Breathalyzer with MQ-3 and Arduino

Hi, I’ve made a Breathalyzer with MQ-3 and Arduino and wrote a full DIY tutorial

if you guys wanna take a look:



Nice! It would be really cool if you could get it to give you accurate readings in numbered digits! We should work this circuit into the Openbar project!


I am thinking of building something similar. Did you feel that the range of the MQ3 was enough? I am looking at the TGS 2620 which is far more sensitive and three times more expensive. Or is that overkill for alcohol testing?



Hi guys,

I bought the MQ-3 sensor. It’s easy to read the value of the sensor with an analog pin.

BUT i have a big problem : i need to calibrate the detector for 0,4mg/L (approximately 200ppm) of Alcohol concentration in air…

How get exactly 0,4 mg/L of Alcohol concentration in air ? :-/

various cryptic charts, should tell you how many beers to drink to get enlighted ;)


Thanks for your link. I also checked but there is no DIY solution…