MQ-4 Methane Gas Detection Sensor Module
MQ-4 Module Pin Out
| PIN NAME | DESCRIPTION |
| VCC | This pin powers the module, typically the operating voltage is +5V |
| GND | Used to connect the module to the system ground |
| Digital Out (DO) | You can also use this sensor to get digital output from this pin, by setting a threshold value using the potentiometer |
| Analog Out (AO) | This pin outputs 0-5V analog voltage based on the intensity of the gas |
MQ-4 Module Specifications
- Sensor type: Semiconductor
- Power: 5V DC
- DO output: TTL digital 0 and 1 (0.1 and 5V)
- AO output: 0.1 – 0.3V (relative to pollutant detection), maximum concentration of voltage ~4V
- Gas detection: Methane / Natural Gas
- Detection concentration: 200 – 10,000ppm (Methane / Natural Gas)
- Interface: 1 TTL compatible input (HSW), 1 TTL compatible output (ALR)
- Heater consumption: less than 750mW
- Operating temperature: -10 – 50°C
- RH related humidity: < 95%Rh
- O2 oxygen concentration: 21% for standard use (Changes in concentration can affect the sensitivity)
- Load resistance: 20KΩ
- Sensing resistnace Rs: 10KΩ – 60KΩ (1,000ppm CH4)
- Preheat time: >24 hours
- Materials: Standard encapsulation bakelite, Metal cap
Sensitivity Adjustment
The resistance value of the MQ-4 is differs for different kinds and different concentrations of gases. So while using this component, sensitivity adjustment is needed. It is recommended to calibrate the sensor for 5000ppm of CH4 concentration in air and use a value of Load resistance (RL) of 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.
