Six years ago, our group member Mark bought the sign at the Baltimore HamFest. Since then, we have been bringing it with us to all of our Hackathons, intending to use it as a side project, just for fun. Unfortunately, we have never gotten the sign into a stable working state. That is, until now.

How it works

The sign is driven using a Teensy 3.1 for the realtime scanout, and a RaspberryPi to generate the frames. A series of applicantions written in Python can be selected in a menu system we developed. The sign is also capable of controlling x10 devices using an Arduino Uno based bridge connected to a TW523 x10 line interface module. This allows our sign to control the warning light that currently adorns it.The game code is all written in Python, and the realtime code on the arduino and the Teensy is written in c.

Challenges I ran into

There are several reasons that this is the first Hackathon where we managed to get the sign working. Perhaps the foremost reason is that the scanout hardware inside the sign is undocumented and was originally designed to display closed captions retrieved from an analog tv signal. Getting the sign to work required the drive electronics being substituted.

Accomplishments that I'm proud of

We made more than a dozen demos for our system, including several multiplayer games, internet enabled services, and cool patterns such as Conway's Game of Life.

What I learned

Quite a lot about reverse engineering! Driving the display requires tight control of a system we didn't build, and several major modifications to the original driver circuit had to be executed.

What's next for LED Sign and Demos

We hope to design more simple games and utilities to our sign and add as much functionality as possible.

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