If you wanted to build a robot that chased light, you might start thinking about Raspberry Pis, cameras, and off-the-shelf computer vision systems. However, it needn’t be so complex. [Ed] of [Death ...

The robot, equipped with a solar panel -- like energy harvester and four wheels, is about the size of a penny, weighs as much as a raisin and can move about the length of a bus in an hour on a cloudy ...