I wonder if anyone has any tips about detecting the movement of a hand a few inches away from a sensor? I want to send a midi signal controlled by hand - I have the midi side of things working, but most cheap PIR detectors seem to operate at 3m or more. I also need this to function in low light (on stage) or in normal light. I've checked other projects here, they don't quite fit the bill.
IR sensors, example : Search Results for sharp - SparkFun Electronics
Than, you can filter in software min, max, speed of distance changing
You could prototype something like the proximity sensors in smartphones - get a 38kHz IR detector, with a 38kHz emitter next to it, but shaded from direct illumination and both pointing outward.