Methane CNG Gas Sensor - MQ-4
This Methane compressed natural gas (CNG) gas sensor is literally the definition of “Magic”. It does a great job at detecting natural gas concentrations (mostly methane CH4). It could even reach anywhere ranging between 200 and 10000ppm, what makes it more interesting is the fact that its response time is fast, you don’t have to wait at all, instantly accomplishes the mission.
Also, it’s very sensitive. An analog resistance is what’s considered as the output of the sensor. By the way, to prove to you how simple the drive circuit it, all you have to do is to power the heater coil with 5V, add a load resistance, and connect the output to an ADC, and that’s it! All ready.