Controlling Triac by Arduino

You'll also need to isolate your phase detection (zero crossing) circuit. For that, you can use a "regular" optoisolator, or a transformer. (In my circuit, I used the same transformer that was powering my microcontroller.)

Yes, I'll use a transformer for isolating the AC power source from the zero detection circuit. For detection, I'm trying with an ET1102 right now.
Let's see...