A 12.48 Inch (1304x984) Three-Color E-Paper Display by Waveshare | Hacker News Reader

A 12.48 Inch (1304x984) Three-Color E-Paper Display by Waveshare

louwrentius.com

55 pointslouwrentius30 comments

$179 for a 12 inch three color display is approaching reasonable. Are eink prices finally going down?

The refresh rate of 16 seconds for the whole display is not reasonable in my opinion. Unless you just use it to display static images that don't change while you're looking at it. With partial refresh it would be ok, I think.

Exactly!

Also count their low-power consumption and you can easy convinced even fans of LCD displays.

Yes. If he is updating the display every minute, that's 25% of the time spent in refresh, where presumably the display is unreadable.

I don't understand why the refresh latency is so absurdly high...can somebody ELI5 why there's not even 1 frame/second possible with eink displays?

This particular screen is slow even by e-ink standards

It’s not slow compared to other 3 color displays. I have tested some from another brand and the b/w version was 2 seconds and the black/white/yellow version was 15 seconds

Because of the weight of the particles that are being moved. They have to shake them, move them a bit, shake them again, move them a bit again. Moving a blob of plastic takes a lot more energy than what LCD's do: who just moves something like 1 electron per 10000 in the layer between the polarization filters.

The way multicolor e-color displays work is by having multiple size/weight particles that are moved by different field strengths, but require being even more careful (because every field, shaking and moving, will move every particle)

Often for eInk screens the problem with speed is the driver (either code or chip), not the paper itself. For example, many drivers don’t support partial refreshes.

I just bought the B/W version of this screen and read the data sheet. Internally, it is four different screens. So I think (haven’t yet received it) each quadrant takes about 2 seconds to refresh (2 seconds is a pretty common refresh time for eInk). A better driver could do all quadrants at once for a ~2 second refresh.

It seems it's actually a refresh of 8 seconds for the black layer and another 8 seconds for the red layer done separately.

Kindles refresh the black layer much faster. I don't see why it's soo much slower.

But since it's literally particles moving inside the display, it will never super fast but 8 seconds is very limiting.

You always pay a huge premium for the bigger screen you want with Eink.

It's neither reasonable nor going down. I remember reading that full colour displays are not much costlier to manufacture than the greyscale ones, yet they still have a large price gap.

I believe this is a niche market. It would be nice to have the volume necessary to drive the price down (ane get the volume up)

That said, having a display that refreshes in seconds vs single-digit milliseconds works to keep it niche.

It’s a niche market because the prices are so unreasonably high. Plenty of people want e-ink displays to use with Raspberry Pis, which would then become prototypes for real products, which would then open up the market. But the e-ink people seem intent on keeping the technology restricted for some reason by keeping the prices high.

I think it's much cheaper than eink's offerings. E.g. they want $149 for a 5.6 inch three color display https://shopkits.eink.com/product/5-65-spectra-3000-yellow-e...

Eink is selling development kits which are always more expensive. They even explicitly say on their web site that what they are selling is not intended for consumers or hobbyists.

Unrelated: I always post when I see e-paper display and e-ink articles that I think baby monitors should be made from this type of screen. The lack of an emitting light all night while trying to sleep would be amazing. The battery life would be greatly improved and less likely to die when you have the monitor unplugged in other areas of the house.

I don't think e-ink screens would be good for a baby monitor. The slow refresh rate would make them a poor choice for monitoring a video stream, and the repeated flashing when changing the image would make them annoying at night.

I suspect the baby monitor is not for monitoring the baby, it is the monitor for the baby to read and watch some fun images.

Generally the term “baby monitor” refers to a microphone or camera watching the child’s crib, and a way to listen to or watch what your child is doing when they’re supposed to be asleep. Maybe somebody somewhere uses it to mean a screen for the baby to watch, but that would have to be some very non-standard usage.

There is lots of interesting code here https://github.com/joukos/PaperTTY

Thanks for the report. I am surprised it takes 30+ seconds just to prepare the images, but I haven’t looked deeply to estimate what I would actually expect. It looks like you could parallelize the imagemagick commands though (unless it already is and I just don’t understand the Python.)

Thats a lot of pixels for what is a tremendously slow SPI interface.

OP says "it takes 16 seconds to refresh the screen".

At 0.0625 FPS, SPI bandwidth [0] is plenty fast with some to spare.

[0] https://www.microchip.com/forums/m770156.aspx

Need something large & portable to read PDFs without eye-strain.

I'd recommend the Remarkable 2 tablet. Runs Linux, active hacker community, gorgeous epaper display.

Sony makes a nice one as well, but it's a lot more expensive and a lot more locked down.

These Waveshare displays are more suitable for Arduino projects.

and Sony recently decided to stop development of new models.

Do you have one? From what I've seen people seem to think the hardware is solid but the software is rather lacking.

I recently bought a Boox Note 2 for this and it works very well. I had previously tried reading PDFs and technical documents on my Kindle but it was pointless since it was so small. The Note 2 is just a little smaller than regular letter size paper and it runs a full Android operating system so it's easy to get whatever document management system you want to use working on it (including the Kindle app).

I hope this gets into ESPhome - that project is amazing.

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