Bac track is a device that tracks your alcohol intoxication when you blow into it. This will help you prevent yourself from getting caught driving by a police officer for driving while drunk. The BACtrack Mobile Smartphone Breathalyzer is a pocket-size breathalyzer that pairs with smartphones and other smart devices via an app and Bluetooth LE, producing an estimate of blood alcohol content (BAC).
This relates to engineering because the engineers have to think about how to track you alcohol intoxication with just your breath. They have applied their knowledge to develop a contraption to make the task more efficient.
https://en.wikipedia.org/wiki/BACtrack
