https://wiki.jw-tech.eu/index.php?action=history&feed=atom&title=9530_%E2%80%93_MQ-3_Gas_Sensor%2Fen9530 – MQ-3 Gas Sensor/en - Versionsgeschichte2026-10-23T23:56:34ZVersionsgeschichte dieser Seite in JW Tech WikiMediaWiki 1.43.9https://wiki.jw-tech.eu/index.php?title=9530_%E2%80%93_MQ-3_Gas_Sensor/en&diff=1970&oldid=prevJWTechPublisher: Freigegebene technische Dokumentation veröffentlicht; Text-only und noindex2026-09-05T22:40:17Z<p>Freigegebene technische Dokumentation veröffentlicht; Text-only und noindex</p>
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'''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.<br />
<br />
== Summary ==<br />
The MQ-3 is a tin-oxide based gas sensor that is primarily sensitive to alcohol and ethanol. It provides an analog output (AOUT) and a digital threshold output (DOUT), whose sensitivity can be adjusted via a potentiometer.<br />
<br />
== Related products at JW Tech ==<br />
* [https://shop.jw-tech.eu/p/9530 9530 – MQ-3 Gas Sensor]<br />
* [https://shop.jw-tech.eu/p/WSAL9530 WSAL9530 – MQ-3 Gas Sensor]<br />
<br />
== Technical overview ==<br />
* Sensing material: tin dioxide (SnO2); conductivity increases as the concentration of alcohol vapor in the air rises.<br />
* Power supply: 2.5 V to 5.0 V; the Pico example uses 3.3 V, the Arduino example uses 5 V.<br />
* Dimensions: 40.0 mm x 21.0 mm; mounting hole diameter 2.0 mm.<br />
* Pinout: DOUT (digital data output), AOUT (analog data output), GND (ground), VCC (power input).<br />
* Pico connection: VCC to 3.3 V, GND to GND, AOUT to GP26, DOUT to GP22.<br />
* STM32 connection (F103RB): VCC to 3.3 V, GND to GND, AOUT to PA6, DOUT to PA4.<br />
* Arduino UNO connection: VCC to 5 V, GND to GND, AOUT to A0, DOUT to D2.<br />
* Preheat time: The sensor needs about one minute to heat the internal sensing material.<br />
* Behavior: When the target gas is present, the module indicator LED lights up; it turns off once the sensor is removed.<br />
<br />
'''Commands and examples – verify before use:''' <br />
<syntaxhighlight lang="text"><br />
sudo apt-get install p7zip-full<br />
cd ~<br />
sudo wget https://files.waveshare.com/upload/1/13/MQ-3-Gas-Sensor-code.7z<br />
7z x MQ-3-Gas-Sensor-code.7z -o./MQ-3-Gas-Sensor-code<br />
cd ~/MQ-3-Gas-Sensor-code<br />
cd Pico/c/build/<br />
cd ~/MQ-3-Gas-Sensor-code/Pico/c/<br />
cd build<br />
export PICO_SDK_PATH=../../pico-sdk<br />
cmake ..<br />
make -j9<br />
cp main.uf2 /media/pi/RPI-RP2/<br />
</syntaxhighlight><br />
<br />
== Notes and version constraints ==<br />
* The provided examples are based on specific boards (Pico, STM32F103RBT6/H743, Arduino UNO). For other boards, connections and code may need to be adapted or ported.<br />
* The exact firmware version for the Pico (rp2-pico-20210418-v1.15.uf2) is version-sensitive; compatibility with newer Pico variants must be verified.<br />
* The preheat time of about one minute is a guideline; it may vary with ambient temperature.<br />
* The instruction “make -j9” applies to standard Pi; for a Pi Zero, only “make” should be run, as noted in the source.<br />
* The source contains no information about certifications, warranty, or safety standards – no such claims are made.<br />
<br />
== Source and revision record ==<br />
* [https://www.waveshare.com/wiki/MQ-3_Gas_Sensor MQ-3 Gas Sensor - Waveshare Wiki]<br />
* Source revision: 68939<br />
* Captured: 2026-08-29T09:41:17+00:00<br />
* SHA-256: <code>7ae04700381d06690eab1205822d40222136a19a4cd38a6f018d1c4526713069</code></div>JWTechPublisher