Hi, my idea for a project is to have a workspace that is active when I'm around (computer powers up, lamps comes on, coffee brewing etc) and powers down when I leave. Ideally, for this to happen I need the sensor to pick up a presence as opposed to movement. I understand IR fails in this department. Also, a radius of say here to the coffee machine (i.e. 5m) should be regarded as a safe zone.
I was came cross heterodyne schematics and I was wondering if that would fit the bill ? Theremins kind of do what I want, they detect a presence. And I think the active radius should be scalable. Also, if I were to massively upset the signal by bringing my cell phone into the zone, hat would still work.
What do you guys think ?