Patent ID: 8405487
Filing Date: 2013-03-26
Classification: G06K,H04Q

Abstract:
1. A sensor tag comprising: a sensor unit configured to sense at least one piece of sensor data; a radio frequency (RF) communication unit configured to perform wireless transmission and receiving of a signal with a radio frequency identification (RFID) reader; a storage unit configured to store commands and data for tag operation and the sensor data obtained by the sensor unit; and a control unit configured to compare new sensor data of the sensor unit with immediately previous sensor data of the sensor unit and write the new sensor data in the storage unit when the comparison result satisfies a predetermined criterion, wherein the control unit comprises a sensor register configured to store the new sensor data of the sensor unit, a memory register configured to store the immediately previous sensor data of the sensor unit, and a comparison unit configured to compare the new sensor data stored in the sensor register with the immediately previous sensor data stored in the memory register to determine whether the comparison result satisfies the criterion, wherein the control unit is configured to overwrite the new sensor data over the immediately previous sensor data on the memory register after determining that the comparison result satisfies the criterion, and wherein the criterion varies according to frequency of operation of the sensor unit.