Automated foosball goalie

Jason Kozmic and Gabriel Ollinger built an automated foosball goalie.

 

(click on images to enlarge)

A laser bounces up an back across the playing field. A photodiode detects when the beam is broken by the ball. A computer times the series of beam interruptions, and determines the trajectory of the ball.
At the last moment, a servo motor moves the goalie into the path of the ball -- fast.
Click on the image to see a quicktime movie of the goalie in action.