Alcohol detectors are mainly used to detect whether the human body has an alcohol intake and intake. It is often used in traffic law enforcement to detect whether to drink and drive and to test personnel in some high-risk prohibited areas. Theoretically, detecting the alcohol content in human blood is the most accurate way, but due to the limitations of the situation, drinking is usually indirectly judged by detecting the alcohol content in human breathing. Therefore, when testing, it is necessary to be able to measure the size of alcohol and exhalation volume respectively. Using pressure sensors to measure the size of the wind pressure when the human body blows is a common way to measure the amount of breath. In daily life, we know that when gas flows, a corresponding wind pressure will be generated. The size of the wind pressure can be seen from the Bernoulli equation that it is closely related to the gas density and flow rate. Therefore, for the same gas, different flow rates correspond to different wind pressure magnitudes. In the alcohol detector, the pressure in the ventilation tube when the human body is exhaled is measured through the pressure sensor, and the flow rate of the gas in the detector can be obtained first; then the flow rate of the gas at the time of the test can be calculated from the calibre of the pipe. After the alcohol content was measured in other parts of the alcohol detector, the volume of exhalation was measured according to the pressure sensor, and finally the concentration of alcohol in the exhaled gas was obtained. Thus, the drinking status of the tested personnel can be judged.

    The Sencoch GZP series is a piezoresistive silicon pressure sensor that provides proportional analogue output to provide pressure readings within the specified full-range pressure span and temperature range. The gauge pressure sensor takes atmospheric pressure as a reference and provides an output value proportional to the difference in atmospheric pressure.