THOSE E-INK PRICE TAGS FROM THE SUPERMARKET SHELF CAN BE REPROGRAMMED TO SHOW ANYTHING
One ESP32 and a second-hand shelf label turn into a house full of battery-powered e-ink screens that run for months on a coin cell.
by OpenEPaperLink contributors
DisplaysHome
- difficulty
- ●●●○○
- time
- a weekend
- license
- CC BY-NC-SA 4.0
- repo
- repo ACTIVE1,774 stars
●●●○○ · a weekend · CC BY-NC-SA 4.0 · 1,774 stars · repo ACTIVE
WHAT YOU’LL NEED
- Electronic parts — full list with part numbers in the repo BOM
- Dev board / microcontroller — runs the project firmware
Partner
COMPAREE VERDICT
OpenEPaperLink reflashes electronic shelf labels — the same e-ink price tags Walmart and Home Depot use — so they show whatever you send them. One tag becomes the radio for an ESP32 access point, and that drives dozens more around the house. People use them for room temperatures, calendars, plant labels, laundry status, and Home Assistant dashboards. The power draw is the reason this works: around 9 microamps idle, e-ink holds the image with no power, and a coin cell disappears into months rather than days. The catch is compatibility. The repository lists which tag families work (Solum, Hanshow, a few others), but not every label you find on AliExpress will flash cleanly, and the README is honest about that. The other catch is the licence: CC BY-NC-SA means this is for home use only — you cannot sell devices or services built on it. If you already run Home Assistant or want a low-power display wall without USB cables everywhere, this is the weekend that pays off for years. If you expect every surplus tag to work first try, plan for a second order.
IN THE REPO
NOT IN THE REPO
- —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.
- —No PCB design files because the hardware is commercial off-the-shelf; you buy used tags and an ESP32.
- —Licensed CC BY-NC-SA 4.0 — non-commercial use only, which rules out selling devices or services built on this.
- —No official bill of materials because tag models vary; the README names compatible families (Solum, Hanshow, etc.) and people share supplier links in discussions.
- —Active development as of July 2026, 1758 stars on GitHub.
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Partner · KickstarterBluHub reads and burns Blu-ray/DVD/CD, adds USB-C, USB-A, SD/TF and 10 Gbps data — plug and play, grand-piano finish.
Videos
Video URL verified from payload; title and length not provided in sources.
Gallery
Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the compatibility list in the repository README before buying tags (Not every shelf label model works — the list names which Solum, Hanshow, and other families are tested.)
- 2.Buy second-hand tags from AliExpress or surplus electronics suppliers(Search for the model families named in the compatibility list, expect a few dollars per tag.)
- 3.Flash the access point firmware onto an ESP32 and wire one tag as its radio (The README has flashing instructions; one tag acts as the 802.15.4 radio, not as a display.)
- 4.Flash tag firmware onto each display label and pair them with the access point(Each tag checks in every 40+ seconds; the first image takes about a minute to appear.)
Resources
Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.
Partner · KickstarterCORE POWER BANK S: 0.2" thin, 2.8 oz, 5000 mAh with 22.5W fast charging. Semi-solid battery, carbon fiber, IPX7 waterproof.
KNOWN ISSUES
- Buying tags without checking the compatibility list — some models will never flash, and you find out after they arrive.
- Expecting every second-hand label to work first try — even compatible families have duds, and the project README is honest about that.
- 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 certain families (Solum, Hanshow, others named in the README) are supported, and even within those some models do not flash. Check the compatibility list before buying.
How long does a coin cell actually last?
Months to years, depending on how often you update the image. E-ink holds the picture with no power, and idle draw is around 9 microamps, so the battery only works during check-ins and image transfers.
Do I need Home Assistant?
No — the access point runs standalone and you can send images over HTTP, but Home Assistant integration is the most common use case and makes the setup much easier.
Can I sell devices or services built on this?
No — the licence is CC BY-NC-SA 4.0, which restricts commercial use. This is for home projects only.
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
Power draw is around 9 microamps idle, each tag checks in every 40 seconds, and transfer hits about 5 kbyte/s under good RF conditions — what would you use a house full of month-long battery displays for?
OpenEPaperLink contributors
Developed by a community of contributors repurposing commercial electronic shelf labels into open-source home displays. The project sits at 1758 stars and is actively maintained as of July 2026.
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DISCLAIMER
- Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM28d agoedited
Practical notes from our verification: the video link and Hackaday coverage are confirmed in the payload, but we were not given a PCBWay or official store link, so there is no board to order — you buy surplus tags from AliExpress or similar. The repository README is honest about compatibility (not every shelf label works) and the non-commercial licence is stated clearly. The biggest trap is buying tags before reading the compatibility list — people have reported entire batches that refuse to flash, even from otherwise reliable sellers. One weekend builder noted that getting the first image to appear took patience, but once the access point was stable, the tags just worked for months.