I am currently building and installing a home automation system. I have currently configured centralized audio system with ceiling mounted speakers in each room with a raspberry pi in each room.
I want to now start controlling the Lights and possibly the wall sockets with these raspberry pi. I have found a lot of information about using mechanical relays to switch lights on and off, which is what I want to do. But I want to maintain the normal switching functionality.
One way I can do this is by interfacing each switch back to the raspberry pi and letting the mechanical relay do all the work. If possible i would like to avoid this.
What I am asking is there a way to configure the normal switch to function as a master, that not be affected by the relay state to switch the light on and off. Below is a diagram (not very good) to demonstrate what im talking about.