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Flip Dot Displays

Our new group project is the restoration (and hacking) of some electromagnetic flip-dot bus display panels. New display cases will have to be fabricated, and control boards for each display. A software interface is also needed for control the panels over a network etc. Suggestions and contributions are welcome, see the mailing list!

What we know so far...

Tom has reverse engineered a schematic for the panel. Combining this with logic analysis Peter performed at the uni has allowed us to discover how we can control the state of each pixel on the panel. Our current setup involves using a breadboard with a few tac switches on it to manually pull some of the address lines high. Our next task is to use a MCU to pulse those same address lines with accurate timing.

scopetrace.sr Δ

Testing
Controlling the panel with a breadboard

The display is controlled column by column, using an array of h-bridges to configure each pixel in the column

The board that came with the displays is a generic MCU (H8)which we are going to reverse engineer and replace with a modern MCU

Photo gallery: https://photos.app.goo.gl/47nwBdrXxcoKn3jY8

To Do List

  • We need to design and build an enclosure / stand that will allow us to show off the displays to the public at EMF. This will likely be built out of bits of wood in order to raise the display to eye level and tilt them up a little to make them easier to see. The enclosure will include a large, plexiglass panel to protect the displays from the elements.
  • We need to come up with an effective solution for controlling all six panels in real time. Our current idea for this is to pair each panel with an MCU that will update its pixels, and then network them together using a SBC (perhaps a Raspberry Pi 3B+) acting a bit like a hypervisor.
  • Once we can control each pixel in the entire display, we need to write software to make it do something cool. Ideas for this have ranged from games such as pacman, a twitter bot, scrolling text and more. Perhaps we could even make a system that would allow EMF attendees to program the panel with to do something else entirely!
Render
Render showing a suggested configuration of six panels

Reverse Engineering Document (now completed)

https://docs.google.com/document/d/1CUAwdkxpGrkr4xf47PyitDyd0ukrCAkWJyJCvSQuNrw/edit?usp=sharing

Blog posts and online resources

Forum with similar setup
https://forums.adafruit.com/viewtopic.php?f=8&t=21599

Demonstration of custom controller - no details provided
http://www.youtube.com/watch?v=IcN_nGvcxeU

Custom arduino controller with info
http://www.youtube.com/watch?v=k7PlNs5B3pl

Github with code and circuit (below)
https://github.com/aacarioca/FlipDotDisplayController

Documented project with similar panels
https://engineer.john-whittington.co.uk/2017/11/adventures-flippy-flip-dot-display/

- Last change July 16, 2018, at 11:07 PM
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