Key finders, also known as keyfinders, key locators, or electronic finders, are small electronic devices fitted to objects to locate them when misplaced or stolen, such as keys, luggage, purses, wallets, pets, laptop computers, toddlers, cellphones, equipment, or tools, and to transmit alerts, e.g., that one's restaurant table is ready or a nurse is needed. Some key finders beep or flash lights on demand.

Types

Sound-based

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. Determining what was a clap or a whistle proved difficult, resulting in poor performance and false alarms. Because of this low quality and unreliability, these early key finders were soon discarded and were unpopular for serious needs.

Radio

As electronics became smaller and cheaper, and battery life improved, radio became viable to locate the keys, which were fitted with a small receiver. A separate transmitter is used to activate one or more receivers. All wireless key finders have to "listen" for a searching transmission, resulting in battery replacement at intervals ranging from three months to a year. Using a radio signal removes the risk of false alarms. 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. The

transmitter In electronics and telecommunications, a radio transmitter or just transmitter (often abbreviated as XMTR or TX in technical documents) is an electronic device which produces radio waves with an antenna (radio), antenna with the purpose of sig ...

can also contain information to help return it to its rightful owner.

Peer-to-peer

Peer-to-peer Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the network, forming a peer-to-peer network of Node ...

key finders no longer require a separate "base"; they are all functionally identical and based on a

communication system A communications system is a collection of individual telecommunications networks systems, relay stations, tributary stations, and terminal equipment usually capable of interconnection and interoperation to form an integrated whole. Communic ...

wherein each device can find all the others individually. The user can, for example, use a digital wallet to find misplaced keys and vice versa, or a

mobile phone A mobile phone or cell phone is a portable telephone that allows users to make and receive calls over a radio frequency link while moving within a designated telephone service area, unlike fixed-location phones ( landline phones). This rad ...

to find a lost TV remote control or eyeglasses. In addition, since the keyfinders have their own transmitters, they can reply to each other by radio as well as by beeping and flashing a light to attract attention. The seeking unit can then follow this beacon to find even a buried set of keys. Having a transmitter in each unit also means that, unlike second-generation units, losing a single transmitter does not result in total loss of the ability to find other items it tracks.

Bluetooth low energy beacon

Bluetooth Low Energy (BLE) beacons are crucial in the functionality of key finders. These beacons, characterized by their efficient energy usage, emit signals that can be detected by compatible devices, usually smartphones, for location tracking purposes. Key finders with BLE beacon technology primarily aid in locating personal items. The beacon attached to an item like keys emits signals that, when in range, are detected by a smartphone app, indicating the item's location. BLE beacons transmit signals that are detected by a compatible device, enabling the device to determine the beacon's location. This technology is widely used in key finders, where the beacon is attached to items such as keys or wallets, facilitating their location through a smartphone application.

Advantages

* Low energy consumption: BLE beacons use significantly less power compared to traditional Bluetooth, extending the battery life of devices like key finders. * Broad compatibility: Most modern smartphones support BLE, making these beacons highly compatible with numerous devices. * Precision: BLE beacon technology provides accurate location tracking within a short range, ideal for finding personal items.

Use in a criminal context

Tracking devices have been implicated in criminal activity, such as

stalking Stalking is unwanted and/or repeated surveillance or contact by an individual or group toward another person. Stalking behaviors are interrelated to harassment and intimidation and may include following the victim in person or monitorin ...

Apple AirTags – 'A perfect tool for stalking'
BBC News. and identifying when properties are empty. Safeguards built in to some tracking devices to notify a person when they are being tracked, are compromised because devices can be turned off once tracking is undertaken sufficiently, can be muffled or hidden out of view, or require an app to notify of illicit tracking, which is not usually in use by a victim.

References

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Bibliography

* http://www.uspto.gov Patent# 6,774,787 Electronic locator system and method Assistive technology Consumer electronics