1 Using Optocouplers with the Raspberry Pi
Explains how an optocoupler isolates a Raspberry Pi from motors, pumps and other noisy loads; answerers recommend it as a clear account of how the part works.
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Explains how an optocoupler isolates a Raspberry Pi from motors, pumps and other noisy loads; answerers recommend it as a clear account of how the part works.
How To Mechatronics explains how to control a relay module from an Arduino, offered to people switching mains loads, though one commenter later preferred another resource.
Linked in answers about switching loads from a microcontroller, with one pointer to the part around 6:30 on optocouplers for electrical separation.
Linked with little comment as a possible way to switch loads, and also as a source for the schematic of a cheap optocoupler and MOSFET module.