For this project, I hacked a Radioshack sound recording module and connected it to a speaker on each side of the headphone, and an accelerometer. I recorded a message that said: “Don’t stop running”, so it would play every time the accelerometer sensed deceleration. This is meant to boost energy of runners, while they are running. A runner can record a message, so whenever he or she gets tired while running, the message automatically plays, encouraging them to go on. When acceleration is picked up by the accelerometer, the sound stops playing.
Here’s the link to the video: