BEAM Trimet

Today, I made this little BEAM Trimet (a symet, short for symmetrical, would have 4 capacitors). It was featured in Volume 6 of Make Magazine. I got all the parts from Solarbotics. The Trimet link is here. It was a fairly intricate soldering job, but it works great. Attached also is a schematic that shows how the charge, trigger and discharge works for the voltage triggered 1381 based solar engine.

It was my first time to try "freeforming" which is soldering the componets directly to each other without a board. The solar cell is attached to the postive supply ring (a paperclip) will some tackless poster sticky. This lets it be removed to look at the circuit. The motor runs intermittently - charging the capacitors and dumping over and over. There is no on/off switch.

I left it sitting under a light most of the day just going around in circles. I love the idea of this little thing scooting in cirlces all alone by itself when no one is around.