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Kalect
01-21-2003, 10:29 PM
Ok, We've all seen them, the little white strips on the inside of every CD you buy, or DVD, or any form of media. After my curious mind wondered exactly what they were, I investigated and found that they are magnetic strips. When magnetized, the alarms can sense them and put out an alarm. So before you leave the store they must be demagnetized.

This is where my question comes in. How? I ask this in hopes of getting answers to several smaller questions, such as:

1. Having only lightly dabbled with magnets, and never having studied them, I have no idea how demagnetization works. How is it done? Whate takes place when it is done?

2. I was told that the demagnetization takes place when the CD is wiped across a black mat type thing on the counter. I was also told this was a magnet. If so, how are VHS tapes not erased when wiped across it? If not, what is it?

3. Do CDs suffer data loss from exposure to a magnet? If so, how can they sit on top of a magnetized tag for weeks or even months and not get erased?

4. Lastly, and absolutely the least seriously, is it possible to remagnetize the strip and stick it to my friend and laugh as he cannot figure out why he sets off alarms? :D

Thanks in advance for your help. I'm a curious mind, and things like this bug me.

Berkut
01-21-2003, 10:32 PM
Originally posted by Kalect
3. Do CDs suffer data loss from exposure to a magnet? If so, how can they sit on top of a magnetized tag for weeks or even months and not get erased?No, they don't. They are optical.

nitroglycerine
01-21-2003, 10:46 PM
Originally posted by Kalect
4. Lastly, and absolutely the least seriously, is it possible to remagnetize the strip and stick it to my friend and laugh as he cannot figure out why he sets off alarms? :D




Ya know.....Something like that could be a lot of fun.

Jon

Kalect
01-21-2003, 10:53 PM
Originally posted by Joey G
No, they don't. They are optical.

Ah, Ok. What about VHS though? I thought VHS was erased by magnets, yet they use the strips on them.

Nitroglycerine: Yes, sure could be. Go through all your old CDs, remagnetizing the strips, and then gain access to a friends dresser, applying a strip to the inside waistband of each pair of his pants. Assuming he doesn't notice, your in for some fun. Even if you can't be there, your bound to hear stories of his trip to the mall, where the alarms went crazy on him.

Berkut
01-21-2003, 11:10 PM
Originally posted by Kalect
Ah, Ok. What about VHS though? I thought VHS was erased by magnets, yet they use the strips on them.There are several types of those anti-theft strips, they aren't all magnetic. Some of them are designed to resonate when passed between those gates at the doors, sounding the alarm. Notice at Blockbuster that they hand the tapes to you around that gate, rather than doing anything to deactivate the strip.

Civil Defense
01-21-2003, 11:13 PM
VHS tapes will be erased by some demagnetizing equipment if the exposure is long enough, much like credit cards will be demagnetized if left sitting on the pad.

As far as sticking tags on your friend, go for it. As someone who worked in retail for a while, it was great entertainment.

Kalect
01-21-2003, 11:15 PM
Originally posted by Joey G
There are several types of those anti-theft strips, they aren't all magnetic. Some of them are designed to resonate when passed between those gates at the doors, sounding the alarm. Notice at Blockbuster that they hand the tapes to you around that gate, rather than doing anything to deactivate the strip.

Right, I know, but I've seen the magnetic variation on VHS tapes at places that use the black pad. They rub the tape, and hand it to you, is the magnetic charge just not very strong?

Kalect
01-21-2003, 11:16 PM
Originally posted by Civil Defense
VHS tapes will be erased by some demagnetizing equipment if the exposure is long enough, much like credit cards will be demagnetized if left sitting on the pad.

As far as sticking tags on your friend, go for it. As someone who worked in retail for a while, it was great entertainment.

What are those pads? Are they magnets then?

As for the tags, how do I recharge them?

Civil Defense
01-21-2003, 11:18 PM
What are those pads? Are they magnets then?

Yes. Frequently, when dealing with magnetic-sensitive merchandise at my former place of employment (coughbigyellowtagcough), we would use a different system which used a handheld demagnetizer and key combo unit to unlock and demagnetize a product.

As for the tags, how do I recharge them?

I really have no idea. Your best bet would be to find a strip of them in the store during stocking times.

Kalect
01-21-2003, 11:24 PM
Originally posted by Civil Defense
Yes. Frequently, when dealing with magnetic-sensitive merchandise at my former place of employment (coughbigyellowtagcough), we would use a different system which used a handheld demagnetizer and key combo unit to unlock and demagnetize a product.


Then what prevents me from waltzing in with a magnet of my own, swiping it over a CD, and walking out? Seems kind of easy to defeat. :confused:


I really have no idea. Your best bet would be to find a strip of them in the store during stocking times.

But then it would set the alarm off as I walked out, wouldn't it?

Civil Defense
01-21-2003, 11:39 PM
Then what prevents me from waltzing in with a magnet of my own, swiping it over a CD, and walking out? Seems kind of easy to defeat.

I'm not sure on the specifics, but I believe it's a little more involved than that.

But then it would set the alarm off as I walked out, wouldn't it?

erm, I'd tell you how to get around that, but that wouldn't really be appropriate here, I suppose. I guess this method only works if your friend is with you.

Kalect
01-21-2003, 11:47 PM
Originally posted by Civil Defense
I'm not sure on the specifics, but I believe it's a little more involved than that.

Ther is one way to find out. I could go get a magnet, and a shopping bag..... heh....


erm, I'd tell you how to get around that, but that wouldn't really be appropriate here, I suppose. I guess this method only works if your friend is with you.

Now I'm intrigued. This place is vBB right? It has Private Messaging.... ;)

Duck Duck Goose
01-22-2003, 12:37 AM
My son set off the alarms at Wal-Mart the other day with one. He happened to have in his pocket the UPC code for an old CD-RW rebate that he'd cut off the box at home, meaning to get the rebate deal all together and mail it on the way home from Wal-Mart. So the UPC code happened to have the anti-theft strip on it, and it set off the Wal-Mart alarm.

Seven
01-22-2003, 02:25 AM
If you learn how to re-activate the strip, don't waste it on your friend. Stick it on a shopping cart so the fun can continue for days (perhaps weeks) to come. :)

David Simmons
01-22-2003, 02:42 AM
Things are usually demagnetized by putting them in an alternating magnetic field that is gradually reduced to zero, or at least a miniscule strength. An alternative way is to have a constant magnetic field in which you place the object which you then move away. This also gradually reduces the field around the object and demagnetizes it.

Popup
01-22-2003, 06:20 AM
There's a very good article about anti-theft gadgetry at HowStuffWorks.com: How Anti-shoplifting Devices Work (http://www.howstuffworks.com/anti-shoplifting-device.htm).
There are several kinds of 'electromagnetic devices', some which use magnetics, and can be re-activated (used a lot in libraries etc), and some that rely on electric fields only, and cannot be re-activated.

Read the article, it's worth it!

Kalect
01-22-2003, 01:26 PM
Originally posted by Popup
There's a very good article about anti-theft gadgetry at HowStuffWorks.com: How Anti-shoplifting Devices Work (http://www.howstuffworks.com/anti-shoplifting-device.htm).
There are several kinds of 'electromagnetic devices', some which use magnetics, and can be re-activated (used a lot in libraries etc), and some that rely on electric fields only, and cannot be re-activated.

Read the article, it's worth it!

I have read it. My questions that remain are:

1. How can I demagnetize strips?
2. How can I re-magnetize them?

Seven: Hmmm.... yes...

Q.E.D.
01-22-2003, 01:40 PM
1. How can I demagnetize strips?
Answering that would basically be telling people how to steal, and wouldn't be appropriate here.

2. How can I re-magnetize them?
The most common type in use uses two small strips of soft steel magnetized in specific orientations and to a specific level (details are on the How Stuff Works site posted above). As such, it would be very difficult for the average Joe to reactivate them.

Ferret Herder
01-22-2003, 01:41 PM
Originally posted by Kalect
It has Private Messaging.... ;)

Which is deactivated. The mods take a very, very dim view of anyone attempting to solicit information to commit crimes with, so I'd watch your phrasing/requests.

Kalect
01-22-2003, 02:48 PM
Originally posted by Ferret Herder
Which is deactivated. The mods take a very, very dim view of anyone attempting to solicit information to commit crimes with, so I'd watch your phrasing/requests.

PMing is deactivated? Damn, thats a little harsh.

Meh, I can understand, but at the same time that's stupid. That coming from someone as anti-censorship as myself, shouldn't be offensive, however.

Civil Defense: My AIM name is Kaleckt999 (Don't forget the k, alot of people do) and my email is NagelJ@maplenet.sparcc.org if you feel like contacting me. Really, I'm just curious. And since the rules here seem to be so strict...

Q.E.D. I'm not looking for info on how to steal. I can get a CD out of it's locking case in three seconds flat with a simple paper clip, it is not hard. With a little seclusion, I can even remove the strip from inside the CD case in about 5 seconds. Also not hard. I'm asking solely because I'm curious, but I can understand your position.

As for remagnetizing, that sucks.

Q.E.D.
01-22-2003, 03:01 PM
I wasn't implying you were. But a lot of people see these boards, and posting ways to deactivate security measures would be a Bad Thing. Besides the mods would take a dim view of me if I did that....and i like it here! :D

effac3d
01-22-2003, 03:31 PM
Well if you really want to steal CDs,DVDs etc.

What about a lead lined purse or a lead liner to slip into a shopping bag?

Kalect
01-22-2003, 08:38 PM
Originally posted by effac3d
Well if you really want to steal CDs,DVDs etc.

What about a lead lined purse or a lead liner to slip into a shopping bag?

That would be overly complicated. As would, I assume, any form of demagnitization. Also, it is nearly impossible to know if it is a magnetic tag or a resonator tag, unless you know the store. All you need is a hoody, shopping bag, or some other thing with large pockets, and a paperclip. I won't go into it here, as I have been warned by the others about that, but you can IM me if you want.

Q.E.D. I understand. I was just pointing out that demagnetization would probobly be the most cumbrous, and likely to get you caught, method of stealing a CD.

ElwoodCuse
01-23-2003, 12:35 AM
How about just ripping them off the outside of the packaging? Wouldn't that work? That seems like a really simple way, though. I mean if it was that simple, why would they have this system at all?

Once I bought a hard drive at Best Buy. Let me tell you, dopers--when you go to the mall to buy a hard drive, make that be your LAST stop, unless you want to set off the alarms in every single store you enter and exit for the rest of your shopping experience.

handy
01-23-2003, 11:01 AM
"How about just ripping them off the outside of the packaging?"

I suppose you could but alot are now INSIDE the packaging.

MSU 1978
01-23-2003, 11:24 AM
Would it be possible for a store that sells magnets to attach an anti-theft device to the product?

NotBob13
01-23-2003, 12:48 PM
Does anybody know where to get these antitheft tags? Does Office Max sell them? Say I wanted to open a store that uses them, someone would sell them to me right? So this would be the easy way to way-lay your friends with the tags.

Q.E.D.
01-23-2003, 12:52 PM
I would assume you'd have to buy them in considerable quantities. Most places that sell things of this nature impose rather large minimum quantities just to keep them out of the hands of the general public. OTOH, maybe try eBay. I've seen some out-there stuff for sale there.

SC_Wolf
01-23-2003, 01:55 PM
An interesting observation from a former employee of a store that used anti-theft strips: after about 3 months of handling tagged merchandise in close proximity to the detectors, I could tell you the exact boundary of the field. If I wanted to, I could smuggle any merchandise I wanted right past the detectors, without setting them off.