Some gadgets are cool because they do something fun and quirky and are quickly thrown together from odds and ends that are lying around. Others are cool because they do something fun and quirky and involve a level of design and construction that can only be described as over the top. Today’s gadget has barely any electronics in it but plenty of laser cut plywood, linear bearings, gears, and timing belts. It definitely falls into the latter category.
In the same way that sunglasses from the 70s have staged a comeback, maybe it’s time for the video game Pong to have a renaissance. It’s already available for xbox and PS3, and now thanks to Dr. Who over at Evil Mad Scientist there is a tabletop version — this one a completely mechanical implementation with the exception of the paddles, which are solenoid driven.
In this version of the 1972 classic video game the knobs turn gears that drive a timing belts, which pull the solenoid operated paddles up and down the edge of the playing field. The paddles themselves incorporate a hinged section of PVC pipe that makes contact with the ball. A microswitch detects the contact, which results in an ATMega microcontroller energizing the solenoid, pushing the section of PVC up and out and propelling the ball across the playing field.
You may remember from the electronic version that the angle of the ball leaving the paddle depended on which part of the paddle it struck – hitting near the middle resulted in a mostly horizontal trajectory, hitting near the end a more vertical trajectory. The section of PVC used as the paddle surface cleverly reproduces this behavior.
The playing field is rounded out with two large number wheels that display the score. These wheels are hand operated. There are suggestions in the comments on how to automate score keeping, but I agree with the authors that an electronically operated display wouldn’t be true to the mechanical nature of the game. I would, however, suggest that a simple analog circuit would be a better choice for operating the paddles than the microcontroller.
Be sure to read the Wikipedia article on Pong, which is linked above. It covers the early history of Atari and has an entertaining story of how Pong came to be developed (It was originally an employment test given to a new employee).