Open Source Firmware for Electronic Shelf Labels with Home Assistant Integration

[main mortar]

Today I want to show off an open-source project we've been working on for quite a while:

openepaperlink.org

This project focuses on giving a second life to Electronic Shelf Labels (ESLs) by developing custom firmware for them. We already support over 70 different display types, ranging from 1.2" to 11.6", and when used with our custom Access Point, you can achieve multi-year battery life while maintaining sub-minute latency.

It’s a great fit if you’re looking to scatter small, low-cost status displays throughout your home—and don’t mind a bit of tinkering!

We also offer an extensive Home Assistant integration that unlocks a wide range of features and allows for rich, customizable dashboards, graphs and much more:
Home Assistant Integration on GitHub
Example use cases in the wiki

If you’ve got questions or want to learn more about how it works, feel free to ask here.

Also, we're interested in exploring deeper integration with Home Assistant, especially around making it easier to design display content—like a graphical editor for layout and visuals.

Here is a great video on how to set it up https://m.youtube.com/watch?v=JOIp4s4YNEs&pp=ygUfQmVhcmRlZCB0aGlua2VyIE9wZW5FcGFwZXJMaW5rIA%3D%3D It is a bit outdated but the setup only got easier 😉

Some displays also have buttons and NFC so you have additional inputs to home assistant. And newer displays also feature a small RGB status led.

[opaque rock]

I've always been super intrigued by your project! I wanted to buy some of the stuff when it was on tindie, but never got around to it

Something that was never immediately clear to me: if I build an AP, is that enough to flash any compatible labels that I buy? Or do the labels themselves also have to be modified before they are compatible with openepaperlink?

[main mortar]

Some APs have the ability to directly flash tags. For most tags(except for BLE ones) You have to physically connect the flasher to the tag to flash them.(Or you can get preflased one on the project discord)

If you want I can send you some preflased tags.

This would be the process for flashing an M3 tag with a Mini AP v4 and the flasher cable

There are also custom jigs with pogo pins for other tags

There is no hardware modification needed for most tags. Most have an accessible debug port under the battery or a removable sticker.

[opaque rock]

Oh that's great, I was thinking there would be soldering involved or something but a debug port looks easy, especially with a jig/cable.

[main mortar]

You can solder the programmer if you have no jig, but you don't have to if you have a jig.

[opaque rock]

Is the Lilygo the best AP to go for if I want to just start using it asap and do as little DIY as possible?

[main mortar]

Yes, the only thing you have to do is flashing the firmware with the web flasher(you have to flash the S3 and H2).

You have to watch out to get the correct version(RS485)

[opaque rock]

Oh thanks I'll keep an eye out for that!

And sweet, just ordered the Lilygo rs485, looking forward to playing around with this!!

[hoary gate]

@main mortar very cool 🙂

are there people selling those tags yet to consumers or does everyone get them second hand ?

[main mortar]

Most of them are bought second hand but there are shops that sell new tags(without firmware + you are not guaranteed to get compatible tags + they are pretty expensive). There are people selling tags with firmware, mostly in Germany. I can send you some if you want (I don't know how to handle customs outside of the EU though).

There is also the possibility to buy BLE based tags, but they are pretty bad value...

[main mortar]

For BLE based tags we are planning to integrate them directly over BLE proxies without the need for a dedicated AP(custom firmware on the tags will be required but that is a simple OTA update)

[opaque rock]

That sounds really exciting! Are the BLE tags very expensive?

[main mortar]

They are around 20€ for a 2.9" tag(for new ones)

You can find compatible ones in the "set display type" dropdown here https://atc1441.github.io/ATC_BLE_OEPL_Image_Upload.html

I would recommend staying away from the LCD based ones

GIKIsky are the easiest to find on AliExpress, they are only supported up to 4.2" though(support for bigger ones would be possible in theory but is not impressed currently)

Be warned though that tags might not be compatible even though they should be because manufacturers sometimes change the IC they are based on for the same model. This is unlikely but the risk is always there(for all tags except for diy ones )

[opaque rock]

Super interesting

Whole new world of gadgets to read into 😁

[main mortar]

And direct BLE support is only planned and not implemented yet, it works in a POC setup though.

[main mortar]

Be careful or you will end up with SAMLA boxes full of them 😉

I justify them by the need to test all types for the HA integration. But I think nobody in the team has all types we currently support.

[hoary gate]

So if you’re planning to use Bluetooth proxies, bdraco has been working on making the ESPHome Bluetooth proxies work without Home Assistant

It makes for easy development

[main mortar]

The BLE part is already working, the main thing still open is to rewrite the integration because it is working on the assumption that it only communicates with that AP and the AP takes care of the communication.

[hoary gate]

Can you get me a name of a manufacturer. Maybe link to Aliexpress ? Do you prefer GIKIsky ?

Is the ble firmware something you guys wrote ?

[main mortar]

The firmware is something custom @atc1441 wrote but is not open source yet(he intends to open source it when he gets time to clean it up a bit). NRF based tags(where some are on the way to you) In theory also support BLE, we just did not get around to implement it. The firmware for them you can find here https://github.com/OpenEPaperLink/Tag_FW_nRF52811

[main mortar]

This would be a link to some would be https://a.aliexpress.com/_Ev2eeYG , please keep in mind that I can not guarantee that they are compatible and and also not all sizes are compatible. And they are not a "preferred" manufacturer, they just happened to sell displays to the public. (I can give you more information about manufacturers but would prefer to do this in a not public Channel) Since I did not send the package yet, I will include a compatible BLE display but it will not be flashed since I don't have enough time to do that today 😉

In theory GIKI tags would be supported with the stock firmware, but the custom firmware is better. And all other BLE tags need a custom firmware. Some did not even talk BLE before the update(if they can not be updated over BLE directly, they can be updated with a web flashed and USB to serial converter)

[still knoll]

I've been very interested by all of this. Lots of plans for these in our home, particularly the BLE type as I have ESPs everywhere already. Built-in support to esphome would be really nice.

I do wish they were more readily (and cheaply) available though. A 4.2" just cost me $65 CAD after shipping 😦

[main mortar]

You can definitely get them cheaper. But I don't know about good shops in Canada though

[still knoll]

I'd settle for a good shop anywhere - I got mine on AliExpress.

[main mortar]

If it does not have to be a shop you can ask on the project discord. Some people sell displays for good prices there

[hoary gate]

@main mortar got my lilygo t-panel today. You know why openepaperlink doesn't implement Improv Wi-Fi ?

that's built into ESP Web Tools so it would be able to install it all in 1 go

[main mortar]

It should use Improv Wi-Fi. I'm going to check why it ist broken.

Did the rest of the install process go smoothly? And did the displays connect properly?

[hoary gate]

didn't even try the e-ink displays yet, got right away to put some UI on the T-Panel 😄

(using https://github.com/balloob/home-assistant-addons/tree/main/puppet)

what's the timeout on the image fetching ?

My Green takes ~10s on cold start to launch browser + make screenshot

I see -11 errors in logs, probably a timeout

[main mortar]

I think the timeout is not set, but this is not something we tested to be honest. https://github.com/OpenEPaperLink/Home_Assistant_Integration/blob/main/custom_components/open_epaper_link/imagegen.py#L1990C1-L2018C91 should be an easy fix.

Let us know if it persists and if it does, we will increase the timeout/set it propperly

[hoary gate]

I don't use the custom component, I configured it here directly

[main mortar]

Oh sorry , there it is different, the timeout is 5 seconds, but we could increase it with the next release https://github.com/OpenEPaperLink/OpenEPaperLink/blob/33c70531211bead57045285bfe02fa3d076183bd/ESP32_AP-Flasher/src/contentmanager.cpp#L1125

Or you could try the custom component 😉

[hoary gate]

yes yes, 1 thing at a time 😄

I powered on the M3 Newton but it claims it can't find an AP

I only had 3 2450 batteries left

[main mortar]

Did you also flash the H2? And what does the AP web page show on the top right?

[hoary gate]

I did flash the AP, let me see

[main mortar]

Does it show online in this view?

[hoary gate]

I guess I need to update, I'm running the version that was on ESP Web Tools

[main mortar]

We keep the web tool version on an old version that is supposed to be stabel, but an update should not hurt.

I am flashing my t-panel now to try to reproduce your error

[hoary gate]

let me try another tag to see if that one is picked up

these battery seals are tight

[main mortar]

The M3 seals are tighter because they are IP67 rated

[hoary gate]

I wonder if my batteries are dead, they were old 2450s

because I put the battery now in 2 zbs29 and nothing is happening

[main mortar]

Hmm, just to be sure, could you try one more M3? You dont have to close the cover.

[hoary gate]

another m3 does boot up but also no AP found

how can i see what my H2 was flashed to ?

it was very fast when I did it with the esp web tools

[main mortar]

If you update to the current firmware, it shows the version of firmare for the H2

[hoary gate]

got the other one to boot, but also no ap found

[main mortar]

Also, Improv should be working now

[hoary gate]

let me flash my h2, there is newer firmware for it too

since the s3 can flash the h2, why ask users to do it themselves instead of doing it automatically ?

[main mortar]

Oh, that is a UI bug

[hoary gate]

ha it's a bit confused and thinks that both are the same version

[main mortar]

This is the only AP where with is not possible

What version does it show here?

[hoary gate]

with updated h2 now it works

[main mortar]

Great, I will investigate why the update was required for you.

[hoary gate]

I might have just messed up the flashing

overall it was pretty easy to get going though

Very impressed with all the things that are running on the ESP32 base station

[main mortar]

Since a few versions ago we managed to run all of this on an S2 4R2, but at some point we ran out of flash. Nic did some amazing work there. But it is made easier by the fact that most of the timing critical RF stuff is handled by the second ESP(or other SOC) depending on the AP.

[hoary gate]

I noticed this on the website

This project is provided solely for non-commercial use under the CC BY-NC-SA 4.0 license.

When you have the version working with bluetooth proxies, why not start a company with some of the project members to start selling pre-flashed tags

[main mortar]

It is a bit complicated because some project members currently work in the industry and we dont want to get into typical ESL Use Cases like supermarkets because of this. Small scale home automation is fine though.

But we are currently trying to figure out a good sollution for BLE tags

[hoary gate]

Yeah, I think BLE tags will make it quite accessible. You can leverage the HA host as the brains, doing heavy lifting

and then bluetooth proxies can reach throughout the house anywhere

[main mortar]

The licence for the custom component is also not restrictive(Apache License 2.0)

[main mortar]

We already have a working POC but just not the time to integrate the functionality yet

And for some BLE display, flashing also does not require a hardware flasher and they can be flashed over BLE directly

[hoary gate]

Running into a weird bug where sometimes the http:// part of my URL is replaced with https://

I've been recently getting very interested in any kind of dashboards

which is also why I wrote my screenshot add-on https://github.com/balloob/home-assistant-addons/tree/main/puppet. Trying to see if we can leverage all the work put in dashboards into other displays.

but the end goal of any project I am looking into is always that I want as many people able to use it for their smart homes, hence I was asking about if you plan on selling off-the-shelf tags

[hoary gate]

Got my batteries.

[main mortar]

It looks like somebody copied this thread with changed links. Is there some way to report this?

https://discord.com/channels/330944238910963714/1370199401540227143

[unreal ruin]

Reporting in Discord will only report to Discord support. Tag a <@&330946878646517761>

[tiny moat]

Gone

[sacred lake]

hello, since yesterday i have a Spagetti-AP and 3 small 2,6" tags.
openepaperlink works

but i ve problems to add this to HA.

Perhaps someone can help to send a Test Message to the Displays...

https://www.youtube.com/watch?v=JOIp4s4YNEs

the instructions did not work for me