Capebuild wrote:Hi Tim. Just saw your post.
... but good luck!
John
Hey John, thanks for the input. I've been spending a good deal of time researching as the temp this morning was 11F with a wind chill of -6F. Spring is not making much headway this week!
I kind of understand what you're getting at. I was just looking at a YouTube video of a drive system a guy built. It gives me some additional ideas for gearing and idler pulleys.
https://www.youtube.com/watch?v=qLJ4XSAUR2U&t=2sHe used a 3D printer drive pulley on his gearmotor rig. It might be a good start for me though in just a few minutes of searching I don't see any of that type of toothed pulley near the number of teeth you are describing for the final output. Not to say a drive belt like that won't work on a homemade pulley of some sort. He is also turning a flexible PV panel and very light weight frame with a 12v gear motor. The control board I have coming only operates at 5 to 5.5 volt and the gearmotor is a 6 volt.
I don't know how RPM of the motor will effect the outcome of this. I'm not looking for speed of rotation as being an issue. If it takes one second to turn the panel a degree or two vs five seconds I don't think it matters much. Once I have the board and motor in hand I can experiment with what it will do and like you mentioned, try to design a system with the final output gear attached to the table to mount the panel. I think you are spot on that the final can be big enough to hold the panel in place even though the final pulley, sprocket, whatever attached to said table can be considerably smaller than the table.
From the little bit of reading I've done so far it seems the critical issue for this type of drive is it shaking back and forth. In other words if the inertia takes the panel too far the brains compensates by reversing immediately and then if that move over compensates the other direction another cycle starts. The manufacture says to remedy that scenario by angling the sun sensors away from perpendicular to the panel to. Basically trial and error until it behaves.
BTW, when I say "table" I just mean some sort of rotating surface or frame that the PV panel will mount to. The rotation probably only needs 90 degrees of travel for my purposes. Let's say southeast to southwest. After that in most locations trees or other obstructions will block direct sunlight.