Anti theft gate things in shops/libraries.

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In summary: The RF causes interference with the audio circuits in the music player. Kind of like a form of demodulation...In summary, the security gates at the library use a low-frequency RFID system to detect if someone is carrying an item they shouldn't. When the person walks through the gate with their earphones on, the RFID system detects the tag and causes interference with the audio circuits in the music player.
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Aight, so I've been going into/out of the library a lot lately to study since my desk at my flat sucks. I usually listen to music on headphone when walking to/studying in the library, and I have noticed that when I walk through the little security gate things (the two panels on either side of the exit that beep if you have an item you shouldn't) my earphones my a high-pitched ring.

I am assuming there is an induced current in the wire of the headphones from my moving them through some field, which made me realize I have no idea how the gate things work.

So, it got my curiosity going, and I figured I'd see if anyone here knew and could explain it to me in understandable terms.

So, yeah. How do they work? Why are my earphones ringing?

Thanks dudebrohamskis.
 
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Thanks man! That article is interesting. Cunning stuff.

I also got a good chuckle out of the lady warning everybody that the tags could be "the real life mark of the beast".
 
  • #5
Jiggy-Ninja said:
Audible frequency radio waves? Wouldn't the antennas have to be gigantic for that?

So those little white plastic tags they stick on some things that are impossible to peel off are RFIDs?

The RF causes interference with the audio circuits in the music player. Kind of like a form of demodulation...

BTW, funny (now) story -- I bought a new wallet one time, and when they blasted it at checkout to blow the diode in the RFID circuit, it turned out that it didn't blow. So every time I walked in and out of a Target store at the mall, I'd set off the beeper things. Very annoying. I looked all through the wallet, and could not find anything, and then finally got desparate one day and practically tore it apart. Finally found the super-thin RFID antenna and circuit. Whew!
 
  • #6
Jiggy-Ninja said:
Audible frequency radio waves? Wouldn't the antennas have to be gigantic for that?
Not necessarily.
So those little white plastic tags they stick on some things that are impossible to peel off are RFIDs?
Usually.
 

Related to Anti theft gate things in shops/libraries.

1. How do anti-theft gate things work?

The anti-theft gate things, also known as electronic article surveillance (EAS) systems, consist of two main components: a tag or label attached to the item and a detection system at the store/library exit. The tag or label contains a small electronic circuit that emits a signal when it passes through the detection system. If the tag has not been deactivated, the detection system will sound an alarm, alerting store/library staff of a potential theft.

2. What types of items are typically protected by anti-theft gate things?

Anti-theft gate things are commonly used in stores and libraries to protect high-value items such as electronics, clothing, and books. However, they can also be used for lower-value items that are frequently targeted by thieves, such as cosmetics, alcohol, and DVDs.

3. Can anti-theft gate things be deactivated?

Yes, anti-theft gate things can be deactivated by store/library staff at the point of purchase or checkout. This is usually done by using a deactivation device that neutralizes the electronic circuit in the tag or label, preventing it from setting off the detection system.

4. Do anti-theft gate things always prevent theft?

While anti-theft gate things are an effective deterrent, they do not completely eliminate theft. Thieves may find ways to remove or deactivate the tags or labels, or they may simply choose to ignore the alarms and attempt to leave the store/library with the item. Additionally, some items may not be properly tagged or deactivated, allowing them to pass through the detection system undetected.

5. Are anti-theft gate things reusable?

Some types of anti-theft gate things, such as reusable hard tags, can be used multiple times. These tags require a special tool to remove them, making it more difficult for thieves to tamper with them. Disposable tags and labels, on the other hand, are typically removed at the point of purchase and cannot be reused.

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