GoKawiilFlipdiscs (or flip dots) are a display type that utilizes electromagnetic pulses to flip a small disc between two colors. Despite being invented over 80 years ago, the underlying technology is mostly the same today. I chose them because I wanted to design a large interactive wall art for my office, and didn’t like the LED glow of traditional screens. Flip displays are an interesting alternative. They have high readability, a long lifespan, and achieves anywhere between 25-60fps. Also, as a pleasant bonus, they emit a sound like rain hitting a window each time one of the disc flips - I find it very soothing. I’ve always wanted unique ways to visualize code, like this pixel knitting app we designed for electroknit knitting machines or this crafting tool for Atom Editor (RIP). Flipdots seemed like a similar fun challenge. I paired with my partner to help code and design the board. Who doesn’t love quality hacking time with their partner?! I’m not sure how many people will find this useful since flipdisc displays are sort of an obscure technology, but here we go!
Contents
Build
Panels
We used 9 Alfazeta panels in a 3x3 grid or 84x42 discs. Each board has (2) 28x7 panels. You can see the measurments of the toal design in this diagram. The PCB features an older ATMEGA128 microcontroller, a couple hundred MELF diodes (be sure to buy extras, because they can pop off easily!) charlieplexed together, and two DIP switches. One DIP switch sets the address, and the other sets the baud rate. Find more information about the AlfaZeta boards, here is the manual.
It’s relatively difficult to source flipdisc boards or components, so your options are limited. If I were to do the project again, I would consider experimenting with designing my own board. These 7-segment flipdiscs also look really neat. Having access to the firmware would be a nice option when tuning performance. I also really wish I could’ve gone larger, but the expense of the panels really adds up fast. Unfortunately, right now, flipdiscs are more catered towards businesses (mostly the transportation industry) than the general consumer. Hopefully that changes.
Power
To power the board, it needs a total 24V 1A per board, or 9A total to send enough power to flip all the dots. We ended up using a 24V 10A Meanwell power supply. MEAN WELL HLG-240H-24
Frame
We built the frame using 80/20 aluminum extrusions, and screwed the PCB standoffs directly onto the frame. Word of caution: the boards and discs are incredibly fragile (My kids love to mess with them!) I read somewhere that flipdiscs are similar to butterfly wings, and I think that’s an appropriate analogy. It’s really easy to lose or break discs in the building process. Make sure to handle by the edges and carefully attach each board one-at-a-time. Here is a list of 80/20 parts that we purchased:
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