I am planning to put together a couple of Microchip PIC based boards in order to control outdoor lights, read PIR sensors, door state (open|closed|locked), temperature and mains supply in a shed/greenhouse.I want a PC-based interface for setting up, direct control and possibly (later) logging of readings from other sensors.
The sensors, relay outputs, etc will be on or directly connected to a board based around one of the 16F or 18F PICs. This will communicate with another board at "Indoor" end via ZigBee modules from Microchip. These are relatively easy to use - assuming you are familiar with micro-controller programming!
I was looking at basing the "Indoor" end around a PIC32 running a basic web server (connected via ethernet) which could then be accessed from wherever required. Then I found out about the Raspberry Pi!
It seems that a lightweight LAMP server will be WELL within it's capabilities and there's an SPI port ! It seems that a driver for the SPI is not yet done, but given the usefulness of SPI on a board like Raspberry Pi, I don't think that will be long being done - I would be willing have a go myself, although I'm far more familiar with micro-controllers than Linux.
There are Zigbee modules from several manufactures appearing and most seem to use SPI to talk to the processor (largely because it's pretty much standard on micro-controllers).
If anyone else who is thinking along these lines is interested in perhaps kicking about ideas for a set of common protocols (I know there are some already out there) that would allow for all the various functions that are controllable - irrespective of underlying comms i.e. effectively between the application 'layer' and the actual communication 'layer', maybe Raspberry Pi forums could be the place to open up this discussion?