You know what this is for ;-)
Collection of software and hardware tools, their source code and design files for communicating with infrared based Electronic Shelf Labels.
See http://furrtek.free.fr/index.php?a=esl for reverse-engineering of the system, the protocol and electronics.
Thanks to @david4599 for infos about color tags.
What can this be used for ?
To have fun experimenting with mass produced devices ! Compatible ESLs can be found on eBay, or directly from stores shelves ;)
The e-paper ones can make cool badges:
Which brands of ESLs are compatible ?
You'll have to guess from the picture and the page on my website. Hint: there's only one.
Can my phone/tablet/handheld/IrDA-capable device work as a transmitter ?
No. The carrier is in the MHz range and the symbol timing must be very precise. IrDA controller limitations and OS latency makes it impossible.
Can I change the display of all ESLs in a store at once ?
No. For two reasons:
Is possession and use of such devices legal ?
There's no cracking, exploit, patent or copyright infrigement going on so IMO it's safe to assume this is perfectly legal. Just don't try changing price displays so you can get discounts, the price in the store's database obviously remains unchanged so you'll end up having to pay the correct price anyways.
My tricolor-capable ESL shows red garbage after an image update Transmit the image in tricolor mode. Transmitting black and white images to tricolor ESLs doesn't clear the red layer.