The MQ-3 Alcohol Sensor Module is a cost-effective and reliable gas sensor designed for accurate detection of alcohol (ethanol) concentration in the air. It uses SnO₂ (tin dioxide) as its sensing material, which reacts sensitively to alcohol vapors. When alcohol is present, the sensor’s conductivity increases, converting gas concentration into a proportional voltage output signal. The module offers high sensitivity to alcohol while maintaining strong resistance against interference from gasoline, smoke, and water vapor — making it ideal for various applications. Key Features Dual Signal Output: Provides both analog (AO) and digital (DO) signal outputs for flexible applications. High Sensitivity: Detects alcohol vapors with a wide detection range of 10–1000ppm. Clear Indicators: Dual-sided PCB with power LED and digital output indicator for easy status monitoring. Adjustable Sensitivity: Onboard potentiometer allows tuning of the digital output (DO) threshold. Easy Installation: Comes with four M3 mounting holes for secure attachment. Stable & Durable: Long lifespan, fast response, and quick recovery times ensure reliable performance. Typical Applications Alcohol Testers: Ideal for DIY projects like building a personal or vehicle alcohol breath tester. Environmental Monitoring: Detect ethanol vapor levels in workshops, labs, or industrial environments. Arduino/MCU Projects: Easily integrates with Arduino, ESP32, Raspberry Pi, and other microcontrollers for automation or data logging applications. Technical Specifications Parameter Specification Operating Voltage DC 5V Current Consumption 150mA Target Gas Alcohol (Ethanol) Detection Range 10 – 1000ppm AO Output (Analog) 0.1–0.3V in clean air, up to 4V at high concentration DO Output (Digital) TTL-level 0/1 (0.1V / 5V) Module Dimensions 32.4mm × 20.4mm Net Weight 5.2g Pin Definition VCC: Connect to 5V DC power supply GND: Connect to ground DO: Digital output (TTL signal, connectable to MCU I/O pin) AO: Analog output (connectable to MCU ADC pin) Important Notes Warm-up Required: The sensor needs about 20 seconds of preheating after power-on for stable readings. Normal Heating: The internal heater may cause the sensor to feel warm — this is normal operation.
