Sunday, October 5, 2008

Hacking the Esquire cover e-ink screen with the Arduino




















Last month, Esquire magazine published a cover that contained an E-ink screen. I was really looking forward to it, actually... so much so that I marked it in my calendar to make sure I picked one up around the corner. There was quite a bit of hype about it, and a lot of people wrote about it on their blogs and websites, and Esquire even encouraged hackers (does that include me?) to play around with the screen. The local store had a couple of copies left over this past week, so I grabbed one, and decided to see what I could do in a couple hours of playing around.








































Of course the first thing I did was rip off the cover:






















I noticed that the cover was a folded-over piece of card stock, so I pried it open:






















The funny part was that it kept on blinking even as I took it apart... felt a bit like the scene in 2001 A Space Odyssey when the guy unplugs Hal:






















This is the back-side of the device:






















And this is what the front side of the PCB board looks like. The components have been identified on other sites, but suffice to say there are a lot of batteries, two shift registers, and a small PIC chip that runs the program.











































I knew within a few minutes of looking at the board that I could either approach this one of 3 ways:

1-Hack the PIC chip, perhaps by reprogramming it
2-Hack into the shift registers, by cutting the input line, and taking them over... but what if they're held in some level by the PIC chip, and there's a via under the chip that I miss?
3-Hack directly into the screen (hoping that there protocol and voltage isn't too difficult to work with, and that I can safely bypass the rest of the circuit with little to no consequences).

I chose method 3, because it seemed like the most straightforward, and the one I could probably get right on the first try. The cable to the screen had 12 wires, and the PCB had resistors lined up in two rows after the connector. I soldered solid-core wire directly onto the small round pads the PCB designers left for me (thanks, guys!), in perhaps the world's sloppiest, hackiest, and odd-looking design ever. Actually, I took a perspective photo of it below, and I think it came out pretty nice!






































I connected the wires from the PCB onto a white mini-protoboard - mainly because of the fragile nature of the PCB-solid core soldering job I did. Even a small jostle would disconnect the wires from the PCB, and I knew I'd be rearranging the wires quite a bit as I discovered which lead was ground, or how they were wired up. I tried a few configurations, including assuming ground was in the middle, far right, or far left of the connector. I found that by applying +5 to one lead, and 0 GND to the ground pin, I could turn a segment on. Then, I found that by applying 0 GND to the lead, and +5 to the ground pin, I could turn the segment back off. This is the same as saying the screen accepts +5 to -5 voltage as it's range, where +5 turns it on, and -5 turns it off. Ugh. That means it'll be a little tricky to work with, but I've seen worse!



















































Ok, so I was fairly proud of my soldering job, so here's another shot of the wires:




















I connected the ground pin to the Arduino pin number 2, and all of the other pins on the first row to Arduino pins 3-7, and the second row from 8-13. I wrote a small piece of code to turn the pins on and off:

void turnon(int pin) {
digitalWrite(2, LOW);
digitalWrite(pin, HIGH);
}

void turnoff(int pin) {
digitalWrite(2, HIGH);
digitalWrite(pin, LOW);
}

After a little experimenting, I mapped each of the connector wires to the segments on the screen:

pinMode(3, OUTPUT); // the 21st century
pinMode(4, OUTPUT); // now
pinMode(5, OUTPUT); // right bar
pinMode(6, OUTPUT); // center bar
pinMode(7, OUTPUT); // boxes around now
pinMode(8, OUTPUT); // right box
pinMode(9, OUTPUT); // background
pinMode(10, OUTPUT); // begins
pinMode(11, OUTPUT); // left box
pinMode(12, OUTPUT); // left bar
pinMode(13, OUTPUT); // middle box

And of course as soon as that was done, I was ready to go... I wrote a small night rider script, and then rewrote it to run on a black background:

void barnightrider( void) {
turnoff(5);
delay(t);
turnon(12);
delay(t);
turnoff(12);
delay(t);
turnon(6);
delay(t);
turnoff(6);
delay(t);
turnon(5);
delay(t);
}


void barnightriderblack( void) {
allon();
delay(t);

turnon(5);
delay(t);
turnoff(12);
delay(t);
turnon(12);
delay(t);
turnoff(6);
delay(t);
turnon(6);
delay(t);
turnoff(5);
delay(t);
}


And then I played around with the text code segments:

void centurynowcycleblack(void) {
allon();
delay(t);

turnoff(3);
delay(t);
turnoff(10);
delay(t);
turnoff(4);
delay(t);
turnon(3);
delay(t);
turnon(10);
delay(t);
turnon(4);
delay(t);

turnoff(4);
delay(t);
turnoff(10);
delay(t);
turnoff(3);
delay(t);
turnon(4);
delay(t);
turnon(10);
delay(t);
turnon(3);
delay(t);
}

Finally, I put all the scripts into functions, and combined the functions to run a little version of the playback demo:



Probably the coolest part of all, though, is the fact that when you unplug the Arduino from power, the E-ink screen stays lit or programmed with whatever was on the screen at the time it was unplugged... cool!






















A final suggestion for the next time Esquire does this... please give us a dot-matrix version, with individually addressable pixels. If you do, I promise I'll hack it, and make it available to everyone to code, and I think that'll pretty much guarentee that I'll buy about 10 magazines just for myself :)

I've uploaded all the source code over at www.liquidware.org. Have fun!

5 comments:

Matt said...

Hey guys, thanks for all the emails. Yeah, I completely agree, the next time they should definitely use the dot matrix screen, because then I could do some really crazy hacks with it :)

Matt said...

Also, since a lot of folks emailed me about it, here are the bigger versions of the photos: http://www.flickr.com/photos/22071518@N04/

Chris said...

Nice hack!

Can't wait for the active matrix e-ink writeup!

Griff said...

Awesome...Cannot believe you hacked a magazine cover!

Catalectic said...

Great tutorial! Very informative in how well worded and descriptive you were! You know they say that if one knows how to describe what they want really well, then life is just as good as how you describe it :)!!!
Its great for people who feel like time is running against them and then land on your blog and feel like a whole burden was just lifted off of their shoulder..!! I admire and respect people who take time to make it easier for others.. Thanks a bunch! :)
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