I've got a wired sensor that's been coming on all night. So I cut back the usual suspects (trees), but still no joy. I thought it might be a spider, so I evicted one tonight. But it seems to be doing it again.
Assuming the spider is back, any human safe home remedies for keeping spiders out?
Here's what I did for many years. It worked for me. Seal the wire and screw mounting holes with a dab of silicon sealant (bathtub caulk works well). Cut a small piece of sponge and, while wearing disposable gloves, saturate it with Raid or any other anti-critter stuff. Place the sponge inside the motion detector and close the cover. In the tightly closed space the stuff lasts for years. It doesn't seem to harm electronics but just to be safe I keep the sponge away from the wires and PCB.
Please note that spiders and other critters are only one possible cause. If there's a hole in the housing, seal it to keep drafts out. Cool (or warm) air blowing directly onto the pyrolitic transducer can wreak havoc with a PIR.
Make certain the detector is firmly attached to a non-moving, non-vibrating surface. The least motion of the detector appears to the unit as though the whole world is jumping around.
I read, perhaps here, that WD-40 and or teflon spray lube leaves a residue that spiders have a hard time dealing with. Others have recommended dousing the area with bug spray. I have a similar problem with IR CCTV cams whose heat and or IR light attract a wide variety of critters. I sprayed the barrels with teflon spray lube and they haven't come back, but that could just be dumb luck. I have a video somewhere of one spider weaving a web using the camera as an anchor point that looks like a cheap sci-fi film.
My guess is that if a spider got it, water could get in, too. I suspect moisture would be far more likely to cause malfunctions than a spider wandering around but that's just a guess. Who knows what a spider crawling around on the surface of the detector can do?
I did have lots of problems with false triggering at night one year, and it wasn't until a snowstorm that I saw the tracks of a possum that had moved into a space under the shed. Now, if I get plagued by falsing, I mount a CCTV cam to monitor the area to see if I can match some sort of physical event to the false triggering. That's how I figured out that passing cars were able to trigger my EagleEyes, and at a considerable distance.
Not sure how a spider could get in there. There's a gasket around the lens and a foam block around the sensor wire. Although I didn't happen to notice the state of the foam when I had the lens off, perhaps it's hardened up with time.
One of the things the sensor(s) do is select the camera(s) in the same location as the sensor and output them to the video system. We use to see the odd coon/possum/cat/teenager/badger/heron/etc., but lately it's a whole lot of nothing for this sensor. I suppose it could be bats or something hard to see, but I suspect gremlins.
I'm not certain it is a spider but they can and do get through some really small openings. In inner city jobs I've occasionally opens a suspect motion detector and seen half a dozen roaches scatter away. Yick!