(if this is off topic for this subforum let me know and I will post in "off topic")
Can I get an advice on what tech solution would be good to solve this:
I would like to make a motion detect interface, working similar to a touch interface.
Three adjacent areas that you can hoover your hand over to send an on/off message. It should work outside, in daylight and optimally through a glass window.
Maybe one could hack pir sensors to just detect a small area (10x10 cm)? Or would this be a job for ultrasonic sensors (not through a glass then)?