Many of the GPIO driven 8 relay controllers that I see out there already are opto-isolated, you just have to drive the input and provide a separate power supply for the relay board itself. Do you have a link for the boards you want to use?
Many of the GPIO driven 8 relay controllers that I see out there already are opto-isolated, you just have to drive the input and provide a separate power supply for the relay board itself. Do you have a link for the boards you want to use?