This is a very easy to use low cost semiconductor Gas sensor Module with analog and digital output. This module uses MQ4 Methane gas sensor as a gas sensing element. It requires no external components just plug in Vcc & ground pins and you are ready to go
Sensitive material of MQ-7 gas sensor is SnO2, which with lower conductivity in clean air. It make detection by method of cycle high and low temperature, and detect CO when low temperature (heated by 1.5V).
