[Video Link] Here's MAKE's latest weekend project – two solar-powered BEAM bots. BEAM stands for Biology, Electronics, Aesthetics, and Mechanics. From Wikipedia: "This is a term that refers to a style of robotics that primarily uses simple analogue circuits, such as comparators, instead of a microprocessor in order to produce an unusually simple design (in comparison to traditional mobile robots) that trades flexibility for robustness and efficiency in performing the task for which it was designed."
The Solar Roller and Symet both use the same circuit design, dubbed "solar engine," named so for deriving its energy from solar light. With various technoscrap parts — we salvaged ours from an old micro-cassette player – and common components (transistors, resistors, LED, and capacitors) hooked up to a solar cell, you can build one of these little critters!
The Solar Roller move forward with bursts of energy, while the Symet spins around on its DC motor's axle. Watch the video above to see both these vehicle being built and in action, then head over to the project page to start making your own BEAM critters!