This is a very easy to use low cost semiconductor Gas sensor Module with analog and digital output. This module uses MQ3 Alcohol gas sensor as a alcohol gas sensing element. It requires no external components just plug in Vcc & ground pins and you are ready to go.
For Digital output the threshold value can be easily set by an on-board potentiometer. Using this module you can easily interface MQ3 Alcohol sensor to any Microcontroller, Arduino or even Raspberry Pi.
Since this Gas Sensor module is sensitive to alcohol it can be used in breathalyser. MQ3 Sensor also has small sensitivity to Benzine.