Just beginning the project. Ordered the TrinketPro and MQ-3 today. I will start drawing up the schematic soon (probably this weekend after final exams are over for me). Primarily this project is going to focus on keeping a low profile; hopefully this can be done with the TrinketPro (for the sake of the Hackaday contest) but would probably make more sense using an ATTiny85 if I stick with only a breathalyzer. That's why I'm considering adding temperature/humidity sensing and possibly other components to make better use of the Trinket.