Marble Adding Machine

Saw this Binary Marble Adding Machine on the Nuts and Volts site I posted about recently. I've watched the video several times now and am fascinated by the mechanical action.

Fun to show in a math class or a programming class. The author had this to say about how he designed the rockers.

"Also tricky was getting the rockers to consistently work. I spent a lot of time figuring out what dimensions to make them so that they would correctly work, even if two marbles arrive onto the rocker right on top of each other. I knew it was physically possible to build such a rocker, because the lego rockers I built into the original Lego marble machine had this property by a fluke. The trick turned out to be to make peak of the rocker, which divides the marbles, short enough, and the rocker shallow enough. That way, if a marble arrives before the rocker has had a chance to flip, the previous marble, which is still on the rocker, will deflect the next marble onto the other side, even if the rocker has not yet flipped. "

The web page has lots of closeup photos and design explanations.



[Image captured from http://woodgears.ca/marbleadd/]