I thought I d share with the arduino community for the benefit of others my latest project: A remotely controlled mains socket designed for easy integration to existing home automation systems.
It can be controlled with either RS485, WiFI or PLC (Power Line Carrier) over existing electrical wires.
The PLC option is limited to a max of 1200bps but it is adequate for the needs of control.
RS485 comms are common to building automation systems. The RS485 chip is on the other side of the PCB. I ve chosen the MAX3085 which supports multiple RS485 tranceivers on the same bus. So you can have a number of these devices daisy chained together. An rj45 socket is used to connect to the RS485 network over CAT5.
I am now developing the code which is designed to automatically detect and switch over to whichever transport medium is available (RS485,WIFI or PLC). One of these devices with access to all three trasports acts as a gateway and passes communication signals to the rest of the devices/ sockets.