We’ve not found a way of changing the refresh behaviour on the 7 colour screens - as I understand it the refresh/clear cycle is mandated by the controller chip on the display itself.
Oh that’s disappointing! Thank you for the quick response.
I was wondering about tweaking the driver (here?) to try to trick the display… specifically whether the palette count 0x08 in the panel setup (PSR) could be changed to a lower number. Of course this might just make the thing expensively brick itself… Is this something you’ve tried?
Another follow-up since you’re here! The Inky wHAT is pretty much perfect for my needs… do you know if there’s a way to get it to talk to the RPi Pico W?
I don’t have too much knowledge myself about how the innards of our drivers work, but apparently our engineering team have found these screens to be fairly robust so reckon it should be safe to experiment a little with different settings.
It’s probably worth bearing in mind though that seven colour E Ink screens are designed to be used in applications when they’re only need to be refreshed infrequently (refreshing every 15 mins is considered a very frequent refresh rate in 7 colour E Ink land!) so if you’re looking for something that needs to be refreshed every minute you’re probably best looking elsewhere.
As @alphanumeric says - possible that you could get Inky wHAT working over SPI from a Pico, but you’d need to locate or write compatible drivers for this panel (CircuitPython might be worth a look, I think Adafruit do a number of three colour E Ink screens).
@hel thank you for your help! I think we’ll look for other components.
A bit more about this project, in case you’re interested: I recently made this AI Clock based on an Inky wHAT and RPi4 – it got a whole bunch of attention (including a mention last week in the New York Times!) and now I have a mailing list full of people who’d like one…
We have proof-of-concept code for a Pico W that would make a self-assembly kit beautifully plug-and-play (wifi setup etc) but the gap is connecting it to a 4" monochrome e-ink screen, or at least something that refreshes in about ~1s given it’s a clock and it changes once per minute.
So I’ve love to put in a product request for an Inky wHAT-style screen with Pico onboard! If you do one of those then I’m sure I could help you shift a bunch.
Aha - I think I saw this project on the Twitters. Very cool :)
We’ve discussed a faster updating mono or greyscale version of Inky Frame in the past but I think we were hunting for suitable screens - I’ll bring it up again at our next dev meeting and see where we’re at!
Awesome! Let me know — I’d much prefer RPi for the near-term kits and to leave ESP32/82 for the future boxes product, and right now it looks like we’d have to jump straight to ESP. There’s a cheeky 4.7” monochrome that looks pretty common rn.
If there’s a specific MOQ you’d need to make this worthwhile, I could see if I could get some commitments from the email list.
The main idea of this project is to reuse all my wonderful Pi-hats with the Pico.
The hardware part is finished, now I am working on porting various drivers from the Pi to the Pico. I do plan to port the wHAT-driver too, since I own one and I would like to switch my project from the Pi Zero to the Pico.
