Neat! I've been thinking of building something similar to this — a portable Linux machine that has an eInk display and little QWERTY keyboard, in a size that's a just a bit bigger than a smartphone.<p>I've had a spare eInk display laying around for some time now, and it's about ~~5"~~ 3.7" in size, I think. I managed to get it working with a Pi Zero, and wrote a small Python script which captures the desktop, and then compares it to the previous capture, and then updates the bounds of where the capture is different. Somewhat slow with a Pi Zero, but still somewhat usable. I really need to look into the possibility of performing partial refreshes on the display to save it from having to invert the screen every time there is a change.<p>I might try and use a Pi 4/ Pi CM4 to drive the whole thing — I believe the bottleneck mainly lies in sending the data over to the display, which the Pi Zero is unfortunately quite slow at doing. Plus, it would potentially be a bit more powerful/useful with the newer processor found on the Pi 4!