Another impulsive buy from Fry’s:
(Got to stop doing that).
Initially I thought that this thing was running on electromagnetism, but upon closer inspection it seems not to be true – most of the power consumed by the unit is going to the LEDs. The bulk of the “work” (and I use that term loosely) is being done by permanent magnets.
It looks like there is a large circular ferrite magnet in the base and a small Ne magnet in the globe. The arrangement alone creates a small “well” in the magnetic field that the Ne magnet can sit in*. The dimensions and center of gravity of the globe’s internal weight stop it from flipping over.
The equilibrium position is very small, so the device is assisted by four small electromagnets inside the main ring. These constantly monitor and adjust the field strength to keep the device inside the equilibrium point.
At some point I’m going to have to make some field detectors and scope out the behaviour of the 4 electromagnets.
How well would run with a Rodin coil?
* This was only a hunch, and there’s been some debate over on Reddit:electronics about whether this really is correct.