Help understand what an Optically Isolated Input is?

I’ve been tinkering with the Sonoff basic esp8266 devices and they work pretty well for switching lamps etc.

I’ve been looking at the Sonoff 4CH which would let me switch 4 lights.
The issue I have is that there is no easy way to use physical switches on the wall to also switch the relay. I could solder some wires into the physical switches on the sonoff but I’d rather not operate on it too much.

I then found these which look promising… A little more expensive but I do see some input connectors. Can anyone say if this would help me achieve what I’m trying to do and that “Optically Isolated Inputs” could be used to wire in physical switches on the wall to activate the relays?

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You will need a small voltage source DC for opto couplers, these are LEDs with photo transistors, so you need 3V to 30V (and a resistor to limit the current to about 10mA each)

Okay so not a simple momentary open/close switch input then…

No, but as the hardware itself needs power supply (and there is a power output at the device) you could use this to feed the switches :wink: