MEMS Sensor Enabled RFID System and Method for Operating the Same

Abstract

A method for providing environmental monitoring of an item with an electronic system includes the steps of operating the electronic system in a deep-sleep mode at a minimal level of power consumption by disabling operation of nonessential portions of the electronic system; activating the electronic system at a monitoring rate to sense an environmental parameter to which the item is subjected; sensing a value of the environmental parameter to which the item is subjected; comparing the sensed environmental parameter with the value of the environmental parameter just previously sensed to derive a rate of change of the environmental parameter; adjusting the monitoring rate to track the rate of change of the environmental parameter; storing the value of the sensed environmental parameter; and returning the electronic system to the deep-sleep mode.

We claim: 
     
         1 . A method for providing environmental monitoring of an item with an electronic system comprising:
 operating the electronic system in a deep-sleep mode at a minimal level of power consumption by disabling operation of nonessential portions of the electronic system;   activating the electronic system at a monitoring rate to sense an environmental parameter to which the item is subjected;   sensing a value of the environmental parameter to which the item is subjected;   comparing the sensed environmental parameter with the value of the environmental parameter just previously sensed to derive a rate of change of the environmental parameter;   adjusting the monitoring rate to track the rate of change of the environmental parameter;   storing the value of the sensed environmental parameter; and   returning the electronic system to the deep-sleep mode.   
     
     
         2 . The method of  claim 1  further comprising providing electrical power to the electronic system only when a passive sensor senses the presence of a predetermined value of the environmental parameter. 
     
     
         3 . The method of  claim 2  where storing the value of the sensed environmental parameter is performed only when the value of the sense environmental parameter has changed from the previously sensed value. 
     
     
         4 . The method of  claim 2  where storing the value of the sensed environmental parameter is performed only when the value of the sense environmental parameter outside a predetermined threshold.