Hacking A Flip Dot Display

While casually lurking on a famous auction website, [TeddyDesTodes] found the gem shown in the above picture and reverse engineered it. This is a flip dot display, the Brose Vollmatrix compact to be precise. It consists of a grid of small metal discs that are black on one side and yellow on the other, set into a black background. With power applied, the disc flips to show the other side. The disc is attached to an axle which also carries a small permanent magnet. Positioned close to the magnet is a solenoid. By pulsing the solenoid coil with the appropriate electrical polarity, the magnet will align itself with the magnetic field, also turning the disc.

After carrying the 25kg display from his post office to home, [TeddyDesTodes] opened it and discovered that the main control board was using two RS422 transceivers. So he fired up his bus pirate, started to sniff the traffic and noticed that several commands were repeatedly sent. [TeddyDesTodes] stopped the transmission, sent these particular commands and had the good surprise to see some dots flipped. From there, displaying something was a piece of cake.

If this is familiar to you it may be because it was shared in one of the Trinket Contest Updates. But the background details were just so much fun we think this deserves a full feature of it’s own. Do you agree?

19 thoughts on “Hacking A Flip Dot Display

  1. There;s an electromechanical 7-segment display (from a scoreboard or something; it’s quite large) somewhere in the space. The segments are hinged and move in and out of view using two magnets.

    1. Hey, I’m looking to build a multiple panel flip dot display. I can see that this is from AlfaZeta, I am wondering how you got started with programming it. Please let me know, thank you.

    2. Hey, I’m looking to make a multiple panel flip dot display. I can see that you are using an AlfaZeta board, which is what I am looking to purchase. Can you please tell me how you got started with programming it? Thank You.

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