False alarms every night from SHM


(larance) #1

Every night in the middle of the night I get an intrusion detected. It’s not at the same time, and it’s not the same sensor. Infact its only motion sensors. I am thinking that it is possibly insects because ST is on a vacant new construction home in a wooded area. But why is it only at night? Sure insects are more active at night but I don’t think I’ve ever had a false alarm during the day. Anyone having similar issues? Or any ideas as to what is causing this?


#2

It could be insects, but it’s more commonly just a temperature differential, like heat coming on. In a cold enough house it can even be caused by a light coming on. Just a draft can do it.

If your motion sensors report temperatures as well, look for temperature changes around the time of the false alert.


(Mark Whipp) #3

If your logs show an actual motion trigger, it is probably your sensor. I have an Aeon Multisensor v1 on my patio as a early warning. If it is raining, windy and trees blowing, or cold/warm front moving through it triggers. It is not set up as alarm, just a siren beep and lights come on. I have been adjusting sensitivity and aim for 6 months to reduce falses, outdoor motion sensors will never be as accurate as a controlled indoor environment.


(ecksomperudenlign) #4

I know this is not a helpful reply and is not comply to the forum guidelines but I can’t help myself.

Ghost apparition perhaps? It can change the temperature in the area dramatically, so I was told.
How about install a video cam, use the motion sensor to trigger the video cam to capture the ghost and share it here!


(larance) #5

The temperature on the sensor dropped 1 degree over the course of 13 hours. And the false alarm occurred in the middle of that time. I also believe that the thermostats are off but will check to make sure


(Geko) #6

The so called “motion” sensors are in fact passive infrared sensors, i.e. they detect changes in the infrared spectrum (a.k.a. heat), not a motion per se. Insects do not emit any heat and are unlikely source of your false alarms. Rapid temperature changes may cause false alarms, particularly if the temperature drops below specified range.


(larance) #7

That’s a little confusing…
won’t the insect be blocking the infrared that’s in the room? The IR light won’t pass right through them, right?
If it’s not insects, and can’t be sudden changes in temperature since the heat was off and no windows open, then what else can it be other than my sensors being defective, which I doubt since it only happens at night


(larance) #8

Seems like the only plausible explanation at this point :joy::joy:


#9

Insects crawling on the lens can definitely set off PIR motion detectors, spiders are a classic. It probably is because they’re blocking rather than radiating. (They don’t get detected when they’re further away.) But it does seem strange that it’s only at night. And a 1degree shift shouldn’t do it.

If you could put two motion sensors on the same plane about 6 feet apart and then see if you get a trigger from both of them, it’s much more likely to be heat differential in the air than it is to be a spider. Otherwise consider putting in a camera and see what you get.


(larance) #10

I actually have 2 motion sensors next to each other pointing in he same direction (I had to temporarily move them by each other so they aren’t in the way of workers). One gave a false alarm one night and a couple days later the other gave a false positive. (They didn’t trigger at the same time/night)
As for cameras I do have live feed cameras and haven’t seen anything noticeable at the time of the trigger.
Off topic, my night vision cameras work on IR so why can’t I see heat coming from the vents when the furnace is running?


#11

It just depends on the noise reduction settings for that particular camera model. Air coming out of a forced air furnace vent is typically around 135° F and drops down the further away it is from the furnace.

In order to reduce false alarms, some “night vision” cameras filter out everything above about 120°, because the assumption is that what you want to record is people or animal movement. So the camera did see it, it just didn’t tell you about it. But you can check the specs on the camera to be sure.


(larance) #12

Interesting information, I also forgot to mention that the “furnace” is a geothermal system, and from what I’m told they run on lower temperatures and lower speeds. Regardless my system wasn’t on at the time so that is eleminated from the probable causes


(Greg) #13

Just to add here, I’ve been getting them too. Ended up disabling it because it was driving us mad!


(Neal (www.zebrablinds.com / www.zebrablinds.ca)) #14

SHM has oddly been rock solid for me for the past 2 weeks. With about 20 door sensors and 6 motion sensors. The only time I had an issue was when my phone’s wifi stopped working and the app showed the system as disarmed when it wasn’t.