Can you link a source where to buy them or a model? I don't have any information. But I'd be interested, too.
homeassistant
Home Assistant is open source home automation that puts local control and privacy first. Powered by a worldwide community of tinkerers and DIY enthusiasts. Perfect to run on a Raspberry Pi or a local server. Available for free at home-assistant.io
Hey, I developed some of these for a different use case at my job.
Generally they use BLE servers to query and update every BLE device one after the other.
I would venture to guess that these tags have a ublox BMD-3xx variant controlling them and you can connect via Bluetooth low energy every X hours.
If you just want the displays they use, here are some kits:
It's also quite common for updates to be sent using a ceiling-mounted infrared transmitter, like this brand which is common where I am:
https://www.pricer.com/products/devices/electronic-shelf-labels
People have figured out the data formatting to update some of the lower-security variants (including that "Pricer" brand):
I have a few Pricer* ones and they're a pita to use.
Have to build an IR blaster to program them.
You also can't use them once the battery is flat or if you remove the battery because it uses volatile memory to store the firmware.
it uses volatile memory to store the firmware
What the what?!
Yuuup, they use an ASIC too.
Here's an attempted teardown https://www.youtube.com/live/AN0CMmFQIi0
Also interesting: http://furrtek.free.fr/index.php?a=esl
Check out these maybe:
https://dmitry.gr/?r=05.Projects&proj=29.%20eInk%20Price%20Tags
http://furrtek.free.fr/index.php?a=esl
There's more but I'd have to search for it, it's a good starting point though.