Solar Tracker

[DampRobot]

A while ago (for my 8th grade science fair project) I built a solar tracker with mechanical feedback.

It had two bimetallic coils (like you'd find in thermostats, that rotate when their temperature changes), mounted on a shaft and wound in the opposite directions. When the temperature of both coils changed, they just pushed against each other and didn't move the shaft. However, when one was heated, it would move the shaft in one direction (as long as the other wasn't heated too).

Then, I constructed shades that would only heat one of the coils if the sun was on one side of the tracker. Basically, it created a mechanical feedback loop, so that if the sun was on one side, one coil would get heated and the tracker would move to the side with the sun until the shades equally heated both coils, and the tracker reached equilibrium.

In the end, it worked pretty well, I saw 14% improvement over a flat mounted panel. All in all, it was a pretty cool project, and definitely different from what most kids built.