Hi, first of all clarify that I am a simple electronic enthusiast. Well the query is that I want to light from my arduino the light of the dining room of my house for example. The circuit in protoboar I have tried it without any problem, but the doubts I have because in the protoboar the alternating current I take out of a socket, but in the box of the wall switch I find a cable with the phase and in the another the return that goes towards the ceiling lamp, where already has the neutral, How do I connect the triac to those cables? I hope you have understood my doubt and thank you very much.