Update: This project is out of date. Check out the Heliostat Projects page for the latest version of the heliostat design.
Here is my first decent sized heliostat. It consists of one 2′ x 3′ mirror which can be rotated around almost 360 degrees for both the altitude and azimuth.
It is based on a gimbal design which seems to be working quite well. (Update: Nevermind. To be honest, this one never really worked quite right. I had assumed that the problem was with the shaky stand because, as the machine’s altitude increased, the weight of the mirror would cause it to shift off balance. It turns out though that the second prototype also didn’t work right. I don’t know if the problems were in any way related, but I personally have decided not to use this design. Check the more recent prototypes for a few other reasons why I made the switch.)
This is still only a prototype though, and I need to work out a few bugs before I can make the plans for putting one together.
In the mean time though, I will at least show off what I have so far.
How Does it Move?
This heliostat moves by using two worm gears. Since I was unable to find any available for purchase, I had to make them myself. Actually, that’s a lie. I was able to find some for sale online. The problem though was that they would have cost $200 each, which is much too expensive.
My goal is to build a heliostat for as inexpensively as possible so that other people won’t be afraid to try and build their own because of the cost.
If you’re interested, I do have some information on how the worm gears were put together which is on the page How to Make a Single Turn Worm Gear with a CNC.
I made the worm gears for this prototype with a CNC machine; however, the final version of the heliostat will only require basic power tools to be put together, so don’t worry if you don’t have one.
The wood I used is not treated, so I painted it to keep it from rotting. I chose green because it blends in well with the surrounding environment. If you look at the picture, the mirror seems as though it is almost invisible. From a distance, you might have a hard time seeing that the heliostat is even there.
I still haven’t weather proofed the stepper motors and worm gears yet. I might just hold off until I make the next version before I go to the trouble. For the time being, I’ve just been covering them up with trash bags when I’m not using it.
The stand that I built for this heliostat is only temporary. When I make the final one, it will be held up with posts set into the ground. As it is right now, it isn’t very stable because finding a way to brace it without interfering with the movement of the heliostat is difficult because of the way I built it.
Pictures of it in Action