Frederic LSo, one morning, I wake up, scroll through some Reddit posts (one of the bad habits I have), and stumble upon a guy posting about his flip dot display.
Well, it didn’t take me long to figure out I ‘needed’ one. Before that day, I had never heard of those displays, though probably I had seen some on busses or at airports, but never thought about it from a technical point of view.
I browsed internet and found that these things are pretty expensive. Especially when you include the shipping fees.
You pretty much have 3 possibilities discussed below:
- Buy a brand new display with a driver ($$ - $$$)
- Make your own display from scratch ($$$)
- Buy a used display with or without a driver ($ - $$, my case)
BRAND NEW DISPLAYS
BRAND NEW DISPLAYS
The brand new route is probably the easiest (and least fun) route, but it will guarantee you get a working display with a proper controller quickly. Though, it comes at a price :
AlfaZeta makes brand new displays, with a controller board. Their XY5 displays (14x28) sells around 500€ (VAT and shipping included). That’s 1.27€ per pixel, but you get the comfort of having a working, brand new, customisable display with a driver/controller board included.
Another high end brand, Breakfast LLC provides plug and play displays for professionals, but their website suggests those would be at a price waaay beyond what I'm willing to put, so I didn't bother asking for a quote :
Breakfast LLC Flip Discs
MAKE IT FROM SCRATCH
If you want to make your own board from scratch, ie. buying flip dots new from a supplier, then make your own PCBs for the display and controller, be ready to break the bank. Each dot is a relatively complex component with coils and moving parts.
These are a few suppliers I could find :
I'm waiting for the quotes of the last two, but Magsign made me a quote for 1000 dots for 3500$, so 3.5$ per pixel, and this doesn't include the manufacturing of the PCBs, controllers, and other required components to make it work. Their dots seem to be of very high quality though, and are rated for more than 100 million flips !!!
Even if I would have liked the flexibility and challenge of making it all from scratch, the price (and the perspective of making a schematic and soldering of 1000 dots + 1000 dual diodes) put me away from this solution.
GET A USED DISPLAY
Most used displays come from urban busses. Either the bus got scrapped and spare parts end up on the market, or they are being retro-fitted with the more modern LED displays.
Some specific reseller offer those displays, such as Rollsign Gallery, or PSV Automobilia.
Common brands include Hanover, Luminator, and ANNAX and eBay is the easiest place to find flip dots displays, though watch out for the delivery and import fees as it may double the advertised price.
At the time of writing, a used Hanover display sizing 98x16 can be found on eBay for 220€ + 270€ for shipping (seller psvautomobilia). That’s 0.31€ per pixel, but that’s a bit too big for my use.
A Luminator (16x28) sells for 100$ + 30$ shipping (USA Only). That's 0.25€ per pixel (at today's USD-EUR rate). (Seller frankie615us11).
A bit further down on eBay I found some ANNAX displays, 30x16 pixels, for a total of 110€ shipping included (seller discountbuys_2012, open to offers). That’s 0.23€ per pixel, best I could find so far, so I took one, and half a day later I decided to take a second one. That’s twice more fun right ?
I should end up with a 16x60 dots display, which will be big enough to display a wide range of stuff (not sure what I'm going to do with it yet, I'm open to suggestions).
The pixels are pretty square and with very little clearance, which makes it cleaner, and the integrated LEDs on each dot would make it possible to read the display at night, although it will require more coding and wiring.
NOW THE FUN PART. Those come without any controller board or driver (available separately on eBay at... 160€!). Which is what this project is about: Designing the control module, by reverse-engineering the flip dot display, and use a micro-controller (ESP32), to drive the whole thing.
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16×60 ? why not 32×30 ? :-)
Please shoot detailed picture of the boards when you receive them :-) both sides !
And measure the coils characteristics, this will heavily influence your controller's design.
Are you sure? yes | no
Hi, sure I thought about stacking them vertically, but the PCB seems to be sticking up and down so it might be hard to have a seamless 32x30. The left and right side of the PCB is flush with the dots, as they were initially designed to be stacked horizontally. I'll have a closer look when I receive the displays and will share pics.
I'll check the coils but I will probably need more equipment (I don't even have an oscilloscope ! haha). Thanks for the inputs.
Are you sure? yes | no
ah yes, I forgot about the protrusions...
Have a look at past posts of the #Dot flippers and see how to characterize the coils : you basically need a lab power supply to set the voltage and current.
BTW : usually, the pulses should be quite short, you don't need to keep the power continuously (in some cases it could damage the coil). The point of the coil is to change the magnetic orientation of the magnetic parts so a pulse (10ms or less ?) at a certain current is enough.
have fun !
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