Fun hobby project for building entirely open source breathalyzer with MQ-3, Arduino sketch for ANAVI Gas Detector and a lot of LEGO bricks.
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.
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.