barren berry
Asked without luck in a longer post.
Will a PIR motion sensor detect motion reflected in a glass window? I have a Hue outdoor motion sensor pointed directly at my front door that has a large window, and it consistently detects motion 4-8 feet behind the sensor, which is otherwise completely obscured to the sensor.
woeful zealot
Yesn't
Full answer: it depends on the wavelengths of light the PIR sensor actually uses, the chemistry of the glass in the window, exact angles and FoV etc.
Experimental answer: yes, it does for your particular arrangement
barren berry
In that case, placing the sensor in a corner at a 45 degree angle to the window so that any possible reflections would be from an adjacent wall should cut down on it sensing people walking behind it?
woeful zealot
Yup