US Patent 7034684 Personal item monitor using radio frequency identification

A personal item monitoring system includes a monitor having a transmitter and a receiver located therein. At least one radio identification tag is adapted to be coupled to a personal item. Alternatively, the radio identification tag may be pre-installed into the personal item. The monitor emits a radio frequency received by the radio frequency identification tag, and the radio frequency identification tag emits a responding signal if within a detection range. The monitor then alerts a user if the radio identification tag leaves the range of detection.