Early reports suggest a laser beam was to measure the speed of the wheel and the ball this data allowed a computer to predict roughly where the ball would settle...
I can't find it anywhere on the net now, but they had a tv show profiling some entrepreneur who made a automated stock buying and selling system. They became famous for making a roulette cheat that went in a shoe heel. They would tap the shoe when the ball got to certain points and it would calculate the speed and final landing point.