Re:Neighbor's house alarm triggers when I put my car in reverse
by moftz on Monday December 18, 2017 @12:43PM
(#15953500)
Seems like there are two possibilities: engine noise is causing windows to vibrate making a sensor go off or the reverse distance sensor that uses microwave radar (X band) is causing the base unit to think a sensor is going off. It is a WRX (lots of rumbling engine noise) so I would imagine that the first scenario is more likely. A home alarm system is most likely going to be 433MHz (or even the wifi/bluetooth bands) but not X band.
For your list, and I’d do a) and not bother with b) and c) as a) eliminates them well enough (point the emitters away from the alarm sensors). For d), I’d put a light cloth in the tailpipe, enough that it will change the exhaust note across RPM range, but the car will still run. Your suggestion leaves the slight possibility of a false positive if we accidentally hit the resonant rpm range. For experimentation only, don’t drive to work a banana in your tailpipe.
One last one: throw it in reverse near the house, but not in your driveway. Could be some weird parabolic blah blah acoustic thing focus thumpy exhaust waves at the house sensors.
I suppose there’s the possibility that a 2.4Ghz radio transmitter of some sort could be responsible, but this way out there and would be way down in my list. SDR and a dongle would be handy here.