Tamper detection and prevention for an object control and tracking system

Abstract

Tamper detection and prevention for an object control and tracking system and particularly a Key Track system is provided. Where objects being tracked are keys, a key card having a touch memory device, RF id tag, or other circuitry for storing and transmitting an ID to a controller is provided. A tether attaches a key to the card. In one embodiment, the tether is conductive and the transmission of the ID code passes through the tether. If the tether is cut, transmission is interrupted to indicate a tampering condition. In another embodiment, the tether is resistive and circuitry is provided to monitor a voltage drop across the tether. A change in the voltage drop indicates a tampering condition. An object of the invention is to detect an attempt to remove the key (or other object) from its ID card while leaving the card intact.

What is claimed is:  
     
         1 . An enhance key tag assembly for use with a Key Track system comprising a key card, an ID code stored on said key card, means for communicating the ID code to a central controller of a Key Track system, a tether connecting a key to the key card, and means for detecting tampering with the tether as an indication of an attempt to remove the key from its card.  
     
     
         2 . The key tag assembly of    claim 1    and wherein said means for detecting tampering comprises a conductive tether and wherein the ID code is communicated to the central controller through said conductive tether, the communications link being broken if said tether is cut.  
     
     
         3 . The key tag assembly of    claim 1    and wherein said means for detecting tampering comprises a resistive tether and means on said key tag for monitoring a voltage drop across said resistive tether, a change in voltage drop indicating that the tether has been cut or tampered with, and means for communicating the detected voltage drop to the central controller of a Key Track system.  
     
     
         4 . The key tag assembly of claim I and further including a shroud covering at least a portion of a key attached to the tether to protect the key from being cut and removed from said tether.  
     
     
         5 . The key tag assembly of    claim 1    and further comprising tether retaining means on said key card, said tether retaining means lockably receiving ends of said tether to attach said tether to said key card.  
     
     
         6 . The key tag assembly of    claim 1    an wherein said means for communicating comprises a touch memory device attached to said card.  
     
     
         7 . The key tag assembly of    claim 1    and wherein said means for communicating comprises an RF antenna on said card.  
     
     
         8 . The key tag assembly of    claim 7    and wherein said RF antenna comprises a capacitive plate antenna.  
     
     
         9 . The key tag assembly of    claim 7    and wherein said RF antenna comprises an inductive loop antenna.  
     
     
         10 . A method of detecting tampering with a tether securing an object to an identification tag, said method comprising the steps of: 
 (a) monitoring a preselected characteristic of the tether; and    (b) noting a tampered-with condition if the preselected characteristic of the tether changes.    
     
     
         11 . The method of    claim 10    and wherein the preselected condition is the electrical conductivity of the tether and wherein step (a) includes passing a signal to be transmitted to the Key Track system through the tether, the signal being interrupted to indicate a tampering condition when of the tether is cut.  
     
     
         12 . The method of    claim 10    and wherein the preselected condition is the resistance of the tether and wherein step (a) includes monitoring a voltage drop across the tether, a change in the voltage drop indicating a tampering condition.  
     
     
         13 . A protective shroud for inhibiting tampering with a key comprising a shroud body configured to be received over and cover at least portion of the key to protect said portion from being cut.