Outdoor PIR Motion detectors


Active Member
Hi. I live in Puerto Rico (not Costa Rica) in the Caribbean and for a reason that I don’t understand yet, the house developers here almost always use Jalousie or louvered windows. Check a few pictures here:


Not only they are very insecure, but also they are not suitable for any of the window based intrusion detector sensors. With some patience, a burglar can bend the metal holding the glass louvers and slide them out one by one (I have left my keys inside my house more than once ;) ). So you cannot use glass break sensors - and if you want to use a magnetic sensor prepare to find a way to install one at every louver. I can focus in the bottom half of the window, but anyway, 7-8 magnetic sensors per window (I have 4 windows in each room) is toooo much.

So I have turned my attention to PIR motion detectors for moitoring my house close perimeter. I want good and reliable outdoor motion detectors. I don’t want false alarms caused by sunlight or a warm breeze (I can see the sea from my home :) )I must also be inmune to the passing cat or the neighbors' german shepherd.

When checking the web pages of three premium PIR makers I see detectors advertising either PET immunity, or dual-mode (heat immune), or outdoor (weatherproof) - but not a single detector claiming all three features!!!!
The closest match is the outdoor OPTEX VX-402 with its dual bean for quasi pet immunity (based on height, not weight) and their "Double Conductive Shielding" for Bright Light Disturbance Immunity. But come on! I cannot be the first person asking for a reliable outdoor motion detector with pet immunity! There must be more out there.

What do you guys recommend?

BTW, these are the direct links to the three manufacturers that I checked. Please add others manufacturers that you know.

NAPCO: http://www.napcosecurity.com/products-sensors.html
VISONIC: http://www.visonic.com/visonic/VisonicHome...lTable?OpenView
OPTEX Outdoor: http://www.optexamerica.com/indexes/gen_in...lass=outdoorpir
OPTEX Indoor: http://www.optexamerica.com/indexes/pisi_index.cfm

I've been looking around for same sensors, so I'm watching to see the responses. I can add that I have Optex INDOOR PIR, and I'm quite happy with them. They seem very reliable and accurate (plus I know it's immune to a 60 lb dog (my parents Standard Poodle)).
There are a lot of options that come to mind that may solve your particular problem.

The sunlight immune motion detectors are VERY expensive and I'm not sure if they will do the trick. Do you mean to mount a motion sensor on every window ledge or have them mounted in every room (standard mounting)?

Having any type of motion sensor right by the window seems to be challenging due to the extreme light changes that can be caused by bright sunlight suddenly shaded due to cloud movement.

I have some of the Visonic "Clip" sensors that can actually be tripped if the sun is shining through a window and all of a sudden a cloud moves by causing a "temperature" change to occur in the room (we usually leave this shade closed when we arm the security system in “Exit†mode).

Motion detectors which advertise immunity to this phenomena do exist, but they seem to be pricy ($70 plus).

I was then thinking about a laser beam break that can be mounted on your window ledges, but then again these seem to be expensive as well. I did find a kit though that looked intriguing and was even wireless, but I don't know how much "tinkering" you are willing to do (this link is below).

Another method that comes to mind would be to mount some sort of "vibration sensor" on say the middle blind, but I was afraid it may be tripped during the opening and closing of the windows.

With all this in mind I continued my search and found a VERY cheap solution, but might not be optimal for you. This solution uses THIS "magna pull" sensor. When the sensor is "pulled" from its socket it will alarm, and is less than $9 per sensor.

This may seem like a crazy idea but listen to the details (again, this is with that "cheap" theme in mind). Could you drill a hole in the metal on each louver and run a string (vertical) through them and attach this sensor to the end. The string would be a fine nylon thread and would "glide" in the holes during the opening and closing of the windows so the sensor would only be "pulled" out if someone would try to remove one of the louvers. Maybe if that wouldn't work you could arrange the thread to make an X pattern across the window, though I am not sure how "visible" that would be. Hopefully you could arrange the string on the side of the windows somehow.

Here are some links below to some systems that came up on my internet search that may interest you if the above solution seems unsatisfactory.

Good luck and keep us updated on your progress!







Do you guys experience false triggers with your X10 sensors caused bu sunlight? I have 7 sensors outside and I have yet to see a sunlight related trigger. The reason I know is my whole house audio system speaks "Master ;) I have detected motion in the Deck area" I also have this same line spoken in the other 6 areas. I rarely here anything from any of the zones except for the one pointing at the street and it announces every time a vehicle goes by. They are all mounted under the eves so maybe this helps?
I have that problem as well, maybe it depends on which direction the motion sensor is facing?
I removed ALL of my (cheap) X-10 motion sensors due to false detections caused by sunlight. I have a wide open area out here in the Las Vegas sun and everytime a cloud moved by it would trip my sensors.
Thank you everybody for you replies.

The former owner of my house placed bars in all windows in the first floor, but then he made an extension to the back of the house in the first floor and an intruder can jump into it and would be level to the windows of the back of the house in the second floor. Those windows do not have bars and are my primary focus right now. I have two rooms in that section of the house. I hate the bars, and they don’t make use of cool technology – so I want an alarm instead. If this work I would be removing the bars from the rest of the house later.

The plan was placing two opposing outdoor PIR detectors covering 180 degrees of this section of the house so that any burglar attempting to tamper either with the windows of the PIR itself would be detected. I would also place PET immune motion detectors in each of those two rooms (I missed to say that we have a cat and a 2 years old kid that will be moved to one of those rooms once I finish installing the alarm). Any intrusion to the outside zone would trigger a warning to the intruder, but an activation of a second zone would be needed before dialing the police. As a last option, the interior PIR detector could be this second zone, but even better I could use one of the many ideas from BSR so that second alarm would be triggered before the intruder enters the house.

The MagnaPull looks interesting. I would have to develop the idea further to see how I can be make it as tamper proof as possible. I was also thinking of a normally open clip that could close if the louver is removed – but would need to build it from scratch – and would not have the EOL load. Hmmm…it just came to my mind the old metal strips used to detect broken glass windows. If I can place a similar strip across every louver top border it would break if the louver is pulled. A lot of work, but it could work. Well…every other louver is OK.

The laser beams and the BX-80 PIR from OPTEX are also interesting, but expensive. The BX-80 by itself is great, but they do not have anti-masking technology. Anybody could walk directly to the detector and block the lens without being detected. The best would be combining this sensor with another one to detect anybody approaching to this sensor. But again, tooooo expensive.

BSR - Do the vibration sensors react to low frequency movement like opening the window? We don’t have a reason to open/close the window while the alarm is active – so that is another alternative.
Another option that has been used for years, although I don't know if they are available to us DIYers or how expensive they may be, are ultrasonic motion detectors. They work by using an emitter/detector pair, emitting an ultrasonic sound that bounces off everything in the room, and listen for a change in the echoes or reflected sound spectrum (maybe even the Doppler effect). The reflected sound can bounce around corners, effectively covering more area than a PIR, and reaching areas that can't be seen from the sensor. Typically, a single strong source would be used with multiple listening sensors, depending on the areas to be covered.

They were used quite a lot in large areas such as department stores and warehouses where there were lots of places (aisles) that were out of line-of-site. The sonic detectors could still be triggered when someone moved into the range of the emitter/detector even if they were not within the line-of-site of the sensor, because their body and movement changed the reflected sound waves.

Finally, you may want to consider just using PIRs in certain locations to cover specific items of interest that would attract thieves or areas of travel such as a hallway. That would narrow down the areas you would need to cover, but it would not give you the tradiitonal perimeter coverage most people seem to want.
Would a curtain sensor work? I have not used them personally, but it looks like they would work great for your application. Here is a link to one made by Seco-larm.

Hope this helps,
huggy59 - This link http://www.nlectc.org/perimetr/full2.htm posted by BraveSirRobin in the previous thread explain the pros/cons of the ultrasound. There are risks associated with environmental sounds, etc.

I read that link yesterday and two forms of a sensor listed there that looks to me like a promising, undeveloped technology. It is basically the same technology, but one uses radio frequency AC and the other uses DC. In both you have some wires tall in the window and other set of wires in the floor or down in the wall. Those wires form either a dipole antenna or a capacitor, depending on the type of sensor. If a guy with 150lbs of water gets close to the window, it will change the impedance of the "antenna" (for the AC type) or the "capacitor" in the DC mode. You will need some electronics to detect it and trigger the alarm.

I remember playing with both concepts during my college years.

I wrote to Visonic, NAPCO and OPTEX during the weekend and only VISONIC answered today. They said that they have no product for the need that I described.

I think that for now I'll use an interior PIR with 80lbs pet inmunity so that its inmune to my kid too (am I making the right assumption?). Any intruder removing any blinds will expose himself to the PIR. Then I might upgrade by placing an IR curtain fence like the one that hotwire described. The one from the link is expensive ($200). But cannot be masked, tampered, etc. I'll have to buy some spikes to place in the border of the window to prevent the birds from stepping there. ;)

Nothing is foolproof - no single technology will cover it all, and security is best applied in layers.

I wish you well in your application and let us know how it works out!
elcano said:
I think that for now I'll use an interior PIR with 80lbs pet inmunity so that its inmune to my kid too (am I making the right assumption?).
I'm not sure that assumption is correct... I think PIRs use height of a moving object as a determining factor, and I assume your son could be taller than a big dog.

My PIRs are pet immune, but my 3 and 5 year old will still trip them.
Rupp said:
Do you guys experience false triggers with your X10 sensors caused bu sunlight? I have 7 sensors outside and I have yet to see a sunlight related trigger. ... They are all mounted under the eves so maybe this helps?
I do get falses from the DS10's I mounted outdoors. The ones under eves not as much. I wrote a condition so that the alert announcements are only made between sundown and sun up, and at night there doesn't see to be any false alerts.