The “smart rock” system, a micropower transponder, is described.
A “smart rock” is a locating device that is buried at a specific site. It is interrogated by a portable source and responds with information about its position, identification number or any data that it has collected since its last interrogation. Ideally, a smart rock, once placed, will wait, listening for its interrogator, for many years, or even for decades. A smart rock buried on a nature trail might send its identification number to a traveler’s handheld transponder, which would decode the identification number and play a message describing ...