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EAS tag with piezoelectric facility for motion detection

  • US 5,168,263 A
  • Filed: 10/03/1990
  • Issued: 12/01/1992
  • Est. Priority Date: 10/03/1990
  • Status: Expired due to Fees
First Claim
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1. In an electronic article surveillance tag of the type comprising an electrical power source, receiver means for receiving coded messages for diverse state disposition of said tag, decoder means for decoding received coded messages and for directing said tag into active and inactive states, alarm means for providing audible output indication of unauthorized activity in respect of said tag in an active state thereof, and motion detector means operative upon disposition of said tag in an inactive state for lessening drain on said electrical power source and further operative on movement of said tag when in said inactive state to dispose said tag in an active state with increased drain on said electrical power source, the improvement wherein said alarm means and said motion detector means are constituted of common electrical circuitry comprising piezoelectric circuit means inclusive of housing means defining a resonant cavity, a piezoelectric element providing a boundary of said cavity and electrical conductor means for connection to said piezoelectric element, said common electrical circuitry being responsive to input signals for providing audible output indication of unauthorized activity in respect of said tag in said active state thereof and generating output signals indicative of said movement of said tag when in said inactive state.

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