Patent ID: 7468664
Filing Date: 2008-12-23
Classification: B82Y,G01R,G11C

Abstract:
1. A tamper detecting enclosure arrangement for enclosures containing an interior space in which a protected item is positioned to which access is to be denied absent providing a subsequent indication that such an access has occurred, said arrangement comprising: a magnetoresistive sensing memory storage cell positioned in or near said protected item in said enclosure having a magnetoresistance versus externally applied magnetic field characteristic with two states of differing resistive values which are each entered from that other by applying an external magnetic field having a magnitude change exceeding a magnitude difference between a pair of relatively small transition field value magnitude intervals each having externally applied magnetic field values occurring therein of a common field direction but with those externally applied magnetic field values occurring therein differing in magnitudes from those in that other transition field value magnitude interval, and a magnet positioned at a selected initial separation distance from said magnetoresistive sensing memory storage cell to thereby provide a magnetic field of initial magnitudes about said magnetoresistive sensing memory storage cell which magnetic field decreases if said enclosure is opened so as to result in substantially increasing a distance separating said magnet and said magnetoresistive sensing memory storage cell, as a resulting opening separation distance, that is larger than said initial separation distance.