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

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

technical field [0001] The invention relates to a method for detecting the blowing action and a detection device, in particular to a method for detecting the action of blowing and an instrument for detecting alcohol content in exhaled gas. Background technique [0002] At present, the exhaled breath alcohol content detectors sold on the market almost all use the pressure sensor to judge whether there is a blowing action. The specific principle is: when there is a blowing action, That is, when there is air flow through the blowpipe, the pressure sensor connected to the side wall of the blowpipe can monitor the change of pressure, and convert the change of the pressure signal into the change of the electrical signal, and then send it to the Into the microprocessor, so as to determine the occurrence of the blowing action; this method is simple and convenient to apply, but the structure and circuit are complicated, and the cost is high. [0003] In order to solve the above exis...

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Problems solved by technology

[0002] At present, the exhaled breath alcohol content detectors sold on the market almost all use the pressure sensor to judge whether there is a blowing action. The specific principle is: when there is a blowing action, That is, when there is air flow through the blowpipe, the pressure sensor connected to the side wall of the blowpipe can monitor the change of pressure, and convert the change of pressure signal into the change of electrical signal, and then after amplification, filtering, analog-to-digital conversion, etc. into the microprocessor to determine the occurrence of the blowing action; this method is simple and convenient to apply, but the structure and circuit are complicated and the cost is high

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