Home Automation update

I've been looking for a home automation system that will (a) be very
low power so I can justify it for just one light and turning the
wirless network on and off, and (b) can be controlled from my mobile
phone.



There are several very basic systems that satisfy (a); only just found
a system which satisfies (b), which is the Pluto home system.


Bad news: it requires an always-on Linux server, so is almost certainly more power hungry than the network;

Good news: if you don't want their hardware, you can get the software
for free, as an open source project! Hmmm... pretty sure I can scare up
a Linux server from somewhere...