BM22S3021-1 is a gas detector digital sensor, mainly used to detect methane (CH₄). When the gas concentration exceeds the preset calibration concentration, the voltage output of the alarm pin (pin 5) changes from low level to high level. It is easy to make a gas detector by supplying power to this sensor and monitoring the alarm output pin.

Each BM22S3021-1 is calibrated before leaving the factory to maintain consistent characteristics. The calibrated alarm threshold is 9% LEL (Lower Explosion Limit), which is about 4500ppm.

BM22S3021-1 can automatically transmit its internal status through the UART interface about once every second. The external host controller can receive the status of BM22S3021-1 in real-time without sending a command. In addition, BM22S3021-1 provides up to 26 commands. You can modify the alarm point and do various tests with the commands. The "restore factory settings" command is used to let the BM22S3021-1 return to the factory settings.