Can This Collaboration Replace Bulky Electromagnets in Ferrofluid Displays with PCB Magnets?

The first collaboration between Simen Sørensen of Applied Procrastination and Carl Bugeja offers some promising progress with ferrofluid and magnetic PCB actuators. With their combined talents, they have demonstrated you can manipulate ferrofluid with PCB-based electromagnets.

Applied Procrastination's Fetch

Applied Procrastination is probably best known for Fetch. It is a large display built around a tank filled with a liquid ferroelectric material called ferrofluid. Magnetic fields attract ferrofluid with an alien-like movement. Behind the tank are 252 Arduino-controlled electromagnets that form a 12 by 21-pixel resolution screen.

Without any doubt, watching Fetch operate is mesmerizing. However, it took an oddly satisfying yet difficult to debug mess of wires connecting to the electromagnet matrix to make it all possible. A dream solution would use a PCB of electromagnets instead of discretely wired devices.

Enter Carl Bugeja.

Bugeja's Actuators

We have written about Bugeja's work in the past. He is well known for creating actuators, or small motors, using flexible PCB materials. These often find their way into robots, like FlexBot. (Check out Bugeja's projects or past stories.)

In the past, Bugeja attempted to control ferrofluid with a flexible PCB electromagnet but found they were too weak. However, his most recent project focused on making a stronger PCB-based magnet. This new design is a rigid 12-layer board. In addition, Bugeja found adding a piece of iron to the assembly provided at least two benefits.

First, there are fewer turns necessary to get a larger magnetic field. This improvement is vital since PCBs have a limit to their number of layers. Second, the iron acts as a heat sink. Sinking the heat means being able to drive the coils even harder.

The hope from both Applied Procrastination and Bugeja was that this new actuator design would be strong enough for ferrofluid.

The Result

The good news? Bugeja's 12-layer PCB magnet can attract and control ferrofluid! The bad news, it still is not as strong as physical magnets. So, for Fetch, these magnets will not solve the wiring problem since they cannot lift the fluid to the top of the tank. But, Sørensen sees strong potential for a smaller, more compact display based on the PCB magnets.

Both sides of the collaboration have many more details. The video by Applied Procrastination shows their experiments with various magnet designs. And on Carl Bugeja's channel, he has a video on the 12-layer PCB design process.