One of our Walmarts has anti-theft wheels
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
I've always been good at returning my carts. Sometimes I'll take it back to the building and sometimes I'll leave it in the cart thing, but if the wheels locked up every single time, I'd be throwing that shit in the planters too.
Oh yeah, 100%. I'm sure there are a ton of people like me that would self govern until you make it difficult for us to do so. Fuck 'em if they want to play that game.
Yup. Never not returned a cart. The day it becomes actively frustrating to do so is the day I place it somewhere really inconvenient out of spite. Maybe figure out the managers car and corral it in.
apparently considering getting security guards to confront people and make them return carts?
Oh that's going to go down just great. How long until some rent-a-cop ends up under a car?
Some Walmart GM must have a brother or something with an anti-theft wheel business because wtf?
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?
I’m not an expert in electricity and magnetism by any stretch of the imagination, but the way that I understand it is with any electrical current, there is an induced magnetic field, and vice versa. So the little parasites the article is referring to are the magnetic fields induced by the current to play the audio in the speaker. That magnetic field is the signal that triggers the antitheft device.
I think they mean that the electromagnetic field generated by sending an alternating current through a coil (or just a wire) induces a current and electrical field on the conductor. I've heard the term "parasitic losses" caused by reactance but I've never heard parasite or parasitic related to generation of EM radiation.
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.
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.
It has to cover a parking lot full of radio signals from cars. They're probably just listening for "close enough".
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.
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.
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.
These most likely lock from a small electric loop around the lot triggering an internal magnet, so y'all found a gap in the loop.
Nice hacking.
You can just lift the wheel about a foot off of the ground when passing the loop that engages the lock. Much easier.
The safeway near my apartment is so ghetto the wheels lock as soon as you leave the store exit. You have to take everything in one trip or wait for your car to pull around to load.
I'm pretty stubborn. I'd probably just drag it across the parking lot like a neanderthal and let the asphalt grind flat spots onto the wheels.
The ones I've seen usually only lock one wheel, maybe two on a side. So you can wheelie the carts just fine.
Even better of you can figure out how to grind the asphalt away with the wheels. Make it reeeeeeally annoying for them.
Pretty much every store in my city has these, didn't realize they weren't a thing everywhere.
It's a litmus test for what type of place you live in. I guess you just found out where yours lands.
Whole thread freaking me out. This is a thing some find normal?!
And lemmy be like, "Fuck cars! Build walkable cities! Live like rats in a cage!"
Uh. No thanks. I'll stick to the bleeding edge of town, thanks.
What does this have to do with walkable cities?
It's an anti-theft mechanism to keep people from stealing carts, generally to prevent homeless from taking them.
I don't agree with it, because the hostility toward homeless people these days is disgusting, but that's how it is.
LOL, I went a little wide of my point. And my point was, this is the kinda crap you see in densely populated environments. Having experienced the city and country, I'll take the country all day long. Mammals were not meant to live in packed populations.
Found out the hard way breeding rats in college. Long story, but they had 6 litters one Sunday morning. By Tuesday, those babies were all eaten, no trace. tl;dr: You pack people together, you get bad behavior.
And I hadn't seen it as an anti-homeless thing! That idea has meat on the bones. Yet another case of American's treating the symptoms and not the disease. Wasn't it Chruchill who said, "You can count on Americans to do the right thing, after they've exhausted every other possibility."?
And if they are like the US Aldi locations, the coin is in the cart. So you even get to take the money with you.
(at least in poland) people usually just leave their coins in the carts, I've never had to put my own coin in there
Just more proof of how stingy we are here in England. But if I worked at a supermarket and people did this, I'd just put away the carts and pocket the cash everyday.
The cart boy would easily find a solution to that weak level of protection. Couple of furniture dollies under a cart instantly restores the rollability and then he could disassemble the wheels back at the shed
for the small price of a hex head wrench, you too can be the owner of a proud new Walmart shopping cart…. I wonder if walmart sells replacement wheels.
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.
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.
We've had these in the UK for a long time, mainly to stop people carting shopping home using the trolley and then abandoning it.
There is a walmart locally that has these or used to have them. Theirs were easy enough to disable.
Do you know how it works? Doesn't seem to be electronic or so... Perhaps mechanical magnet based or so
There's a talk at DEFCON on YouTube about hacking them. Great way to see how it works.
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
But what powers the wheels? Charged by spinning? What happens if they don't get used long and the wheel dies.
By spinning yes, they operate mostly passively and therefore last a long time, including by having terrible security to save battery life.
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.
Just have the greeters chase down any missing carts, they're already on security detail anyway.
I'm guessing a magnet that engages if it's given a kill signal? RFID for location. Must have some sort of battery too.
Yeah, at least in germany these are all just magnets. And outside of the store there is a long metal line, and when you roll over it, the wheel with the magnet completely locks. This happened to me as a kid, and it was sheer impossible moving the cart back to the store.
You ever seen those invisible dog fences? Once it crosses an electrical barrier it triggers an alarm of sorts and in this case I assume it engages some sort of brake 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.