MQ-4

MQ-4

MQ-4 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.

This sensor has a high sensitivity and fast response time. The sensor’s output is an analog resistance. The drive circuit is very simple; all you need to do is power the heater coil with 5V, add a load resistance, and connect the output to an ADC.

This sensor comes in a package similar to our MQ-3 alcohol sensor, and can be used with the breakout board below.

MQ-4 manual  data sheet is available here.

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Description

Sensitive material of MQ-4 gas sensor is SnO2, which with lower conductivity in clean air. When the target flammable gas exist, the sensor’s conductivity gets higher along with the gas concentration rising. Users can convert the change of conductivity to correspond output signal of gas concentration through a simple circuit. MQ-4 gas sensor has high sensitivity to methane, also has anti-interference to alcohol and other gases.

Features

It has good sensitivity to methane in wide range, and has advantages such as long lifespan, low cost and simple drive circuit &etc.

Main Applications

It is widely used in domestic gas leakage alarm, industrial flammable gas alarm and portable gas detector.

Instructions:

The above fig is the basic test circuit of MQ-4.The sensor requires two voltage inputs: heater voltage (VH) and circuit voltage (VC). VH is used to supply standard working temperature to the sensor and it can adopt DC or AC power, while VRL is the voltage of load resistance RL which is in series with sensor. Vc supplies the detect voltage to load resistance RL and it should adopts DC power.