Description

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.

The sensors of the MQ series use a small heating element with an electronic-chemical sensor. They are sensitive to various gases and are suitable for the use in rooms.

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.

This sensor is ready for connection to a microcontroller, an Arduino board for example. For the use with a Raspberry Pi, an AD converter is required.

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.