CN102594327B - Capacitive sensing key and key detection method - Google Patents
Capacitive sensing key and key detection method Download PDFInfo
- Publication number
- CN102594327B CN102594327B CN201110007159.2A CN201110007159A CN102594327B CN 102594327 B CN102594327 B CN 102594327B CN 201110007159 A CN201110007159 A CN 201110007159A CN 102594327 B CN102594327 B CN 102594327B
- Authority
- CN
- China
- Prior art keywords
- key
- button
- value
- capacitance
- induced
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Electronic Switches (AREA)
Abstract
The invention relates to a capacitive sensing key and a key detection method. The capacitive sensing key comprises a capacitive touch key (20) and a microprocessor (21), wherein the capacitive touch key (20) is provided with a sensing electrode (201), and the sensing electrode (201) is connected with the microprocessor (21); and the microprocessor (21) is connected with the capacitive touch key (20) through an input/output port (210) and is used for repetitively charging and discharging the capacitive touch key (20), detecting a touch sensing capacitor (Cf) of the sensing electrode (201) and generating key detection signals (AD0 and ADf). Since the capacitive sensing key and the key detection method adopt the working principle of capacitor charge transfer, the circuit structure is simplified, the product reliability is increased, the cost is low, the sensitivity is high, the interference resistance is high and the capacitive sensing key and the key detection method are suitable for all kinds of electronic and electric products.
Description
Technical field
The present invention relates to contactless electronic button, more specifically, relate to a kind of capacitive induction button and key detecting method thereof.
Background technology
Capacitive induction button is a kind of conventional contactless electronic button, and compared to traditional mechanical key, the advantage such as have waterproof, life-span length, stable performance, be quick on the draw, in the middle of the control panel being thus widely used in various electric equipment products.
As shown in Figure 1, the operation principle of employing " relaxation oscillator " realizes the detection to human finger or felt pen contact induction button to the capacitive induction button of prior art.As shown in Figure 1, existing capacitive induction button comprises: capacitance touch button 10, N road multidiameter option switch 11 (N be generally 4,6,8,16 etc.), comparator 12 and timer conter 13; Wherein, capacitance touch button 10 has induction electrode, corresponding touch sensible electric capacity Cfn (n=1 ~ N), and has outside distribution stray capacitance Con (n=1 ~ N); Capacitance touch button 10 is connected to the input of N road multidiameter option switch 11; The output of N road multidiameter option switch 11 is connected to the negative input of comparator 12, and the electrode input end of comparator 12 connects the threshold level (not marking automatic electric-level setting device in figure) of Lookup protocol; The output of comparator 12 connects timer conter 13, and connects the negative input of comparator 12 as feedback loop.The operation principle of existing capacitive induction button is: the electric capacity in described capacitance touch button 10 and comparator 12 form the oscillating circuit of a continuous charging and discharging jointly; If the induction electrode of human finger or felt pen not touch sensible capacitance touch button 10, then this oscillating circuit keeps the charging-discharging cycle of a fixed frequency, and its fixing frequency of oscillation is timed counter 13 count detection.When human finger or felt pen contact the induction electrode of touch sensible capacitance touch button 10, itself and induction electrode form an inductance capacitance Cf1 by medium, namely the capacity (Cf1 and Co1) of external capacitive adds, thus making the charging-discharging cycle of described oscillating circuit elongated, frequency of oscillation changes.Timer conter 13 measures the change of frequency of oscillation, the touch action of button just can be detected, reaches the object that touch key-press detects.
The shortcoming of existing capacitive induction button is that circuit structure is complicated, and need the induced signal adopting special chip detection human finger or formed between felt pen and induction electrode, product reliability is lower, and cost is high.Thus, in the urgent need to a kind of capacitance key of improvement in prior art, replace existing " relaxation oscillator " capacitive induction button.
Summary of the invention
For the above-mentioned defect of existing " relaxation oscillator " capacitive induction button, the invention provides a kind of capacitive induction button of improvement, the working method that it adopts " capacitance charge transfer " replaces traditional " relaxation oscillator ".Present invention also offers the key detecting method of this capacitive induction button.
Capacitive induction button of the present invention comprises capacitance touch button (20) and microprocessor (21); Wherein said capacitance touch button (20) has induction electrode (201); Induction electrode (201) connects described microprocessor (21); Microprocessor (21) connects capacitance touch button (20) by input/output end port (210), the touch sensible electric capacity (Cf) of described induction electrode (201) detects to described capacitance touch button (20) repeated charge, generate button detection signal (AD0, ADf).
Wherein, described microprocessor (21) comprises further: capacitance charge carry circuit (211), to parasitic capacitance (Ch) repeated charge and the Charger transfer of described capacitance touch button (20) and microprocessor (21); Analog to digital converter (212), after acquisition Charger transfer of repeatedly sampling, capacitance touch button (20) is some to input signal values (AD1, ADh); Digital signal processing module (213), what obtain keep analog to digital converter (212) conversion to repeatedly sampling after is described some to input signal values (AD1, ADh) carry out depositing, differential comparison computing, digital filtering and dual threshold compare, obtain button detection signal (AD0, ADf).
Further preferably, wherein, described charge transfer circuit (211) comprises the first discharge and recharge terminal (RA0), first control switch (K1), second discharge and recharge terminal (RA1), the second control switch (K2) and charge transfer switch (K0); Wherein the first discharge and recharge terminal (RA0) connects described capacitance touch button (20) by described first control switch (K1); Second discharge and recharge terminal (RA1) connects the parasitic capacitance (Ch) of microprocessor by the second control switch (K2); Charge transfer switch (K0) connects described capacitance touch button (20) and described parasitic capacitance (Ch) and Charger transfer both controlling.
Further preferably, wherein, described digital signal processing module (213) comprises register (2131), deposits the described input signal values (AD1, ADh) obtained after keeping analog to digital converter (212) conversion through repeatedly sampling; Differential comparison computing module (2132), what obtain keep analog to digital converter (212) conversion to repeatedly sampling after somely carries out differential comparison computing to described input signal values (AD1, ADh) and obtains several differential signals (ADn); Digital filtering and button judge module (2133), carry out digital filtering to described several differential signals (ADn) and dual threshold compares the described button detection signal (AD0, ADf) of acquisition.
Further preferably, wherein, described differential comparison computing module (2132) is carried out differential comparison computing to some obtain several differential signals (ADn) to the input signal (ADh, AD1) after analog to digital converter (212) conversion.
Still more preferably, described digital filtering and button judge module (2133) comprise first order digital filter (2133a), second level digital filter (2133b), third level digital filter (2133c), induced key fiducial value computing module (2133d) and button judge module (2133e), wherein:
First order digital filter (2133a) removes maximum, the peaceful mean operation of minimum value to several differential signals (ADn) in very first time interval, obtains first order digital filtering value;
Second level digital filter (2133b) removes maximum, the peaceful mean operation of minimum value to the multiple first order digital filtering values obtained in second time interval, obtains second level digital filtering value;
Third level digital filter (2133c) to be averaged value computing to the multiple second level digital filtering value obtained in the 3rd time interval, obtains third level digital filtering value, as key induced signal value (AD
kEY);
Induced key fiducial value computing module (2133d) calculates induced key fiducial value (AD when capacitance touch button (20) is not pressed
ben);
The more described key induced signal value (AD of button judge module (2133e)
kEY) and induced key fiducial value (AD
ben), judge whether described capacitance touch button (20) is pressed, generate button detection signal (AD0, ADf).
Utilize above-mentioned capacitive induction button, present invention also offers a kind of key detecting method of capacitive induction button, comprise the following steps:
Step 1: by a microprocessor (21) to capacitance touch button (20) repeated charge and Charger transfer;
Step 2: detected the touch sensible electric capacity (Cf) on described capacitance touch button (20) by microprocessor (21), generates button detection signal (AD0, ADf).
Preferably, in described key detecting method, described step 1 specifically comprises:
Step 1a: to touch sensible electric capacity (Cf) and outside distribution stray capacitance (Co) electric discharge of described capacitance touch button (20), the parasitic capacitance (Ch) of microprocessor (21) is charged; Then parasitic capacitance (Ch) is made to charge to touch sensible electric capacity (Cf) and outside distribution stray capacitance (Co), when after three's charge balance, acquiring touch inductance capacitance (Cf) and outside the first input signal values (ADh) distributed in stray capacitance (Co);
Step 1b: to touch sensible electric capacity (Cf) and outside distribution stray capacitance (Co) charging of described capacitance touch button (20), the parasitic capacitance (Ch) of microprocessor (21) is discharged; Then touch sensible electric capacity (Cf) and outside distribution stray capacitance (Co) is made to charge to parasitic capacitance (Ch), when after three's charge balance, acquiring touch inductance capacitance (Cf) and outside the second input signal values (AD1) distributed in stray capacitance (Co);
Step 1c: repeatedly perform step 1a, 1b and obtain some to the first and second input signal values (ADh, AD1).
Further, in described key detecting method, described step 2 specifically comprises:
Step 2a: some to described differential comparison computing is carried out to the first and second input signal values (ADh, AD1) obtain several differential signals (ADn);
Step 2b: multi-stage digital filtering is carried out to described several differential signals (ADn) and generates key induced signal value (AD
kEY);
Step 2c: calculate induced key fiducial value (AD when described capacitance touch button (20) is not pressed
ben);
Step 2d: more described key induced signal value (AD
kEY) and induced key fiducial value (AD
ben) judge whether described capacitance touch button (20) is pressed, thus generate button detection signal (AD0, ADf).
Wherein, described step 2b specifically comprises:
Maximum, the peaceful mean operation of minimum value is gone to several differential signals (ADn) in very first time interval, obtains first order digital filtering value;
Maximum, the peaceful mean operation of minimum value is gone to the multiple first order digital filtering values obtained in second time interval, obtains second level digital filtering value;
The multiple second level digital filtering value obtained in 3rd time interval is averaged value computing, obtains third level digital filtering value, as described key induced signal value (AD
kEY).
Wherein, described step 2d specifically comprises:
If a predetermined quantity key induced signal value (AD continuously
kEY) than induced key fiducial value (AD
ben) more than large first threshold, then judge that capacitance touch button (20) is not pressed;
If a predetermined quantity key induced signal value (AD continuously
kEY) than induced key fiducial value (AD
ben) more than little Second Threshold, then judge that capacitance touch button (20) is pressed;
After capacitance touch button (20) is pressed, if a continuous predetermined quantity key induced signal value (AD
kEY) than induced key fiducial value (AD
ben) below little 3rd threshold value, then judge that capacitance touch button (20) discharges.
In sum, capacitive induction button of the present invention and key detecting method thereof have employed the operation principle of " capacitance charge transfer ", compared with traditional " relaxation oscillator " capacitive induction button, abandon special induced signal detection chip, enormously simplify circuit structure, add product reliability, reduce product cost, keystroke sensitivity is high, and antijamming capability is strong, can be widely used in various electric equipment products.
Accompanying drawing explanation
Fig. 1 is the structural representation of the capacitive induction button of prior art;
Fig. 2 is the structural representation of the capacitive induction button of the embodiment of the present invention;
Fig. 3 is the structural representation of the digital signal processing module of the embodiment of the present invention;
Fig. 4 is the digital filtering of the embodiment of the present invention and the structural representation of button judge module.
Embodiment
By describing technology contents of the present invention, structural feature in detail, realized object and effect, accompanying drawing is coordinated to be explained in detail below in conjunction with embodiment.
Fig. 2 is the structural representation of the capacitive induction button of the embodiment of the present invention.Capacitive induction button of the present invention adopts " capacitance charge transfer " working method, directly be connected with the induction electrode 201 in capacitance touch button 20 by microprocessor 21 (CPU), described microprocessor 21 is with I/O (I/O) port of analog to digital converter 212 (A/D) function.The touch sensible electric capacity Cf produced when microprocessor CPU human body finger or felt pen contact induction electrode, thus produce the button detection signal representing actuation of keys.Owing to having outside distribution stray capacitance Co at capacitance touch button, and microprocessor chip inside has parasitic capacitance Ch, the touch sensible electric capacity Cf produced when human finger or felt pen contact induction electrode and outside the differing of stray capacitance Co and parasitic capacitance Ch that distribute all little, in order to eliminate Ch and Co to the impact detected, microprocessor adopts difference A/D comparison operation method to detect touch sensible electric capacity Cf, thus reaches the object of detecting actuation of keys.
As shown in Figure 2, capacitive induction button of the present invention comprises capacitance touch button 20 and microprocessor 21; Wherein said capacitance touch button 20 has induction electrode 201; Induction electrode 201 connects described microprocessor 21.When human finger or felt pen contact with induction electrode 201, the two forms described touch sensible electric capacity Cf by medium; If human finger or felt pen do not contact with induction electrode 201, be then equivalent to touch sensible electric capacity Cf=0.Capacitance touch button 20 also has outside distribution stray capacitance Co.As Fig. 2, microprocessor 21 connects capacitance touch button 20 by its input/output end port 210.Microprocessor 21 is repeatedly charged by its input/output end port 210 to described capacitance touch button 20, discharges, and detects the touch sensible electric capacity Cf of described induction electrode 201, generates button detection signal AD0 or ADf according to the change of touch sensible electric capacity Cf.
Wherein, the structure of described microprocessor 21 comprises further: capacitance charge carry circuit 211, analog to digital converter 212 and digital signal processing module 213, and the chip internal of microprocessor 21 also has parasitic capacitance Ch.
Capacitance charge carry circuit 211 is connected to outside described capacitance touch button 20 by input/output end port 210, and controls repeatedly to charge to the parasitic capacitance Ch of described capacitance touch button 20 and microprocessor 21, discharge and Charger transfer.Particularly, described charge transfer circuit 211 comprises the first discharge and recharge terminal RA0, the first control switch K1, the second discharge and recharge terminal RA1, the second control switch K2 and charge transfer switch K0; Wherein the first discharge and recharge terminal RA0 connects described capacitance touch button 20 by described first control switch K1; Second discharge and recharge terminal RA1 connects the parasitic capacitance Ch of microprocessor by the second control switch K2; Charge transfer switch K0 connects the touch sensible electric capacity Cf of described capacitance touch button 20 and outside distribution stray capacitance Co and described parasitic capacitance Ch, and the Charger transfer both controlling, thus touch sensible electric capacity Cf and outside distribution stray capacitance Co and described parasitic capacitance Ch is made to reach charge balance.
Analog to digital converter 212 is sampled repeatedly, keep, analog-to-digital conversion (A/D conversion), obtain after Charger transfer reaches charge balance, capacitance touch button 20 some to input signal values AD1 and ADh, the input signal values also namely on touch sensible electric capacity Cf and outside distribution stray capacitance Co.
Digital signal processing module 213, obtain keep analog to digital converter (212) conversion to repeatedly sampling after described some input signal values AD1 and ADh to be deposited, differential comparison computing, digital filtering and dual threshold compare, and obtains button detection signal AD0 or ADf.
Key detecting method the following detailed description of above-mentioned capacitive induction button of the present invention:
When normally working, the charge transfer switch K0 in charge transfer circuit 211 disconnects, and the first control switch K1 and the second control switch K2 closes; The level of the first discharge and recharge terminal RA0 is set to " 0 ", makes touch sensible electric capacity Cf and outside distribution stray capacitance Co electric discharge; The level of the second discharge and recharge terminal RA1 is set to " 1 ", and parasitic capacitance Ch is charged.Then, first control switch K1 and the second control switch K2 disconnects, charge transfer switch K0 closes, parasitic capacitance Ch is charged to touch sensible electric capacity Cf and outside distribution stray capacitance Co, when after three's charge balance, analog to digital converter 212 carries out sampling, keep, A/D conversion, obtains the first input signal values ADh on touch sensible electric capacity Cf and outside distribution stray capacitance Co.
Afterwards, the charge transfer switch K0 in charge transfer circuit 211 disconnects, and the first control switch K1 and the second control switch K2 closes; The level of the first discharge and recharge terminal RA0 is set to " 1 ", makes touch sensible electric capacity Cf and outside distribution stray capacitance Co charging; The level of the second discharge and recharge terminal RA1 is set to " 0 ", and parasitic capacitance Ch is discharged.Then, first control switch K1 and the second control switch K2 disconnects, charge transfer switch K0 closes, touch sensible electric capacity Cf and outside distribution stray capacitance Co is charged to parasitic capacitance Ch, when after three's charge balance, analog to digital converter 212 carries out sampling again, keep, A/D conversion, obtains the second input signal values AD1 on touch sensible electric capacity Cf and outside distribution stray capacitance Co.
Repeatedly perform the process of above-mentioned charging, electric discharge and charge balance, and analog to digital converter 212 is with fixing sampling holding frequency, repeatedly sample, keep, A/D conversion, obtain the input signal values after Charger transfer reaches charge balance, thus obtain some to the first and second input signal values AD1 and ADh in very first time interval.Such as, at the present embodiment, analog to digital converter 212 carries out 12 samplings in every 10ms, namely gathers 6 AD1 and 6 time ADh respectively, thus obtains 6 couples of AD1 and ADh in every 10ms, is expressed as AD1n and ADhn (n=1 ~ 6).
The structure of digital signal processing module 213 as shown in Figure 3, comprises register 2131, differential comparison computing module 2132 and digital filtering and button judge module 2133.Register 2131 is deposited through repeatedly sampling, keeping, A/D conversion, described input signal values ADh and AD1 obtained; Differential comparison computing module 2132 somely carries out differential comparison computing to the first and second input signal values ADh and AD1 to what above keep obtaining after analog to digital converter (212) conversion through over-sampling, obtains several differential signals ADn.In the present embodiment, in every 10ms, differential comparison computing module 2132 carries out differential comparison computing respectively to 6 couples of AD1 and ADh, i.e. ADn=ADhn-AD1n (n=1 ~ 6), thus obtains 6 ADn values in every 10ms.Digital filtering and button judge module 2133, again to through repeatedly sampling, keeping, A/D conversion, several differential signals ADn obtained carries out digital filtering and dual threshold compares process, filtering common mode, differential mode interference, and obtains final button detection signal AD0 or ADf.
Fig. 4 shows in detail the structure of digital filtering and button judge module 2133.Described digital filtering and button judge module 2133 comprise first order digital filter 2133a, second level digital filter 2133b, third level digital filter 2133c, induced key fiducial value computing module 2133d and button judge module 2133e.The step of the process such as described digital filtering and dual threshold compare specifically is introduced below in conjunction with Fig. 4.
First order digital filter 2133a removes maximum, the peaceful mean operation of minimum value to several differential signals ADn in very first time interval, obtains first order digital filtering value.As described above, in every 10ms, differential comparison computing module 2132 exports 6 ADn values.First order digital filter 2133a carries out first order digital filtering, remove 6 ADn worthwhile in maximum ADnmax and minimum value ADnmin, get remaining 4 ADn value and be averaged, as the first order digital filtering value in this 10ms, be designated as AD
10ms, thus just export a first order digital filtering value every 10ms first order digital filter 2133a.
Second level digital filter 2133b removes maximum, the peaceful mean operation of minimum value to the multiple first order digital filtering values obtained in second time interval, obtains second level digital filtering value.As described above, when a first order digital filtering value will be exported every 10ms first order digital filter 2133a, obtain 4 first order digital filtering values every 40ms second level digital filter 2133b, be designated as AD
10msN(N=1-4).Maximum AD is wherein removed to above 4 first order digital filtering values
10msmaxwith minimum value AD
10msmin, all the other 2 first order digital filtering values are averaged, as the second level digital filtering value in this 40ms, are designated as AD
40ms, namely obtain a second level digital filtering value every 40ms.
Third level digital filter 2133c to be averaged value computing to the multiple second level digital filtering value obtained in the 3rd time interval, and obtain third level digital filtering value, this filter value is namely as key induced signal value AD
kEY.As described above, obtain a second level digital filtering value every 40ms, then every 120ms obtains 3 second level digital filtering values, is designated as AD
40msN(N=1-3).To be averaged value computing to 3 second level digital filtering values, mean value is export as third level digital filtering value.This filter value is also as key induced signal value AD
kEY.
In order to realize key induced signal value AD
kEYdynamic tracking, the method that sliding window is dynamically followed the tracks of can be adopted.As described above, every 10ms carries out 12 secondary data collections, and utilizes the data gathered in 120ms can calculate an AD
kEY; By sliding window Dynamic Tracking, every 10ms, the data gathered in first 10ms are removed, using the data that gather in next 10ms again as the data that a 10ms gathers, the rest may be inferred rearrange before gather data, and the data that nearest 10ms gathers are entered the data gathered in last 10ms, recalculate AD
kEY.So dynamically follow the tracks of, ensure that the reliability of detection, real-time and accuracy, farthest avoid and decrease the impact disturbed and key induced signal value is detected.
Induced key fiducial value computing module 2133d calculates induced key fiducial value AD when capacitance touch button 20 is not pressed
ben, with induced key fiducial value AD
benas judging the benchmark whether capacitance touch button 20 is pressed.Circular is: when electrification reset, when namely capacitance touch button 20 is not pressed yet, gathers 16 second level digital filtering values, is designated as AD
40msN(N=1-16).Calculate the mean value of these 16 second level digital filtering values as initial baseline value AD
640ms0; Determining initial baseline value AD
640ms0afterwards, namely along with the increase of running time, every 40ms, using the second level digital filtering value of up-to-date acquisition as AD
40msnew, be calculated as follows AD
ben:
AD
ben＝(AD
40ms1+AD
40ms2+AD
40ms3+......AD
40msN+AD
40msnew-AD
640ms0)/16(N＝1～16)
Wherein, to AD
benthe calculating method that also utilizes sliding window dynamically to follow the tracks of follow the tracks of; Namely every 40ms, the second level digital filtering value of first 40ms is removed, using the second level digital filtering value of next 40ms again as the data that a 40ms gathers, the rest may be inferred rearrange before gather data, and the data that nearest 40ms gathers are entered as last second level digital filtering value, recalculate AD
ben.By dynamic tracking, also ensure that reliability, accuracy and real-time that induced key fiducial value calculates, at utmost avoid the impact that interference calculates induced key fiducial value, also can eliminate due to after use for a long time, the factors such as the surface dirt accumulation of capacitance touch button 20 and circuit stray capacitance variation are on the impact of induced key sensitivity simultaneously.
The more described key induced signal value AD of button judge module 2133e
kEYwith induced key fiducial value AD
ben, judge whether described capacitance touch button 20 is pressed, thus generate button detection signal AD0 or ADf.Described key induced signal value AD
kEYreflect the capacitance of capacitance touch button 20.Wherein, if human finger or felt pen not contact induction electrode, namely Cf is that 0, Co remains unchanged, and the key induced signal value now obtained is designated as AD
kEY0, at this moment AD
kEY0with induced key fiducial value AD
benbe more or less the same.If human finger or felt pen contact induction electrode 201 generate touch sensible electric capacity Cf, will change the value of (Cf+Co), the key induced signal value now generated is designated as AD
kEYf, meeting and induced key fiducial value AD
benthere is larger difference.Thus, by more key induced signal value AD
kEYwith induced key fiducial value AD
benthe object of detecting actuation of keys can be reached.
Button judge module 2133e is to key induced signal value AD
kEYwith induced key fiducial value AD
bencarry out dual threshold to compare, specifically comprise:
If continuous 8 key induced signal value AD
kEYthan induced key fiducial value AD
benbe greater than more than 1 A/D conversion unit value, then judge that capacitance touch button 20 is not pressed, button judge module 2133e generates button detection signal AD0;
If continuous 8 key induced signal value AD
kEYthan induced key fiducial value AD
benbe less than more than 5 A/D conversion unit values, then judge that capacitance touch button 20 is pressed, button judge module 2133e generates button detection signal Adf;
After capacitance touch button 20 is pressed, if continuous 8 key induced signal value AD
kEYthan induced key fiducial value AD
benbe less than less than 3 A/D conversion unit values, then judge that capacitance touch button 20 discharges, button judge module 2133e regenerates button detection signal AD0.
In sum, capacitive induction button of the present invention and key detecting method thereof make use of the operation principle of " capacitance charge transfer ", and circuit structure is simple, reliability is strong, filtering interfering, reaches the object of detecting button, can be widely used in various electric equipment products.
The foregoing is only embodiments of the invention; not thereby the scope of the claims of the present invention is limited; every utilize specification of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.
Claims (7)
1. a capacitive induction button, is characterized in that, comprises capacitance touch button (20) and microprocessor (21); Wherein said capacitance touch button (20) has induction electrode (201); Induction electrode (201) connects described microprocessor (21); Microprocessor (21) connects capacitance touch button (20) by input/output end port (210), the touch sensible electric capacity (Cf) of described induction electrode (201) detects to described capacitance touch button (20) repeated charge, generate button detection signal (AD0, ADf)
Described microprocessor (21) comprising: capacitance charge carry circuit (211), to parasitic capacitance (Ch) repeated charge and the Charger transfer of described capacitance touch button (20) and microprocessor (21); Sampling keeps analog to digital converter (212) repeatedly, and after acquisition Charger transfer of repeatedly sampling, capacitance touch button (20) is some to input signal values (ADl, ADh); Digital signal processing module (213), what obtain keep analog to digital converter (212) conversion to repeatedly sampling after is described some to input signal values (ADl, ADh) carry out depositing, differential comparison computing, digital filtering and dual threshold compare, obtain button detection signal (AD0, ADf)
Described digital signal processing module (213) comprises register (2131), deposits the described input signal values (ADl, ADh) obtained after keeping analog to digital converter (212) conversion through repeatedly sampling; Differential comparison computing module (2132), what obtain keep analog to digital converter (212) conversion to repeatedly sampling after somely carries out differential comparison computing to described input signal values (ADl, ADh) and obtains several differential signals (ADn); Digital filtering and button judge module (2133), carry out digital filtering to described several differential signals (ADn) and dual threshold compares the described button detection signal (AD0, ADf) of acquisition.
2. capacitive induction button according to claim 1, it is characterized in that: described charge transfer circuit (211) comprises the first discharge and recharge terminal (RA0), first control switch (K1), second discharge and recharge terminal (RA1), the second control switch (K2) and charge transfer switch (K0); Wherein the first discharge and recharge terminal (RA0) connects described capacitance touch button (20) by described first control switch (K1); Second discharge and recharge terminal (RA1) connects the parasitic capacitance (Ch) of microprocessor by the second control switch (K2); Charge transfer switch (K0) connects described capacitance touch button (20) and described parasitic capacitance (Ch) and Charger transfer both controlling.
3. capacitive induction button according to claim 1, it is characterized in that, described differential comparison computing module (2132) to some keep analog to digital converter (212) conversion to repeatedly sampling after input signal values (ADl, ADh) carry out differential comparison computing and obtain several differential signals (ADn).
4. capacitive induction button according to claim 1, it is characterized in that, described digital filtering and button judge module (2133) comprise first order digital filter (2133a), second level digital filter (2133b), third level digital filter (2133c), induced key fiducial value computing module (2133d) and button judge module (2133e), wherein:
First order digital filter (2133a) removes maximum, the peaceful mean operation of minimum value to several differential signals (ADn) in very first time interval, obtains first order digital filtering value;
Second level digital filter (2133b) removes maximum, the peaceful mean operation of minimum value to the multiple first order digital filtering values obtained in second time interval, obtains second level digital filtering value;
Third level digital filter (2133c) to be averaged value computing to the multiple second level digital filtering value obtained in the 3rd time interval, obtains third level digital filtering value, as key induced signal value (ADKEY);
Induced key fiducial value computing module (2133d) calculates the induced key fiducial value (ADben) when capacitance touch button (20) is not pressed;
The more described key induced signal value (ADKEY) of button judge module (2133e) and induced key fiducial value (ADben), judge whether described capacitance touch button (20) is pressed, generate button detection signal (AD0, ADf).
5. a key detecting method for capacitive induction button, is characterized in that, comprises the following steps:
Step 1: by a microprocessor (21) to capacitance touch button (20) repeated charge and Charger transfer;
Step 1a: to touch sensible electric capacity (Cf) and outside distribution stray capacitance (Co) electric discharge of capacitance touch button (20), the parasitic capacitance (Ch) of microprocessor (21) is charged; Then parasitic capacitance (Ch) is made to charge to touch sensible electric capacity (Cf) and outside distribution stray capacitance (Co), when after three's charge balance, acquiring touch inductance capacitance (Cf) and outside the first input signal values (ADh) distributed in stray capacitance (Co);
Step 1b: to touch sensible electric capacity (Cf) and outside distribution stray capacitance (Co) charging of capacitance touch button (20), the parasitic capacitance (Ch) of microprocessor (21) is discharged; Then touch sensible electric capacity (Cf) and outside distribution stray capacitance (Co) is made to charge to parasitic capacitance (Ch), when after three's charge balance, acquiring touch inductance capacitance (Cf) and outside the second input signal values (ADl) distributed in stray capacitance (Co);
Step 1c: repeatedly perform step 1a, 1b and obtain some to the first and second input signal values (ADh, ADl);
Step 2: detected the touch sensible electric capacity (Cf) on described capacitance touch button (20) by microprocessor (21), generates button detection signal (AD0, ADf);
Step 2a: some to described differential comparison computing is carried out to the first and second input signal values (ADh, ADl) obtain several differential signals (ADn);
Step 2b: multi-stage digital filtering is carried out to described several differential signals (ADn) and generates key induced signal value (ADKEY);
Step 2c: calculate the induced key fiducial value (ADben) when capacitance touch button (20) is not pressed;
Step 2d: more described key induced signal value (ADKEY) and induced key fiducial value (ADben), judges whether capacitance touch button (20) is pressed, thus generates button detection signal (AD0, ADf).
6. key detecting method according to claim 5, is characterized in that, described step 2b specifically comprises:
Maximum, the peaceful mean operation of minimum value is gone to several differential signals (ADn) in very first time interval, obtains first order digital filtering value;
Maximum, the peaceful mean operation of minimum value is gone to the multiple first order digital filtering values obtained in second time interval, obtains second level digital filtering value;
The multiple second level digital filtering value obtained in 3rd time interval is averaged value computing, obtains third level digital filtering value, as described key induced signal value (ADKEY).
7. key detecting method according to claim 5, is characterized in that, described step 2d specifically comprises:
If continuously a predetermined quantity key induced signal value (ADKEY) is than more than the large first threshold of induced key fiducial value (ADben), then judge that capacitance touch button (20) is not pressed;
If continuously a predetermined quantity key induced signal value (ADKEY) is than more than the little Second Threshold of induced key fiducial value (ADben), then judge that capacitance touch button (20) is pressed;
After capacitance touch button (20) is pressed, if continuously below predetermined quantity key induced signal value (ADKEY) the 3rd threshold value less of induced key fiducial value (ADben), then judge that capacitance touch button (20) discharges.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110007159.2A CN102594327B (en) | 2011-01-14 | 2011-01-14 | Capacitive sensing key and key detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110007159.2A CN102594327B (en) | 2011-01-14 | 2011-01-14 | Capacitive sensing key and key detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102594327A CN102594327A (en) | 2012-07-18 |
| CN102594327B true CN102594327B (en) | 2015-04-15 |
Family
ID=46482592
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201110007159.2A Active CN102594327B (en) | 2011-01-14 | 2011-01-14 | Capacitive sensing key and key detection method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102594327B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106775177A (en) * | 2017-02-15 | 2017-05-31 | 江苏沁恒股份有限公司 | A kind of induced key detection method and detection means |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102998619B (en) * | 2012-11-28 | 2015-07-15 | 深圳和而泰智能控制股份有限公司 | Method, device and system for testing sensing buttons |
| CN103475352B (en) * | 2013-09-06 | 2017-07-25 | 深圳市芯海科技有限公司 | The detection circuit of capacitance touch button |
| CN104796129A (en) * | 2015-04-17 | 2015-07-22 | 厦门市芯网电子科技有限公司 | Capacitive touch key identification device with self-calibration function |
| TWI566143B (en) * | 2015-08-28 | 2017-01-11 | 宏碁股份有限公司 | Method of controlling touch-sensitivity of touch-display and electronic device |
| CN108228010B (en) * | 2016-12-13 | 2024-09-06 | 佛山市顺德区美的电热电器制造有限公司 | Capacitive touch sensing key detection circuit and method and household appliance |
| CN109412572A (en) * | 2017-08-17 | 2019-03-01 | 深圳指芯智能科技有限公司 | Low-power consumption touch sensible wakes up system and method |
| CN109245791B (en) * | 2018-07-25 | 2020-12-08 | 上海皇和信息科技有限公司 | Wrist-off detection device and detection method for smart bracelet |
| WO2020047715A1 (en) * | 2018-09-03 | 2020-03-12 | Texas Instruments Incorporated | Touch sensor circuit |
| CN109560804A (en) * | 2018-11-07 | 2019-04-02 | 珠海格力电器股份有限公司 | Touch key control method, control circuit and chip |
| CN109495100A (en) * | 2018-11-15 | 2019-03-19 | 西安中颖电子有限公司 | A kind of adaptive key touch detecting system and method |
| CN109428578B (en) * | 2018-11-30 | 2023-08-08 | 珠海巨晟科技股份有限公司 | Capacitive touch key anti-interference detection device and detection method |
| CN110739953B (en) * | 2019-10-18 | 2023-05-09 | 四川中微芯成科技有限公司 | Scene type signal self-adaptive processing method of capacitive touch key and electronic device |
| CN110798194B (en) * | 2019-11-04 | 2023-08-11 | 四川中微芯成科技有限公司 | Quick detection method and system for capacitive touch multi-key |
| CN111769828A (en) * | 2020-07-14 | 2020-10-13 | 成都芯思源科技有限公司 | Capacitive touch key circuit and electronic equipment |
| CN114895809A (en) * | 2022-07-14 | 2022-08-12 | 深圳贝特莱电子科技股份有限公司 | Improve anti-jamming capability's spaced touch circuit, touch button and touch product |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6452514B1 (en) * | 1999-01-26 | 2002-09-17 | Harald Philipp | Capacitive sensor and array |
| CN1832349A (en) * | 2006-04-19 | 2006-09-13 | 北京希格玛晶华微电子有限公司 | Capacitor measuring touch sensing identifying method and implementing device |
| CN101213461A (en) * | 2005-06-03 | 2008-07-02 | 辛纳普蒂克斯公司 | Methods and systems for detecting a capacitance using SIGMA-DELTA measurement techniques |
| CN201956996U (en) * | 2011-01-14 | 2011-08-31 | 苏州路之遥科技股份有限公司 | Capacitive sensing key |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8427450B2 (en) * | 2009-01-12 | 2013-04-23 | Microchip Technology Incorporated | Capacitive touch sensing and light emitting diode drive matrix |
-
2011
- 2011-01-14 CN CN201110007159.2A patent/CN102594327B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6452514B1 (en) * | 1999-01-26 | 2002-09-17 | Harald Philipp | Capacitive sensor and array |
| CN101213461A (en) * | 2005-06-03 | 2008-07-02 | 辛纳普蒂克斯公司 | Methods and systems for detecting a capacitance using SIGMA-DELTA measurement techniques |
| CN1832349A (en) * | 2006-04-19 | 2006-09-13 | 北京希格玛晶华微电子有限公司 | Capacitor measuring touch sensing identifying method and implementing device |
| CN201956996U (en) * | 2011-01-14 | 2011-08-31 | 苏州路之遥科技股份有限公司 | Capacitive sensing key |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106775177A (en) * | 2017-02-15 | 2017-05-31 | 江苏沁恒股份有限公司 | A kind of induced key detection method and detection means |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102594327A (en) | 2012-07-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102594327B (en) | Capacitive sensing key and key detection method | |
| CN201956996U (en) | Capacitive sensing key | |
| CN101419522B (en) | Capacitance touch detection device and detection method thereof | |
| EP2680018B1 (en) | Method and apparatus for detecting key | |
| CN102667690B (en) | Methods and apparatus for performing capacitive touch sensing and proximity detection | |
| CN102915138B (en) | Sensor electrode array control circuit, control method and touch-control sensing system thereof | |
| CN101799734B (en) | Key detection method for capacitive touch screen | |
| CN102902393B (en) | Detecting electrode Array Control Circuit, control method and touch detection system thereof | |
| CN102193032A (en) | Self-capacitance change measuring circuit with high precision and high stability | |
| CN102522975B (en) | Adaptive-environmental touch key circuit and key touch detection method | |
| CN104104375B (en) | Strengthen the method and circuit of the anti-mobile phone interference of capacitance type touch key | |
| CN102193033A (en) | Self-capacitance change measuring circuit with quick response | |
| CN109245754A (en) | A kind of capacitance touch button circuit for detecting and method | |
| CN102185604A (en) | Differential detection circuit for capacitive touch | |
| CN102346607B (en) | Touch control sensing circuit and method | |
| CN110739953A (en) | Scene type signal self-adaptive processing method of capacitive touch keys and electronic device | |
| CN103823598A (en) | Touch sensing circuit and touch sensing method | |
| CN115202515A (en) | Touch key detection method and detection circuit, microcontroller and touch detection system | |
| CN113644905A (en) | Capacitive touch key detection system | |
| KR101421464B1 (en) | Control system of a touch panel and a control method thereof | |
| CN111459340A (en) | Touch key anti-interference processing method and touch key device | |
| CN116203411A (en) | Touch key capacitance detection method and system applied to MCU | |
| CN202177879U (en) | Sensor electrode array control circuit and touch sensing system thereof | |
| TWI400456B (en) | Used in capacitive touch buttons and proximity sensing sensing circuits and methods | |
| CN103049154A (en) | Touch signal acquisition method for capacitive touch switch |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |