MQ-9 Carbon Monoxide Gas Sensor Module



The sensor has a high sensitivity and fast response time, but it takes a few minutes to give accurate readings because the sensor needs to heat up. The measured values of the sensor are output as an analog value, which can be easily evaluated with a microcontroller.

Easy-to-use sensor for measuring the concentration of carbon monoxide and flammable gases such as methane and LPG in the air.

The MQ-9 measures a gas concentration of 100 to 10000ppm and is ideal for detecting a gas leak, as a gas alarm or for other robotics
and microcontroller projects.


Pin assignment:

  • VCC power supply 5V
  • GND ground connection
  • AOUT – Analog output
  • DOUT – Digital Output

To set the threshold, the module has a potentiometer. On the digital pin, the sensor outputs only a 0 or 1, depending on whether the set threshold value is exceeded.



  • Resolution: 100 ~ 10000ppm
  • Accuracy: ≥ 3%
  • Response time: ≤ 1s
  • Response time after switching on: ≤ 30s
  • Heating resistance: 31Ω ± 3Ω
  • Heating current: ≤ 180mA
  • Heating voltage: 5.0V ± 0.1V / 1.5 ± 0.1V
  • Heating power: 350mW
  • Working voltage: 5V
  • Dimensions: about 3.5 x 2.2cm (1.4 x 0.9inch)


More Information:

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Additional information

Weight 0.015 kg

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