The MQ-9B is a CO and CH₄ gas detection sensor form Winsen. The sensing material of the MQ-9B is SnO2, which has a low conductivity in clean air. It detects carbon monoxide (1.5V) by method of cycling high and low temperature. The sensor’s conductivity gets higher with the CO and CH₄ gas concentration rising. The sensing range is 10-500ppm CH₄. A simple circuit makes measuring this change in conductivity and turning it into data fairly straight-forward, but does require some calibration.
For easy Solderability; use our [Gas Sensor Breakout Board](https://www.sparkfun.com/products/8891).