Wireless Power Transfer

Now that the art grants for chromodynamics are out of the way [as well as the proof on concept, as demonstrated in the Night Market video], I’ve been looking to keep the momentum going with some other personal projects. As always, it’s a mix of wrapping up old projects and coming up with ideas for new ones.

I’ve been intrigued by several wireless ‘levitating’ lamps that I’ve seen. Most recently Crealev has come out with an entire line of levitating lamps, though Fiat Lux by Constance Guisset was the first levitating lamp design I saw, and the one that inspired me to build my own. I love the simplicity of appearance combined with the complexity of physics going on behind it. It’s really taken something that people have a hard time understanding (magnetism) and turns it into something beautiful.

In the past I’ve worked with magnetism to make a magnetic levitator. I think with a bit of work I could repurpose the old circuitry to suit this purpose. So the next trick is to figure out how to transmit power to a levitated object.

I decided to use a technique called resonant inductive coupling to transmit the power. I made two coils (each one with 8 turns wrapped around the same coffee mug), and slapped a 100 nF capacitor on each one to make the coil ring. The circuits should be identical in theory, so the same capacitor on each coil should give them identical resonant frequencies. I used a function generator to find the resonance (which was around 149 kHz), and was able to transmit power at about 36% efficiency. Not very good, but I did zero tuning of the circuits (by changing capacitors) to really match their resonant frequencies, and I didn’t look too hard for the optimal frequency (I could probably squeeze a few hundred more millivolts out of it by fine-tuning the frequencies). A video of my first test is below:

Wireless Power Transfer via resonant inductive coupling

Overall, I’d say a good job for an hour’s worth of work. The next trick will be to transfer power across non-identical coils — I’ll use a large ‘primary’ coil so transfer power as far as possible (the distance I can transfer power wireless is about equal to the diameter of the primary coil) and a small secondary coil to receive the coil (so I can fit the secondary inside the levitated object).

On the chromodynamics front, Rachel and I received a grant from the Council for the Arts” at MIT! The grant represented the majority of the funds for the project, so it looks like we’ll be able to get a dome and some more LED lights for it. I’m really excited to see how this goes!

For those of you attending Boston Decompression, I’ll be bringing Sandtrap and Chromodynamic Playground (with Rachel) to the event.


~ by asymptoticdesign on 1 November, 2011.

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