Wearable, solar-powered, motorized earrings.
In direct sun, they twirl vigorously, spinning back and forth at about 60 rpm. In outdoor shade they twirl less often. Indoors, they require bright, gallery light (1000 lux) and then they twirl every minute or so.
Best with short hair. They could get tangled in wisps of hair. Not powerful enough to hurt you.
Solar Earring
The prototype, 2015
Four solar cells in series. Solar cells are photodiodes, which are inefficient when used as solar cells. Produces about 1.2V.
Since the solar cells are wrapped around the circuit board, some are shaded.
Solar Earring II
Next version, 2016.
Easy to make because the solar cells can be reflow soldered (except I don’t, since there are components on both sides. You could glue the solar cells onto the pasted pads, and then reflow.)
Since only three cells in series, produces less voltage. All solar cells are in the same plane so usually none are shaded. Thus, loosely speaking, it requires the same light as the first earring.
Solar Origami Earring
Made from folded, flexible printed circuit board.
Four solar cells in series. You can trace out the series circuit through the solar cells in the image of the PCB.
A Hackaday project. You can find more information there. You could even build your own, I shared the board design files.
The flexible plastic PCB is about five times more expensive than the ordinary fiberglas PCB. About six dollars each. Partly because you must pay for the bounding rectangle of the board, so the cross shape of this board has much wasted space that you pay for.
The PCB before and after folding. The components end up on the bottom.
