Unlocking the secrets of “product denial”

I found a security cap lock to a liquor bottle lying in the street, and I decided to take it apart to see how it worked. I was surprised to find what looked like a solenoid inside, which was the heart of the lock mechanism.

[I was wrong about it being a solenoid; see below. It is a coil that sets off alarms.]

The blue thing is one inch long with a ferrite core rod, each side of which moves in such a way that if activated, it would unlock the pins so it could turn and push down the plastic spring clamp gripping the top of the bottle. What fascinated me is that while the “solenoid” (if that’s what it is) looks like it should slide on activation, it does not slide and cannot be moved no matter what I do.

There is no battery or power source, which means it must be activated externally. But how? No amount of fiddling around with magnets could get it to move, and there would be no way to get electrical current inside the cap. There are two depressions in the plastic lid for turning it, but it would only turn once that tiny solenoid is activates to unlock the steel pins that prevent rotation.

The internal mechanism is similar to that shown here at the bottom of the page. The author does not know how it works:

Supposedly the coil is non-deactivatable which does make it a bit different than the other devices above.

I can find no way to activate it, which is what puzzles me.

How might it work?

The only difference is between “mine” and the one above is that mine has two depressions in the top lid.

The manufacturer’s web site does not explain how it works, other than to state it has a twofold purpose (the usual RFID article surveillance strip, plus the electronic “denial” device):

Bottle locks have become a very popular device for preventing shoplifting. These bottle locks prevent the opening of a bottle of liquor in the store and the thief either pouring it off into another container or drinking it there.

So it doubles as a “regular” anti-theft device against ordinary thieves, and as a way to prevent people who cannot buy from drinking. In other words, minors can’t easily open the bottle and pour it into another container, or else just chug it in the store.

Interestingly, if “product denial” is to be maintained in a credible manner, these devices would seem to be dependent on glass bottles, for any thief can easily cut a hole through a plastic bottle and pour out the contents. With glass, it’s a mess. Drilling holes is a major pain requiring special tools, and breaking the neck off a bottle risks breaking the whole bottle. (It would almost be easier to just put the bottle in a bucket and break it, then pour through a sieve into another container.) Which all in all would mean the best method would be to simply saw or grind out the plastic lock itself.

I couldn’t help noticing that the bottle lock I found reeked of sweet booze, so I suspect someone just smashed the bottle and made a mess, then threw it into the street.

Still, I’m curious as to how that little solenoid can be activated from the outside without a battery, and why I can’t get it to budge even with a fairly strong magnet.

Anyone know how?

MORE: It seems as if my magnets were not strong enough. According to this video, all you need to open these devices are four neodymium magnets. These make the steel pins snap up and out the way.

The thing I thought was a solenoid seems to be merely a security device.

Never knew about any of this stuff. Turns out it was a lot easier to find the answers on Youtube than Google.

AND MORE: Now I understand why that coil would be non-deactivatable. They don’t want the bottle locks walking out the door, period, because they cost money and are reused. (Doh!) And they have them inside the removal devices too, which prevents them from either leaving the store, or being brought in from the outside.

MORE: This video shows how to remove the exact device I found in the street:

It is amazing what is on Youtube. Must be a little discouraging to the people who develop these security products, although I suspect your average thief is a grab-and-run type as opposed to a hacker.

It’s a little like the “bump key” phenomenon. Your average burglar doesn’t carry or use a bump key. Rather than fiddle around with picking locks, he will just look for unlocked doors, or else just do a smash-and-grab.