Estimates vary, but somewhere around 25% of people bite their nails. Just about every single one of them wants to stop and has made attempts to stop, but conventional fixes just don't work.
We augmented the HackIllinois hat to detect nailbiting with very high accuracy using a pressure sensor. We connected this to a Spark Core, so your nailbiting habits are pushed to the cloud. Using the Twilio API you are sent an SMS every time it catches you biting. A web interface lets you visualize your progress over time and see how long you've gone without biting.
All of this tracking is done for you, without any self-reporting required. We feel we have made something that can have a huge impact on a lot of people!