Would it be possible to create a passive homing device?

For those of us who are in the habit of misplacing keys, eyeglasses and wallets, it would be convenient to have a small device which could be attached which does not need a battery, but which would somehow respond to a second device. Suppose, for example, that the device had a diaphragm which would vibrate and emit a sound when the other device made a sound at the same frequency. It would be set up to only operate at relatively close range.