在翻转点显示器上实现FLIP流体模拟的工程复盘

FLIP Fluid on Flip Dots

24 Sep 2026

Progress: Complete

Here's the story of how I put a FLIP fluid simulation on a flipdot electromechanical display. FLIP stands for Fluid Implicit Particle, and yes, the primary motivation behind doing this was the wordplay.

It was built as an installation for EMF2026. This page will mostly focus on the technical details, but for the overview and demo of it working, watch the following youtube video.

• Intro
• Path to Some Panels
• Connect the Dots
• To KiCad
• Second Circuit
• Mounting Dreams
• Panel Preparations
• Prototype Polish
• Framework
• Decoder Boards
• Power Supply
• Joystick
• Motherboard and Power Bus
• Logo
• The Event
• Conclusion

Flippin' fluid simulations

For the last few years I've been building all kinds of fluid simulations, though the only things I've made videos about are the volumetric display and the fluid pendant.

While most of them are still secret (I'll publish them eventually) they all have a common deficit, that is, the LED liquid is utterly silent. I'd been wondering whether I could simulate some swishing noises when it occurred to me that an electromechanical display, such as flipdots, would make the noise for us. Realising that it would also make a great pun sealed the deal.

But flipdot displays are crazy expensive. From what I can gather, there's only one manufacturer still in existence, and they have exclusive deals with a small number of artistic studios. Breakfast Studio is probably the most well known, and they aren't interested in talking to anyone with a budget of less than $50,000.

By pure coincidence, at one point I did a bit of contract work for a company that happened to own a big flipdot display, and I tried to convince them to let me play with it. I genuinely offered to forfeit my salary in exchange for putting a fluid sim on their display, and to my astonishment they turned me down. I guess that sealed it: I would have to do it the hard way.

Path to some panels

Asking around, especially at hackercamps, led to a bunch of interesting conversations. A lot of people are interested in flipdots. There was even talk of forming a collective and ordering newly made flipdot panels from China. Surely if anyone can produce these displays for cheap, it's someone in China. But the manufacturing process is remarkably complicated. Even the disks themselves are a sandwich of maybe six different materials – here I've dismantled one of the disks I eventually used:

It's not as simple as just a coil moves a magnetic part. The dots are non-volatile, so they hold their position when the power is removed. There are two permanent magnets (one inside the dot, above, and one in the base) and two cores which can be polarised to set the state of the dot.

Some people I spoke to had some of the new flipdot displays from AlfaZeta, but most people had old ones from eBay almost exclusively manufactured by Hanover, who still exist but no longer make these types of displays.

Aside: a number of my projects have been copied by people in China. If, after publishing this, some company in China starts churning out cheap flipdot displays I think we'll call that a win.

Eventually I got in contact with Sam, aka Look Mum No Computer. His museum of obsolete technology has put him in the enviable position of occasionally receiving cool donations of weird old tech, and one of these donations was an enormous pile of old flipdot displays. It's unclear if they are reclaimed from old buses, or were new-old-stock. A lot of them are in pretty poor condition, but that may just be from how they were stored. Sam's plan was to turn them all into one huge display, but doing that would be a monumental amount of work, for reasons that will become clear in a moment. He was very happy to let me have a few panels to play with, with the promise of more if I could come up with a good way of driving them.

Here's one of the panels:

I kept this one for spare parts as it had some impact damage near the edge. At the top right I've managed to unsolder one group of dots.

The date code is 2007, which is younger than I expected.

The rear of the panel had a protective sheet, which I've removed here.

Note the resolution is 13 by 28. The dots on this panel were manufactured in groups of seven, which is where the 28 comes from. The 13 is probably a result of the designer's affinity for prime numbers.

Connect the dots

The number one problem with these panels is that the circuit board protrudes over the edges, which means we can't tile them seamlessly in that direction.

The number two problem is that the existing drive circuitry is quite slow, taking about one second to update the display. The whole panel is wired up as one big matrix, which puts a limit on how fast we can update it.

Sam was able to get a bunch of the panels working with their original drive circuits, first building an etch a sketch and then a bigger display using a few of the panels. He mentioned that at least one other person had got them working with the original circuitry as well. But building one very wide display isn't enough, we want to tile them vertically too!

The person who got furthest is Mike from mikeselectricstuff, and his flipdot video was extremely informative, acting as my primary reference on how the dots work. The most interesting point is that while it takes around 60 milliseconds for a dot to flip over, it only needs a very short pulse to polarise the cores, maybe a millisecond at most.

Longer and higher voltage pulses can get the dot to flip slightly faster, but not significantly. One thought is that by using higher voltages, we can use shorter pulses, which would let us scan through the matrix faster. Taken straight from Mike's video, the matrix layout is something like this:

To set the first dot, you'd set the first column either high or low, and then pulse the relevant row line. As I understand it, the original driver circuit would hold the column line in one state, pulse through each dot that needs to be set one way, then change the polarity of the column line and pulse all the remaining dots in the column, and then advance to the next column.

It may be possible to build a faster matrix by pulsing all of the dots in the column in just two goes. Hold the column line high, simultaneously pulse all the relevant rows, then hold the column low and pulse the others. If the pulses are one millisecond, we could potentially update all 28 columns in as little as 56 milliseconds, which is about as long as it takes for a dot to flip anyway.

There are two problems with this approach. One is that the power requirements are substantial. Each coil has a resistance of about 18 ohms, which would be 666mA at 12V. For faster pulses we might be looking at 15, 20 or 24V, with over an amp per coil. For these panels with just 13 rows, having a driver circuit which can push and pull 13 amps for every column is going to be tricky. The bigger panels would need even beefier parts.

We might be able to split it into multiple smaller matrices, but the next issue is that any matrix will have visible artefacts. Even though it takes tens of milliseconds for a dot to flip over, if different dots start flipping even slightly out of sync, there is a visual glitch as they progressively change. Even with small matrices of say 8x8, or even 4x4, when you flip the whole display, there would briefly be a kind of checkerboard as each matrix wipes over. For what I want to do, that's not acceptable.

Logically the next avenue to explore is desoldering all of the dots, and mounting them onto new circuit boards.