Tile multiple small eink screens to make a cheaper big screen?

Was pretty stunned to see this 12.48in eink panel from Waveshare is in fact 4 smaller eink panels tiled together - in the pics & videos shown, I can’t even make out the seam between the 4 smaller panels!

youtube video of the display

It costs $179.

image

Does anyone own one of these in real life? Are the seams really that hard to see?

If so, it seems one way to make eink panels cheaper would be to tile small cheap eink panels together. The same could probably be done for RLCD / RLCD-MIP displays.

This may be one of the best methods for getting cheaper large sized eink panels!

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Yes I own a black/white one. And I made a class to drive it with ESP32 / Esp-idf framework:

Both monochrome and black / red models are supported. Is not possible to see the junctions of each epaper but is possible to see that they are 4 since the refresh signal comes some milliseconds later to some of them. It’s a nice epaper.

But I don’t think is a good idea to do this with separate epapers since
A You will always see the separation
B You can daisy chain the SPI but then you will use Chip select to communicate with each and the communication will be one per time, which will make sending data much slower.

This displays from Waveshare have a interconnection where one is slave from the other making the data transfer speed much wiser. So it’s possible to do it, but it has to be done in the factory, I see no real advantage in trying to do a DIY version.

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Hey, what do you mean by ‘data transfer speed much wiser’?

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I have the black/white/red one coming. When it arrives I will do everything I know to try and figure out just what it is and how it does it.

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Edit: Updated URL for LilyGo T5
I’m not sure, but Martin mentioned the LilyGo T5 uses parallel, so maybe that could be used- some of the Waveshare displays support other interfaces- i do not know which ones may be parallel, if any:

I mean that is not the same to have a 4 SPI epaper that is already made from factory and is internally wired, than to do it yourself. This is my analysis:


That I made to create the class to control them.
And check that it has 4 Chip selects, but only one Data command per side, I don’t understand why but I guess is because of the Master -> Slave internal configuration.
Imagine how it will be to wire all this 4 different epapers :slight_smile: That’s why I think this kind of contructions are better when come already mounted from fabric.

If you want to use ESP32 to control it’s possible with our component:

But it needs a hack since the ESP32 slot that comes from Waveshare is not ready to use an ESP32-WROVER or similar with PSRAM.
This display has a 160Kb buffer per color so it’s impossible to drive with an ESP32 without SPI Ram. The hack is described in the Monochrome version and is quite straight-forward to do.

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