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Toys Science

Cart Locking System Released as Open Source 323

An anonymous reader writes "You may have noticed that over the past few years it has become increasingly common to find supermarket and large retail store shopping carts equipped with 'boots' designed to lock up if you try to take the cart outside of the store. Now, someone has discovered through some clever analysis the signal used to both lock and unlock carts, and has designed a portable system that locks up all carts within 20 feet of the emitter! They have released the schematics, software, and detailed instructions for assembling the systems on Instructables, an online magazine dedicated to releasing howto's for everything from rat taxidermy to Shopping Cart EMPs under a Creative Commons License."
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Cart Locking System Released as Open Source

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  • by kryten_nl ( 863119 ) on Sunday July 01, 2007 @07:51PM (#19711101)
    Like with most highly sophisticated systems, an unfolded paper clip will do fine.
  • sigh. (Score:3, Interesting)

    by Anonymous Coward on Sunday July 01, 2007 @07:56PM (#19711135)
    1. nerdy does not imply not-asshole
    2. this was not actually designed by a competent engineer. a competent engineer would have put the transmit coil in an lc circuit tuned to the right frequency and thus made it way more powerful while consuming way less electricity. this is essentially an electric heater that radiates a small magnetic field.
  • by OzPeter ( 195038 ) on Sunday July 01, 2007 @08:06PM (#19711183)
    We didn't need some fancy electronic locking device to stop trolleys leaving the car park (translation to American: carts leaving the parking lot)

    Instead each trolley stacked up in the waiting area had a small mechanical lock that attached a pin to the trolley in front by a chain. In order to release the next trolley in line you had to insert a $1 coin, which was retained in the lock. When you finished using your trolley, you locked it back up again and your coin was returned. No high faluting electronics, a built in incentive to return the trolley, and no mysterious lockups.

    Of course trolley wheels have been designed since day one to lock up without any fancy electronics inside them ..
  • by QuantumG ( 50515 ) <qg@biodome.org> on Sunday July 01, 2007 @08:58PM (#19711497) Homepage Journal
    It matters because they invented the term. Just like all those people in the 80s use threw around the term "object oriented" when they weren't even close (yes, I'm looking at you Oberon). Some words have meaning that is free to change with use. Other words are jargon and have very specific meanings which are defined by an authority, and are not subject to change.
  • No degree needed. (Score:2, Interesting)

    by Whammy666 ( 589169 ) on Sunday July 01, 2007 @09:56PM (#19712017) Homepage
    This ain't rocket science. You don't need a CPU to do this, let alone a PCB board. Doesn't anybody know how to build stuff using discrete logic anymore? Eesh. I could have built this on a perfboard when I was 15.
  • by hendersj ( 720767 ) on Monday July 02, 2007 @12:13AM (#19713151)
    Yep, that's exactly what it's aimed at.

    Used to work for the corporate side of a large food & drug retailer in the US; those shopping carts, wobbly wheels and all, cost on average about $120 each - and that's before the wheel lock systems were put in place (no doubt that has driven the cost up).

    The ironic thing here is that some of the supermarkets have parking spaces outside the lot, but the carts don't roll outside the lots, so sometimes people can't get their shopping back to their cars. On the flip side, I watched one lady try to steal one of these carts - she got about 3/4 of a block away with it, and it was quite a struggle for her. Clearly she hadn't read the signs that said the cart wouldn't work outside the parking lot. It also was clear that what was in the cart wasn't her shopping.

    Loss prevention is big business. This is what happens when people steal from local stores - the stores end up having to put measures in place that inconvenience everyone.
  • by Anonymous Coward on Monday July 02, 2007 @04:15AM (#19714653)
    I don't quite know the exchange rate for kroner, but I doubt a bad-willing person will be poor enough to care about 10-20 kroner.

    They probably won't. But why do shopping carts disappear in the first place? Mostly kids having fun, I guess. And kids don't have enough money to waste on that. Other times they disappear because someone thought that taking the cart home was easier than carrying their groceries all the way. So they'll bring back the cart next time they go shopping, rather than dumping it. It may not be a lot of money, but over time it adds up.

    And when a shopping cart is abandoned somewhere, some kids are likely to find it and think "Ohh, money... Candy...", and bring it back. Easy money earned.

Solutions are obvious if one only has the optical power to observe them over the horizon. -- K.A. Arsdall

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