I need to make a isolated switch.
The problem is that I don’t have any power on the switch side, and they can’t be grounded together.
The idea I had was to have a tiny AVR to switch a small transformer with a serial resistor. And then put the other side of the resistor to an ADC.
So now if I short the sec. side of the transformer (my switch) ADC readings will change. (to avoid making noise I will probably rectify my switch side.)
Are there a better way to do this ?
I know that I need some protection diodes etc.