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The open-source solar panel that passively tracks the sun using nothing but water & gravity:
(lemmy.ml)
I thought this ingenious invention might interest some folk on here:
The SunSaluter is a solar panel rotator designed for the developing world. Using only the power of gravity with a water clock, the SunSaluter enables a solar panel to passively follow the sun throughout the day, boosting energy output by 30% and producing four liters of clean drinking water.
Only one axis. So only really useful near the equator?
You only need one axis for the daily movement (it's not horizontal except for the rare few days between the tropics but you can modify the design to use a slanted one). A manual yearly movement can be done by having the user move a lever to the next date mark when refilling the bottle every day.
I beg to differ. But one axis is definitely better than zero axes.
Earth rotation is, by definition, about a single axis. Therefore you only need one to track it. You are neglecting the possibility of an array normal that isn't perpendicular to the axis of rotation.