Physical Computing Final: The Ferrofluid/Electromagnet Arduino/Servo Motor Disaster

Overview:
For my final project for Physical Computing, I attempted to create a device that would allow the user to control a sculpture via brain waves.  The device is comprised of a hacked Mindflex (a toy EEG) that,via a processing sketch and an Arduino microcontroller, controls a variable magnetic field, based upon the user’s level of concentration.  This magnetic field, in turn, alters the shape of a highly magnetizable fluid (ferrofluid).

Ferrofluid in a Magnetic Field:
Ferrofluid is a liquid suspension of iron nanoparticles that are small enough to remain suspended by Brownian motion (meaning, the iron does not separate easily from the suspension liquid).  This liquid becomes magnetized  in the presence of a magnetic field and a cone like pattern emerges in the fluid along the lines of the applied magnetic field:

As seen in this experiment performed by scientists at MIT, when confined to two dimensions and subjected to a variable magnetic field, ferrofluid takes on lesser known, otherworldly forms.


Process (What Not to Do):

Disassembled Mindflex

After reading fellow ITP student Eric Mika’s extremely helpful blog entry on his Mindflex hack, I cracked open the case to the Mindflex headset, loaded the Arduino brain library, connected my Arduino, and began reading data packets from the serial monitor.  The Mindflex toy works by sending the EEG readout from the headset to a receiver on the base, which in turn controls a variable DC voltage that regulates the speed of a fan.  I thought that if I could locate the variable DC voltage, I would be able to somehow connect it to an electromagnet to create a variable magnetic field. So, I cracked open the Mindflex base, which required removing many hidden screws and breaking plastic pieces.

I considered creating an electromagnet from scratch by winding magnetic (copper) wire around a soft iron core made of coat hanger pieces.

 

 

I scratched this idea when I found a pre-made electromagnet that was run by 2 6V batteries.

2 different Ferrofluid solutions

I had considerable difficulty working with ferrofluid.  Essentially, ferrofluid is both extremely messy and extremely sensitive to magnetic fields.

The combination is disastrous.  Ferrofluid will stain any container that you place it in (glass or acrylic) and find even the smallest of cracks in said container to leap through, when a magnetic field is near.  Placing the ferrofluid in an isopropyl alcohol/deionized water mixture is supposed to reduce the staining power of the ferrofluid.

However, in my experience, the mixture (even in varrying concentrations) alters the consistency of the ferrofluid (transforming it into a chunky metal suspension in water).  Ferrofluid is also very expensive and not so widely available.  Thinking that my first ferrofluid purchase might have been of  inferior quality, I ordered another bottle from a different company.

Unfortunately, the staining/consistency issues where repeated with the second batch.  Finding an airtight container was also an issue.  I sealed a petri dish with a hot glue gun in an attempt to replicate the 2D surface of ferrofluid used in the MIT experiments.  I am still cleaning the resulting mess from this experiment.

Weary of the effect of the strength of the electromagnet on such a unstable substance/contraption, I decided to switch to using a magnetic field created by servomotors and rare earth magnets.  The EEG readout from the headset (via a processing sketch and an arduino) controls the motion of a servo motor, which has a rare earth magnet attached to it.

The Future:
As it stands now, I have created a machine that succeeds in making a massive mess.  Over break, I hope to create some form of my original idea.  I’m hoping to find a way to fashion a leak proof container of ferrofluid made of a material that does not stain.

Animation: Schroedinger’s Cat

Seeing as it was my team’s time to present for Red’s Applications class, I decided to work by myself on this project, as I knew that my schedule would be wacky. I chose to animate Erwin Schroedinger’s famous thought experiment involving a cat and a steel box. I wanted to use Schroedinger’s actual words and wrote a brief introduction to lead up to it. Here is a translation (by Joseph M. Jauch) of the cat paradox published in 1935 (E. Schroedinger, Naturwiss. 48, 52)

A cat is placed in a steel chamber, together with the following hellish contraption…in a Geiger counter there is a tiny amount of radioactive substance, so tiny that *maybe* within an hour of one of the atoms decays, but equally probably none of them decays. If one decays then the counter triggers and via a relay activates a little hammer which breaks a container of cyanide.
If one has left this entire system for an hour, then one would say the cat is living if no atom has decayed. The first decay would have poisoned it. The wave function of the entire system would express this by containing equal parts of the living and dead cat.

This was my first time working with After Effects and even with a generous one-on-one tutoring session from Marianne, it took me a while to learn how to navigate the software. I also struggled with finding images to use, as I was hesitant to draw anything of my own. If I had more time, I would probably draw some of the elements, redo the voice over, make the clock hands move with time, have the cyanide bottle break, and add some more content to the beginning of the piece.

Video Project: Fratres

For this project, I worked with Lynn, Suvarchala, and Naliaka.  We all entered this project with very different ideas and it took some rehashing before we decided to create something that would express four unique experiences of four very different women with one common thread.  We borrowed a baby, 2 men, took over the Physical Computing bathroom and a playground, and spent eons filming, lighting, and laughing. We chose to make it a silent piece and used one of my favorite pieces, “Fratres” by Arvo Part, as the soundtrack.  It’s a bit…dramatic…but, we had a blast working together.

Fratres from Lynn Burke on Vimeo.