Game Boy vs. Electronic Shelf Labels

SANYO DIGITAL CAMERAWhile they’re probably rare as hen’s teeth in the US, there have been a few major stores around the world that have started rolling out electronic shelf labels for every item in the store. These labels ensure every item on a shelf has the same price as what’s in the store’s computer, and they’re all controlled by an infrared transceiver hanging on the store’s ceiling. After studying one of these base stations, [furrtek] realized they’re wide open if you have the right equipment. The right equipment, it turns out, is a Game Boy Color.

The shelf labels in question are controlled by a base station with a decidedly non-standard carrier frequency and a proprietary protocol. IR driver chips found in phones are too slow to communicate with these labels, and old PDAs like Palm Pilots, Zauruses, and Pocket PCs only have an IrDA chip. There is one device that has an active development scene and an IR LED connected directly to a CPU pin, though, so [furrtek] started tinkering around with the hardware.

The Game Boy needed to be overclocked to get the right carrier frequency of 1.25 MHz. With a proof of concept already developed on a FPGA board, [furrtek] started coding for the Game Boy, developing an interface that allows him to change the ‘pages’ of these electronic labels, or display customized data on a particular label.

There’s also a much, much more facepalming implication of this build: these electronic labels’ firmware is able to be updated through IR. All [furrtek] needs is the development tools for the uC inside one of these labels.

There’s a great video [furrtek] put together going over this one. Check that out below.

Comments

  1. v665f6atu3 says:

    Brian, that video link 404s. Plus, their SSL certificate is sketchy. Plus, WOT labels both the original and the redirected page as non-trustworthy.

  2. fartface says:

    Some states in the USA have a law that requires price tags on the product, so you will not see these shelf tags for a very long time here in the USA in common use.

  3. sneakypoo says:

    Ever since those things first started popping up in stores around me a few years ago I’ve wondered how easy they would be to access. Very easy apparently… It’s a bit sad that so many of these types of products are mostly based on security by obscurity to keep them safe.

  4. shlonkin says:

    Here in Japan these are very common in supermarkets. The fancier ones display names, sale/regular prices, special icons etc. I’ve seen some with error messages too.

  5. Tony says:

    I worked on this stuff about 25 years ago. It’s deva-ju all over again.

    The idea back then was to update the tags by blinking the lights in the store, either causing the drunks wandering past to start an impromptu rave or finding a pile of epileptics outside at opening time.

    One version futzed with the frequency of the fluorescent tubes, so no blibking. Not sure how exactly that worked (if at all).

    • rj says:

      Talking Lights? It’s just FM. It turns out electronic (not magnetic) ballasts for fluorescent tubes have a bandwidth somewhere around 1/10th of the resonant frequency without visibly changing brightness. So for a standard 8kHz CFL, that’s already 800bits/sec (assuming 2FSK) of continuous data transmission.

      • Tony says:

        Nah, not them, this was back in age of the dinosaurs.

        The tags I worked with were optical (IR), not sure about the flouro ones. The ballasts would have been old-school stuff.

        I think it worked by using the flicker rate as the clock, and every so often dropped a cycle. So at 50Hz you’d get 100 pulses/sec, every so often one would be missing so that was a bit.

        Can’t remember exactly, it’s been while!

        The IR stuff could be done by senders on the roof, or by hand-held units.

  6. Sven says:

    These turned up here in the 90’s, most stores have phased them out again. I think they were stolen too often, and since you are always restocking anyway you might as well change the tags at the same time. It’s more of a gimmick than a necessity.

    The only thing this would be really useful for is stores with prices that change extremely often, such as computer stores.

    • Whatnot says:

      Over here the managers don’t restock themselves ..but instead they use cheap labor of (2/3rd gen. immigrant) male kids, and unfortunately those seem to be rather frequently not even able to read. so not the types you entrust with changing labels I expect.

      • Greenaum says:

        That’s pretty terrible of your country’s schooling. Over here (UK) most kids who were born here end up speaking and reading / writing English as well as anybody, on top of their at-home language. Maybe it’s your culture. You don’t mention your country, but I’ve had a guess.

  7. Sam Jackson says:

    Some of the price signs at Kohl’s in the US are electronic. The tags them self are paper.

    • Thinkerer says:

      I saw those the other day and was wondering what keeps people from “Borrowing” those as a source of cheap LCD displays…

    • Whatnot says:

      I’m told the use of ‘themself’ should be discouraged and ‘themselves’ should be used instead.
      But meh.

      • vpoko says:

        Themself is becoming more accepted, but I don’t like it.

        • Andrew says:

          Even if it’s accepted it’s still wrong.

          tags -> plural
          them self -> singular

          So, wrong on two counts.

          • vpoko says:

            The reason it’s gradually creeping into the English language is that “them” (along with “they”) is becoming accepted as a singular but gender-neutral pronoun. So “themself” is shorthand for “him or herself”. It sounds strange to me it’s not considered correct in most grammar manuals and style guides, but language is an evolving thing and if the usage becomes common, it may suddenly become correct.

          • vpoko says:

            Err, that should be “it sounds strange to me and it’s not considered…”

  8. Brian from Denmark says:

    I’m surprised that there is no encryption or at least some some of “password” needed to update these displays, it could just be a 16 to 32 bit number within the transmission, it could even be part of the CRC.
    Because although it’s not the end of the world if somebody changes the prices, it could still be a burden for the stores if there price tags constantly are wrong and the need to deal with a lot of unsatisfied customers.

  9. Daniel says:

    Here in Sweden they have been using a tag with a graphical e-paper/bistable lcd display of about 4″ size for years. And ever since I saw them I have wanted one just for that display. I just refuse to steal one though and they also seem impossible to buy…

  10. Kaz says:

    Interesting, but what I don’t get is, why do you even need to go to the trouble to overclock a Gameboy Color to do this? Why not just hook an IR LED to a small micro that can run that speed, and work your magic that way?
    If the idea is to go all stealthy with it, a Gameboy Color in 2014 is suspicious already. Might as well buy some cheap dollar store toy for the case.

    • furrtek says:

      IR interface, tile-based display, user inputs, $10.

    • Greenaum says:

      I wonder why it’s overclocked, is it generating the carrier itself in software? Cos that’s massively wasteful. Would it still work using as oscillator for the carrier, and gating it from something like the Gameboy’s serial port?

      I say serial port, it’s more of a GPIO with just a couple of pins. Surely that, with something like a 7400 NAND with a crystal as oscillator, gated using one of it’s gates, feeding an LED through a small transistor would be much easier. A couple more components, but easier to program, and no need to hack around inside the Gameboy itself, this would all plug in externally.

  11. Krinkleneck says:

    I have a suggestion on what you can do with this. Mark all the prices ARM&LEG

    • Greenaum says:

      I think A55 is funnier. Can it do the whole alphabet? You can approximate most letters with 7 segments, even if a few of them look a bit awful. Does it accept by-segment control or what? The presence of the “A” shows it does more than numbers. Unless it’s just hex. Still, plenty of amusing words in the English to Hexadecimal dictionary.

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