Description: This is a simple-to-use compressed natural gas (CNG)sensor, suitable for sensing natural gas (composed of mostly Methane [CH4]) concentrations in the air. The MQ-4 can detect natural gas concentrations anywhere from 200 to 10000ppm.
Operating voltage 5V
Operating current 40mA
Both digital and analog output
Popular sensor - a lot of examples available for different platforms
Port explanation : AO for analog output, DO for digital output, GND for ground, VCC for 5V voltage input