PCB Electromagnet vs Ferrofluid

I made a 12-layer PCB Electromagnet to control Ferrofluid!

Tools I use: (some of these are affiliate links)

Social Media:

Time Makers:
00:00 - Intro
00:30 - Moving Magnet Idea
01:01 - Coil Stacking
01:51 - Thicker Copper
02:41 - Designing New PCBs
03:26 - Altium Ad
03:53 - PCBs Unboxing
04:08 - 12-layer 2oz PCB Coil Testing
05:03 - 4-layer 1oz PCB Coil Testing
05:39 - Ferrofluid Testing
06:31 - Electromagnets Comparison
07:06 - PCB Coil 12V Testing
07:45 - Ferrofluid Displays?

#electronics #ferrofluid #engineering

Music:
Sayonara - Blue Wednesday
All Stars - Patrick Patrikios (YouTube Audio library)
Staycation - Corbyn Kites (YouTube Audio library)
You Should - Patrick Patrikios (YouTube Audio library)

[AppliedProcrastination]

What a pleasure it was to collaborate with you on this project, Carl! The 12-layer coil was super impressive, and I can't wait to see where you take this design next!

[WalidIssa]

Use two coils with differential driving

[derarchitekt]

Is the glass-layer really needed between the fluid and the PCB? Choosing a Fluid/[Film]/PCB/Glass stackup could improve performance. It also would allow dissipating heat into the fluid, creating some sort of passive fluid-cooling. The circulation of the fluid through the change in the displayed image would further increase the distribution of heat inside the display (fluid). This in turn would allow for a higher voltage and hence result in increased performance.

Further ideas for improvement:
- Remove the need for a glass-back altogether and instead use the PCB directly as the backplate.
- Thermally couple the PCB with heatsinks using thermal-paste for even greater driving voltage (see channel "tech ingredients" for example on cheap thermal-paste).

[veloxsouth]

When that intro started all I got was *word sounds* piss see bee coils *word sounds*. I understood the second time, but this guy's excitement for his project was really showing.

[max_kl]

I think it'd make more sense to talk about current instead of voltage, since it's the current that causes the magnetic field. That should make the different coils more comparable

[etienne]

You could add a magnet that produces a magnetic field equal to what your coils can produce. Powering up your coil will double the magnetic field. Inverting the polarity of the power supply, will create an opposite magnetic field that will cancel the one from the magnet.

The main drawback is that your coil needs to be powered all the time (either in one polarity or another) and it could be a problem regarding their temperature...

[andershestad]

You could try to thermally couple the metal backing to the PCB with some thermal paste perhaps? If you're able to make the metal plate work as a large heat sink then you might be able to drive the magnet with a high voltage while keeping temps under control?

[DprintedLife]

This is great! Can't wait to see how far you take the design

[KX]

As I have previously commented, you could try running FlexAR at 300kHz where it's mostly acting as an inductor, rather than DC where it's mostly acting as a resistor, to lower the heat losses. The caveat to my claim being that I only use coils as inductors and transformers, not as electromagnets. If you look at the phase angle when you show the LCR meter, the 2 layer board has a phase angle of 0 at 1kHz so it's pretty much entirely resistive. The 12 layer board has a phase angle around 10 degrees so at least that's starting to get a little more inductive at 1kHz and the best inductive frequency for that would be much lower than the FlexAR, although still over 1kHz.

You could possibly try using the LCR meter to stimulate the coils at 1kHz, 10kHz, 100kHz and measuring the change in magnetic field strength between the frequencies on that other meter, although I'm not entirely sure how that particular LCR meter works, whether it is actually running at a simple single frequency as displayed or the waveform is more pulsatile/complex. Can't compare to putting a high DC current through them though as that's totally different than the low current stimulation from the LCR meter.

[Reptex_cs]

Adding ferromagnetic metal to the center will improve the magnetic field quite a bit. Or possibly a thin ferromagnetic disc between the coil and petri dish? Might work too.

[AdityaPrakash-ktrf]

Awesome collab Carl! And the new PCB coil has more green, which I always love!

[Culturedropout]

I always enjoy your videos because you're so methodical about your investigations, but are still excited and enthusiastic about your work. Watching you feels like watching science (or at least engineering) happening.

[dimitarnikolov]

I think you can design coils that go directly inside the ferrofluid mixture. That way the coils are both physically closer to the ferrofluid and water cooled. The solder mask would electrically isolate the windings from the wetter and the solder joints would be above the reservoir.

[Morgernstein]

Had the idea for trying to make a transformer from something similar to your pcb coils, just with a hole in the centre for an iron ring to be the core. Then to actually have a difference in turns you either use two different coil layouts or using two different coil pcb thicknesses

[kevinbissinger]

can you put the coils inside the tank so the liquid keeps it cool?

[Jandodev]

This is amazing! I strive one day to make pcbs like you!

[jasontemlett]

The moment when you pop onto YouTube and somebody's busy working on the exact same project as you are

[Roobotics]

Maybe route out a hole in the center for an iron slug to seat into? Now that you are trying to make one magnet instead of a PCB motor for this project.

[immernochanders]

you could make a pcb thatr ataches at the back to an heatsink that you can cool with a fan or just make it big enough that it can disipate the heat. with this method, you could potentialy run the pcbs at a higher voltage.

[MegaBlackJoe]

Hi Carl, can you make a video on smd connectors for flexible PCBs?