PIR's and rooms with lots of windows

[lugnut]

The installation instructions for most PIR's say not to have windows in their detection region. So far I have been able to locate all my PIRs so that windows are only at the outer fringes. Mostly these are old Bravo-2's and 3's that have been in place for 10+ years before my recent upgrade. In all those years I have never had a false alarm.

In that timeframe I added a "sun room" which has loads of windows on the 3 sides that are exterior walls. In the original purpose of the room, security wasn't important but things have changed and now it is.I've been shying away from protecting that room with a PIR because of all the windows. There is no way around the PIR pointing at some of the windows.

How much of a concern are windows with PIR's really? Are there certain PIR's that have better false alarm immunity relative to windows than others? Anything else I should be considering to protect this room (besides a ceiling mount glass break which I'm planning to add also)?

(a couple additional points: to make a long story short there is no possible way to add window contacts of any kind at this point. There is one (unprotected) exterior door, and no possible way to add door contacts (well, except wireless and I'd rather not do that). There is also a dog door in this sun room, from the back yard, so I'll need pet immune to 45lbs on a PIR).

Any thoughts/ideas would be appreciated. This has me stumped, as far as not having lots of false alarms.

 

[rfdesq]

I have never had a dual technology, i.e. PIR/Microwave/Ultrasonic detector false because of a window. That being said, how about a 360 degree ceiling mount detector such as http://www.optexamerica.com/productpage.as...p;l2=&id=42? Depending on the masking features you could block out any potentially troubling windows. And, it is pet immune, but ymmv.

 

[sic0048]

Make sure you mount it in the one of the exterior corners with windows on each side and choose the corner that gets the most direct sunlight. That way it is facing the wall of windows that gets the least amount of direct sunlight and the interior wall.

 

[CollinR]

Use a dual technology unit.

 

[lugnut]

I have never had a dual technology, i.e. PIR/Microwave/Ultrasonic detector false because of a window. That being said, how about a 360 degree ceiling mount detector such as http://www.optexamerica.com/productpage.as...p;l2=&id=42? Depending on the masking features you could block out any potentially troubling windows. And, it is pet immune, but ymmv.

I wouldn't be able to use a ceiling mount detector unfortunately (it would be by far the easiest to install though). The room is pretty small (12x20), 12 foot ceilings, has a 60" ceiling fan on a downrod on one half, and a 5'x5' storage platform on pulleys from the ceiling on the other half. Hmmm...I wonder if there is a way to mount a ceiling type detector to the underside of that storage platform on pulleys. It would need exposed wires and slack though.

I don't think I will be able to run wires to mount a detector in one of the corners, because of the construction. I might be able to put the detector in the middle of the wall, but that would require a 180* detector. Dual technology sounds like a good idea. Most that I recall looking at were 90* though.

 

[Sandpiper]

Another idea is to put up two PIRs in different locations and then cross-zone them.

Cross-zoning requires both sensors to trip within a certain amount of time before the alarm is tripped. The Elk M1 can cross-zone, but most other standard panels cannot.

 

[lugnut]

I'm still coming up empty in looking for a 180* (or nearly that) dual technology motion detector. Also need it to be pet immune but I can't even find a 180* at all.

Anyone recall any brands that might have such a beast?

I guess the other alternative is two 90* units side by side

 

[rfdesq]

I'm still coming up empty in looking for a 180* (or nearly that) dual technology motion detector. Also need it to be pet immune but I can't even find a 180* at all.

Anyone recall any brands that might have such a beast?

I guess the other alternative is two 90* units side by side

Look at these detection zones http://www.optexamerica.com/productpage.as...;l2=5&id=35. If you put the detector in a corner, it's as close to 180 degrees as you can get.

 

[pete]

I'm still coming up empty in looking for a 180* (or nearly that) dual technology motion detector. Also need it to be pet immune but I can't even find a 180* at all.

Anyone recall any brands that might have such a beast?

I guess the other alternative is two 90* units side by side

I use normal PIRs (pet resist, not dual-tech, ademco 998PI I think) in my dining and living rooms, I have them in a corner opposite the front wall which has (4) ~5ftx2ft windows in each room, which face south, about 13-18ft away from the MD . . no problems with false trips . . YMMV

found this info , they call 90deg wide angle? and it has 100deg option

 

[lugnut]

Rfdesq: On that Optex MX40, I'm not sure what you mean by 180*, since it looks like a 90* (or 85* according to the specs) pattern. But in any event (and you might have missed this from earlier in the thread) I cannot see a way to put the detector in the corner with the outside wall; I can only get wiring to a column in the middle of that wall. That is why I'm looking for a 180* pattern.

I just got an Optex DX40 for other purposes, but it looks to be very similar to the MX40 you linked to, except the DX40's microwave detector operates at 10.53GHz rather than 2.45GHz. Given a choice I want to avoid microwave detectors operating at 2.45GHz.

The only way I can put the detector in a corner for this room is to use a corner on the opposite wall. That would mean the detector is pointing at (exterior) walls of windows on the 3 sides of the room it reaches.

I guess I could temporarily wire in the DX40 in that corner facing the exterior walls, but the problem is, different seasons and different times of day, there are different windows on those 3 exterior walls that get direct sun. All the high windows are uncovered, which guarantees direct sun into the room.

(This room is oriented as follows: on the north side is an exterior wall, about 20 feet long, with lower windows and upper windows, pretty much filling the wall, and a French door in the middle. The east and west sides (about 12 feet length) are also exterior walls, with the same upper and lower windows. The south wall is a joint wall with the interior of the house (the kitchen), and it is also mostly glass (double French door and windows, but none of these windows are a sunlight source).)
I think the preference would be to aim the detector at the south wall (mount it on the north wall), and the only way I can see to wire that is in the middle of the north wall, whic would mean I need a 180* detector).

 

[rfdesq]

Rfdesq: On that Optex MX40, I'm not sure what you mean by 180*, since it looks like a 90* (or 85* according to the specs) pattern.

I see where the confusion is. I look at being able to cover a complete room, four 90 degree corners, i.e. 360 degrees with one PIR. When placed in a corner, I understand that you have a problem there, it sees the entire room. How about, and I've done this before, putting a PIR at the top of a 2"X4"X8' board with a 12 volt battery and a sounder. Move it around the room and see/hear what your coverage is and best placement.

 

[CollinR]

I assume all you really need to cover is the door, you just want to prevent entry to the house correct?

If so just get a decent dual tech and mount it above the door and open up the look down.

 

[Photon]

"Given a choice I want to avoid microwave detectors operating at 2.45GHz."

Because. . . ???

 

[lugnut]

"Given a choice I want to avoid microwave detectors operating at 2.45GHz."

Because. . . ???

I'm not seeking to get into a debate about it; it's just a choice. The 2.45GHz ISM band is populated with far more unlicensed emitters than the 10.xGHz band. Since Optex makes no claims of tested resistance to for example, receiver blocking/overload from those in-band emitters, and since I know of devices operating in that band where unintended emitters are an interference problem, and since I have a choice to select a motion detector in a microwave band far less likely to have such unintended emitters, I elect the latter. I have no proof there is an issue, but since I have an alternative, I choose the alternative. That's all.

It's admittedly a pretty weak justification, but I have no means to make it stronger, and I don't see any downside of just going with an alternative microwave band.

 

[lugnut]

I assume all you really need to cover is the door, you just want to prevent entry to the house correct?

If so just get a decent dual tech and mount it above the door and open up the look down.

Thanks guys, you've given me a few things to try. I'm very limited in the placement of the detector, due to the knee-high to ceiling, and wall-to-wall, windows (and the full-hip concrete tile roof which means pretty much solid wood headers above and between the windows and doors, and no real drilling access). Also, the interior walls of this room are sand-finish stucco so it's not as flexible as hacking drywall.

One thing that might help give me more flexibility in placement of the detector is if I could live with exposed wires for the last several feet of the run. Have any of you guys ever had a case where you had to have some exposed wiring for a motion detector? Any tips or tricks?

(PS, Collin: my original intent was to cover this whole room, not just the door. But it's a good thought, and a motion above the door would only leave a couple blind spots. Not the ideal solution, but one worth considering since I'm not going to get the ideal solution. This room configuration is just too obscure)