Articles you might want to read up on

http://en.wikipedia.org/wiki/Home_automation
http://www.nest.com/
http://en.wikipedia.org/wiki/Sensor
http://www.societyofrobots.com/sensors.shtml
http://www.detectors.saint-gobain.com/Plastic-Scintillator.aspx
http://en.wikipedia.org/wiki/Scintillator
http://www.grainger.com/Grainger/GARRETT-METAL-DETECTORS-Handheld-Metal-Detector-1ZRZ6
http://www.titech.com/specialist-sorting/organic-waste-separation-10710
http://arduino.cc/en/
http://processing.org/
Though not immediately relevant to this you can also check out this link to learn about some function generators :
http://www.youtube.com/watch?v=Q43jYypIYdA&feature=g-hist

Also to learn about any sort of hobby electronics :
www.afrotechmods.com 
--- Knock yourselves off..  :P

And as Einstein famously puts it : 
The secret to creativity is knowing how to hide your sources...