Everyone loves sharing photos, and with most pictures being taken on smartphones now, digital frames are more convenient than finding a photo printer. [Wolfgang Ziegler] used an e-ink screen to create a colorful digital picture frame.
Starting with a seven color e-ink HAT he’d forgotten he had, a spare Pi Zero, and analog photo frame, he pieced the parts together into a pretty slick, sunlight readable photo frame. [Ziegler] details how he set up the frame to display new images using the Pimoroni inky library. He set a fifteen minute refresh interval since the color e-ink display takes 30 seconds to refresh to keep it from looking weird too often.
With the holidays coming up, this might make a perfect gift for family that wants to see the latest from your travels without blasting it to the whole internet. We’ve covered a few different options from a lightweight ESP8266 build, to this one that can rotate, and even issues with some of the commercial options.
I hate that we’re stuck with these rubbish 7-colour panels being the only sanely affordable option. The lack of cyan makes it borderline impossible to render satisfying images.
Same. Moreover you have all these lovely but otherwise broken e-readers with large displays that could be repurposed for lots of projects but are next to impossible to interface to.
pocketbook has a great alternative atm, which is more or less a greyscale e-ink with a lcd translucent panel for color… but I haven’t seen any breakout board for such screen…
I really hope that we get cheaper epaper displays in the near future. Waveshare has an amazing one. 13.3″, 1600×1200, 1ms refreshrate (0.3ms for partial refresh), Pi support. It’s the (well, my) dream. But 408 dollar, which is 375 euro’s, but with (guesstimate) 50 dollars shipping, I have to pay 110 in added local taxes etc, on top of the display. That’s just not funny anymore. Rather frustrating as it’s the perfect display for me. How cool would that be for a super long lasting battery in a cyberdeck? Something that could survive a zombie apocalypse on battery power alone. Well, 500 hours on a 50.000mAh batterybank. Close enough. If anyone knows a good alternative, I’m all ears.
Just a disclaimer on the waveshare and other e-ink displays. The refresh rates and parameters are a bit of random, you shouldn’t trust them too much. These numbers are what they managed with their messy example code, and the code looks literally like a cat barf. Also I suspect that all displays are able to run in 2bpp mode with right LUTs, but I haven’t had time to prove that yet.
I did play with their 7.5″ v2 display and managed to get much faster refresh rates and also partial refresh, which is now fast enough to be usable with terminal.
See:
http://gfxprim.ucw.cz/backends_display_waveshare_7_5_v2.html
http://gfxprim.ucw.cz/backends_display.html
Thank you for the warning. I only have a tiny version on my pwnagotchi and the refresh rate is not relevant there. 1ms refreshrate should be plenty for a proper display, even when doing more than terminal work. Ofc it will never be as fast as a normal display, but it’s a trade-off.
I’ve found out that once you have a partial refresh that is less than 1s and if you merge subsequent repaint requests terminal is quite usable. If you type fast, the letters are painted on every third or fourth letter. I would say that having UI on e-ink is a bit more about being smart about how things are repainted rather than about the raw e-ink speed.
And the same goes for GUI, my widget library is quite usable on e-ink as well, since it was designed to be minimalistic to begin with.
And of course repaint in a few ms is a few orders of magnitude faster, it would be awesome if such displays were cheap enough, but for now I’m working with things that can be bought for a reasonable price.