floating key chain?

Hi i need help making a self inflating key chain that uses a balloon or something to carry keys to the surface of the water,
it needs to inflate when fully submerged but can handle some minor splashes.

something similar to this:      www.water-buoy.com

orksecurity7 years ago
The usual solution is just to attach a piece of closed-cell foam large enough to support the keys. It's a bit bulky, but it works and there's no risk of it failing to work when you need it.