Arduino Compatible Alcohol Sensor Module

MQ-3 packaged works well!

Gotta say, this component works a treat. It simplifies using the raw MQ-3 sensor on its own (with its extra, and necessary heater connectors etc.), and just makes it as simple as it can with its either analog or digital outputs. The device works on the principle of SnO2 changing resistivity as concentration of ethanol (or other alcohols) changes ... basically: Increase [EtOH] = lower resistance (which you measure on eg. your Arduino board). Just provide the power through Vcc and a GND, and measure output variation through either DO (for digital processing - you need more logic to do this) or AO for simple resistivity output eg. in went 5 volts, out came 3. Note: you would need to calibrate the sensor to make it accurately say something. There is a simple calibration variable resistor on board if and only if you have quality reference points for [EtOH]. (Sorry using official terms for ethanol (booze) and concentrations thereof!).