Vibrating bracelets is an excellent idea, but I wonder if they would work for a really deep sleeper. Back when I had a pager and was on call, I'd set it on top

Vibrating bracelets is an excellent idea, but I wonder if they would work for a really deep sleeper. Back when I had a pager and was on call, I'd set it on top of a shallow pile of coins. The racket it would make and the sound of coins falling onto the (hardwood) floor was enough to wake the dead.