This particular set of robots were originally created for Burning Man, but it’s no surprise to me that they would tour around the more sciency venues of San Francisco. I’d never really considered a spherical robot before… but I guess it’s a “thing”. Go ahead! Google it!
Now to me, the easiest way to get a sphere moving would be to have a rod running through an axis of the ball and you roll around it using either weight or a gyroscope on whatever internal mechanism you’ve got driving. In this design you effectively have one HUGE wheel. These robots, however did not seem to do that. They were able to roll in arbitrary directions. They didn’t have to turn to change direction.
My initial gut feeling was, it used a pair of gyroscopes offset from each other by some angle. When the orientation of the two gyroscopes change, the sphere’s effective center of gravity would shift causing it to move. After doing some reading, though, it seems like that is not the case. A more likely scenario is… you have a large pendulum style structure which is moved around with a pair of solenoids. This apparatus is dangled from a stable platform. When the pendulum is pushed in a direction by the solenoids, the center of gravity shifts and the ball rolls. The amount that the pendulum can move the ball is proportional to the weight at the end of the pendulum.
All of this conjecture has lead me to conclude that I need to try it out. So… I’m off to learn a little bit of robotics. So… how does one get started in robotics? One dives right in!
My first goal will be to familiarize myself with the Arduino programming language and generally make myself comfortable with the tools involved.
There is some soldering involved. You can see in the above image, my new toys. The blue circuit board is the actual Arduino itself. Below the magnifier is an add-on board that will allow me to control two motors. (some assembly required). I have a 2nd add-on board coming which will have add a small LCD display. I’m sure that board will be the one I play with the most (At least at first).
Naturally, I had to try to put together the motor controls, but it seems like fate would have other plans… Look at what happened to my soldering pencil: