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THOSE E-INK PRICE TAGS FROM THE SUPERMARKET SHELF CAN BE REPROGRAMMED TO SHOW ANYTHING

An ESP32-based access point turns surplus e-ink shelf labels into a house full of battery-powered displays you can update over the air.

by OpenEPaperLink contributors

FULL CAD BOM FIRMWARE DOCS

DisplaysHome

Built withESP32

difficulty
●●●○○
time
a weekend
license
CC BY-NC-SA 4.0
repo
repo ACTIVE1,848 stars

WHAT YOU’LL NEED

Videos
1
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COMPAREE VERDICT

OpenEPaperLink reflashes electronic shelf labels, the e-ink price tags used in shops, so they show whatever you send them. An ESP32-based access point (the project publishes its own AP and flasher designs, and some off-the-shelf boards work too) drives many tags around the house, and people use them for calendars, weather, labels and Home Assistant dashboards. Low power is the point: the project aims for around 9 microamps on the tag with check-ins every 40 seconds or so, and e-ink keeps the image without power. The catch is compatibility: the wiki lists the supported tag models (mostly SoluM-made tags, plus some Chroma, Opticon and Pricer models), and anything not on the list may never flash. You also need a flasher to program the tags. The README itself says it is largely obsolete and points to the wiki, so follow the wiki. The licence is CC BY-NC-SA 4.0, so you cannot sell devices or services built on it. If you already run Home Assistant or want low-power displays without cables everywhere, this is a weekend that pays off; if you expect every surplus tag to work first try, check the list before you buy.

GOOD TO KNOW

  • —Firmware is split into access point code (ESP32) and tag firmware (for the labels themselves).
  • —The repository contains the code, flashing guides, and a compatibility list — not every shelf label model works.
  • —The tags are off-the-shelf shelf labels, but the project publishes PCB designs for its access point and tag flasher in the Hardware repo.
  • —Licensed CC BY-NC-SA 4.0 — non-commercial use only, which rules out selling devices or services built on this.
  • —No bill of materials for tags, because you reuse existing shelf labels; the wiki lists supported models, and the project's Discord is where people sell AP kits and share sources.
  • —Actively developed (last push October 2026), around 1,850 stars on GitHub.

Parts to buy

4 items

From our check of the build. Exact quantities and part numbers are in the creator’s BOM.

  • Second-hand electronic shelf labels from supported familiesFind
  • Supported ESP32-based access pointFind
  • Tag flasher (or the project's combined AP + flasher board)Find
  • USB cableFind

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Can I build this?

Printnothing required
Buysecond-hand electronic shelf labels from supported families (see the wiki), a supported ESP32-based access point, a tag flasher (or the project's combined AP + flasher board), USB cable
Toolscomputer for flashing, a tag flasher or programming jig, soldering iron if you build a DIY access point, optionally a 3D printer for enclosures
Skillscomfort flashing ESP32 firmware and tags with a flasher, reading the supported-tag list, basic soldering for a DIY access point, and patience debugging tags that do not respond first try
Timea weekend — half a day flashing and wiring the access point, the rest configuring Home Assistant integration and placing tags around the house
Cost$$: no official cost; you need an access point (DIY or a supported off-the-shelf board), a flasher, and as many tags as you want.
SafetyCoin cells around children are a choking and chemical burn hazard if swallowed. Otherwise this is low-voltage, low-power radio electronics; the tag boards are fragile, so open the labels carefully.

Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.

Videos

Aaron Christophel's OpenEPaperLink startup guide — from flashing to the first image on a tag.

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Gallery

Start here

Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.

  1. 1.Read the supported-tag list in the project wiki before buying tags (Not every shelf label model works; the wiki lists the tested models, mostly SoluM-made tags plus some Chroma, Opticon and Pricer models.)
  2. 2.Buy second-hand tags from AliExpress or surplus electronics suppliers(Search for the exact model numbers on the wiki's supported-tag list.)
  3. 3.Build or buy a supported access point and flash it (Follow the wiki, not the old README: tags are no longer used as the access point's radio. The wiki lists the AP hardware options and has a beginner's 'Spaghetti AP' guide.)
  4. 4.Flash tag firmware onto each display label and pair them with the access point(Each tag checks in every 40 seconds or more, depending on radio conditions, so new images are not instant.)

Resources

Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.

KNOWN ISSUES

  • Buying tags without checking the compatibility list — some models will never flash, and you find out after they arrive.
  • Expecting every label to work first try: only models on the wiki's list are supported, and the boards inside are tiny and fragile, so handle them carefully when opening and flashing.
  • Missing that the licence is non-commercial — you cannot sell devices or paid services built on OpenEPaperLink.
  • Underestimating the minimum 40 second latency — these are not instant displays, they check in on a schedule.
  • Assuming transfer speed will always hit 5 kbyte/s — that is under favourable RF conditions, walls and distance slow it down.
  • Placing tags too far from the ESP32 access point and wondering why images never update — test range before mounting them permanently.

Can I use any electronic shelf label I find?

No. Only the models on the wiki's supported-tag list work, mostly SoluM-made tags plus some Chroma, Opticon and Pricer models. Check the exact model number before buying.

How long does a coin cell actually last?

The project does not publish a battery-life figure. Tags aim for around 9 microamps between check-ins, e-ink holds the image without power, and most energy goes into check-ins and image transfers, so update frequency and radio conditions decide how long a cell lasts.

Do I need Home Assistant?

No. The access point has its own web interface and can generate content itself (calendars, JSON templates) or accept images you push to it. There is also a Home Assistant integration if you use it.

Can I sell devices or services built on this?

No. The licence is CC BY-NC-SA 4.0, which rules out commercial use; personal and other non-commercial projects are fine, and changes must be shared under the same licence.

What is the one thing most likely to go wrong?

Buying a batch of tags that look compatible but refuse to flash — even within supported families, some hardware revisions do not work. Order from sellers with reviews mentioning OpenEPaperLink, or plan for a second order.

Community builds

No community builds yet — be the first, we feature the best ones.

Discussion1

FROM THE COMPAREE TEAM

Tags check in with the access point every 40 seconds or so, idle power is around 9 microamps, and transfers reach about 5 kbyte/s in good RF conditions. What would you use a house full of battery-powered e-paper displays for?

CompareeTEAM2mo agoedited

Practical notes from our verification: you do not need a custom board to start. You reflash surplus electronic shelf labels, and the project publishes its own hardware designs for the access point and the tag flasher (Mini AP, combined AP and flasher), plus ESP32 access point firmware. You will need a flasher to program the tags. Note that the README itself says much of it is obsolete and points to the wiki for current information; for example, using a tag as the access point's radio is no longer supported. The licence is CC BY-NC-SA 4.0, so no commercial use. The biggest trap is buying tags before checking the wiki's list of supported tags: not every shelf label model works, and some tags make better access points than others. The project is actively developed, with commits in October 2026, and Aaron Christophel has a startup-guide video for it. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.

OpenEPaperLink contributors

Developed by a community of contributors repurposing commercial electronic shelf labels into open-source home displays. The project has around 1,850 stars and is actively maintained (last push October 2026).

GitHub

Star the project on GitHub

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