Instructions | Do It Yourself Breathalyzer with MQ-3 & LEGO Brick

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Do It Yourself Breathalyzer
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Arduino sketch for ANAVI Gas Detector with MQ-3

An Arduino sketch for MQ-3 and ANAVI Gas Detector is available at GitHub. Download it and flash it to ANAVI Gas Detector through Arduino IDE.

Function detectAlcohol reads data from the pin connected to the analog output of MQ-3. Depending on the retrieved data and hardcoded threshold values, text is displayed on the mini OLED display.
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Building a case with LEGO bricks

ANAVI Gas Detector is placed on a big green LEGO® plate. LEGO® bricks are placed around it in a way to keep it in the same position. There is a whole for micro USB cable and placeholders for the mini OLED display and the MQ-3 sensor module.
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Calibration and Testing

MQ-3 is not very accurate and requires calibration depending on the air quality, the temperature and the humidity in the environment in which it will work. After doing the one-time pre-heat procedure, you can test the sensitivity of MQ-3 to various alcohol drinks.

Do It Yourself Breathalyzer with MQ-3 & LEGO Brick