wokwi-mq2-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	part 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:

1. Connect VCC to 5V power supply
2. Connect GND to ground
3. For analog readings:
   • Connect AO to an analog input pin
   • Read the analog value to get relative gas concentration
4. For threshold detection:
   • Connect DO to a digital input pin
   • The pin will read LOW when gas concentration exceeds threshold
   • Adjust threshold using the threshold attribute

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.

Simulator examples

• MQ2 Gas Sensor Digital Example