Best motion detector option for a Qolsys system

I’m looking at some Qolsys compatible pet friendly motion detectors and trying to figure out what the best option is. The Qolsys IQ Motion detector has some elaborate instructions on how to mount it in a way that is pet friendly, taking the length of the room, height of the pet., etc, into account, and suggests removing objects that the pet might climb or jump on (chairs? couches?) else the sensor might be triggered. The instructions don’t exactly instill me with confidence about this sensor’s ability to avoid false alarms from my pet, but I’m really just wondering why all of this position stuff matters - isn’t that the whole point of PIR?

Looking at the Interlogix SAW sensor, the instructions specifically say it should be mounted tilted downwards, but doesn’t mention pets. The resolution products sensor doesn’t mention pets either.

Any idea if/why angle/position really matters for a PIR motion detector, what the deal is with the motion IQ versus the other options, and which is the best?


The Qolsys IQ Motion detector instructions are very accurate then, including all of those details.

Motion detectors do not all function the same. Horizontal beams of varying degrees based on the lens detect heat signature change in its detection field. The manufacturer instructions should always be followed regarding mounting. The angle of the detector changes its detection field.

Passive Infrared Detectors with pet immunity will ignore heat signatures up to a certain height (they give weight limits as a general “how big the animal can be” but weight is less important than height.)

The higher a heat-emitting object is and the closer it is to the detector, the more likely it is to cause a false alarm. Pets climbing on furniture is the bane of most detectors.

Most will have a very specific height requirement as well which should be followed.

From the RE110P Manual: "Mount at 7.5 foot height for optimum performance between: Catch
performance, Pet Immunity and False Alarm prevention. "

We have found the Resolution Products motion detectors to be very good overall at limiting false alarms due to pets.

Thanks for the response Jason.

The product page in the suretydiy store for the RE110P mentions do not use with cats. That’s actually what I have - 2 cats. Is there another recommendation for my situation?

I did try a Qolsys detector pointed straight ahead mounted at ~7 feet, and it didn’t catch me walking towards it until I was very close. Pointing it slightly down did a better job, but then the instructions say this is not ideal for pets. Similar with an interlogix SAW sensor I tried out - straight ahead didn’t catch much, pointed down a bit better.

As long as you use the motion detector in such a way that the cats do not climb on furniture in its field of view you should be alright. Often a motion detector is used to cover an entire living room, etc. It depends on what you are looking to cover. For example, if you are placing the motion detector to watch a hallway you should be fine.

It also depends on how active the cats are of course.

Does that apply to the RE110P? It’s not clear to me why it would be appropriate for large dogs but not cats.

Cats usually don’t play well with motion detectors and the discussion about whether a motion detector will work with pets usually revolves around the “size” of a dog. As Jason said,

Passive Infrared Detectors with pet immunity will ignore heat signatures up to a certain height (they give weight limits as a general “how big the animal can be” but weight is less important than height.)

This is because cts, in general, will climb on furniture. Dogs, in general, are less likely to end up moving around in areas above the their own height. So a large dog will reach considerably higher than a small dog in most cases, whereas even a small cat might jump up and move around at a level higher in the room than a huge dog. That being said, we have seen cats that don’t ever set off motion detectors, as they don’t climb on furniture, and small dogs that do cause false alarms (because they’re jumping on beds or couches…) Its highly dependent on the layout of the room, the position of the motion detector and the behavior of the animals that may be roaming the area.

Thanks for the response. This makes me wonder if my house is well-suited for any sort of motion detector…

The house is an L shape with long hallways that open to spaces on either side of the house. On one side, from one end of the hallway to the end of the house is 50+ feet. The other direction is about 35 feet. If I put a motion detector pointed down the hallway to the far end of the house, is it likely that a pet, even walking on the ground, would get detected somewhere out there near the end of that range? Any tips on testing this out?

You could try using a motion detector programmed as Zone Type 25, Local Safety. Set a notification to alert you whenever it is tripped, but it will not generate an alarm as Zone type 25. Testing this for an extended period should tell you if the location is prone to false alarms.