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My daughter seems to be interested in robots so I set out to look for some sort of robot for her. Unfortunately there’s not a lot of stuff out there for a 3 year old. I figured that if nothing else I could build something and then let her play with it and tell her how it worked. I googled around for a bunch of stuff and eventually came across BEAM bots. They seemed nice and simple and interesting. I decided to order some solar panels from solarbotics and set out to build a trimet. I had just dismantled an old all in one radio, tape, cd player that was going in the garbage so I had managed to salvage a handful of motors from this. A trimet is real simple, you have a DC motor, you hook the solar panel up to some capacitors and then wire the capacitors to turn the motor on when they store up enough juice. It’s really a neat little thing. Here’s a picture of the guts of it all.


You can see the resistor, two transistors and the 1381 voltage detector underneath the solar panel. The body of the motor is used as ground for the circuit and then a paper clip ring is formed to be the postive rail. Then all the components hook up in the center and the solar panel on top. Here’s another shot of the trimet closed up.


The only thing I was really disappointed about was that there really hasn’t been a sunny enough day here to get the little thing going. It scoots around but not nearly as fast as if I just hooked up a straight 5v supply to it. I ordered up some extra solar panels so maybe I’ll make some other BEAM bots too.