Schematic and PCB

A project log for E-Ink Display Adapter

Using a replacement Kindle screen with an Arduino/whatever

sapirsapir 09/29/2015 at 22:552 Comments

I uploaded the schematic etc. to github. Of course, it's heavily based on the previous schematics (see project links). There are a few differences: My board doesn't include a microcontroller. Instead, it's basically a breakout board + specialized voltage regulators. I tried to breakout as many of the FPC pins as possible, even the ones that supposedly aren't connected, and almost none of them are hardwired to each other, to try to minimize the chance I'll need a new PCB if I discover that my display has a slightly different pinout. Also, there were slight differences between the two previous schematics, so mine is sort of a mix. Some resistor/cap values I wasn't sure about are annotated in the schematic file.

PCB layout was difficult. I really wanted to keep to a 2-layer board with the bottom layer as a ground plane, so everything except ground has to be on a single layer and none of the signals can cross each other. (I assume this is obvious for anyone who, unlike me, has ever done any PCB work.) This was difficult enough for some of the logic signals but then I had all the special voltage outputs to deal with, each coming from a different part of the board. I ended up using jumper wires for all the power outputs and another zero-ohm resistor to allow some of the logic signals to cross each other.

The exported gerber files are on OSH Park now, though I'll try to recheck some more stuff like the FPC connector pinout before I actually order. - I'm still not 100% sure about the FPC connector pinout (which side is 1 and which is 39?), even after staring at the datasheet.

btw, I got through the sparkfun "Simon Says" SMD soldering tutorial kit. Very nice! The thought put into it shows. My only complaint was that the troubleshooting section was a bit short, so I got to learn a bit of troubleshooting the hard way :) so maybe a good thing. One of the LEDs wasn't working - the manual suggests reversed polarity and the kit even has a way to reverse them by soldering some jumpers. But the polarity was correct (multimeter continuity tester lit them up). It turned out that I hadn't properly soldered all of the microcontroller pins, so it couldn't turn the LED on. Also one of the buttons wasn't working for the same reason.

My adapter board will probably be a lot harder to solder as it's a lot denser.


sapir wrote 10/10/2015 at 22:05 point

looked closely at sprite's gerbers and photos, and found that my current PCB really does have the FPC connector completely backwards. the cable would have come in the wrong side and the pins would have been backwards, too.

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sapir wrote 09/30/2015 at 21:08 point

The board is actually no longer on osh park as I remove it and fix it and re-upload it it and so on.

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