wokwi-gas-sensor Reference
MQ2 Gas Sensor module
Pin names
| Name | Description |
|---|---|
| VCC | Positive power supply |
| GND | Ground |
| DO | Digital output |
| AO | Analog output |
Attributes
| Name | Description | Default value |
|---|---|---|
| ppm | Initial gas concentration (in parts per million) | "400" |
| threshold | Digital output threshold voltage | "4.4" |
Operation
The MQ2 Gas Sensor is a semiconductor sensor that can detect the presence of various combustible gases including LPG, Propane, Hydrogen, Methane, and Carbon Monoxide. The sensor has both analog and digital outputs:
- The analog output (AO) provides a continuous voltage reading that corresponds to the gas concentration (ppm). Higher gas concentration results in higher voltage output.
- The digital output (DO) acts as a threshold detector - it goes LOW when gas concentration exceeds the threshold set by the potentiometer.
To use the MQ2 sensor:
- Connect VCC to 5V power supply
- Connect GND to ground
- For analog readings:
- Connect AO to an analog input pin
- Read the analog value to get relative gas concentration
- For threshold detection:
- Connect DO to a digital input pin
- The pin will read LOW when gas concentration exceeds threshold
- Adjust threshold using the
thresholdattribute
Note: In real hardware, the sensor needs a pre-heating time of about 20-30 seconds before taking readings. The simulator provides readings immediately.
Digital output
The digital output (DO) pin will read LOW when gas concentration exceeds the threshold. The threshold is set by the threshold attribute. The default threshold is 4.4V.