IRA-S210ST01 PIR sensor can still work through the glass cover?

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Joined Nov 14, 2020
Does anyone know if the IRA-S210ST01 PIR sensor can still work through the glass cover?
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Joined Oct 8, 2019
It should work. A while back I used a different type of IR sensor. It was an IR emitter and detector in the same package mounted on a pair of eyeglasses to detect eye movement. The glass did not affect the sensitivity.
As far as I know, - through the glas (not plastic) not at all, because PIRs detect the body temperature, and the glas is opaque for the IR wave lengthes below 100^C. I am not sure, but recall a "myth busters" video, if it were possible to hide behind a glas panel from the PIR detectors of the alarm systems, and it worked.


Joined Dec 4, 2015
Yes, I'll second ColdWeather's advice.
Certainly the PIR sensors used in alarm systems do not trigger if the subject is behind a single sheet of 4-mm window glass.
The "cover" on PIR motion sensors is normally thin polypropylene or polyethylene moulded as a Fresnel type lens.
If the sensor did trigger through glass, every local cat would set it off.
One external PIR sensor sensor I have, with plastic lens, will pick up objects as small as a rat at 5 or 6 metres.


Joined Jan 29, 2010
If the PIR sensor is fitted with an IR emitter for night work, the glass will give a problem.
I have found that the glass reflects a highish level of IR back into the PIR and reduces the detection sensitivity,

If you use a night IR camera with IR emitter, the reflected IR from the glass washes out the night image on the camera.