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

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.