None of the others in town have these, thought it was unusual enough to share
My local store uses these but they lock up if you bring them out to the 2nd row of parking spaces out front. It’s enough to get the cart to your car, then you go to return it and it’s totally locked, so everyone just shoves them into the planters in a big pile of tipped over carts instead of physically lifting the whole thing and hefting it to the cart returns to return it. The store has signs everywhere now telling people not to throw carts into the planters, and the employees know the problem, and the city has evidently complained multiple times, but district management evidently refuses to believe it’s got anything to do with the cart locks and I was told by an exasperated checker that they’re apparently considering getting security guards to confront people and make them return carts?? lmaooo
They’d be better off getting security guards to help people carry shit to their cars.
some models use a wire in the ground that emits a low frequency radio signal… which can be also be transmitted by the speaker in a phone by simply playing these mp3 files: https://www.tmplab.org/2008/06/18/consumer-b-gone/ (!)
Of course, it’s not the sound that blocks the wheel but the electromagnetic parasites that are produced by the coil in any speaker
What the fuck am I reading?
Given the current behavior of autocorrect, I’m assuming that’s not the author’s fault. My brain has reached the point that it skips over that and just reads “currents.” I don’t know how you get from a typo for currents to become parasites, but I’ve seen even worse corrections in my writing.
Can you imagine what would happen if someone went into a crowded store with a device playing this. A short loop through the isles and til queues would wreak havoc.
Sounds like a basis for a fantastic prank.
It’s absolutely insane that a speaker coil works as an antenna in this case, but perhaps even more insane that the signal survives mp3 compression.
Why is that insane? The entire point of an mp3 file is to be able to reproduce signals with reasonable accuracy. Seems like the signal has a frequency of around 8khz, which is very much in the range of human hearing and should be preserved by an mp3.
No, the point of MP3 is to compress audio in a lossy manner while minimizing the introduction of artifacts detectable by human hearing using psychoacoustic analysis. The coincidence that the necessary parasitic EM signal induced by speaker drivers happens to be created by a signal that doesn’t suffer degradation by a relatively specific lossy compression method is remarkable.
Right, but artifacts in the ~8khz range will be detectable by human hearing. mp3s are going to be perfectly acceptable for many sounds in that frequency range… The fact that this works is evidence of that.
Plus, you know what else is lossy? Radio. If the signal is that fragile there’s a good chance the locking mechanism wouldn’t work in the first place.
Go actually read about MP3 compression before you continue misusing the term “lossy.”
It’s just going to be pulses of an 8khz signal. Why would an MP3 not encode this just fine?
Like I said before, the coincidence is what’s remarkable.
Those things have been around for a long time.
I remember them being introduced at least 15 years ago. My manager at the time would wait and laugh at people trying to take them past the parking lot. She was a really miserable person.
I wouldn’t be surprised if they don’t even work anymore just because of how long they’ve been around.
I’ve never bothered to try it recently though.
They likely get repaired/replaced when they die. When the batteries die the brake locks shut so you can’t move it. No idea how long they last though
Bubbles would be really disappointed
It depends on the exact location of the store… pretty common in urban areas. Makes sense as carts cost hundreds of dollars and people will just walk off with them and ditch them once they get home, or of course homeless people often take them and use them for a while. First time I saw this was in Uptown Minneapolis about 20 years ago. Seen them all over since then. I found a brand new Safeway cart in the alley behind my house and was ‘great!’. I wheeled it into my yard and then wondered wtf I was planning to do with it exactly. Apparently, if you call them they have someone who goes around picking up carts, so I let them know and someone from the store came and got it.
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these are pretty common at supercenters in Chicagoland
I’ve only ever seen these in malls so you don’t take the carts to other places in the mall. Do they really use these for carts going out to the parking lot too? How’re you supposed to get your groceries out of the store?
I’ve only seen these in action by accident. Happened to me when I tried to go around a planter to reach the eating area at a Whole Foods. Apparently that was beyond the perimeter and I got stuck.
I saw one just last week lock up right at the door of Safeway when a lady was trying to go out to her car (it’s not supposed to block you from exiting the store). She was stuck in the door, cart half outside.
But people who actually do want to take the carts away know exactly how to avoid the mechanism.
Locking or not, at least the American buggies don’t have rotating back wheels. I don’t know what Australia & England were thinking, but these bad ideas got imported where I live nom & they are needlessly difficult to maneuver.
My grocery store just got these and I didn’t know about it. Mine went off as I was going out the door and I was like “wtf is happening here” until the self checkout girl saw and came over to release it.
Do you know how it works? Doesn’t seem to be electronic or so… Perhaps mechanical magnet based or so
https://www.youtube.com/watch?v=-QKcprQD0zc
It’s a fancier version of the electric dog collars. If you go over a perimeter line it’ll turn on a parking brake for that one wheel.
Probably an electrical fence type deal. When the signal gets too weak the pins pop out to prevent the wheel from rotating. Didn’t park near the edge of the property to test it lol
There’s a talk at DEFCON on YouTube about hacking them. Great way to see how it works.
How do they work
I’m guessing a magnet that engages if it’s given a kill signal? RFID for location. Must have some sort of battery too.
Many grocery stores in my area have these wheel locks. If I recall from college, if you took the cart out of the parking lot by carrying it over the plant beds, the lock would not engage.
