Why does my motion sensor respond to fire trucks/ambulances that DO NOT have sirens running? IR emissions?

This is weird, but I’ve confirmed this behavior time and time again. I have some motion sensors:

Enerwave ZWN-BPC Z-Wave Ceiling Occupancy Motion Sensor PIR 360 Degree Sensor, Battery Powered,

I’m generally happy with them, though I see the ratings are not great. Strangely, anytime a fire truck/ambulance goes by, despite their sirens NOT being on, it triggers motion. No other vehicle does this. They even get triggered through the garage door’s frosted translucent plexiglass, so no clear line of sight.

I’m guessing the fire trucks/ambulances are emanating something in the infrared, but it is weird.

Anyone else ever experience this?

Oh, and if the consensus that maybe I just need different ceiling motion sensors, which do you recommend?

Very odd. :thinking:

Just to be sure, you are operating on a zwave frequency which is conforming with your region, right? Not operating a US hub in the UK or vice versa?

The primary reason that zwave has different frequencies in different regions is because of potential interference with local first responder communications.

Youre probably right, when I was a Firefighter we used to have a Federal Signal Opticom Infrared System installed on the light bar of our rigs that would prioritize our vehicles to traffic signals when we were running code 2 (lights) or Code 3 (Lights / Sirens)

I dont know what it did when ‘off’


By the way, plexiglass does transmit IR, where regular glass does not, so that’s definitely possible. you might be able to get an IR blocker decal to put on the plexi and see if that helps.


Interesting line of thought. My hub and sensor were bought in California via Amazon. I find Amazon can be sketchy on authenticity, but I think they are all US. How would I know for sure?

The garage door, via the plexiglass, seems to be the primary one to react to a fire truck or ambulance. Another one in the house would only have line of sight via glass, so perhaps this explains why those rarely react, though just as plausible, I have the blinds sufficiently closed every time a fire truck or ambulance goes by.

I’m thinking about adding a motion sensor. I may install it temporarily next to the other in the garage, to see if they both react to the next fire truck or ambulance. Sadly, we have a lot of ambulance activity, as there is a lot of seniors living nearby, so my future experiment won’t take long to test out.

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I think you should be fine on the region since you’re in the US. The issue would have been more likely if you had been using a US hub in a different country with a different zwave frequency, which does sometimes happen with people who bought their system when on a trip to America.

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