CN102305877A

CN102305877A - Blowing behavior detection method and detector for alcohol content of exhaled gas

Info

Publication number: CN102305877A
Application number: CN 201110133466
Authority: CN
Inventors: 闫玉卿; 候宗合; 刘柯; 高锋; 刘宁; 郑建利
Original assignee: Henan Hanwei Electronics Co Ltd
Current assignee: Hanwei Technology Group Ltd By Share Ltd
Priority date: 2011-05-23
Filing date: 2011-05-23
Publication date: 2012-01-04
Anticipated expiration: 2031-05-23
Also published as: CN102305877B

Abstract

The invention provides a blowing behavior detection method and a detector for the alcohol content of exhaled gas. The method comprises the following steps of: connecting a sampling resistor and a thermistor arranged in a blowpipe in series to obtain a voltage-dividing sampling circuit; applying fixed voltage to two ends of the voltage-dividing sampling circuit, and continuously acquiring voltage U2 at two ends of the sampling resistor; blowing gas into the blowpipe; and if the voltage U2 is continuously reduced, regarding the blowing behavior as an effective blowing behavior, and if the voltage U2 is not continuously reduced, continuously blowing gas into the blowpipe. The detector comprises a microprocessor circuit, a blowing behavior detection circuit and the blowpipe, wherein the blowing behavior detection circuit comprises a thermistor, a sampling resistor, a direct-current power supply, a resistor and a capacitor; one end of the thermistor is connected with the direct-current power supply, and the other end of the thermistor is connected with one end of the sampling resistor and one end of the resistor; the other end of the sampling resistor is grounded; the other end of the resistor is connected with one end of the capacitor and an input/output (I/O) port of an analog-to-digital conversion module of the microprocessor circuit; and the other end of the capacitor is grounded. The method has high practicability; and the detector has low cost and accurate detection results.

Description

Air blowing motion detection method and alcoholicity of exhaled gas detector

Technical field

The present invention relates to a kind of air blowing motion detection method and checkout equipment, specifically, related to a kind of air blowing motion detection method and alcoholicity of exhaled gas detector.

Background technology

At present; The alcoholicity of exhaled gas detector of Xiao Shouing on the market; Every air blowing measuring ability of having; Almost judged whether to blow to move through pressure transducer entirely and taken place; Its concrete principle is: action takes place as blowing; When promptly having air flow stream to cross blowpipe; The pressure transducer that is connected to the blowpipe sidewall can monitor the variation of pressure; And be the variation of electric signal with the change transitions of pressure signal; After handling through amplification, filtering, analog to digital conversion etc. then; Send into microprocessor, thereby judge the generation of the action of blowing; The method is used simple and convenient, but structure and complicated circuit, cost is higher.

In order to solve the problem of above existence, people are seeking a kind of desirable technical solution always.

Summary of the invention

Goal of the invention of the present invention is the deficiency to prior art; Thereby the air blowing motion detection that a kind of method is simple, practical, accuracy of detection is high, with low cost method is provided, also provide a kind of simple in structure, cost is low, testing result alcoholicity of exhaled gas detector accurately.

In order to realize the foregoing invention purpose, the technical scheme that the present invention adopted is: a kind of air blowing motion detection method, and it may further comprise the steps:

Step 1, with sampling resistor R2 be arranged on the thermistor R1 series connection in the blowpipe, constitute pressure sampling circuit;

Step 2, apply fixed voltage, and constantly gather the voltage U 2 at sampling resistor R2 two ends at said pressure sampling circuit two ends;

Step 3, in blowpipe, blow;

Step 4, if voltage U 2 continues to descend or rise, then being considered as once effectively blowing action, otherwise, return step 3.

Based on above-mentioned, in step 4,, then start the timer timing in case voltage U 2 descends or rises; If voltage U 2 continues to descend or rise, and timer reaches predetermined timing time, then being considered as once effectively blowing action, otherwise, return step 3.

Based on above-mentioned, in step 2, apply fixed voltage to said pressure sampling circuit two ends through on-off circuit, and the conducting of dynamic adjustments on-off circuit and shut-in time, make voltage U 2 be stabilized in fixed voltage value.

Alcoholicity of exhaled gas detector based on above-mentioned air blowing motion detection method; It comprises microcontroller circuit; Air blowing motion detector circuit and blowpipe; Said air blowing motion detector circuit comprises the thermistor R1 that is arranged in the blowpipe; Sampling resistor R2; Direct supply VCC; Resistance R 3 and capacitor C 1; Wherein, Said thermistor R1 one end connects said direct supply VCC; The said thermistor R1 other end connects said sampling resistor R2 one end and said resistance R 3 one ends respectively; Said sampling resistor R2 other end ground connection; Said resistance R 3 other ends connect the I/O mouth of the analog-to-digital conversion module of said capacitor C 1 one ends and said microcontroller circuit respectively, said capacitor C 1 other end ground connection.

Based on above-mentioned; Said air blowing motion detector circuit comprises current-limiting resistance R4 and triode Q1; The said sampling resistor R2 other end connects the collector of said triode Q1; The grounded emitter of said triode Q1; The base stage of said triode Q1 connects said current-limiting resistance R4 one end, and the said current-limiting resistance R4 other end connects the output port of the pulse width modulation module of said microcontroller circuit.

Based on above-mentioned, said microcontroller circuit comprises microprocessor, analog-to-digital conversion module and pulse width modulation module, and said microprocessor connects analog-to-digital conversion module and pulse width modulation module respectively.

The relative prior art of the present invention has outstanding substantive distinguishing features and marked improvement property; Specifically; This air blowing motion detection method is through being positioned over the thermistor in the blowpipe; Whether detect has breath to flow through blowpipe; Whether have the action of air blowing to take place thereby detect, it has the advantage that method is simple, practical, accuracy of detection is high, with low cost;

This alcohol content detector is through being positioned over the thermistor in the blowpipe; And cooperate sampling resistor, RC filtering circuit, microprocessor, transistor switching circuit with analog-to-digital conversion module and pulse width modulation module; Whether whether detecting has breath to flow through blowpipe, have the action of air blowing to take place thereby detect; Whether the characteristic of its employing thermistor detects effective air blowing action and takes place, and not only structure and circuit are simple, and cost is very low, and testing result is accurate.

Description of drawings

Fig. 1 is the electrical block diagram of said alcoholicity of exhaled gas detector.

Embodiment

Through embodiment, technical scheme of the present invention is done further detailed description below.

A kind of air blowing motion detection method, it may further comprise the steps:

Step 2, apply fixed voltage to said pressure sampling circuit two ends, and constantly gather the voltage U 2 at sampling resistor R2 two ends through on-off circuit; Simultaneously, according to the voltage U 2 that collects, the conducting of dynamic adjustments on-off circuit and shut-in time, make voltage U 2 be stabilized in fixed voltage value;

Step 3, in blowpipe, blow;

In case step 4 voltage U 2 descends or rises, and then starts the timer timing; If voltage U 2 continues to descend or rise, and timer reaches predetermined timing time, then being considered as once effectively blowing action, otherwise, return step 3.

As shown in Figure 1; A kind of alcoholicity of exhaled gas detector; It comprises microcontroller circuit; Air blowing motion detector circuit and blowpipe; Said air blowing motion detector circuit comprises the thermistor R1 that is arranged in the blowpipe; Sampling resistor R2; Direct supply VCC; Resistance R 3; Capacitor C 1; Current-limiting resistance R4 and triode Q1; Wherein, Said thermistor R1 one end connects said direct supply VCC; The said thermistor R1 other end connects said sampling resistor R2 one end and said resistance R 3 one ends respectively; The said sampling resistor R2 other end connects the collector of said triode Q1; The grounded emitter of said triode Q1; The base stage of said triode Q1 connects said current-limiting resistance R4 one end; The said current-limiting resistance R4 other end connects the output port of the pulse width modulation module of said microcontroller circuit; Said resistance R 3 other ends connect the I/O mouth of the analog-to-digital conversion module of said capacitor C 1 one ends and said microcontroller circuit respectively, said capacitor C 1 other end ground connection.

Whether the present invention adopts thermistor to detect the air blowing action effective, and wherein: the resistance of thermistor R1 can change along with variation of temperature; Sampling resistor R2 and thermistor R1 series connection constitutes pressure sampling circuit, when the change in resistance of thermistor R1, and the voltage at sampling resistor R2 two ends, promptly the voltage-to-ground that A is ordered among Fig. 1 also can change, and wherein, the CE voltage after the triode Q1 conducting can be ignored; Resistance R 3 is formed filtering circuit with capacitor C 1; Triode Q1 also can select metal-oxide-semiconductor for use for the control triode, and current-limiting resistance R4 is the current-limiting resistance of triode Q1 base stage, and the two forms on-off circuit; Analog-to-digital conversion module in the microprocessor can be digital signal with the analog-signal transitions that collects, thus the change in voltage that monitoring A is ordered; Pulse width modulation module output high-low level, the conducting of control triode Q1 and closing; Direct supply VCC is that circuit provides dc supply.

Concrete workflow is: at first; The I/O mouth output high level of the pulse width modulation module of microprocessor; Make triode Q1 conducting; At this moment; Have electric current and flow through thermistor R1; Then the electric energy of thermistor R1 consumption can change the heat energy of self into; Self temperature of thermistor R1 is raise; Simultaneously microprocessor can calculate the resistance of thermistor R1 through gathering the voltage that A is ordered, and then according to the corresponding relation of thermistor temp and resistance; Draw the temperature of thermistor R1; Like this, microprocessor just can obtain the temperature of thermistor R1 through monitoring the voltage that A is ordered;

After the temperature of thermistor R1 is elevated to a fixed temperature value; Microprocessor starts the width modulation function; Conducting through dynamically regulating triode Q1 and the ratio of shut-in time; Thereby about this fixed temperature value, notify the temperature stabilization of thermistor R1 this moment the user can begin to blow; Wherein, generally the environment temperature than instrument is slightly high for said fixed temperature value;

When the user begins to blow, when flowing through blowpipe fast, the temperature of thermistor R1 is descended suddenly owing to air-flow; It is big that the resistance of NTC type thermistor R1 then becomes suddenly; Thereby the voltage that microprocessor monitors is ordered to A is descended suddenly, and then thinking blows begins, and starts the timer timing; Wherein, during air blowing, if PTC type thermistor, then temperature descends, and resistance diminishes;

When air blowing continues to carry out, then the temperature of thermistor R1 can continue to descend, and the voltage that A order also continues decline; When timer reaches preset gassing time, thinking that then the action of once effectively blowing accomplishes, otherwise thinking to blow and interrupt; So far, a complete air blowing motion detection flow process is accomplished.

What need special instruction is; In other embodiments; Said microcontroller circuit comprises microprocessor, analog-to-digital conversion module and pulse width modulation module; Said microprocessor connects analog-to-digital conversion module and pulse width modulation module respectively; That is, analog-to-digital conversion module can be the separate modular that is connected respectively with microprocessor with pulse width modulation module.

Should be noted that at last: above embodiment is only in order to technical scheme of the present invention to be described but not to its restriction; Although with reference to preferred embodiment the present invention has been carried out detailed explanation, the those of ordinary skill in affiliated field is to be understood that: still can specific embodiments of the invention make amendment or the part technical characterictic is equal to replacement; And not breaking away from the spirit of technical scheme of the present invention, it all should be encompassed in the middle of the technical scheme scope that the present invention asks for protection.

Claims

1. air blowing motion detection method is characterized in that it may further comprise the steps:

Step 3, in blowpipe, blow;

2. air blowing motion detection method according to claim 1 is characterized in that: in step 4, in case voltage U 2 descends or rises, then start the timer timing; If voltage U 2 continues to descend or rise, and timer reaches predetermined timing time, then being considered as once effectively blowing action, otherwise, return step 3.

3. air blowing motion detection method according to claim 1; It is characterized in that: in step 2; Apply fixed voltage through on-off circuit to said pressure sampling circuit two ends, and the conducting of dynamic adjustments on-off circuit and shut-in time, make voltage U 2 be stabilized in fixed voltage value.

4. based on the alcoholicity of exhaled gas detector of each described air blowing motion detection method of claim 1-3; Comprise microcontroller circuit; Air blowing motion detector circuit and blowpipe; It is characterized in that: said air blowing motion detector circuit comprises the thermistor R1 that is arranged in the blowpipe; Sampling resistor R2; Direct supply VCC; Resistance R 3 and capacitor C 1; Wherein, Said thermistor R1 one end connects said direct supply VCC; The said thermistor R1 other end connects said sampling resistor R2 one end and said resistance R 3 one ends respectively; Said sampling resistor R2 other end ground connection; Said resistance R 3 other ends connect the I/O mouth of the analog-to-digital conversion module of said capacitor C 1 one ends and said microcontroller circuit respectively, said capacitor C 1 other end ground connection.

5. alcoholicity of exhaled gas detector according to claim 4; It is characterized in that: said air blowing motion detector circuit comprises current-limiting resistance R4 and triode Q1; The said sampling resistor R2 other end connects the collector of said triode Q1; The grounded emitter of said triode Q1; The base stage of said triode Q1 connects said current-limiting resistance R4 one end, and the said current-limiting resistance R4 other end connects the output port of the pulse width modulation module of said microcontroller circuit.

6. alcoholicity of exhaled gas detector according to claim 5; It is characterized in that: said microcontroller circuit comprises microprocessor, analog-to-digital conversion module and pulse width modulation module, and said microprocessor connects analog-to-digital conversion module and pulse width modulation module respectively.