Patent ID: 8659419
Filing Date: 2014-02-25
Classification: G08B

Abstract:
1. A system for preventing person, animal or items from getting lost comprising, one master tag and at least one slave tags, wherein said master tag is wirelessly coupled to each one of said slave tags, said master tag and said slave tag being capable of being conveniently carried by a person or being attached to an animal or a personal item, wherein said master tag comprising: a first control circuit; a memory device coupled to said first control circuit for storing an identification information; a wireless transmitter circuit coupled to said first control circuit for transmitting wireless signals containing said identification information when activated; and a first wake-up timer circuit coupled to said first control circuit for periodically generating a wake-up signal to activate or de-activate said wireless signal transmitter circuit, whereby significantly reducing average power consumption of said master tag to allow a longer battery life; said slave tag comprising: a second control circuit; a wireless receiver circuit coupled to said second control circuit for receiving wireless signals transmitted by said wireless transmitter circuit; a memory device coupled to said second control circuit for storing an identification information; and a means coupled to said second control circuit for estimating physical distances between said master tag and said slave tag; and an audible signal generator circuit coupled to said second control circuit for generating audible signals upon activation by said second control circuit when estimated physical distance is longer than a predetermined threshold, thereby giving warning to the person or animal carrying the slave tag and at the same time also helping the user locating the person, animal, or item; and a second wake-up timer circuit coupled to said second control circuit for periodically generating a wake-up signal to activate or de-activate said wireless signal receiver circuit, thereby significantly reducing average power consumption of said slave tag to allow a longer battery life; and a synchronization circuit coupled to said second control circuit for estimating based on received signals, the wake-up period of the first wake-up timer circuit in said master tag, and substantially matching the wake-up period of the second wake-up timer circuit in said slave tag to the estimated period.