The first step of a big project like this is doing the research to
see what work has already been done and what needs to be done. In
reviewing the information provided on the websites in the description, I
think I have found all I need to make this work with a few
Petteri Aimonen of the website
essentialscrap.com has put together a pretty in-depth look at the
ED060SC4 screen and how to drive it. His website has numerous links to
datasheets and brochures on e-ink displays as well as diagrams showing
the pitfalls he has encountered in making this display function for his
needs. His project drives the screen with an STM32 programmed in C. He
also has an excellent schematic which uses Texas Instruments op-amps to
supply the necessary positive and negative voltages.
This is an excerpt from his schematic, I'm going to use this part for the voltage generation:
I should be able to use that part without any major modifications. The other part drives the screen with the micro controller:
Thispart will be roughly the same, but the micro controller will be aRaspberry Pi instead of an STM32. There's 8 data lines and a few pins
dedicated to clock signals, screen mode changes, and turning the control
voltages on and off in the correct sequence.
SpriteTM has a similar
project, using an ED060SC4 paired with a ESP8266 to make a wifi-enabled
whiteboard. There are a few significant differences between his version
and Petteri's, the biggest being that he uses a shift register to clock
the data in since the ESP8266 doesn't have very many exposed GPIO to
work with. Here's the relevant portion of his schematic:
The screen has a 39-pin connector, although a few are NC (not connected). Here's the datasheet showing what all those pins need:
schematics and information from the essentialscrap website are more
applicable to my usage scenario, but I may adapt the shift register
after I get a prototype working. My next concern now that I have a
schematic is the board to drive it. I'm still debating making a board in
KiCAD or just prototyping on a breadboard where I can modify the design
to suit my needs.
After that, I need code to get my pixels onto the
screen. Petteri Aimonen has posted his C code on github, and I'm hoping
that I can just change his pin definitions to the GPIO used on the
Raspberry Pi and it will just work, but let's face it; it won't be that
While I was doing research, I was also playing with some of
the components to get an idea of the layout. For some reason, the final
layout drives my design decisions so it's one of the first things I
envision. Also this is the first Raspberry Pi A board I have owned, and
they are so small and cute!!!
last tidbit for this update: Power!!! Some back-of-the-napkin
calculations tell me that this contraption should pull about 250 mA per
hour, and even this only if the screen was constantly updating. If these
calculations are correct, I should be able to get 20 hours of operation
from my 5000 mAh battery pack that's pictured above. This is also good
because the solar panel I'm eying supplies about 330 mA per hour, which
means I could charge it and use it at the same time.
for now, thanks for all the follows and skulls!!! It's great motivation
to keep me working. My next step will be to replicate the schematic and
make the e-ink display something.