There was a post not to long ago about a guy who made drum sticks that make drum sounds as you beat them in the air. His first prototype was sensors strapped t

There was a post not to long ago about a guy who made drum sticks that make drum sounds as you beat them in the air. His first prototype was sensors strapped to cardboard tubes. I would suggest doing something similar have your first prototype be anything you can get to work regardless of form factor. After you prove the concept then work on more realistic prototypes.