I just read an article at linux journal about smart homes
now, I had no previous experience with smart homes and it sounded intriguing so I gave it a look
the story is simple, you have one master device (actually a wifi router with probably some logic) and a bunch of small devices for various things like dimming lights, turning them on/off, controlling garage door, room movement, security cameras etc.
they work just by plugging it in the socket since it uses wifi for communication
there are also some other details but read that yourself