esquire magazine e-paper circuit-board

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esquire magazine e-paper cover October 2008.
xxv has some more info and an oscilloscope image tracing the signal for one of the sections of the display. also see his esquire e-ink web-page.
here's more info from a comment by maushammer about the makezine article Esquire E-Ink cover hacking? - take apart photos and more...:

ISP Pinout:
Pin 1: VDD
Pin 2: GND
Pin 3: VPP
Pin 4: pin 6 (ICSPCLK)
Pin 5: pin 7 (ICSPDAT)

PIC 12F629
Pin 1: VDD [3 volts]
Pin 2: not used
Pin 3: not used
Pin 4: VPP/MCLR and S1
Pin 5: goes to R5/Q3/R6
Pin 6: goes to R3/Q2/R4
Pin 7: goes to R1/Q1/R2
Pin 8: GND

S1 (the unpopulated switch) is connected to pin 4, which is a reset pin... but it can also be programmed as an input. It acts like a reset, though. [pauses while shorted; resets when released. --just mike]

Battery 6 powers the microcontroller only. (3 volts)

Batteries 1-5 generate 14.86 volts - available at C3
... I wonder which power supply will run out -- battery 6, or batteries 1-5.
Q1-3, R1-6 convert 0-3 volts from the CPU to 0-15 volts for the high-voltage drivers (U2 & U3).

U2 & U3: HEF4094BT - 8 stage shift-and-store bus register
Pin 3 is the clock - 30 Hz - it's slow because the Q1-3 voltage translator is slow.
Pin 2 is the data - varies depending which segments need to be lit
Pin 1 is the strobe - 2.7 Hz - allows all the outputs to switch simultaneously.

  1. xxv ages ago | reply

    At least on my board, shorting S1 seems to be a reset. It starts over, first flashing all white, all black, turning on a few of the segments, all white, all black then starting from the top of the animation.

  2. xxv ages ago | reply

    The screens seems to be driven by sending a +15V@19mA signal down the individual segmented display connectors. I'm guessing that there are the individual segments that one would expect plus one "reset" segment that covers the whole display (in the case of the car ad, to pull it all black).

  3. just_mike ages ago | reply

    @xxv: you're right! i went back and checked and it pauses only while the contacts are shorted, then resets and starts the cycle from the beginning when the contacts are released. i updated the note.

  4. xxv ages ago | reply

    @just_mike: well, "pause" in e-inkland simply means that it is not actively being changed (when there's no power). I connected it to my oscilloscope and got some of the timings:

    Turns out, there's one common electrode and an electrode for each segment. You pass +15v between the common and the segment electrodes and it will flip from white/black. If you reverse the polarity, it reverses the color. Pretty simple!

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