This gear train provides a 512-to-1 reduction in speed, so the cam spins at about 1 rpm.
Many different types of sprinklers use water power in the same way. Some are jet-powered rather than turbine-powered, but they are all using the force of moving water to create linear or rotational motion. In theory, you could create a little water-turbine electrical generator and attach it to your hose to create several watts of power -- you could power a flashlight bulb while you water your lawn at night!
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