The Steel Ball Table - Click To see Youtube video Demo
Steel Ball Positional Placement Table

This is a 7x5 inch table that a steel ball rests upon and is positioned using closed loop servo control techniques.   

The ball sits upon a X-Y resistive panel and an Arduino microcomputer allows the steel ball to be positioned to a given X-Y placement.   You may or may not know it but to get a ball to rest on any given position requires closed loop control code such as is used in this project.

The demo video shows the ball roll in a square pattern as the setpoints are changed from
the program automatically.  Any sort of slow movement is possible using this code.
Mark-World - Tech Projects To Amuse The Curious
Steel Ball Table