I once saw a very elegant solar tracking mechanism with no moving parts. The panel array was hinged to swivel freely. 2 solid tanks sat below the fore and aft e

I once saw a very elegant solar tracking mechanism with no moving parts. The panel array was hinged to swivel freely. 2 solid tanks sat below the fore and aft edges, and were connected by a solid copper tube. As the sun moved though the sky, if one tank got more light, a working fluid would move from one to the other moving the center of mass. This caused the panel to swing to bringing them back into equilibrium.