That's it exactly! I must not have used the right key words. Usually I can find anything through Google Reader.

Fun anecdote: one of my wife's college roommates was horribly prone to losing her keys as well. One of her friends bought her a device to solve the problem. It worked by whistling. I don't know what kind of evil device it was, but you didn't have to whistle to set it off, all you had to do was turn on the faucet, pour cereal, talk at normal volumes, or stand still, and the horrible little thing would beep incessantly. To make matters worse, it did not have a removeable battery or even a screw to allow you to take it apart (when removed from the packaging, one of those little plastic pull-tabs would start the device).

The only solution was to bury it deep within the freezer. If you walked closely to the fridge you could hear it. It took a week to die.