How well can a PIR MS detect motion on the other side of a glass window?
- Thread starter NeverDie
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Window glass typically doesn't pass wavelengths over about 2.5 microns, and some some solar treated glass not over 1 micron. PIR detectors pick up body heat in the mid-IR spectrum from around 5 to 15 microns. So unless you get very very expensive special glass, which does exist, a PIR is not going to detect through it.
NeverDie
Senior Member
Interesting that some of these higher frequency devices can detect not just through windows but allegedly walls as well: https://solarbotics.com/product/35007/
Not sure how that one, which is around 10Ghz, compares to RCR, which is around 5Ghz.
How accurate (sensitive and specific) are these types of devices typically for detecting motion through walls? Sorry for the vague question, as I suppose it depends a loton the Tx power, but I'm just trying to get some feel for what's common.
Not sure how that one, which is around 10Ghz, compares to RCR, which is around 5Ghz.
How accurate (sensitive and specific) are these types of devices typically for detecting motion through walls? Sorry for the vague question, as I suppose it depends a loton the Tx power, but I'm just trying to get some feel for what's common.
TX power would normally be governed by the FCC with a maximum set by the license the manufacturer has. Frequency is mainly a function of what sort of rejection the receiver is going to be providing vs. background MW technologies being used in any given area.
I used a bunch of the first gen RCR detectors (GE) when they came out in an application where I was forced to upgrade some non-functional PE beams (flush mount duplex outlet style). I still have a bunch sitting in a milk crate in the garage. The later generations added the PIR and made them a "dualtec" type device. Just like everything else, adjustment is the key metric here. The GE units had a setting for range in feet, pretty accurate. 3rd party add on devices, you'd be on your own to figure all that out.
I used a bunch of the first gen RCR detectors (GE) when they came out in an application where I was forced to upgrade some non-functional PE beams (flush mount duplex outlet style). I still have a bunch sitting in a milk crate in the garage. The later generations added the PIR and made them a "dualtec" type device. Just like everything else, adjustment is the key metric here. The GE units had a setting for range in feet, pretty accurate. 3rd party add on devices, you'd be on your own to figure all that out.
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