Pellerin combined the card with a cellular phone receiver and antenna. He added a layer of aluminum shielding to keep the components from interfering with each other. There's no ringing when it is contacted, so as not to tip off a kidnapper. The signal can be reached anywhere that has cell phone coverage, and is strong enough to be detected from the trunk of a car. The GPS cannot be reached from inside a building, but its memory can play back its last 100 locations.
Officials say it worked splendidly.
The first five units have been sent to Child Search, a Houston-based nonprofit group that hunts missing children, to be given to five children considered most at risk. Dr. Brandon Ward, operations officer of Child Search, says the concept has been discussed for years. Smith, a consultant on the project, says its possibilities are numerous. The device now is about the size of a box of animal crackers, but work is under way to make it smaller, stronger and more accurate. Fugawi Software, the Toronto firm that did the mapping, is developing a tracking system that can be run on a home computer.