7.5" Wall ink device
The 7.5 inch wall-ink device includes the printed circuit board, the 7.5" Wall-ink case, the E-ink display, and a few battery clips and screws to hold everything together. The full parts list including example suppliers is provided.
There is also some support for the 4.2" 400x300 pixel Waveshare display. The wall-ink-server can handle the 400x300 resolution, as can the firmware. Some server plugins can also handle almost any size display, but the firmware may require some modification. The general scheduler plugins only have included layouts for 640x384 and 400x300 displays. There are no included 3d case designs for any screen size other than the 7.5" display.
It may be in your best interest to build a development board prototype before going to all the effort of building a full wall-ink device. This will allow you very quickly test all of the software and do a proof of concept exercise before building the full device.
The printed circuit board will work with a screen of any size and could be used in any device that required periodic wake from deep sleep. There is a separate article explaining the details of the printed circuit board including eagle files, gerber files, ordering boards, soldering, etc.
The 7.5" wall-ink device case has three pieces, a case back that is permanently attached to the wall, a case front that houses all of the electronics and batteries, and the faceplate that holds the screen on to the case front. The CAD files are all available for download as part of this project to be 3d printed. The faceplate can either be 3d printed, or milled on an engraver for a more "professional" look. See the article on the 7.5" wall-ink case for full details.