Support ESL (electronic shelf label) BLE displays

[Misiu]

Describe the problem you have/What new integration you would like

There are projects that allow users to use ESL'a as a portable displays and with long battery life, they are ideal for dashboards. Recently some BLE based tags showed up, like this one: https://pl.aliexpress.com/item/1005002399342939.html We can pick 2.1, 2.9, 4.2, 7.5 and 10.2 inch displays.

Projects like https://github.com/OpenEPaperLink allows using ESP32-S3 as a gateway to communicate with the display. This requires additional hardware (another ESP32) and a dedicated integration to be able to display anything from HA.

With dedicated support we could use ESPHome draw API to create content and send it to the ELS displays.

Please describe your use case for this integration and alternatives you've tried:

I have currently two displays in my house, both are used to display waster collection data, but I already plan to add additional ESL's (4,2 inch) to display weather info and some NAS statistics.

This is my design so far:

Additional context

See example displays for inspirations: https://github.com/OpenEPaperLink/Home_Assistant_Integration/wiki/1.54%22%2C-2.9%22-and-4.2%22-Weather-display-using-met.no%2C-Moon-phase%2C-Gotham-Round-font

[nagyrobi]

How do these work? You actually just send over the rendered bitmap in data chunks to the display?

[Misiu]

@nagyrobi Sadly I'm not that technical. Currently, I use the integration to create the image, the integration sends it to the AP (running OpenEpaperLink) and the image is sent to the tag via Bluetooth. In the mentioned issue there are links to the ble_filter and able writer: https://github.com/OpenEPaperLink/OpenEPaperLink/blob/master/ESP32_AP-Flasher/src/ble_filter.cpp https://github.com/OpenEPaperLink/OpenEPaperLink/blob/master/ESP32_AP-Flasher/src/ble_writer.cpp

There is also a webpage created by one of the authors that allows sending images to the displays: https://atc1441.github.io/ATC_GICISKY_Paper_Image_Upload.html

[nagyrobi]

create the image, the integration sends it to the AP (running OpenEpaperLink) and the image is sent to the tag via Bluetooth.

https://github.com/OpenEPaperLink/OpenEPaperLink/wiki/Building-an-Access-Point#why-do-i-need-an-esp32-s3-and-a-esp32-c6

So I assume that means we need a display platfrorm, which could pass the image rendered to the AP side of things, which is an ESP32-C6 running in IEEE 801.15.4 mode continuously, talking to the tags. The AP firmware on ESP32-C6 can stay original as OpenEpaperLink, we only need ESPHome on the other ESP32 which renders the display information and is connected to the WiFi/Ethernet network.

We need documentation of the communication protocol between the two ESPs.

[Misiu]

@nagyrobi my FR was about BLE based Tags, like this one: https://pl.aliexpress.com/item/1005002399342939.html I have a single ESP-S3 flashed with OpenEpaperLink (they have a standalone Bluetooth-only AP). It works perfectly. Ideally, I'd like to use a single ESP-S3 to run ESPHome, and ESPHome should send the image directly to the TAG.

[nagyrobi]

Bluetooth and WiFi coexistence is a difficult thing, that's what the OpenEPaperLink wiki page also states. If you look at their Yellow AP, the proper solution usable by anyone would be as described above, have the ESP32-C6 run OpenEPaperLink firmware, and have the ESP32-S3 run ESPHome firmware.

[Misiu]

If you want to connect to other types of tags then yes, you need additional ESP. But there is BLE only AP - https://install.openepaperlink.de/ I asked about that just weeks ago - https://github.com/OpenEPaperLink/OpenEPaperLink/issues/307#issuecomment-2156772501 You need ESP32-S3 N16R8, you flash the BLE-only firmware and you have an ESP flashed with firmware that allows connection to BLE-only tags. So if that firmware can connect to the BLE tag and my wifi I think the same thing could be done in ESPHome - generate the image data and send it to the tag.