Earlier quoted context omitted.
So what was it?
Not him but I'd bet 5 bucks it was a smoke alarm with depleted batteries.
Here is $5. You are right.
Neighbor's house alarm triggers when I put my car in reverse
41–50 of 316 posts
Re: Neighbor's house alarm triggers when I put my car in reverse
#42Earlier quoted context omitted.
So what was it?
And what was the app?
I forget now. Was over a year ago now. It was just one that allowed me to zoom in on a specific point in the past 60 seconds of sound in real time to see an exact dB reading for a very specific and tiny spike.
To my ears it always sounded the same volume. And to some apps. It wasn't considered loud enough to be read in a meaningful way.
Re: Neighbor's house alarm triggers when I put my car in reverse
#43Earlier quoted context omitted.
I’d be super surprised if that turned up anything. For one thing, okay, we did that and the alarm didn’t go off. What did we eliminate? Alternatively, if the alarm did go off, this ex-mechanic would be at a loss as to how a car with no powered systems could do that. At that point my suggestion is to call a priest.
Theres a small but non zero chance it's something to do with ultrasonic backup sensors - so I'd try this with everything powered up but without the engine running, mostly because it's a super easy test rather than any real expectation that it'd be the problem.
Ah, engine off, but powered electronics, got it. Yeah, small chance of finding a bug but offset by being an inexpensive test to run.
Re: Neighbor's house alarm triggers when I put my car in reverse
#44Interestingly, I used to have a 433MHz wireless doorbell (a "1byOne", specifically) that would spuriously chime every time a specific one of my neighbour's cars set off.
I assumed it was interference from some sort of PIR motion detector transmitting a signal to say it saw some motion, but I suppose it could conceivably have been caused by the car going into reverse.
I never debugged it, I just threw the doorbell away and bought another.
Re: Neighbor's house alarm triggers when I put my car in reverse
#45Someone explained it properly in the reddit thread, it's the exhaust generating noise while driving in reverse (only happens in the morning when cold and at specific RPM, exhaust generates a specific frequency which vibrates the windows and triggers the alarm).
> Someone explained it properly
That's a hypothesis, a very good hypothesis, but the Reddit thread and Hacker News offer many other reasonable-sounding hypotheses. I can't tell you the number of times I've tracked down a bug or other type of malfunction where I was 100% sure of the cause since my hypothesis made so much sense, but it turned out to be wrong. It was something else.
Re: Neighbor's house alarm triggers when I put my car in reverse
#46Is it just me who'd love something like this to happen to me? Would be great fun tracking down the source of the problem (if it was my car; probably less so if I was in the house...) There's a lot of options to try to isolate the problem, just thinking out loud here - a) Back into the driveway returning from work. See if alarm goes off. Next morning, see if alarm goes off as you drive out. b) Remove fuse for reverse…
> Is it just me who'd love something like this to happen to me? I love reading about interesting problems and creative ways to solve them. I used to wish for the same. But then I was given a super annoying one. In my apartment I heard this beep about once every 90 seconds or so. I tried ignoring it for a while hoping it'd go away. And just so at the right frequency and infrequent enough Impossible to determine direct…
My buddy's dad was an EE and built tiny devices made to create this exact situation. Easily hidable, they emitted a loud beep sound at a varying interval (~40-120 seconds). He called them Annoyers and would leave them behind pictures frames, in plants, etc. after parties.
Re: Neighbor's house alarm triggers when I put my car in reverse
#47Got a kick out of this gem from the reddit comments:
> My S2000 car alarm would be set off whenever I microwaved blueberries. Some experimentation revealed it was anything with excess water. Buying a new microwave solved the issue but I don't like thinking about how poorly shielded the old microwave was. I tried moving the for further from the kitchen or keeping the keys far away to no avail.
Re: Neighbor's house alarm triggers when I put my car in reverse
#48Earlier quoted context omitted.
> Is it just me who'd love something like this to happen to me? I love reading about interesting problems and creative ways to solve them. I used to wish for the same. But then I was given a super annoying one. In my apartment I heard this beep about once every 90 seconds or so. I tried ignoring it for a while hoping it'd go away. And just so at the right frequency and infrequent enough Impossible to determine direct…
My buddy's dad was an EE and built tiny devices made to create this exact situation. Easily hidable, they emitted a loud beep sound at a varying interval (~40-120 seconds). He called them Annoyers and would leave them behind pictures frames, in plants, etc. after parties.
There's a version of these called the Annoyatron that you buy online. Know how I know this? Because one of them was left behind a cabinet in a rental house we moved into and we couldn't find what was making that damn noise for three months!
Re: Neighbor's house alarm triggers when I put my car in reverse
#49Is it just me who'd love something like this to happen to me? Would be great fun tracking down the source of the problem (if it was my car; probably less so if I was in the house...) There's a lot of options to try to isolate the problem, just thinking out loud here - a) Back into the driveway returning from work. See if alarm goes off. Next morning, see if alarm goes off as you drive out. b) Remove fuse for reverse…
My fire alarm goes off once every few months at 3 AM.
From what I heard this is not uncommon.
Re: Neighbor's house alarm triggers when I put my car in reverse
#50Earlier quoted context omitted.
It could have backup sensors. Rear cross detection and blind-spot detection is an option package. This allows my car (2016 WRX Limited) to warn me about cars flying by when I am backing up out of a parking spot for example.
I have that on my Mazda 3 and it's absolutely brilliant. The range and sensitivity of that system is rather amazing.
FYI car makers are starting to collect data from connected cars using their ultrasonic sensors for collision avoidance, among other sensors. You can indeed use them to map surroundings fairly accurately.