MQ-4 Gas Sensor (Methane & Natural Gas)

The MQ-4 Methane Gas Sensor is a gas sensor that detects the presence of methane gas at concentrations from 200 ppm to 10,000 ppm, a range suitable for detecting gas leaks. The sensor's simple analog voltage interface requires only one analog input pin from your microcontroller.

The MQ-4 Methane Gas Sensor detects the concentration of methane gas in the air and ouputs its reading as an analog voltage. The concentration sensing range of 200 ppm to 10,000 ppm is suitable for leak detection. For example, the sensor could detect if someone left a gas stove on but not lit. The sensor can operate at temperatures from -10 to 50C and consumes less than 150 mA at 5 V.

Connections

Connecting five volts across the heating (H) pins keeps the sensor hot enough to function correctly. Connecting five volts at either the A or B pins causes the sensor to emit an analog voltage on the other pins. A resistive load between the output pins and ground sets the sensitivity of the detector.The resistive load should be calibrated for your particular application using the equations in the datasheet, but a good starting value for the resistor is 20 k.

Features
High sensitivity to CH4 and Natural gas
Slight sensitivity to alcohol, smoke
Fast response
Stable and long life
Simple drive circuit

Connection is a easy as this with a module:

VCC - 5V
GND - GND
A0 - Analog pin0
D0 - Not connected