I would like to measure a phase controlled 240Vac waveform as a digital PWM input for an arduino. The signal would look something like this:
My intent was to use a zener clipping circuit to limit the positive portion of the waveform to 5V, and measure that signal. However, I want to make sure I'm properly grounding these items. This is what my proposed circuit looks like, with all components inside a metal chassis.
I feel like ideally I would isolate this waveform from the system controller/light with a 1:1 transformer, but I'm unsure if that is feasible given its irregularity. Can I safely connect the arduino ground to the system's neutral, or am I barking up the wrong tree?