This Hacker News discussion revolves around the concept of shopping cart anti-theft wheels that lock up when they leave a designated retail area. The conversation branches into several key themes: admiration for the ingenuity of exploiting this system, personal anecdotes and frustrations with the wheels themselves, discussions about the technical aspects of how these wheels are triggered, and broader observations about shopping cart management and cultural differences.
Admiration for the "Hacker Spirit" and Ingenuity
A significant portion of the discussion expresses admiration for the cleverness displayed in bypassing the shopping cart locking mechanisms. Users see it as an embodiment of the "hacker spirit," finding ways to interact with and exploit technology in unexpected ways. The LoLRa project, which transmits LoRa without a radio transceiver, is cited as a similar example of this ethos.
- "This perfectly embodies the kind of hacker spirit that I love." - Liftyee
- "Reminds me of the LoLRa project from cnlohr that transmits LoRa without a radio transceiver." - Liftyee
Frustration and Negative Experiences with Locking Wheels
Many users share deeply negative personal experiences with the locking wheels, highlighting their unreliability and the inconvenience they cause. One user recounts a particularly frustrating incident where the wheels locked up unexpectedly in a busy parking lot, forcing them to unload children and shopping manually. This frustration leads to a desire for retaliatory, equally inconvenient, actions from other users.
- "I despise these wheels. About 15 years ago, my wife and I went to Target and first went to lunch at the far end of the parking lot. After lunch we headed into the store, grabbed a cart, now loaded with our newborn in his car seat, and our two year old sitting in the cart. A quick shopping trip later, we headed back to the car. When crossing the Target parking lot, the wheels locked up, in the middle of the road. Cart wouldn’t budge. Traffic all over the place, and now I have to pull both my children out, along with the shopping, and carry them all to my car. Pissed is an understatement." - jmpman
- "Why did they need to put the wire in the middle of the road???" - jmpman
- "I hope someone attaches Bluetooth speakers to their shoes and locks every cart in target, so they have to remove the system." - jmpman
- "I find the locking wheels annoying, because they're so often defective and make it a noisy struggle to get your cart through the store." - axiolite
- "Avoiding these stupid wheels is probably the biggest reason I shop at Costco" - alostpuppy
Technical Explanations and Analogous Hacks
The discussion delves into the technical mechanisms behind the locking wheels, specifically focusing on how audio frequencies can trigger them. Users explain the concept of parasitic EMF generated by phone speakers as a means of transmission, referencing the DEFCON talk. There's also a shared memory of DIY projects from years ago that aimed to disrupt these systems.
- "It needs the electromagnetic / rf field. It can work if your phone is nearby becaause of the 'parasitic EMF from your phone's speaker to "transmit" a similar code by playing a crafted audio file' according to the article and the DEFCON talk" - foreman77
- "Around that year, or maybe even earlier, I remember reading an article about how to DIY one of those devices with a PIC microcontroller and wreck havoc on the store. It might have been something very similar to this: [Instructables link]" - tecleandor
- "Since 7.8 kHz is in the audio range, you can use the parasitic EMF from your phone's speaker to 'transmit' a similar code by playing a crafted audio file" - jadamson
- "The range of human hearing is about 20 to 20000 Hz. As a by-product of producing physical vibrations at those frequencies (i.e. producing sound) via an electromagnetic coil, a speaker will produce an EMF with the same frequencies." - jadamson
- "However when charged particles (like the electrons in a wire) accelerate they create radio waves, so the magnetic coil in the speaker will also create a small amount of radio waves in the same frequency as the sound it is producing. This is what's called parasitic EMF, and in this case it turns out that this small amount of radio signal is enough to interact with the radio in the wheels." - PMunch
Historical and Prevalent "Cart Wrangling" Methods
Users reminisce about earlier, and sometimes more disruptive, methods of cart manipulation. This includes instances of locking entire groups of carts, intentionally stranding them, and even a chaotic incident in college involving RF transmission that resulted in minor injury. The conversation also touches on the motivations behind these actions, such as spite or a desire to cause pandemonium.
- "Friends did this college in like 2005. Cambridge area, Shaws Market I think. I imagine the hardware setup was a bit different. All the details are hazy but I recall their lock transmission signal had a huge range and locked all carts in a wide area." - varenc
- "I suppose now I can admit that we did this in college in 2003 (with RF, not audio), and had great fun seeing a grocery store descend into utter pandemonium, until the power electronics overheated and burned the signal carrier to whose chest the circuit had been taped, who started yelping in the store and drawing a lot of suspicion to himself." - asdfa456sdf33
- "It was completely counterproductive, too. The edge of the zone was about 50% of the way home. Out of spite, we'd push the cart up to the edge, and leave it stranded there, carrying everything the last 200m ourselves. Not proud of that in retrospect; it goes to show that you can't stop assholes with technology." - isoprophlex
- "This brought back a memory of living in Byron Bay Australia in 1999 - there was a person who’s full time job was driving around town with a trailer, collecting shopping trolleys and returning them to the Woolworths supermarket." - ljf
The "Flat Mooner" Joke and Off-Topic Diversions
A brief but notable side thread emerges from the author's bio line mentioning "flat mooner." This sparks a humorous discussion about the absurdity of believing the moon is flat, leading to lighthearted jokes about its shape.
- "Author's bio line says they are a 'flat mooner'. Which gave me quite a chuckle." - 3eb7988a1663
- "What's the meaning? Like, they have a flat ass?" - MangoToupe
- "They're (jokingly) saying they believe the moon is flat. Like a flat earther, but the moon instead of the earth." - DrAwesome
- "They believe the moon is a flat circle (not a sphere)." - ta8903
- "Which is perfectly ridiculous. It's obviously carrot-shaped!" - Dilettante_
Shopping Cart Management and Cultural Differences
The conversation broadens to discuss various methods of shopping cart management used in different countries, particularly contrasting the US approach with systems in Europe. The coin-deposit system, its effectiveness, and the impact of COVID-19 on its usage are highlighted. Users also discuss the reasons behind the prevalence of locking wheels, with some attributing it to issues with homeless populations and elderly individuals taking carts, while others point to lazy behavior or the difficulty of transporting groceries via public transport.
- "Locking shopping cart wheels just aren't a thing here in the Netherlands (or neighbouring countries). It used to be that most required a €1 coin inserted to unlock its link tethering it to the next car in the row, but then covid happened and a lot of shops simply disabled those locks and concluded that the system worked better without — probably driven in part by an increasing number of people who don't carry any cash." - Freak_NL
- "It's most common in places with lots of elderly or homeless, both groups find these carts very useful and will simply take them, homeless to keep, elderly to abandon near their home once they have transported their groceries. It's more also common in places where people walk, since it can be hard to bring groceries home on public transport. So yes, very localized." - ars
- "Aldi does it for a quarter and it works pretty well to get people to return them." - mattmaroon
- "Larger stores in Sweden also use the coin system, even though as in the Netherlands it feels like use is declining in favor of just unlocked carts." - unwind
- "The coins are so that people put them back in their designated storage area, not to prevent theft. A significant fraction of the population are lazy asshole who tend to leave carts next to where their car was parked instead of walking the 10-20 meters it take to return them." - prmoustache
- "In the United States, carts are free. There is no particular need to change this, because one person can only use so many shopping carts. If you maintain the price at "free", demand saturates and people stop stealing carts." - thaumasiotes
- "The coin insert system is to incentivise people to return the trolley though not to prevent thefts." - jansper39
- "I think when they removed the coins during Covid they just noticed that most people were already well-behaved enough to return the carts to their places, so the incentive is just not needed anymore. Actually in Belgium, Colruyt had never had coins for their carts and it just works." - seszett