9529 – MQ-2 Gas Sensor/en

Documentation notice: This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

Summary

The MQ-2 gas sensor uses tin dioxide (SnO2) as the sensitive material. Conductivity rises with the concentration of flammable gases such as LPG, propane and hydrogen. The module provides analog and digital outputs and is connected to a Raspberry Pi Pico, STM32 or Arduino UNO.

Related products at JW Tech

Technical overview

Sensitive material: tin dioxide (SnO2); low conductivity in clean air
High sensitivity to liquefied petroleum gas (LPG), propane and hydrogen; also suitable for natural gas and other combustible vapors
Analog output AOUT produces a voltage that increases with rising gas concentration
Digital output DOUT provides a threshold signal
Power supply 2.5 V to 5.0 V; boost chip PT1301
Module dimensions 40.0 mm × 21.0 mm; mounting holes 2.0 mm
Example code provided for Raspberry Pi Pico (C and MicroPython), STM32F103RBT6 / STM32H743 and Arduino UNO
Pico connection: VCC to 3.3 V, GND to GND, AOUT to GP26, DOUT to GP22
STM32 connection: VCC to 3.3 V, GND to GND, AOUT to PA6, DOUT to PA4
Arduino connection: VCC to 5 V, GND to GND, AOUT to A0, DOUT to D2

Commands and examples – verify before use:

sudo apt-get install p7zip-full
cd ~
sudo wget https://files.waveshare.com/upload/f/f2/MQ-2-Gas-Sensor-code.7z
7z x MQ-2-Gas-Sensor-code.7z -o./MQ-2-Gas-Sensor-code
cd ~/MQ-2-Gas-Sensor-code/Pico/c/build/
export PICO_SDK_PATH=../../pico-sdk
cmake ..
make -j9
cp main.uf2 /media/pi/RPI-RP2/
sudo apt upgrade thonny

Notes and version constraints

Before measuring, the sensor must preheat for about one minute so the sensitive material reaches operating temperature.
The provided examples are based on specific boards (Pico, STM32F103RB, Arduino UNO). For other boards, connections and code may need to be adapted.
Heating of the sensor during operation is normal because the sensitivity material must be heated.
For other STM32 boards, the code may need to be ported manually.
Exact threshold values for the digital output are not specified in the source; they must be calibrated per application.

Source and revision record

MQ-2 Gas Sensor - Waveshare Wiki
Source revision: 68902
Captured: 2026-08-29T09:40:01+00:00
SHA-256: da1348f553419a2f2d267d7396668e8c072769b464908b9727da1d14d745c2f4