Key finder

Early models of key finder were sound-based, and listened for a clap or whistle (or a sequence of same), then beeped for the user to find them.

As electronics became smaller and cheaper, and battery life improved, radio became viable to locate the keys, which were fitted with a small receiver.

All wireless key finders have to "listen" for a searching transmission, resulting in battery replacement at intervals ranging from three months to a year.

Some distributors include a cost-effective key-return service that assists in returning the keys should they be lost in a taxi, bus or other public place, provided the customer registered their devices and contact information.

These beacons, characterized by their efficient energy usage, emit signals that can be detected by compatible devices, usually smartphones, for location tracking purposes.