The resistance value of MQ-4 Gas Sensor is the difference between various kinds and various concentration gases. So, When using this component, sensitivity adjustment is very necessary. we recommend that you calibrate the detector for 5000ppm of CH4 concentration in air and use the value of Load resistance ( RL) about 20KΩ(10KΩ to 47KΩ). When accurately measuring, the proper alarm point for the gas detector should be determined after considering the temperature and humidity influence.

This sensor is composed of micro AL2O3(Aluminium Oxide) ceramic tube, Tin Dioxide (SnO2) sensitive layer, measuring electrode and heater are fixed into a crust made of plastic and stainless steel net. The heater provides necessary work conditions for work of sensitive components. The enveloped MQ-4 Gas Sensor has 6 pins,4 of them are used to fetch signals, and other 2 are used for providing heating current.

Sensitive material of MQ-4 Gas Sensor is SnO2, which with lower conductivity in clean air. When the target combustible gas exists, The sensor’s conductivity is higher along with the gas concentration rising. The MQ-4 Gas Sensor has high sensitivity to Methane, also to Propane and Butane. The sensor could be used to detect different combustible gas, especially Methane, it is with low cost and suitable for different application. And it is a simple drive circuit.

WORKING PRINCIPLE OF MQ-4 Gas Sensor :

The MQ-4 Gas Sensor can detect natural gas concentrations anywhere from 300 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.

USES OF THE SENSOR:

  • Domestic gas leakage detector
  • Industrial Combustible gas detector
  • A portable gas detector, etc…

PICTURE:

SPECIFICATIONS:

  • Sensor Type: Semiconductor
  • Standard Encapsulation: Bakelite (Black Bakelite)
  • Concentration: 300-10000ppm
  • Loop Voltage: ≤24V DC
  • Heater Voltage : 5.0V±0.2V ACorDC
  • Load Resistance: Adjustable
  • Heater Resistance: 31Ω±3Ω(Room Temp.)
  • Heater consumption : ≤900mW
  • Sensing Resistance: 2KΩ-20KΩ (in 5000ppm CH4 )
  •  Sensitivity : Rs(in air) / Rs(5000ppm CH4)≥5
  • Slope : ≤0.6 (R5000ppm / R3000ppm CH4)
  • Temp. Humidity: 20℃±2℃;65%±5%RH
  • Pin Definition:  1-Output  2-GND  3-PWR
  • Standard test circuit : Vc = 5.0V±0.1V; VH = 5.0V±0.1V
  • Preheat time: Over 48 hours

SIMPLE PROJECT: 

Materials To Be Required: 

  • Arduino
  • MQ-4 Gas Sensor
  • BreadBoard
  • Jumper Wires

Connection with Arduino: 

VCC - 5V
GND - GND
S   - Analog pin0


CODE:

SERIAL MONITOR:

OTHER IDEAS: