Hi Skfir,
Hope your test went well. It would be really cool if you could post a video clip demonstrating what the user hears in their headphones as various objects are approached.
I am heartfelt impressed with what you accomplished here. The design and construction of your device involves programming, analog and digital interfacing, switch-mode power conversion, thermal management, acoustics, PCB layout, industrial design, and electronic construction techniques. This would be at least an enviable BSEE senior project -- and you're a music major. May your friend enjoy using it for a long time.
Bob