Hungry Hungry (Robo) Hippos

Perhaps you remember playing a game called Hungry Hungry Hippos as a kid (or adult). I would suppose that this game would be fairly easy to automate, as when played by humans it generally consists of punching the “eat” lever over and over as fast as you can until all of the balls are gone. Michael Kohn, however, after failing to get his coworkers to play this classic board game with him, chose to program the hippos to play with him automatically.

Making this story even sadder/more awesome is that he eventually decided to let it play by itself, not even making the effort to play with his new robotic friend. What makes his approach different than human players is that his hippos attempt to eat the marbles intelligently, instead the normal lever!-lever!-lever!-lever! method of play.

The system tracks the marble or marbles rolling around in the circular arena with a Sony Playstation 3 camera, and a simple C++ image processing routine running on a notebook. A W65C265SXB board uses this data to intelligently control servos hooked up to each of the four hippos’ mouth levers via a string.

To top this project off, Kohn also integrated control using Alexa and Electric Imp. He’s now able to voice control the different hippos to attempt to eat a marble, which obediently bite and reply via an Amazon Echo Dot with an audible “yum” whether or not the small sphere was eaten.