DIY_Breathalyzer
Read BAC with MQ-3 sensor and display on 7-Segment Shield. "Tested" with the SparkFun RedBoard.
Full tutorial can be found on Hackster.
The wishlist of all the parts can be found here.
The code is beerware (seems appropriate); if you see me (or any other SparkFun employee) at the local, and you've found our code helpful, please buy us a round!
Distributed as-is; no warranty is given.