MQ-3 Alcohol / Ethanol Gas Sensor

🔹 MQ-3 Alcohol / Ethanol Gas Sensor Module – Semiconductor Type

The MQ-3 is a highly sensitive semiconductor gas sensor designed specifically for detecting alcohol vapors (ethanol). It features fast response time and high sensitivity to alcohol while having good resistance to interference from gasoline, smoke, and humidity. Ideal for breathalyzer projects, alcohol detection systems, and safety alarms.

✅ Specifications:

• Sensor Type: MQ-3 Metal Oxide Semiconductor (MOS)

• Target Gas: Alcohol / Ethanol (C₂H₅OH)

• Detection Range: 0.04 – 4 mg/L (alcohol concentration)

• Operating Voltage: 5V DC

• Heater Voltage: 5V AC/DC

• Heater Power Consumption: ≤ 750mW

• Load Resistance: Adjustable (via onboard potentiometer)

• Output Signals:

  • Analog: 0–5V (proportional to gas concentration)

  • Digital: TTL (trigger threshold adjustable via potentiometer)

• Module Interface: 4-pin header (VCC, GND, DO, AO)

• Onboard Features: Power LED, Status LED, Sensitivity adjustment potentiometer

• Preheat Time: ≥ 48 hours (for initial stabilization)

• Dimensions: ~32mm x 20mm x 22mm

• Operating Temperature: -10°C to +50°C

📦 Features:
✔️ High sensitivity to alcohol vapors
✔️ Good selectivity (low sensitivity to gasoline, smoke, humidity)
✔️ Fast response and recovery time
✔️ Simple drive circuit (analog voltage output)
✔️ Long life and stable performance
✔️ Both analog and digital outputs for flexible interfacing

📦 Applications:
✔️ Breathalyzer / Alcohol breath testers
✔️ Drunk driving prevention systems (automotive)
✔️ Industrial alcohol vapor detection
✔️ Safety alarms for laboratories and chemical storage
✔️ Food processing (fermentation monitoring)
✔️ Arduino and IoT-based alcohol detection projects
✔️ Educational demonstrations on gas sensing

⚠️ Important Notes:

• Preheat time is critical. For accurate readings, the sensor requires a burn-in period of at least 24-48 hours before initial use.

• Calibration recommended. For precise measurements, calibration against known alcohol concentrations is advised.

• Cross-sensitivity. The sensor may respond to other reducing gases; refer to the datasheet for selectivity details.

• Requires a stable 5V power supply capable of providing sufficient current for the heater (~150mA).