magnetism in stores

[MrDudeMan]

how do those things work? ive always wondered how if you buy a hard drive and walk through the big magnetic things at the door how they dont hurt it or anything....


how do those things work anyways? the little white strips anyways...


i want to put them on some stuff in my room because my friends think its funny to take stuff. i want to get the big magnetic door pieces and put them (concealed) around the entry to my room...


is that possible? how does it work?

 

[everman]

I really don't know but my guess is that the door pieces can detect the magnetic field but I doubt they emit one, or if they do it is very weak. And the strip on merchandise could be shielded I suppose, again not very strong.

 

[Peter]

Most of these impressive exit door thingies are dummies anyway. Besides, those that actually do something don't have fields strong enough to erase storage media while you walk through.

 

[ScottMac]

Many of thoses systems aren't magnetic per se; the strips are transponders. When you check out, the transponder is read and "approved" (within the point-of-sale system) to leave the store (and inventory is reduced).

Some systems use low-level emitters that cause the alarm to trigger when passed through the gate (like the white plastic squares they affix to clothing).

There are a bunch of different kinds of systems. In your case, I'd be looking for some new friends ...

FWIW

Scott

 

[Gunbuster]

I thought only a few places were using transponders on a limited test basis, they still cost $.25-1.00 a pop

 

[Mark R]

The most common method of doing this uses three main components - a small radio transmditter at the door, and opposite it a receiver, and attached to the items a small coil of wire integrated into the tags.

The door-exit devices come in pairs (or sometimes threes) where one is a transmitter constantly broadcasting a low-level signal at a specific frequency. At the other edge of the door, a receiver constantly monitors the strength of the signal.

Inside the security tags, a coil of wire acts is designed to act as an antenna tuned to the radio frequency in use - the antenna is connected to a 'dummy load' designed to dissipate the received signal. When one of these labels is placed near the transmitter it picks up the signal, and dumps it internally. As some of the transmission is absorbed by the security tag, a 'shadow' is cast by it - and the drop in signal strength is picked up by the receiver, which sounds the alarm.

Some of these devices can be deactivated by placing them over a security 'pad' at the till. In these cases, the 'dummy load' includes a tiny fuse. Inside the pad is a more powerful transmitter - when the label is placed directly against it, enough energy is transferred into the device to cause the fuse to blow thereby disabling the antenna circuit.

These coils can be built using flexible printed circuit technology, and can be incorporated into bar-code or pricing stickers, or even hidden inside the article: for example, several book publishers now build these devices into the spines of their books, so the retailer needs no additional tags - only the security equipment.

 

[MrDudeMan]

Originally posted by: Mark R
The most common method of doing this uses three main components - a small radio transmditter at the door, and opposite it a receiver, and attached to the items a small coil of wire integrated into the tags.

The door-exit devices come in pairs (or sometimes threes) where one is a transmitter constantly broadcasting a low-level signal at a specific frequency. At the other edge of the door, a receiver constantly monitors the strength of the signal.

Inside the security tags, a coil of wire acts is designed to act as an antenna tuned to the radio frequency in use - the antenna is connected to a 'dummy load' designed to dissipate the received signal. When one of these labels is placed near the transmitter it picks up the signal, and dumps it internally. As some of the transmission is absorbed by the security tag, a 'shadow' is cast by it - and the drop in signal strength is picked up by the receiver, which sounds the alarm.

Some of these devices can be deactivated by placing them over a security 'pad' at the till. In these cases, the 'dummy load' includes a tiny fuse. Inside the pad is a more powerful transmitter - when the label is placed directly against it, enough energy is transferred into the device to cause the fuse to blow thereby disabling the antenna circuit.

These coils can be built using flexible printed circuit technology, and can be incorporated into bar-code or pricing stickers, or even hidden inside the article: for example, several book publishers now build these devices into the spines of their books, so the retailer needs no additional tags - only the security equipment.

that is cool...i always wondered how those things worked


thanks for the help guys

 

[Evadman]

The ones that we used at my store in Home Depot were 2 little strips of metal, just thicker than foil. They were held in a stick on long thing piece of plastic. ( the entire device was like 3/8" by 1" long, by 1/8" tall ) When you put them on the sensormatic, the pieces of metal would vibrate up and donw ( or torards each other would probably be a beter description ) If you took 5 or 6 of them and held them in your hand, then put your hand over the deactavator in the registers, it would shake your whole hand for about 1/2 of a second. Then they would no longer go off when going though the sensormatic checkpoints.

Someone who shall remain nameless acidently put a box of these stickers on the checkout, forgetting that the deactivator was on. It made one hell of a racket, then basicly tossed the box off the counter. Now, I did not actually see this, but I heard it, and saw him picking up 100's of little packets of these from the floor.

Home Depot probably has the most extensive use of these tags, with all different types being used in the store. I know we had the stick on ones, ones that went into boxes, ones that were actually inside tools direct from the manufacturer ( so if they were taken out of the box, they would still go ff on the way out ) They had the ones that go on the cable that can not be turned off that just make the register go insane when you put them on the pad, along with another that I forget. ( I know we had one more, but I can not remember it )

I bet the gateway went off every 3-4 minutes easy. Everyone who tried steeling something was caught by the gateways ( I am going to guess 90+% have the gateway go off ) Of course one of the gateways in our store was broken, and was turned off. I think theves have a way of knowing, but I don't know how. the traffic through that door went way up over time.

 

[Jeff7]

Originally posted by: Evadman
The ones that we used at my store in Home Depot were 2 little strips of metal, just thicker than foil. They were held in a stick on long thing piece of plastic. ( the entire device was like 3/8" by 1" long, by 1/8" tall ) When you put them on the sensormatic, the pieces of metal would vibrate up and donw ( or torards each other would probably be a beter description ) If you took 5 or 6 of them and held them in your hand, then put your hand over the deactavator in the registers, it would shake your whole hand for about 1/2 of a second. Then they would no longer go off when going though the sensormatic checkpoints.

Someone who shall remain nameless acidently put a box of these stickers on the checkout, forgetting that the deactivator was on. It made one hell of a racket, then basicly tossed the box off the counter. Now, I did not actually see this, but I heard it, and saw him picking up 100's of little packets of these from the floor.

Home Depot probably has the most extensive use of these tags, with all different types being used in the store. I know we had the stick on ones, ones that went into boxes, ones that were actually inside tools direct from the manufacturer ( so if they were taken out of the box, they would still go ff on the way out ) They had the ones that go on the cable that can not be turned off that just make the register go insane when you put them on the pad, along with another that I forget. ( I know we had one more, but I can not remember it )

I bet the gateway went off every 3-4 minutes easy. Everyone who tried steeling something was caught by the gateways ( I am going to guess 90+% have the gateway go off ) Of course one of the gateways in our store was broken, and was turned off. I think theves have a way of knowing, but I don't know how. the traffic through that door went way up over time.

That's the kind I'm familiar with. One of the strips is slightly magnetic, and the other is not; when they pass through the pedastal fields, they resonate. The pedastals pick this up, and sound the alarm.
The deactivator at the register is able to sense these tags, and when it does, it sends a pulse through a series of wire coils, becoming a fairly powerful electromagnet. This destroys the magnetic pattern in the one strip, preventing it from resonating at the right frequency, if at all. These things aren't actually "intelligent" - when the item is scanned at the register, it has to be deactivated too; the pedastals can't tell anything about whether an item has been rung up. They only sense an active tag. Morons take advantage of this and stick the tags to carts to give more false alarms. Be nice to attach one of those people to a cart and just send it off into the parking lot at high speed and see how many things it'll hit.

That's how those strips work; I don't know about things like "ultra gator tags" on clothing, as they aren't deactivated by the smartpads at the registers. They might use a permanent magnet.

 

[MrDudeMan]

thanks for the great replies guys