MQ Gas Sensors – Troubleshooting

This page contains some tips in case you are experiencing problems using this product.

Check wiring

Ensure that your Qwiic cable is properly connected and in good condition. Try using the same cable with another easyC-compatible device to verify that it works. If the issue persists, swap it out for a different cable to rule out any possible damage or defects.

Scan for I2C devices

Run an I2C scanner sketch on your microcontroller to check if the sensor is detected. If the scanner does not find any devices, there might be a wiring issue, incorrect pull-up resistors, or a problem with the microcontroller’s I2C bus.

Try reinitializing

If the sensor fails to initialize on the first attempt, try calling mq.begin() again in your code or resetting your microcontroller. Some initialization issues may be resolved by a simple reboot.

The sensor might be drawing too much power when uploading a sketch.

Disconnect the wires connected to the sensor

Before uploading the sketch, disconnect the wires connected to the sensor. After it is done uploading, reconnect them.

Connect an external battery

Connect an external battery so that the board receives enough power.

Preheat the sensors

All MQ sensors require a preheat time so they can clean themselves of any impurities that have stuck to them. This is mandatory, and each sensor has its own preheat time, which you can check in the datasheet.

Create a custom configuration

Depending on your needs, the predefined configuration structure for your sensor may be inadequate. Creating a custom configuration structure may help. You can see the example for creating one here.