Here is a heliostat project that was shared with me via email by its creator, David. Some of the code he wrote for this project was made possible by referencing the code in the Arduino Sun Harvester program. Very cool!
This heliostat uses a friction drive for motion and an encoder to keep track of its position in case it accidentally moves due to outside forces. This friction drive doesn’t lock the heliostat into position like a wormgear or linear actuator does, but it is cheaper and somewhat less complicated to build. Clever idea!
More videos of both this heliostat and a solar tracker can be found on his YouTube channel Nova Solar.