Pistol sets off inventory loss alarm?


September 27, 2007, 08:19 AM
This happened to me twice, two and a half weeks ago, and again two days ago. I went to the pet store to get overpriced, highfalutin, designer cat food for my pudgy cat. On both occasions, I triggered the shoplifter alarm twice, when I entered the store and when I left. Of course, I was carrying concealed. Both times, I just kept on walking. I didn't want to have to explain anything to management.

Should I assume this particular store has a simple metal detector and not an electronic inventory tag system? I'll try and remember to shop at the other franchise, and hopefully not deal with this again.

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September 27, 2007, 08:26 AM
I've seen some cell phones set them off.

Double Naught Spy
September 27, 2007, 08:34 AM
To what gain would a pet store attain by having metal detectors? Of their stock, a tremendous amount isn't even metal. They are not a security area. Metal detectors are an expensive accessory for a store to have. Security scanners are as well, but security scanners serve a very specific purpose of helping prevent inventory loss. So why would you think they have metal detectors?

It may be a cell phone or you have in your possession a security tag that isn't fully deactivated. You may not know it as some are made into products.

September 27, 2007, 08:35 AM
Electronic inventory tag systems often are desgned to detect tightly wound coils of wire (look at the underside of the merchandise stickers). Such configurations can be found in many electronic and electrical devices using coiled wire. I used to carry a ball of telephone cord to work and it would set off the alarm almost very time.

September 27, 2007, 08:41 AM
All springs, including those in firearms, have self-resonant characteristics which may fall in or near the search field frequency of these detectors. Whether or not the field can penetrate to the springs and set off the alarms depends mainly on whether the springs are surrounded by steel. For example, the coil mainspring in revolvers are usually under wooden or plastic grips. This self-resonance characteristic is also true of flat mainsprings.

Thus it is, to my mind, well within the realm of possibility that a gun can set off one of those things. But it's one of those situations where everything has to happen to be just right.

I think it's happened to me with a Colt Detective Special in an ankle holster, but I did not want to experiment --i.e., take off the gun and walk through it again.

Every time this subject comes up I get tempted to dig out my grid-dip oscillar and look for resonances in the springs of various guns. However, since I see it as a distinct possibility, the motivation to "prove" it is not very strong.

With the thousands of times firearms go through these detectors every day, I am not surprised that occasionally one might get set off just by a chance convergence of many factors.


(1) Double-Naught: OP is not talking about metal detectors, OP is talking about those "gates" which detect the little inventory control chips on the merchandise.

(2) Most of the time the beepers get set off (a lot of things can trigger them) they just wave me through, since I seem to radiate "innocence." However, if I am ever seriously challenged, I decided that I would let them search me, but I would tell them not to touch my gun. IF they feel that is necessary, I will tell them I will wait right there until a Commissioned Peace Officer arrives to search me. And I would tell them that when they make the call, make sure they mention that I have a CCW license. That's my plan. Hope I never have to implement it.

May I emphasize Commissioned Peace Officer?

DEwd0xxx 73

September 27, 2007, 09:47 AM
I once thought that was happening to me. Door alarms started going off often as I entered or left stores. My first assumption was that maybe my carry weapon was setting it off. Turned out that a wallet I had recently purchased still had the anti-theft chip hidden inside. Something to consider.

Blue Line
September 27, 2007, 09:50 AM
I carry every day and have never had my gun, mag or flashlight, cell phone, pager, or car keys or anything else I normally carry, set off one of those detectors. I bet you have one somewhere on your person like a jacket, shoe, something that has one that has not been deactivated. Most of the time I see the store clerks ignore those things anyway, kind of like car alarms.

September 27, 2007, 09:57 AM
Wallets, shoes, boots especially, some belts. Jeans will sometimes have them in the 5th pocket. Mechanics brand gloves have them sewn into a tear away strip. Next time it happens, try standing outside the gate (usually more than a foot from the gate itself) and stick each foot through. 99% of the time that it's not an actual shoplifter, it's a leather boot. Depending on the system, you have to scrunch the things down on their top to get the pad to activate. If it's not your boots, check you wallet. If it end up being that, make sure you take anything with a mag-strip out of the wallet before they deactivate it. Any magnetic field that can pull a stapler down from 6" above the pad is not healthy for anything magnetic.

September 27, 2007, 10:02 AM
My wallet will occasionally get magnetized. I usually just take out the credit cards and ask the cashier to "deactivate" it. Go back and leave the pistol in the car. If it doesn't go off....uh...ask the cashier to deactivate your gun?

:o Tell her you don't want the alarms going off at the airport.*


*I'm being facetious. Please don't do this. It would probably lead to a mass exodus of sheep from the store.

September 27, 2007, 10:05 AM
The devices that you pass through at retail entrances are there to monitor radio frequency chips that many inventory items have embedded in the package or even the price sticker.

I guess something else like a cell phone or pager Could set one off but I doubt it. A gun? That would really be a stretch!

If you really want to know, try leaving the gun in your car and, wearing exactly what you wore before and having exactly what was in your pockets with you, walk through.

I have never had an EAS sensor alert on my cell phone, pager or gun. The cell phone and pager go everywhere with me - the gun to those places where it can legally visit.

Charlotte, NC

September 27, 2007, 10:29 AM
I thought it might have been my pistol on two occasions. First occasion I had a new sweatshirt on and I eventually found the security tag in the sleeve about the bicep area. The other time I had a new wallet and the security tag was in the compartment under where you put your credit cards. Both took me a little time to figure out. I knew it couldn't be the gun. I figured there was no way they could have a metal detector at the door, or everyones cell phones, keys, and whatever else would set it off. It would be going off non-stop.

September 27, 2007, 10:34 AM
Did the alarm go off when you went INTO the store or just when walking out?

September 27, 2007, 10:41 AM
I had that happen a few times, too...

Turns out that the combination of cel-fone in left front shorts pocket, car keys w/remote door locks in right front pocket, and wallet with my workplace 'gate key card' would set off the alarms at ONE store. If I had any of those items in hand, instead of pocket, alarms didn't go off

September 27, 2007, 10:43 AM
I suppose it could be a newish pair of jeans. I've been into that store many times, and this has only happened on my two most recent visits. Who knows, I could've worn the same pair of jeans both times.

I can't imagine the store would tolerate the incessant beeping and chirping if cell phones, pagers, keys, credit cards, or any common thing set it off. Everyone has a cell phone and credit/debit card these days.

I'm not going to experiment with it, I'll just go to another store. Leaving the gun in the car would be like leaving the pants in the car. I'm just used to it.

September 27, 2007, 10:46 AM
I bet you have one somewhere on your person like a jacket, shoe, something that has one that has not been deactivated. Most of the time I see the store clerks ignore those things anyway, kind of like car alarms.I was waiting at the customer service desk(near the door) at a dept. store for like an hour one day. That alarm went off about a half dozen times. None of the staff ever raised an eyebrow, they just tuned it out. Seems to me many of these systems may be maladjusted. ;)

September 27, 2007, 11:44 AM
Many printed circuit boards have traces on them that act as a coil... of course most firearms have springs in them... a coil of wire.

Not really surprised.

September 27, 2007, 11:53 AM
They aren't metal detectors, they're RFID readers. the little tags in the stuff they sell has to be deactivated wit ha magnet before you can walk thru them without setting it off. Your gun didn't and cannot set them off. Likely you have a speedpass or something like that on your person, or maybe a cell phone.

September 27, 2007, 12:54 PM
All springs, including those in firearms, have self-resonant characteristics which may fall in or near the search field frequency of these detectors. Whether or not the field can penetrate to the springs and set off the alarms depends mainly on whether the springs are surrounded by steel

So no Glocks then?


September 27, 2007, 01:55 PM
Your gun didn't and cannot set them off.

I respectfully disagree. As I said, I believe it is well within the realm of possbility. Maybe it doesn't happen, but this does not mean it can't happen.

The inventory chips are detuned when they are demagnetized. In fact, you don't even need a coil.

I discovered a thin ferrous wire in the backing of a library book once. Magnetized it, went into the library, set off the alarm, got waved in.

Picked some books up, slipped the wire into one of them (so there were two wires in the book) and when both went over the demagger at the checkout counter, it was also demagged, and I therefore exited with no alarm.

Chances are best that it was something else that set off OP's alarm, but it is not impossible that it was his gun.

So no Glocks then?

Not that familiar with Glocks, but if it's striker-fired, the firing pin spring (and of course the recoil spring) is probably shielded by the slide, and the mag spring would probably be shielded by the mag itself. But not impossible.

The last time we went through this (on PDO?) there were two camps (as there will be here). Those who said it never happened to them, and it was therefore impossible, and those who recognized that springs (and even straight wires) have self-resonant characteristics which might fall in the sensing frequencies of the tag detectors.

As I mentioned, I am well aware that such is a possibility, and don't feel a need to prove it. Which is why I never bothered to unlimber my GDO (Grid-Dip Oscillator, a device designed to determine resonant frequencies) to check it out. There are so many variables involved which would affect a spring's tuning, including the size of wire in the spring, its diameter and length, whether it's compressed or not, whether it happens to have a little residual magnetism picked up from somewhere, etc, etc, that it is not likely that any particular gun will happen to have its springs juuuust right to set off an inventory control detector.

Therefore, negative attempts to set off an inventory detector with a particular gun mean nothing.

DE wd0xxx

A grid-dip oscillator:

September 27, 2007, 02:07 PM
To me it sounds that one of the tags wasn't deactivated, if it was something you had on your person the alarm would be triggered going in or out.

September 27, 2007, 02:08 PM
a Magnetized spring huh??.. Thats kinda stretching a bit, dont ya think??

Green Lantern
September 27, 2007, 02:32 PM
I CCW a Glock 19 or a Kel-Tec P3AT, or both. Gone into lotsa stores with those fixtures, but have never set one off.

Curious - those that have set one off, (like the OP), what kind of gun do you carry?

Anyway, I personally would NOT just keep on walking. What are they gonna do, pat you down? In my experience, they'll just wave you on, assuming that they didn't de-activate your tags right, or it's something else, if you stop. If you had stolen something, though, would you really stop when you're at the door and most people should know that staff can't chase/use physical force on shoplifters?

Now, where I work is unique, the sodding "de-activators" we have DO NOT BUZZ to let us know the tags HAVE been deactivated. Don't know what idiot thought that would be a good design. So, 99.9% of the time when our alarm goes off, we don't think "SHOPLIFTER!"

No, we think, "Aw, *$#@*!!! Must not have swiped that *insert merchandise here* right when they rung her up!"

September 27, 2007, 08:20 PM
a Magnetized spring huh??.. Thats kinda stretching a bit, dont ya think??

Ooog! That was punny! :)

Actually, they'd collapse slightly when magnetized. When I was a kid, one of the esperiminks I performed, copying Mr. Wizard, was to take a segment of a Slinky(TM) suspended through a conductor connected to one end of one of those enormous doorbell batteries with screw termnals, and with the other end bent down and dipped in a mercury pool connected to the other battery terminal.

It was fun to watch the Slinky(TM) dip in and out of the mercury pool as it magnetized from the current flowing through it, would pull itself out of the pool of Hg, become demagnetized, and dip into the pool again.

With a teeny spark each time it pulled itself out of the Hg.

Oh, the mercury vapors it must have produced as it cycled! You could never perform that experiment today with mercury.

Don't do this at home.

Hak! Koff!

September 27, 2007, 09:46 PM
I guess something else like a cell phone or pager Could set one off but I doubt it.

My fire dept pager a Motorola minitorII would set them off all the time. I got tired of showing the Best Buy guy my pager every time I walked out the door.

September 27, 2007, 10:00 PM
pretty much everything I purchase, I disassemble to find and remove those annoying little plastic-filled-with-metal-strips/squares-with-coiled-wires that they tuck and hide away. It's in most DVD/Xbox games, and the sneakiest one I've found yet, was in a Daisy airsoft gun (one of the older ones before they started with the orange blaze barrels) one was tucked away on the underside of BOTH GRIP panels! (it was a beretta 92 lookalike that disassembles somewhat correctly :) )

Whenever I run across those little buggers I rip them in half to disable the Gov't's secret tracking bug :D

I never knew how those security systems worked and that they could be set off by random things like that. I've never brought a gun through one of those systems before so I didn't know that they could do that either.

One good thing though is that I haven't found any of those sticky security tabs inside any of my guns...yet ;)

September 27, 2007, 10:49 PM
I work in the alarm industry and I go into literly 1000's of places with my equipment. I was in an Auto Zone not to long ago and my 10 year old drill kit (that I might add has been in this store before) set off their stupid shoplifting alarm. Sometimes it's not you it's the equipment.

Then there was the time I bought my son a new pair of work boots, at Kmart, they deactivated the tag (I was there), went through the system and nothing happened. Then every store he went into for 2 months he was setting off their equipment, coming and going. Finally got tired of the problem (doesn't look goo dfor the security company employee to set those things off all the time. Went to my local Auto zone (yes I spend alot of time in there) and ask the mgr to help find what was causing the problem. Told me to have him take his shoes off and toss them through the "gate" and sure enough it set them off, he deactivated them and no more problems, ever.

I wonder if different stores have different tags and some manufactures put both of them in the same article since both places buy the same stuff?

September 28, 2007, 03:53 AM
You know now that you said that. I work for a Printing company and we were running the paper packaging that goes inside blister packs for san-disk flash drives and there were two spots for the placement of those tags. One was marked Sensormatic and I can remember what the other was labeled. But your theory is a good one.

September 28, 2007, 04:17 AM
My old keycard for the badge readers at Sprint would set off the alarms at the video store every time. Sometimes i'd do it for fun... "hey... its fixin to beep, be sure to turn it off".

The base inside these things is a kind of RFID w/ a lil bitty chip and a coil of copper around the outside of the badge. (just inside the plastic)

My new one's at my new job haven't set anything off yet. Maybe they operate on a different frequency.

All that being said... i can't say how many times they stopped me at the door and re-did the magical make your DVD you just bought not set off the alarm thing.


September 28, 2007, 04:40 AM
I decided that I would let them search me, but I would tell them not to touch my gun. IF they feel that is necessary, I will tell them I will wait right there until a Commissioned Peace Officer arrives to search me.

I am not a lawyer, and I didn't sleep in a Holiday Inn Express last night but I would not mention the word firearm or consent to a search by any store employee. Your state laws may be different, but I doubt it. Nobody is putting their hands on me, except another LEO or a loved one.

If you mention firearm to the store emplyee you have a good chance of them calling in a "Man With A Gun" call. What I would do is stop and explain that I didn't shoplift anything and that their machine must be faulty or that the clerk that rang you up didn't "demagnetize" whatever the heck it is you bought. I would then say something like, "If you feel that I need to be searched please call a Law Enforcement Officer. In fact I will call for you, or you can even use my phone." You can offer to let them look through your bags, I do that, but like I said, they are not putting their hands on me.

If you didn't steal anything chances are you would have the grounds for a great lawsuit and "own" the store so to speak :D if they did put their hands on you or called the Police. Your state laws may be different, talk to your local attorney.


September 28, 2007, 11:24 PM
Most of them are NOT RFID tags - the tags are just a printed coil or bimetalic strip that causes a disruption in the electrical field that the plates at the side of the door generate. Even cheaper than RFID.


September 28, 2007, 11:28 PM
I had a roll of 22/4 stranded alarm wire set one off today, coming in only. Guess I took enough wire off the roll while ther so it changed it's properties going out.

September 28, 2007, 11:55 PM
Sometimes stores without security systems will still get merchandise with the tags - and won't bother to deactivate the stuff because they don't have the alarms to go off. Most of the time they won't even have the disabler system, so they can't turn them off.

One of the stores in the local mall had such a problem with items bought from another shop at the mall that they put a sign up stating the situation- and that they'll gladly disable any of the devices that set off their alarms.

September 29, 2007, 12:01 AM
1 word Tungsten.

Many stores use Tungsten strips on items and these are what set off the alarms. Your gun might have some tungsten in it and this may be the problem.

September 29, 2007, 02:11 AM
My right leg sets them off. I can always tell when the maintenance gets done at the door scanners at two of the shops in town, as I set them off going into each store for about 2 weeks. We did some experiments and decided it is probably the shrapnel in my leg (wearing shorts, no shoes, no shirt, nothing in pockets, no glasses - still pings me.)


10 Ring Tao
September 29, 2007, 02:24 AM
Definitely not metal detectors, they're RFID or coil detectors.

I had one hidden in a ball cap, and I would always set those damn things off until I narrowed it down to that hat, and found the little bugger.

September 29, 2007, 02:31 AM
when one of these things goes off and the walmartian scurries over to me i always tell them "it's my sidearm, it always sets these things off" that always sets them back on their heels and sometimes even makes them scurry back into their dens without comment. i did have one older gentleman with a ruptured duck pin on his cap laugh at me.


September 29, 2007, 12:40 PM
Geez a simple google search will tell you how they work , most of the time when either the wife or i have set off the detectors its because some of the shoplifter have become proficient at finding and removing the tags and usually just drop them on the floor . One jokester actually attached them to shopping carts , usually we find them stuck to the bottom of our shoes .

How RFID tags really work

September 29, 2007, 04:17 PM
It is far more likely that it was your cell or pager setting it off, not your gun.

September 29, 2007, 07:50 PM
My old cell phone used to set of the alarm at Wally World. I always kept walking because I know that they do not have Loss Control there.

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