I am working on a weather station project using a Pi zero 2 and an inky WHAT display.
I want to add a clock to the screen, but as I found out, the e-ink screen refresh rate is not good enough to have a clock. I think I will just need to refresh the inky screen once a day with the weather information.
So my next thought is to add a second OLED screen, and plug that into the breakout pins on the back of the inky screen.
I have found one on the PiHut website that looks like it has the same pins as the available ones on the inky screen :
The pins it has are :
3-6V
SDA
SCL
GND
Looking at the breakout on the inky, I have all of those available.
So will this screen work for what I want to do?
Another one I found on the site is this :
But it looks like it has pins like CS, COPI etc. And I don’t see those on the inky breakout.
The I2C display will work, the SPI will probably also work, since it uses different CS and DC pins (sharing the SPI-bus with SCLK and MOSI is ok).
The big question is: why do you use an e-ink display, if you operate in always-on mode? E-inks are optimized for low-power, i.e. you update them, then turn the device of. If you are always on, you can find cheaper full-color displays and use only a single display.
This is my first project, and I did not know how these eInk displays work. I have a kindle, and it refreshes pretty quick, so I thought, that looks like it would be cool as a clock.
I like the viewing angles, and the fact that it takes very little power, so I was eventually going to add a battery etc.
But then when I started coding it up, I realised these screens arent really made for always-on type display. :(
SO my next thought was to have 2 displays. But I suppose I should just get an oled.
I was hoping there would be a way to just refresh part of the screen, but after a pretty exhaustive search online, I think that is impossible sadly.
I think the screen itself supports partial update. The problem is the Linux-driver that generates a complete image (canvas) and just sends that to the screen.
One thing in your argumentation is correct: the viewing angle is nice and it does not have such a glare as normal displays have. So there is some point to use it also as alway-on display. But you still have the problem of slow updates. The b&w Inky-wHat is rather fast compared to the color e-inks.
For larger color displays, have a look at what Waveshare offers. I have a number of displays from them, e.g. I am using a 4" touch spi-display and a 7" touch hdmi-display. These are not as nice as Pimoronis Hyperpixel displays, but they don’t use up all the GPIOs and are much cheaper.
@bablokb - Just took a look at your repo. Very impressive stuff!
I am working on my own version of the exact same thing, since I am learning python and coding on a PI, I wanted to start from scratch and figure it out myself. But your repo is going to help guide me, so thanks for sharing!