I've created a setup with which I can control my lights (and other electrical devices) from Google Calendar. One of the goals is to turn on the lights when I'm not home.
The linking pin is of course the Raspi: the Raspi gets the schedule from the Google Calendar agenda, and then sets the needed GPIO pins.
The setup needed soldering (connection between the Raspi and an existing Elro Home Control remote controller) and programming (python code to parse the Google Calendar and drive the GPIO pins).
See the explanation on http://eva-quirinius.blogspot.nl/2012/0 ... ights.html
Indication of the costs:
- Raspi: €42
- Elro set: €15
- a few transistors, a few resistors, a connector, a euroboard: €7
- some hours analyzing the Elro, soldering and programming
My next goal is to use my Raspi as a thermostat.