As soon as I became interested in solar trackers, I quickly realized that what was needed was a cheap practical mount. The Wright brothers and many others have been inspired by bicycle mechanisms. One day I happened to glance at a bunch of old bikes, and I suddenly saw a vision of the bike upside down with a moving panel on the front forks. The bicycle frame becomes what an astronomer would call an Alt-Az mount because it rotates about the horizontal axis (altitude) and the vertical axis (azimuth). The handle bar is a perfect example of a control arm designed to rotate a shaft to a desired angle. While the azimuth axis is practically ready-built, the altitude axis and panel frame require some basic fabrication.
I wanted to design a tracker that was practical and durable, with a good chance of surviving a bad storm. The use of satellite dish linear actuators, which have already been designed to withstand outdoor weather, is a key factor in achieving this goal. One of my design criteria was to make it so that the average skilled person, anywhere on the globe, could fabricate the frame. With the exception of the welding, all the work can be done with basic hand tools including a drill and an angle grinder, and except for the linear actuators and electronics, all parts and supplies should be locally available.
The dual axis bicycle frame solar tracker is well suited for a variety of purposes. Mounted at the correct angle, it becomes a polar mount. Besides PV panels it may also be used with small parabolic dishes or fresnel lenses. With a mirror frame adapted, it can also serve as a heliostat.
Materials cost lest than $100, and professional welding should also cost less than $100. Dual single-axis tracking controllers and linear actuators add about $200, or a digital controller and actators would be about $300 additional. So for as little as $200-$400 you could have a single-axis solar tracker, or for $300-$500 you can have a great little dual-axis solar tracker. A really skilled person could probably finish the frame in about 8 hours, or you can stretch it out over a couple weekends. At any rate, it's not hard to build, and hopefully you'll enjoy the results for years to come.