I just bought this IR-detector+lamp device: http://www.biltema.se/sv/Bygg/Belysning-och-lampor/Arbetslampa/Halogenstralkastare-med-IR-detektor-46191/
It turns the light on for a certain time when motion is detected. I want my Raspberry Pi to detect when there is a motion sensed by this device. What is the best way to achieve this? Can I have some sort of power measure device in the circuit(on the power cable) connected to the pi unit?
This could be expensive - I want a simple solution that is cheap as well.
What are my options?