I used: - magnetic contact sensor: http://www.amazon.com/Magnetic-Sensor-Window-Warning-Switch/dp/B0050N7SM0 http://www.amazon.com/Magnetic-Sensor-Window-Warni

I used: - magnetic contact sensor: http://www.amazon.com/Magnetic-Sensor-Window-Warning-Switch/dp/B0050N7SM0 http://www.amazon.com/Magnetic-Sensor-Window-Warning-Switch/... - raspberry pi: http://www.raspberrypi.org/ http://www.raspberrypi.org/ Wired up all contact sensor and connect to gpio on pi. Use pi to detect circuit break and send messages or phone calls via google voice.