So I am a google programmer getting interested in hardware hacking.
What I want to do: Use Arduino or a similar microcontroller to control the lighting in my house, of course for as cheap as humanly possible.
Proposed Method: Using the power line itself for the communication (similar to ethernet over AC). A base station would be plugged into one power outlet in the house, that would send signals to N number of microcontrollers which are plugged into other power outlets. The communication between the devices needs to be very simple. Sending a packet containing the UID of the microcontroller to trigger, and command code (on/off). This command would trigger a relay to switch the power current on/off.
Reason for Proposed Method: Most devices that do this use Wifi. Which having a Wifi device on every outlet would be very, very expensive. Having the base station only be Wifi would decrease costs tremendously.