This project uses MQ-3 gas sensor for detecting the alcohol level in the vapor.
MQ-3 gas sensor has high sensitivity to Alcohol and has good resistance to disturb of gasoline, smoke and vapor. The sensor could be used to detect alcohol with different concentration, it is with low cost and suitable for different application.
Principles
Sensitive material of MQ-3 gas sensor is SnO2, which with lower conductivity in clean air. When the target alcohol gas exists, The sensor’s conductivity is more higher along with the gas concentration rising.
Link
Arduino Project: Breathalyzer using MQ3 alcohol sensor 0.96' 128x64
Arduino DIY Breathalyzer With MQ3 Alcohol Sensor & OLED Display