An object locating system employing tags and a handheld locator. A unique low power tag circuit enables highly compact form factor and extremely long operating life even from the smallest available batteries. The tag employs an efficient passive RF energy detector circuit rather than an active receiver, as well as a novel low-power temperature-compensated biasing circuit to provide uniform sensitivity over a broad temperature range. The locator device transmits a tag activation signal, receives tag RF responses, and reports presence and optionally proximity changes to the user. An alternate tag design directly conveys proximity changes. The locator may also incorporate tag functionality to aid in finding a misplaced locator.
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