MQ3 Alcohol Sensor Module

The MQ3 Alcohol Sensor Module uses a semiconductor gas-sensitive material (SnO₂) that changes resistance when exposed to ethanol or alcohol vapors. As alcohol concentration increases, the sensor’s conductivity rises and generates an analog voltage signal proportional to the intensity of detected alcohol.

The module includes a comparator circuit with an adjustable potentiometer to set a detection threshold and provide a digital output alarm signal when the concentration exceeds the predefined level. LED indicators are provided for power and alert status visualization.
Due to its strong sensitivity to ethanol and lower sensitivity to smoke and other gases, it is widely used in alcohol breath analyzers, vehicle safety systems, industrial monitoring, access control systems, and smart automation platforms. It can interface easily with Arduino, ESP, STM, and Raspberry Pi.