Systems and methods of extending battery life in inventory control devices are disclosed. A passive receiver configured to wirelessly receive an initiation signal having an associated energy field from a remote control system and to output a mode change signal is provided. The passive receiver is configured to be powered by an energy field associated with the initiation signal. A functional module coupled to the passive receiver and configured to be powered by a self-contained power source when the functional module is in an active mode is provided. The functional module is further configured to receive the mode change signal from the passive receiver and to change from an inactive mode to the active mode. The functional module draws more power from the power source in the active mode than in the inactive mode.