Solar Tracker

Check Mother Earth News for good solar trackers. I saw a great one there long ago. It was two freon tanks set up so if one got hot, the freon would expand and move to the other one, shifting weight, and moving the solar array.

Another one was using photocontrollers, like for night lights. Two were set up so a motor would move the array until one of the controllers saw the sun.

Both were very simple, elegant devices.

A 24-hour clock drive (telescope equatorial mount) might serve as a good starting point.