Solar Track Rack

Here is the latest rotor (I've added another coupler and section of pipe to extend the T on the actual rack, I should have made the top pipe longer, but I can adjust it later)

The first pic shows most things broken out vertically but where they end up horizontally in the final assembly.

The motor is inside the thin walled "21 200" piece and is glued inside, and the pipe glued to the gear housing. That piece goes into the coupler on the right. The gear housing fits inside the larger T at the bottom (1-1/4 thru, 1 side) to the middle (bottom pic). The 1-1/4 tube holds the motor in from the left side, and the motor-cork goes inside the smaller and slightly longer pipe (fits into the 1" T or a coupler) which goes all the way to lightly sit on the motor housing.

I was trying to use a bolt with a hex head and grommet but it wouldn't quite fit right, so I switched to a (real) cork.

The coupler is held loosely by the T connector, but holds the bottom of the motor.

The larger pipe supports the smaller. I'm not using lubrication since it seems to work when clean. The T rotates around with the smaller pipe and sits on the housing, I drill a hole in the pipe into the coupler for the wires to come out. The assembled version is pic 3.

I needed to use a 1-1/8" cork, cut the top off, and drill a hole. And added some glue:

I should have updates shortly, but the main thing is you need to use PVC cement to prevent bending, sag, etc.

Although the panels were screwed to the joints, there was enough slop for them to sag bynhaving the pipes rotate.

Using PVC cement locked thempanels flat and stiff. Also fixed the base.

Still experimenting with the upright (and the screwdriver body fits loosely into a 1-1/4 coupler).

It is why fixed panels work so well, but also an advantage here. 8 degrees off only drops 1%, so for an hour, you still get 99%.

18 degrees, (about 2 1/2 hours) you are still at 95%. So some slip or error or sag will still give me most of the energy. It doesn't have to be precise.

But at 60 degrees off - you only get 50%, so if you have clear mornings, but cloudy mid-days you won't get most of the energy.

Also the tilt is part of the error. If you are pointing at your latitude, or below (you would want more in winter) this adds to the error.

http://www.grc.nasa.gov/WWW/K-12/airplane/tablcos.html

Oops. PVC pipe is sold with a little extra. "2 foot" precut is actually 25 1/8 inches. I also had to verify how deep it actually goes into the joints (11/16, elbow and T, 13/16 cube vertex - different brands probably vary more). So I have some recalculation to do for the upright, then some cutting

To open the MPJA screwdriver, push the two metal posts which are close to where it connects to the battery-motor (dark gray) body.

I'm also waiting for an H-bridge.

One expected problem now confirmed (so far not severe) is wind gusts moving the panels - it does. I was hoping for a pull-only design but might need push-pull.

Got the solar panels from Amazon, and some thin walled "one inch" PVC pipe, a section of 1-1/4", and various couplers, tees, crosses, elbows, etc.

The result is in the gallery. Self-tapping screws were used to attach the panels to the pipe (they flex so need support).

I might need to stiffen it or add some Kevlar thread to avoid the little bit of sag, but it works so far.

The central cross (could have been a T but I might put the actuator on top) has friction to each side to hold the solar angle (which only needs to be adjusted every few days at most), but going downward is a thick walled 1" PVC pipe that fits loosely inside the 1-1/4 so as to be the axle for the day rotation.

Next step is the tracker. Dollar Tree has "solar lights" (for $1 each) with a 1"x1" amorphous solar cell that should make a good sensor, and I have a number of AVRs but will probably use a Pololu A-Star and a battery powered (reversible) screwdriver.