I working on a home (rather room) automation system using a Raspberry Pi as 'brain' and an Arduino as sensor board.
I find it quite difficult to come up with a solution to reliably track if a person is currently inside the room or not (to trigger the lights).
Here are my current ideas and what I think about them:
- PIR: only for movement detection, probably can't see when I'm sitting at my desk: would need to wave to the sensor every once in a while.
- Door counter: not reliable if someone decides to turn on his heels.
- camera: too difficult to program reliably.
- IR thermo array: probably the most reliable, but expensive for high resolution, not sure if something about 4x16 would be enough. [Edit] I have found that the Panasonic Grid Eye 8x8 thermopile sensor (~30$) is advertised by Panasonic themselves as that it could span a whole room and indicate the position of a person in the room. Even though I think that this won't work for the entire room, it will surely be enough to get a nice movement vector in the area of the door if someone enters or leaves the room (if the sensor is faced more to the door instead into the whole room).
- microwave sensor: haven't really found information about sensitivity in comparison to PIR.
Does anybody have some more ideas or thoughts on the ones listed above?