Patent ID: 8508378

Claim:
An inventory control device comprising: a passive receiver comprising: a first antenna configured to wirelessly receive an initiation signal having an associated energy field from a remote control system; a capacitor; a rectifier circuit coupled between the antenna and the capacitor, the rectifier circuit configured to convert the initiation signal into a direct current for charging the capacitor; and a signal generator coupled to the capacitor and configured to be powered solely by the capacitor and to output a mode change signal when the capacitor is charged above a threshold voltage; and a functional module comprising: a second antenna configured to wirelessly receive a data signal from the remote control system, the data signal comprising identification (ID) data; an indicator comprising at least one of an audio indicator and a visual indicator; a self-contained power source; and a controller coupled to the second antenna, the indicator, the power source, and the signal generator, the controller comprising a stored ID indicative of the inventory control device, an inactive mode wherein the controller is not responsive to signals received by the second antenna, and an active mode wherein the controller activates the indicator upon receipt through the second antenna of a data signal that comprises ID data that matches the stored ID, wherein the controller is configured to change from the inactive mode to the active mode in response to receipt of the mode change signal from the signal generator, the functional module drawing more power from the power source in the active mode than in the inactive mode.