OpenEPaperLink notes: Difference between revisions
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(Created page with "<!-- The idea seems to be that, since every tag has a 802.15.4 radio, if you add an ESP32 to just one of these tags, you now have a tag "AP": you can talk to it over wifi, it can talk to all tags over 802.15.4 (not technically zigbee). You can also integrate with home assistant - this uses websockets over wifi(?) Regular API-like access can be made to the AP -- https://github.com/jjwbruijn/OpenEPaperLink/wiki/Image-upload Which suggests the Tags use e...") |
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OpenEPaperLink is a project that uses various [[E-Paper]] devices -- primarily the little programmable labels that supermarkets use, | |||
because they tend to | |||
* a display controller | |||
* a microcontroller | |||
* some communication in them | |||
The tags it focuses on are 802.15.4-based devices. | |||
Regardless of how they worked originally, these will poll a shop AP, which sends them new information when they should. | |||
(a shop will also spend a lot of time trying to keep track of the thousands of labels they have around. We can afford to be a bit messier.) | |||
--> | |||
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This project's idea seems to be that, | |||
since every tag has a 802.15.4 radio (its own protocol?), | |||
if you add an ESP32 (with specific firmware) to just one of these tags (with a specific connection - the tags have a debug header), | |||
you now have a tag that can ''be'' that central checkin point of the tags, saving one more device to buy. | |||
And since ESP32s have WiFi, you can now talk to that AP-Tag via WiFi, while ''it'' talks to the rest of the tags over 802.15.4. | |||
There is a "just add APs and it will sync everything automatically and give better coverage" thing | |||
The amount of tags an AP (or set?) can handle (remember images for) is around 30 for a xx MB PSRAM ESP32. | |||
Regular API-like access can be made to this WiFi AP. | |||
: e.g. https://github.com/jjwbruijn/OpenEPaperLink/wiki/Image-upload | |||
You can also integrate with home assistant - this uses websockets over wifi(?) | |||
Tags use a moderate amount of energy to send and/or receive data, so to last a long time they check in as little as possible. | |||
Every 40 seconds is the ''fastest'' in normal use, apparently weak signals increase this to 10 minutes (because it would drain faster otherwise). | |||
Also, they send in the most basic "do you have something new" and unless it gets a response within ''milliseconds'', it sleeps again. | |||
Revision as of 17:03, 29 April 2024