Physical Construction and Design
The table is entirely out of legos. There were two main reasons for this. First off, legos are the ultimate prototyping equipment. They are manufactured to a high degree of precision (.00798m+-0.000002m), have good mechanical properties, are easy to build with, and are not “consumed” by the prototyping process (or at least, not as long as you keep away from the glue bottle.).
Secondly, legos are cool. (There, I said it. Search your feelings, you know it be true.)
After physically building the table, the next question was how to measure the position of the ball. We considered many technologies, from resistive and/or conductive plates, such as touch screens, to laser tracking, and finally finished with a simple webcam. The webcam is cheap, flexible, and gives us, in theory, all the information we need to precisely measure the position and orientation of the ball.
There are advantages and disadvantages to every system, and others have chosen different technologies, but we stuck with the webcam. In any case, we work in an image analysis laboratory, so there are plenty of people around who can help us out when we're stuck.
The most recent version saw an upgrade to a $1200 IIDC industrial camera, but this is by no means necessary for basic versions.