Last year I saw this video on Youtube that featured a 7-Color E-Paper display from Waveshare. I immediately thought it was cool and after seen the Slowmovie project by Mike Szczys I had to make my own.
As far as I know, nobody has made something like this with a color E-Paper display so even if it isn't a new concept, it brings a new twist to the game.
The plan is to make a standalone battery-powered device in a nice 3D printed case. It has to be as low power as possible since I want the batteries to last at least a couple of months. I haven't decided yet on what battery chemistry to use, the two candidates are lithium-ion or rechargeable NiMH AA. If I go with lithium-ion it will be rechargeable via USB, otherwise, AA batteries will have to be replaced when empty.
Eventually, I plan on making a custom PCB with all the components, but for the initial prototype/proof of concept, I'll be using an STM32F4 Discovery board. The following picture shows the connections between the SD-Card, the display, and the development board.

E-Paper displays ara ideal for this task because they draw power only when the image is changing. The display module comes mounted on a breakout board that converts the flat flex cable into a convenient connector, but it also has some additional circuitry. When the RST line is held LOW a MOSFET in series with the VCC line cuts power to the module. The SD-Card on the other hand as a non-zero quiescent current and so to prolong battery life, a switch must be added. This is not shown in the schematic because I will focus on the firmware side first: reading files from the SD-Card, decoding the jpeg images, dithering algorithms to increase the available number of colors.
Thanks for the suggestion @Wayne but the problem is that this display doesn't support partial updates. The documentation provided by Waveshare states that the display must be completely cleared before every update.
The documentation doesn't specify what controller is used in the display, searching the internet I found that it can be an IST7106 but I can't confirm it because the datasheet is not available.