I bought an ANNAX 16x30 flipdot display panel -- an electromechanical dot matrix -- on eBay. These were used in high-visibility environments, like on a bus to show the route number and on road construction signage. They're just about obsolete now.
We'll explore how it works and flip some dots. Future parts describe building an Arduino Nano- and ESP8266-based controller for it, writing some software, and playing a game on it.
Special thanks to John Barber for finding the eBay seller and letting me borrow his panel; and to Brian Adams for helping with proof-of-concept and general encouragement.
The KiCad design and Arduino code is on GitHub at https://github.com/CarlRaymond/AnnaxFlipdotDriver/