FlipMaster 9000 Part 1: Flipping the Dots

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 github.com/CarlRaymond/AnnaxF...

[@Nullzero98]

This device makes the best sound of any electronic device ever.

[@hansdietrich83]

Omg finally someone that actually explains how these work and explains how the controller is built, thank you for that

[@Variety_Pack]

You know what you must do next....

[@brandonlink6568]

That is so cool. A mall nearby called The Hub had a huge sign made of something very similar to these, if you were within 50' of it you could hear the clicking of hundreds of them flipping about every 15 seconds. I don't know how old it was but there were always a bunch stuck on green or black and in the 00s they replaced it with a boring LED dot matrix board. That had a similar problem with bulbs stuck on or off so it only lasted a few years before being removed too, now the whole sign is gone to make way for a roundabout.

[@MMuraseofSandvich]

There's an effect in the main menu for

[@LeeHambley]

Just scores some similar boards on ebay, thanks for walking through how the H/L lines work and all the diode setup. I was struggling to reverse the wiring.

[@emeraldzebra9360]

Used to love programming / flipping through destinations on the buses with these here in the UK

[@embracethesuck1041]

This is really cool. My Dad used to install and service these, later sell them, for stock exchanges, road signs and some similar functions.

[@ccricers]

Besides buses and trains I mostly remember these displays from old episodes of game shows like Family Feud.

[@dergrafikfehler7563]

Those Annax BiLED panels were in use in new vehicles for quite some time. The last trams with them were delivered here in 2016.

[@blizteredthumbs7911]

For flip sake! I always wanted to know how these worked. The problem is my interest was always on / off / on / off ... but cheers for explaining :)

[@LordPhobos6502]

Pixel width limitations were generally based on size limitations of the transit vehicle in question.

[@rfmerrill]

They replaced the flip dot displays on buses with LED signs and they're not as easy to see in bright sunlight

[@nigeypants5500]

People are absolutely still making these and they're still in use many places around the world.

[@gaius_enceladus]

I'd

[@Alkatross]

That explains why you can't energize the entire matrix at once to form an image quickly. You would need individually addressable dots, like active matrix panels. You could design a board like that.

[@davidgretlein9384]

Very cool to see these again.

[@delu3709]

I'm pretty sure that BUSE still makes those. A lot of depots still use them, too.

[@teytreet7358]

I remember seeing these at the airport. They were so cool.

[@sschueller]

We have these on some light rail trains here. The LEDs are in fact on and you can see them when the train goes into a tunnel at which point you can't see the yellow of the flip mechanism. They are very readable in direct sunlight as well as in complete darkness thanks to the LEDs. As these trains are not that old these mechanisms are still available. Newer trains have all LED and that is because the new generation is readable in direct sunlight.