During the First Meeting of Electronic Arts in FlorianÃ³polis, we built a Breathalyzer using the Alcohol Gas Sensor MQ-3 and an Arduino Board to use in the last day of the meeting, in which we gave a party. You can see a quick video two posts below. Last days I received many emails asking for the code or how to make one, so I decided to build the sensor again, take pictures/videos and make a tutorial showing how you can make one, so here it is.
- Arduino Board
- 10x 5mm LEDs (Green, Yellow and Red)
- 100KÎ© Potentiometer (to calibrate the sensor)
- 10x â‰ˆ 220Î© Resistor (anything between 220Î© and 470Î© is OK)
- MQ-3 Sensor from Sparkfun
Here are some pictures from the building process:
To make the LEDs work, I have connected them in sequence using the Digital Pins 2 till 11 (ten LEDs total). Remember to use a resistor between 220Î© and 470Î© for each LED, like shown on the picture below:
To connect the sensor, you have to connect one of the H pin to +5V Supply (use an external power supply for that, it may be too much current for the arduino) and the other one to Ground.
Pin B (any of them) you connect to Ground. And the A pin (also any of them) you connect to the 100KÎ© potentiometer as shown on the picture below. In the same pin where you are connecting the pin A, you need to connect a wire to the Analog/Digital Converter in Arduino, that is where you are going to read the Alcohol information.
This is a quick and easy DIY project, but if you have any problem building it, please feel free to post questions!
And now, have a great drinking!!!
Remember, if you gonna drive, don’t drink,
but if you do, call me!!