RotoBall is coming along. I have figured out how to make the balls water-tight. The magnets are strong enough. The main problem I am having now is getting the balls t0 remain a constant distance away from each other. Because of the size difference of the balls in the lower segment, the inner ball has too much freedom. When the ball begins to move dynamically, the inner, floating ball shifts towards the side and the top ball slips down, allowing the magnets to get too close to one another. The result is a frozen sculpture, rather than a rolling ball. I tried using marbles as bearings to no avail. The best solution seems to be to find another ball that is in between the bottom two in size. It will create a buffer layer around the inner ball. Also, I could try using ball-bearings, fixed to the inside of the larger ball.
RotoBall Prototype 2February 25, 2008