MQ-137 GAS SENSOR

🔹 MQ-137 Gas Sensor Module – Ammonia (NH₃) Detector

The MQ-137 is a high-sensitivity semiconductor gas sensor module designed for detecting Ammonia (NH₃) concentrations in the air. It also has sensitivity to other gases like amines and is ideal for air quality monitoring, industrial safety, agricultural applications, and environmental sensing projects. The module provides both analog and digital outputs, making it easy to interface with microcontrollers like Arduino, ESP32, and Raspberry Pi.

✅ Specifications:

• Sensor Type: MQ-137 Metal Oxide Semiconductor (MOS)

• Target Gas: Ammonia (NH₃) – High Sensitivity

• Also Detects: Amines, other alkaline gases (cross-sensitivity)

• Detection Range: 5 – 500 ppm (NH₃)

• Operating Voltage: 5V DC

• Heater Voltage: 5V AC/DC

• 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, recommended for accurate readings)

• Dimensions: ~32mm x 20mm x 22mm

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

📦 Applications:
✔️ Industrial ammonia leak detection (refrigeration systems, chemical plants)
✔️ Agricultural monitoring (livestock farms, fertilizer storage, composting)
✔️ Air quality monitoring in laboratories and cold storage facilities
✔️ Environmental sensing and pollution studies
✔️ Smart agriculture and greenhouse gas monitoring
✔️ Food processing and cold chain monitoring
✔️ Arduino and IoT-based gas detection systems
✔️ Safety alarms for confined spaces

⚠️ 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 ammonia concentrations is advised.

• Cross-sensitivity. The sensor may respond to other gases like alcohol, hydrogen, and methane. Refer to the datasheet for selectivity details.

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