E-Ink Price Tags Fall Off Store Shelves Onto Your Workbench

There’s always a magic moment for our community in the lifecycle of any piece of technology: the point at which it first becomes available for pennies on the surplus market. Something which could previously be had only at a price is rendered down to mere pennies, and we are free to hack to our heart’s content.

Such a moment came for [Aaron Christophel] when he bought a quantity of used e-ink price tags (German, Google Translate link) that had formerly graced the shelves of a supermarket. A pile of readily hackable e-ink displays lay before him, so he set to work.

Cracking them open he found the display itself as well as a PCB with its own microcontroller, but he soon identified it as compatible with a WaveShare module for which he had data. Since its interface was thus identified as SPI he could desolder the unknown CPU and break out the pins for an Arduino or other board. The display itself turned out to be a custom model with a few quirks for price tags, it had a black border that could be enabled, and for some reason it appeared as a two-colour red-and-black model in which its black pixels responded as though they were the red channel. He has a quick overview video that we’ve placed below the break.

These displays have started appearing in our community, not least in electronic conference badges. This source of cheap components from the surplus market makes them ever more accessible, and we look forward to the projects that will come from them.

33 thoughts on “E-Ink Price Tags Fall Off Store Shelves Onto Your Workbench

    1. Surplus is great. Technology is changing, improving all the time. Being on surplus, doesn’t mean useless junk, simply means there are better options available. A lot of places upgrade frequently, their old equipment is still useful, but they need to dispose of it, hopefully quickly, since it cost money and space to store, with no reason to go back. Some places simply toss it in the dumpster, others simply take the quickest offer, happy just to get it hauled off. Usually don’t make much money, holding onto something you don’t want or need, by waiting far a buyer, who will meet a reasonable price. Surplus warehouses have the space, and can wait for buyers. They can sell whole, or parts, or load it on a pallet, and sell to another surplus business in bulk. Surplus can be good for finding repair parts as well…

    2. Or else (everyone join the list!) the supermarket is being closed down. Netto, Aldi, and Lidl all operate on very tight profit margins, so maybe it’s become uneconomical and being closed. Or else (wait!…)

      Or they found asbestos in the supermarket, and nobody’s willing to pay to clean it, or else it’s just not worth cleaning it.

      Or maybe this was an experiment, I think Netto quit the UK so I haven’t been in one for a few years. So maybe this was an experiment to see if it’s profitable to pay more for E-ink rather than just using paper.

      Most of the employees, and it’s the same in Aldi, walk around with powerful computers in their hand. Actually most supermarkets that’s true. Do they have a little printer than can produce sticky labels on-site? If that isn’t patented btw I’m having it. So yeah, they experimented with E-ink but it didn’t bring the savings they wanted, or else just took too long to amortise the capital outlay of buying the system. And maybe they weren’t as reliable as paper. It’s no good if you need to pay a geek to hang around every day in case the system breaks. If there’s no prices, you can’t really run a supermarket.

      Actually that brings to mind the terrible amount of fun you could have, if these things aren’t using encryption, wandering round with a computer in your jacket, transmitting bits of pr0n in barely-legible 1-bit mode, would be possible. You could also create chaos by changing prices drastically. Legally a shop isn’t bound to sell anything at the price advertised. Technically it’s an “invitation to treat”, the contract only starts once you’ve swapped money for the item. So the shop could refuse to sell these atrocious bargains, customers will get pissed off and start quoting made-up laws, and to be even worse, you could change the price BACK while they’re arguing!

      This wasn’t the point of the article at all! But still that’s what naughty people might do once the protocol’s figured out, assuming there’s no encryption, which would make it the supermarket’s liability.

      Another option would be to put your own tags out, disguised as legitimate ones. You could even steal the real ones, and dump them somewhere else in the shop so you haven’t properly stolen it I am not a lawyer. Very much so. I’m often bugger-all help to anyone, but sadly I can’t charge hundreds of pounds per hour for that.

      I do like the ones with red on. How’s that done? Different polarity? It’ll be great if they get CMYK going. Obviously there aren’t 4 polarities in electricity but they could just separate them spacially one way or another. Speeding them up, too, would make them great competition with LCDs.

  1. He’s right, not much information about the SEM9110 IC on the tag but a FCC report about a similar device lists it as a IEEE 802.15.4-capable (Zigbee) Cortex M3 SOC with the MAC address available as a bar-code on each device. The user manual lists a gateway but it sounds like these are ripe for hacking via the radio.

    https://fccid.io/2AFWN-ST-GR4300N/User-Manual/User-Manual-3884640
    https://fccid.io/2AFWN-ST-GR42003N/Internal-Photos/09-ST-GR42003N-IntPho-3578045
    https://aminoapps.com/c/maker/page/blog/electronic-shelf-labeling-esl-possible-to-hack/vdWT_nu5EYpm8rQrDDjQ5WbWNQ06YY

    A similar system hints that images are downloaded via the radio link (in this case monochrome 200×96 pixels)

    http://ftp.opticonusa.com/Downloads/ESL%20User%20Manual.pdf

      1. Keep a reciever in your pocket, in sniffing mode, then just hang around the supermarket for a while. You can do your shopping while you’re at it, so you’re not even wasting time! Maybe a Raspberry Pi with an SDR dongle.

        Supermarkets often mark down prices toward the end of the day, when stuff has neared it’s sell-by date. I’ve only seen it done with stickers, but then so far I haven’t seen these E-ink things in the wild.

        1. I figured out the protocol for the barcode for one firm over here (I’m sure I’m not the only one but it wasn’t published on the net). They’ve since changed it. It wasn’t very secure. You could easily create valid codes and enter them by hand.
          Of course with one of these in your hand you could generate the barcode on demand…

  2. I wanted to get my hands on some of the video screens at WalMart, used in the display boxes for various fancy projector Christmas yard lights. Push the button labeled “Try Me” and you get a short video showing how the light works.

    Nobody at the store had any clue what would happen to the display boxes after the season. Nobody at the Texas company that manufactured the lights admitted to knowing WTH I was asking them about.

    I think a great way to repurpose a batch of them would be for museums. Make videos showing all-round views of the artifacts, and for mechanical things, include clips of the item in use. Replace the original light demo video then mount the case in a sturdy enclosure with an arcade machine button, replace batteries with a wall wart. Then museum visitors can bang the button many thousands of times to watch the videos.

    1. I managed to get 2 of these.. have a little board on the back with 128mb and a microusb on back and a battery box with 8 aa batteries… Will play whatever videos you put in the storage (MP4). I was going to incorporate in a costume for Chewbacchus parade but ran out of time… BTW They THREW all of the rest out!!!!! I pulled one from trash and other one batteries had run out so they let me take it.

      1. Any identifying markings so it might be found out where to get some more? If you’d managed to snag a lot of them you could’ve sold them on eBay after deleting the videos from them.

  3. So, uh…has anyone tried going to the supermarket, picking one off a shelf at random (say, 45c) and taking it through the check-out?

    Because that would be illegal. So…you know…don’t.

  4. Why didnt he use the conveniant pads next to the processor? Looks like everything is broken out for testing.

    Esp. The txd and rxd pins can provide extra debugging info. Perhaps even programming. Just desoldering and whack an arduino/pi in it is too easy.

    1. Hi. I did test these pads. They are only the spi from the SEM9110 chip and not the E-Ink display. At the end of the second video a talk aboout them. The RX and TX give only something out when the test pin is pulled high or low. The output is something like “Tea Time” have to do it again i dont remember correctly.

  5. I think they made an appearance here. Still working on getting a few but should be encrypted.
    The biggest problem seems to be the battery life as these ones use CR2032 IIRC and not cheap.

    1. If you put “battery life” and “e-tag” on the same question, you are probably thinking on the wrong problem. e-tags only need power to change state, and can display the same info indefinitely without needing power.

  6. I’m surprised these e-tags are not used more often but I guess one reason for the paper tags still being the norm is to make sure stock gets rotated and any thing passed it’s expiration date removed.

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