A method and apparatus for controlling a radio frequency identification
(RFID) reader to detect the proximity of an RFID device based on
observing a change in effective inductance. The RFID reader includes an
excitation signal generator and a resonant filter that combined are
capable of generating and transmitting a detection signal, an RFID device
detector for measuring a detector parameter indicative of the change in
effective inductance, and a detection signal receiver for determining
whether an RFID device is present. The method includes awakening from a
detection sleep state at a preselected time, generating and transmitting
a detection signal, measuring at least one detector parameter indicative
of the change in effective inductance, and determining whether the RFID
device is present. When the RFID device is not present, the method
returns to the detection sleep state and, when the RFID device is
present, the method exits the detection sleep state.