Patent ID: 7183673

Claim:
A system for remotely activating a deployed device, the deployed device having a load and a battery, the system comprising: (a) a transmitter, remote from the deployed device, for generating an AC magnetic field; and (b) a receiver disposed at the deployed device, the receiver including (i) an antenna and a voltage detector coupled to said antenna for sensing the AC magnetic field and generating an output signal in response to the sensed AC magnetic field, wherein said voltage detector only generates said output signal when the sensed AC magnetic field induces a voltage in said antenna and said voltage exceeds a threshold voltage; (ii) a switch coupled in series with the load and the battery; and (iii) an integrating delay circuit coupled between the voltage detector and said switch for integrating the output signal, said switch being responsive to said integrating delay circuit to couple the battery to the load, thereby activating the deployed device, and wherein said voltage detector includes at least one semiconductor device, said semiconductor device having a cutoff mode and an active mode, and wherein said semiconductor device operates in said cutoff mode when said induced voltage is below the threshold voltage, and operates in said active mode when said induced voltage is above the threshold voltage.