This is a six- sided solar motor. I had 50ea. 2" x 2" solar cells from China, and wanted to use some of them for a project. I also had all the other parts, so why not?
I originally though of making a Mendicino type motor because I already made one. But those motors use magnets to suspend the rotor, and if the rotor is out of balance, the motor will wobble enough for the magnetic bearings to jump out of position and the motor fails to rotate further.
The hex motor uses bearings making it easier to run. The coils and pulsing circuit rotate with the solar cells, and the magnet is stationary, glued to a fixed axle shaft supported by a plywood base. I used a clear acrylic tube as part of the support, this helps show how it is constructed, but isn't required; a 3/4" schedule 40 PVC pipe (for US sprinkler systems) would work as well.
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Step 1: Parts
2" x 2" solar cells, 6 ea, AliExpress (50 cells for $10.50)
5/8"d x 1/8"id x 58" L , diametrically magnetized ring magnet, 1 ea. K&J Magnetics ($6.30)
1/8" x 6" music wire, hardware store ($3.00 for 3 feet)
3/8" x 1/8" ball bearing, 2 ea., Ebay ($5.65 for 5 ea.)
3/16" balsa sheet, hobby store ($3.00)
1/8" basswood plywood, hobby store ($4.00)
#26 awg copper magnet wire Ebay ($6.00)
5/8" id vinyl tube, Lowes hardware ($1.00)
3/8" id vinyl tube, Lowes hardware ($1.00)
1/2" id vinyl tube, Lowes hardware ($1.00)
3/8" brass tubing, hobby store ($3.50)
1/4" wood dowels ($2.50)
Tools and extras:
Hot melt glue gun (for tacking things together)
Soldering iron, solder
Heat shrink tubing or electrical tape
Drill and 1/8" drill bit
Step 2: Construction
Cut the 3/4" pipe to about 4" long, and cut the 1/8" axle about 4.5" long. Use a file to reduce the axle diameter slightly to fit the 1/8" id bearings on both ends- one end of the axle will have about 1.5" long area reduced (at the bottom of the shaft) so the shaft can extend down into the plywood base, and have the bearing inside the pipe. Use the 3 different sizes of vinyl tube and 3/8" brass tube to hold the 3/8" bearing inside the pipe. Glue the magnet to the shaft, and install the bottom bearing and vinyl inside the pipe.
Make a hexagonal paper template geometry with 2.1" sides with a 3/4" central hole, then use an Exacto knife with the template to cut 2 ea. balsa top and bottom pieces to slide over the acrylic pipe. Cut 4 ea. 1/4" x 2.5" wood dowel spacers to separate the top and bottom pieces. Wind 2 ea. coils with #26 awg enamel wire, the coils can be wound using a couple of fender washers threaded onto a 1/4 x 20 screw chucked to a cordless drill per my other instructable https://www.instructables.com/id/Solar-Motor/ The coils are about 1" diameter and 1/2" thick each, no need to count turns as it isn't critical. I covered these coils with epoxy once i removed them from the winding tool, then sandwiched them between a couple of 2" square Teflon sheets (1 mm thick) and put a weight on them until the epoxy dried. The Teflon does not stick at all to the epoxy, and the result is a nice looking coil.
Test the coils so the coil faces that will be placed on either side of the pipe produce a north field on one face and a south field on the other face while attached in series with a 3 volt battery. Check with a compass. This is so that the magnet, one side which is north, and the other side south, can be attracted to the coils with correct orientation when powered. Solder them in series, marking the sides that will be placed against the pipe. Glue the dowel spacers to the top and bottom balsa pieces arranged with the coils against the pipe.
Make the removable solar cell outer shell (place to attach solar cells):
Place an additional 6 balsa rectangles against the sides of the top and bottom hexagons, making them slightly wider to allow for beveling the edges so they fit nicely around the top and bottom hexagons. Use a drop of hot melt glue to hold the rectangles temporarily, then use epoxy plus a string to hold them while the glue dries. The rectangles should not be glued to the top and bottom balsa hexagons. Cut a larger basswood plywood hexagon with 3/4" hole at the center to cover the top of the rectangles; glue with epoxy and place a weight on top while glue dries. Cut 6 rectangular holes for the wires from the solar cells to fit through. Solder flexible color coded (red = +, black = -) wires to the fragile solar cells and thread through the rectangular holes- the solar cells should be able to lie flat. Insert the wires though the rectangular holes and epoxy the solar cells to the balsa wood. Use white copy paper to position cells, but apply only gentle pressure to avoid cracking the cells. Wire the solar cells in series, and test that 3 volts or more is obtained in sunlight. Insulate wires with electrical tape or heat shrink tubing.
Make or buy the simple electronic trigger circuit per Solarbotics . Solder the supply and coils to the trigger circuit. Place the trigger circuit near the coils, use hot glue to secure. Place an equivalent weight on the opposite side to balance. You can trim the top balsa hex smaller to allow wires from the solar panel to reach the coils and trigger circuit, as the top basswood plywood hex holds the cells in position on the top. The bottom balsa hex keeps the solar cell assembly centered on the bottom.
Step 3: Testing and Results
The solar motor works well, turning 200 to 500 rpm in sunlight. It requires a spin to get it started, and will run either direction equally well. The motor even runs in the shade of our patio, but can't run indoors. The motor makes a interesting sharp clicking sound one per revolution, but is not related to something rubbing or dragging. It makes the same sound when configured as a pendulum, so who knows?