in gating 12 road signals carry out digitized and handled; Two 8 tunnel analogue signal multiplexers are formed one 16 tunnel multiplex electronics; Satisfy the needs of 12 road signals, the effect of analog-digital converter is the analog signal digital with gating, so that main control unit is handled and is sent on the computer; That adopt is 8 analog-digital converter ADC0804; The control of the responsible whole hardware circuit of master controller reaches the work with compunication, adopts 89SC52 as main control unit, and its built-in serial ports controller can communicate with computer easily.
Embodiment 2: combine Fig. 1-Fig. 5, overall structure block diagram of the present invention is as shown in Figure 1.
1. Hardware Design
The hardware designs block diagram is as shown in Figure 2.The present invention has at first proposed pressure is converted into the pressure sensor design of the signal of telecommunication, has proposed afterwards pressure transducer is installed on the Machine Design under each button, and last, the present invention has designed an interface circuit and handled the signal of telecommunication that is converted by pressure.
1.2 pressure sensor design
The design adopts the basic induction original paper of foil gauge as pressure transducer.Foil gauge is a kind of material that can deformation be converted into resistance variations.When foil gauge is pressed, the deformation that its resistance will cause along with pressure and produce respective change.But small resistance variations also is not easy to gather, so the design uses four foil gauges to form a Hui Sitong full-bridge circuit, the variation that changes in resistance is converted into voltage is gathered again.The pressure transducer sketch map that Fig. 3, Fig. 4 design for the present invention.(1) is one of four foil gauges among the figure, and (2) are the elastomeric elements that pastes foil gauge, and (3) are buttons.
1.3 Machine Design
For sensor designed of the present invention being installed in each button bottom, we have carried out careful Machine Design to the installation of pick off.The Machine Design sketch map is as shown in Figure 5.In Fig. 5, (a) part is the button of a QWERTY keyboard, comprise keycap like (9) and resilient mounting among the figure like (10) in scheming.(b) part is the base that designs for sensor installation.(5) are lower clapboard among the figure, and (8) upper spacer, upper spacer have 12 holes, face 12 pick offs.(6) be last fixed support, (7) are used for fixing pick off for following fixed support.(4) are pressure transducer among the figure.When the user pushes button, resilient mounting (10) will be out of shape, and the convexity of its bottom will be touched the button of pressure transducer, and pressure is passed to pressure transducer.After the user unclamps button, resilient mounting will recover shape, and keycap is lifted.
1.4 interface circuit design
After pressure transducer converts pressure into voltage signal, need an interface circuit to handle this signal, native system has been designed and Implemented a special interface circuit for this reason.Fig. 6 is an interface circuit block diagram of the present invention.Interface circuit comprises amplifier, multichannel final election device (MUX), analog-digital converter (ADC) and four major parts of master controller (MCU).Wherein the effect of amplifier be amplify faint millivolt magnitude voltage signals extremely ± 5v, the selection of this numerical value is the input requirement according to ADC.That adopt among the design is the instrument amplifier AD620 of low power consumption high-precision.The effect of multichannel final election device is that a road in gating 12 road signals carry out digitized and handled.Use two 8 tunnel analogue signal multiplexers (CD4051) to form one 16 tunnel multiplex electronics among the design, this design can be satisfied the needs of 12 road signals.The effect of analog-digital converter is the analog signal digital with gating, so that main control unit is handled and is sent on the computer.The design adopts is 8 analog-digital converter ADC0804, and 8 resolution can satisfy the demand of this living creature characteristic recognition system.The control of the responsible whole hardware circuit of master controller reaches the work with compunication, and the design has adopted common 89SC52 as main control unit, and its built-in serial ports controller can communicate with computer easily.
2. software design
2.1 Design of Firmware
Native system has designed a program that runs among the MCU and has controlled whole hardware circuit and and compunication, i.e. firmware program.Firmware program is operation automatically after device power, after its operation beginning then cycle detection whether have key to be pressed.In case it is closed to detect certain key, then sends a commencing signal to computer, tells computer to have key to be pressed.In being right after a byte of commencing signal, firmware program number is issued computer with the key of closed key.After the key byte was sent end, firmware program begins to send force value, and was released up to the key of closure.When button was decontroled, firmware program sent the end signal of a byte and gives computer, told computer keystroke release this time.If there is not key to be pressed, firmware program will not send commencing signal and key number to computer, but still send force value (pneumatics power).Capture program on the computer will leave these force value in the corresponding pressure array of sky button in.The pneumatics power of gathering button is in order to weigh keystroke blanking time, and the length of the pneumatics power array between twice button has characterized the size of keystroke blanking time.Keystroke blanking time, identification was a significant data equally to keystroke characteristic.
2.2 capture program design
Native system has designed a program that runs on the computer, is responsible for gathering the data that the pressure sensitive keyboard sends.Capture program saves as binary crelation < key number, pressure array>with the data of gathering.After capture program operation is whether cycle detection receives the commencing signal that firmware program is sent, if receive and show that then certain key is pressed, and next the data of a byte are key number.So there are the data of the next byte of commencing signal in the key number in capture program.Data after the key number are existed in the pressure array of this key correspondence, until receiving end signal.When capture program was not received commencing signal, program existed key number in the empty pairing pressure array data of receiving.Weigh keystroke blanking time with this.
Claims (1)
1. real-time keystroke pressure acquisition system, it is made up of pressure transducer and interface circuit, it is characterized in that: pressure transducer connecting interface circuit; Described pressure transducer uses four foil gauges to form a Hui Sitong full-bridge circuit, and the variation that changes in resistance is converted into voltage is gathered again, and pressure transducer is installed in the bottom of each button of QWERTY keyboard; Comprise keycap and resilient mounting, two dividing plates are set, upper spacer has 12 holes; Face 12 pick offs, two row's fixed supports are used for fixing pick off, when the user pushes button; Resilient mounting will be out of shape, and the convexity of its bottom is touched the button of pressure transducer, and pressure is passed to pick off; After unclamping button, resilient mounting restores to the original state, and keycap is lifted; Described interface circuit comprises amplifier, multichannel final election device, analog-digital converter and master controller, and amplifier connects multichannel final election device, multichannel final election device connection mode number converter, and analog-digital converter connects master controller; Wherein the effect of amplifier be amplify faint millivolt magnitude voltage signals extremely ± 5v; The selection of this numerical value is the input requirement according to ADC, adopts the instrument amplifier AD620 of low power consumption high-precision, and the effect of multichannel final election device is that a road in gating 12 road signals carry out digitized and handled; Two 8 tunnel analogue signal multiplexers are formed one 16 tunnel multiplex electronics; Satisfy the needs of 12 road signals, the effect of analog-digital converter is the analog signal digital with gating, so that main control unit is handled and is sent on the computer; That adopt is 8 analog-digital converter ADC0804; The control of the responsible whole hardware circuit of master controller reaches the work with compunication, adopts 89SC52 as main control unit, and its built-in serial ports controller can communicate with computer easily.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110196411.9A CN102389317B (en) | 2011-07-14 | 2011-07-14 | A kind of real-time keystroke-pressure acquisition system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201110196411.9A CN102389317B (en) | 2011-07-14 | 2011-07-14 | A kind of real-time keystroke-pressure acquisition system |
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| CN102389317A true CN102389317A (en) | 2012-03-28 |
| CN102389317B CN102389317B (en) | 2016-02-10 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104251802A (en) * | 2013-06-26 | 2014-12-31 | 名硕电脑(苏州)有限公司 | Key resilience time measurement apparatus and measurement method thereof |
| CN109815655A (en) * | 2017-11-22 | 2019-05-28 | 北京纳米能源与***研究所 | Identification and verifying system, method, apparatus and computer readable storage medium |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5742242A (en) * | 1996-12-19 | 1998-04-21 | Compaq Computer Corporation | Keyboard using pressurized fluid to generate key stroke characteristics |
| CN201035519Y (en) * | 2007-01-31 | 2008-03-12 | 联想移动通信科技有限公司 | Keyboard |
| CN101738280A (en) * | 2008-11-24 | 2010-06-16 | 河南理工大学 | Mems pressure sensor and manufacturing method thereof |
-
2011
- 2011-07-14 CN CN201110196411.9A patent/CN102389317B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5742242A (en) * | 1996-12-19 | 1998-04-21 | Compaq Computer Corporation | Keyboard using pressurized fluid to generate key stroke characteristics |
| CN201035519Y (en) * | 2007-01-31 | 2008-03-12 | 联想移动通信科技有限公司 | Keyboard |
| CN101738280A (en) * | 2008-11-24 | 2010-06-16 | 河南理工大学 | Mems pressure sensor and manufacturing method thereof |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104251802A (en) * | 2013-06-26 | 2014-12-31 | 名硕电脑(苏州)有限公司 | Key resilience time measurement apparatus and measurement method thereof |
| CN109815655A (en) * | 2017-11-22 | 2019-05-28 | 北京纳米能源与***研究所 | Identification and verifying system, method, apparatus and computer readable storage medium |
| WO2019101016A1 (en) * | 2017-11-22 | 2019-05-31 | 北京纳米能源与***研究所 | Identity identification and verification system and method based on keystroke dynamics |
| CN109815655B (en) * | 2017-11-22 | 2021-04-02 | 北京纳米能源与***研究所 | Identity recognition and verification system, method, device and computer readable storage medium |
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| CN102389317B (en) | 2016-02-10 |
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