Description
The MQ-138 is a gas sensor module specifically designed for detecting formaldehyde (HCHO) along with a range of volatile organic compounds (VOCs). It provides analog and digital outputs and is ideal for applications involving air quality monitoring and indoor pollution detection.
Key Features
- Formaldehyde Detection: Sensitive to HCHO and VOCs
- Dual Output: Analog voltage and TTL digital signal
- Adjustable Sensitivity: Onboard potentiometer
- Rapid Response: Fast gas concentration detection
- MCU Friendly: Easy to interface with Arduino, ESP32, etc.
- Stable Operation: Long lifespan and reliable performance
Specification
- Model: MQ-138
- Target Gases: Formaldehyde (HCHO), Benzene, VOCs
- Operating Voltage: 5V DC
- Output Modes:
- Analog (AO): 0V – 5V proportional to gas concentration
- Digital (DO): TTL signal (adjustable threshold)
- Heater Voltage: 5V DC
- Preheat Time: ≥ 20 seconds
- Response Time: <10 seconds
- Sensitivity Adjustment: Via onboard potentiometer
- Module Size: ~32 mm × 20 mm
- Weight: ~5 g
Application
- Indoor air quality monitoring
- Formaldehyde and VOC leak detection
- Smart home environmental sensors
- Office and hospital pollution alarms
- Arduino-based air safety projects