Every week I seem to be writing about how someone has used an Arduino to fashion an interesting gadget, and today's - while not as obviously useful as, say a Pong-playing wristwatch - is still impressive. Using an Arduino, a Hall effect sensor and an electromagnet, the microprocessor board can keep a floating magnet perfectly positioned.
Video demos after the cut
The Hall effect sensor monitors the field of the permanent magnet and uses that information to modulate the magnetic field of the electromagnet, with everything being crunched by the Arduino. It's basically keeping the magnet dangling by pulling it upward at varying rates, changing the power according to the changing magnetic field.
So far the smaller magnet can be kept hovering for a few minutes, while the larger magnetic dart can be maintained seemingly indefinitely. They'll stay perfectly positioned no matter what passes between them and the electromagnet.
[via Hack N Mod]