Don't drink and drive. Ever. Now that we've got that out of the way, Breathometer, the smartphone-powered breathalyzer, has reached its Indiegogo goal about six times over. What does that mean for you? Cheap BAC tests for everyone! The $20 device aims to make it inexpensive and easy to know when you're too intoxicated to drive. This will, naturally, replace the more commonplace test of "Have I had any alcohol? Yes? Okay, then I shouldn't drive."
The keychain-sized device plugs in to your smartphone's 3.5mm headphone jack, so it's almost universally compatible with every smartphone on the market. It will also support Android devices 2.3 and up.