New Project: Interfacing to and/or Driving a FlipDot Display

For my next trick, I’ll be learning the intricacies of running a FlipDot (aka flip-disc) display made by ANNAX:

The image above is from the FlipDotBlog site that the ebay seller maintains… some of the panels have full electronics, and some are just the board and the dots.

I’ve always been fascinated by FlipDots and the sounds they (and related technologies) make (the *clack-clack-clack!* of train signs for example). En masse, FlipDots are sublime – and a bit loud:

I’m hoping I can make it all work using the standard RS-485 comms the board with full electronics provides, but we shall see. Interestingly, it seems to have LEDs in addition to the dots, and apparently they are controlled independently. Bonus!

First, though, it all has to arrive safely from halfway around the world. More updates when I’ve had some time to play around with it!

PS: After I drafted this post I looked closely at an SF Muni bus on the way to work – lo and behold it appears to use the exact same dots (should’ve snapped a photo.)

Update: I finally got a close-up of said Muni signage – while it’s similar, it’s not the same:

The ones I’m getting look more like this (but still not exactly because mine will have the auxiliary LEDs as well):

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  1. Hi Martin!

    I purchased the same flipdot modules on ebay from the fellow in Australia. I’ve managed to discover much about the control module, but I still haven’t figured out the serial protocol required to talk to the microcontroller. Heck, I’m not even sure which serial mode it’s configured to receive!

    Had any luck with the RS485 comms yet?



    1. Did you get the whole sign? I managed to test it but haven’t had time to do more with it (I need to make some kind of an enclosure/frame to hold it all together during testing). One thing I wouldn’t do is use the Mean Well RD-125 power supply with it – that one requires at least 2A of load on the 5V rail just to turn on properly (pretty sure it needs that on both rails, and that’s a lot of waste heat to dump just to keep a PSU on). I’ve got a couple of RSP-150 supplies (5V and 24V) that I’ll be using to bench test it going forward (they don’t have a minimum load requirement).


    2. Hi Sean, I realize this comment is over 2 years old but I bought the same Australian flipdot sign off of eBay. I have it powering up and doing the dot check (flips all dots on and off). Trying to communicate with it via a USB->RS485 dongle but having no luck. Did you ever figure this out? If so, could you possibly point me in the right direction?

      Thank you!


  2. Hi guys,

    I join the club as I just bought some of those units, but the display panel only, not the control/driver board. So I’ll have go make my own driver board.
    I’d appreciate if you can share any of your findings and recommendations as of how to use it, schematics, code etc, if you’re willing to, as it would save time reverse-engineering it.

    Take care,



    1. Cool! When I figure things out I’ll share them – right now I’ve become swamped by other more urgent projects.


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