A while back I was turned onto an anklet that would let you know which direction you were facing. It turns out that the human body will learn to filter out common sensations, such as vibration, over time while still intuitively sensing the changes in said vibration (a phenomenon well known in haptic devices). With this in mind I begun designing a device that will use a pair of microphone earrings to pass audio through an Arduino that will power a pair of vibration motors, clipped to the sides on the belt. This will allow, I hope, my wife to be able to determine the direction of sound. A schematic and parts list is forth-coming and a prototype will follow soon after.
Originally the project was all analog, that proved to be more complicated than it was worth, given the ubiquity of the Arduino, I decided to go that route.
I have got a small Proof of Concept set up, but my Arduino is not accepting uploads for some reason. I had a new one delivered in the mail today and will be testing the circuit that is currently this project's image.