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Library Store Scanners

  1. Mar 30, 2004 #1
    If anyone has been to a library or a store, they have scanners at the entrances that set off an alarm when someone goes by with a stolen product. Anyone have some more information about how these work or what they are called?
  2. jcsd
  3. Mar 30, 2004 #2


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    A strip of magnetic material is impeded in the books or tags on merchandise. The detectors sense the presence of this strip.
  4. Mar 30, 2004 #3
    Its the same with DVDs and CD's at my workplace (target). We have to run them over this black magnetic strip thing when we check people out, so the detectors don't go off. Not to imply that we have some sort of security that would do anything about it. *chuckle*
  5. Mar 30, 2004 #4


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    The stores use little devices called EAS (Electronic Article Surveillance) tags. You can learn a lot about them by searching on google. Here's a good site to get you started:


    The tags you'll encounter most frequently are the acousto-magnetic types.

    - Warren
  6. Mar 31, 2004 #5
    Thanks for the replies. I know most implementations use some type of magnetic sensors. But at my school library, I am quite sure that they do not run the magnetic strip (on the book) through anything, which perplexes me. I'll have to do some more investigation...
  7. Mar 31, 2004 #6


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    Often the de-arming device is built into the checkout counter. All the attendant has to do is lay the book on the counter to deactivate the tag.

    - Warren
  8. Sep 25, 2004 #7
    thank you!
  9. Sep 25, 2004 #8
    Recently I've noted what appear to be flat, inductive coils (as opposed to magnetic strips) on a patch attached to the item. How does the store disarm one of those? (I couldn't get through to the above suggested site.)
  10. Sep 26, 2004 #9
    Me too.

    I've searched google and find it difficult to get answers to the following questions. Would anyone kindly answer them here?

    1. What kind of waves (?) is received by the receiver?
    2. How can the receiver identify the theft regardless of the orientation of the tape?

    thank you very much
  11. Sep 26, 2004 #10
    An E-M signal at the door can make the inductive coil resonate, like one of the best bugs once created by the USSR.
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