need some help with motion sensor placement

[shenandoah75]

I have 3 detectors to use in the following app... My original plan was one in the office in the top left corner between window/doors so it wasn't visible, two in the garage wired in series so both had to fire to trip an alarm (reducing false alarms due to motion outside one of the two windows)... Ceiling are 8'...

However, based on some threads i've been reading it's better to have the detectors sense across/towards rather than away. So on the office side, thinking the bottom right corner would be better, only thing is that i have book shelves along that wall. If i put the dectector way up almost in the coner at the ceiling, it would probably clear/cover, but i think 6' is ideal. (Note Compressor is not really in that location (out to the left a little) - bookshelves line the right wall instead - and the big rectangle at top left is a couch)

For the shop, was thinking the upper left/right corners. I don't think i can get perfect results anywhere in here because the tools/bench, etc are everywhere and block a lot of things, but would like to do something...

Any tips, appreciated...

thx in advance
-brad


FYI: dectectors are Napco C-100STE20's - i currently have no window coverings at all...

Also, I may be able (and pln to) to put some hardwired contacts on the doors... Windows would likely have to be wireless though.

 

[rfdesq]

My original plan was one in the office in the top left corner between window/doors so it wasn't visible, two in the garage wired in series so both had to fire to trip an alarm (reducing false alarms due to motion outside one of the two windows)

General rule of thumb I use, PIR's get mounted in corners for the best coverage. Regarding your wiring your PIR's in series, I think that is a bad idea. They would both have to be firing at the same time for an alarm to activate. I can't remember your panel but if you have an ELK I would use the cross zone option for the PIR's.

 

[shenandoah75]

Well i guess my main concern is the potential that wind/moving bushes,rain, squirrels, ect outside any of the windows could set off an alarm...

Indeed have the elk... just read up on cross zone... i like that better for sure...

That said, am i ok putting the single office unit in the corner next to door/window based on prior "cross/towards" feedback or will the "cross/away" still work?

thx again
-brad

 

[rfdesq]

For the office I like the top left of the picture inside the double doors. That way it won't see the window but will see someone coming through it. The other option is top right if you want the PIR to see the hallway also when the double doors are open.

 

[TCassio]

I don't think that motion outside you windows will trip your MS. I beleive they work on heat (change of temp).

 

[R1PLUS]

I don't think that motion outside you windows will trip your MS. I beleive they work on heat (change of temp).

The C-100STE is a dual technology detector. The PIR portion can not see through glass. However, sources that cause PIR's to false alarm can come from or through the glass. Therefore, do not have it look at glass. The microwave portion does see through glass, as well as most anything else. So take care to be aware of what is beyond the walls because it can keep the microwave portion in alarm and you are then relying solely on the PIR detector.

You should not need to do any thing in the garage except a single detector. Unless of course, one detector does not cover the area completely.The dual technologies should be fine there. As suggested before, cross-zoning will give an added measure of reliability.


As far as mounting height is concerned, follow the manufactureres guidelines.

Infrared detectors are better suited to "catch" an intruder walking across the detection pattern. Conversely, microwave detection works on the doppler principle and is more sensitive when moving toward or away from the detector. That said. it is part of why dual technlogy detectors are less prone to nuisance alarms. Again, follow the manufacturers guidelines for placement and mounting height.

Hope this is of some value.

 

[shenandoah75]

Napco C-100STE20 : Combo PIR / Microwave

 

[R1PLUS]

Napco C-100STE20 : Combo PIR / Microwave

Sorry, I edited my post. Should have read closer the first time.

 

[shenandoah75]

Well - here are the results after install...

(1) in the upper left corner for office - all the way where the walls meet the ceiling (and set the height index to 8'ish)
(2) 1 in each of the upper corners of the shop - tis time about a foot from the ceiling and indexed to 7'ish


Office
-------
fairly good coverage from the moment i come into the door and around most of the room with one exception. Does not pick any movement up when i'm sitting behind the desk even if i create a comotion while moving/rolling around in my chair. Also, it's not very good coverage on the floor. Per directions, at 6' high, i should get floor coverage at a 5' radius - since i'm a little higher, ok i understand it would be a bit further out. However I don't get much at al even on the far walll... Maybe the proximity of desk is blocking... Not sure if the PC's / LCD's would cause interfance either...


Shop
------
results are not so good. I'm not sure if all the furniture/clutter/cast iron or the hanging JDS air cleaner pose issues, but there are several areas of the shop where i have line of sight to the sensors, but one or both won't fire. I also have 2 sets of dual flourescent fixtures - not sure if they could interfere either. With that kind of spotty coverage, i took off the cross zone flags on the Elk. I think i have more chance of someone eluding one zone at a time (and for an extended period) than of false alarms.


Also seems like these may have some kind of sleep thing going on as when they sit idle for a while, takes a sec for the LED to light/recognize... minor...


thx again... been interesting
-brad

 

[shenandoah75]

Well, i went in this morning with the flourescents off and coverage is better for sure...

-brad