Buckyball-moving machine by Dave Johnson
Here is a fantastic new kinetic piece by Dave Johnson, which advances spherical rare earth magnets (AKA Buckyballs) around a course using a variety of creative techniques and mechanisms. At one point, he uses the magnets' ability to form a chain to wind them up a dowel. Also, be sure to check out the clever use of the large plastic drywall anchor!
From the YouTube description:
This machine manipulates small spherical rare earth magnets, slicing one at a time from the end of a long chain, moving it around a bit, then dropping it back to re-connect at the tail end of the chain.
It also demonstrates a little snippet of science called eddy currents. Watch how slowly the magnet falls through the aluminum tube compared to falling through air: the falling magnet generates an electrical current in the tube, and that current in turn generates a magnetic field that opposes the movement of the magnet, slowing it down dramatically.
I used a plastic drywall anchor for the main screw drive that pulls the chain of magnets through the machine. The 2 other driven axles -- the slicer and and the lifter -- are geared directly to the screw drive. Steven Garrison's gear cutting method was invaluable to make the gears operate smoothly. The lifter is based on a standard four bar linkage (a film advance mechanism) but was modified to dip very low before lifting back up and stroking its straight vertical line at the top.
Dave Johnson points out that these magnets are currently a popular toy, and can be purchased on the web or in stores -- usually in a set of 216 (for a 6x6x6 cube). There are many different brands: Zen Magnets, Buckyballs, nano dots, NeoCube, and more.