
Neighbor's house alarm triggers when I put my car in reverse - whalesalad
https://www.reddit.com/r/cars/comments/7k12fs/neighbors_house_alarm_triggers_when_i_put_my_car/?st=JBB8L3HN&sh=163d3254
======
remyp
This reminds me of a “bug” I found when working for a company that sells
package lockers to apartment buildings. We used iPads for the user interface
and had monitoring in place to alert us if an iPad went offline.

At only one location with two iPads one would go offline almost every day (but
not every day) between 12pm and 1pm, for 10-20 minutes. Never the same time of
day, and never the same length of time. It was always the same iPad, the other
one on that network stayed online the entire time.

We replaced the iPad and the problem persisted. Finally I got fed up, put my
phone on silent, ignored everything, and watched the Dropcam feed for the 2
hours near the usual time. Slowly I saw the sun light up the lockers,
eventually shining on the iPad. Ten minutes later, after sitting in direct
sunlight, it went offline. As the sun moved, the iPad went back in to shadow
and came online on its own.

It was overheating and shutting itself off until it cooled down. The time
changed because day lengths change, and the days it didn’t go offline were
cloudy.

~~~
AndrewHampton
This reminds me of a story one of my college professors told about the days
when he helped automate factories in the 80s. Every night, the control server
hey installed would go offline around 1am then come back up a few minutes
later. It was never the exact same time or duration. After a few days of
diving through the code with no progress, one of his co-workers decided to
stay up all night at the factory and just watch the server. Around 1am, the
cleaning lady came in, unplugged the server and plugged in her vacuum.

~~~
vxNsr
There's a lot of permutations of this story including life support systems in
hospitals I find them all apocryphal. The cleaning staff would notice right
away if they just shut down a huge computer. Esp. in the 80s I doubt it even
used the same outlet as a regular vacuum cleaner.

~~~
timzentu
Some of them even had the mains wired directly into the case, so you couldn't
unplug without an ax.

------
DonHopkins
I posted this before in the "My wife has complained that OpenOffice will never
print on Tuesdays" discussion [1], but it's worth repeating:

I heard a story about a terminal in a public terminal room that a user was
able to consistently log in to if they were sitting down in a chair in front
if the terminal, but never if they were standing up.

They thought it might be static electricity, or some mechanical problem, or
"problem exists between keyboard and chair", but finally they noticed
something else was amiss...

It turns out some joker had re-arranged the 1234567890 keys to be 0123456789,
so when the user was standing up, they looked down at the keyboard and typed
their password (which contained a digit, of course) by looking at the keys.

But when they were sitting down, they touch typed without looking at the keys,
and got their password correct!

[1]
[https://news.ycombinator.com/item?id=11717010](https://news.ycombinator.com/item?id=11717010)

~~~
mabbo
Had something like that over a decade ago doing tech support for a government
reporting agency.

Report: "If my secretary logs with our account, it works. If I do, the website
logs in but then later shows me errors message when I try to submit a
report".[0] Entirely repeatable. Screenshots sent showing it exactly. All of
us scratching our heads. How could our web server know who was sitting in
front of the keyboard?

Root cause: the username was a number with a leading zero. The login didn't
care if you used zeros or not, but the internal logic _did_ care. She logged
in with them, he logged in without them (or was it the other way around?).
Once logged in, the username was taken from a cookie or something that had
been set at login time and fed into the internal logic, which barfed.

Lessons learned: either don't have forgiving logins, or have forgiving
functionality when users use inconsistent logins.

[0]They were indeed sharing an account with the same username and password. It
was 2005 and government website, so this made sense.

~~~
infogulch
I would take a different lesson: use internally generated ids, not user
generated usernames when communicating between services in your backend.

~~~
mabbo
Well technically, the username the user had was generated _by us_ when we
signed them up. I honestly think this issue probably would have presented for
1/10 users whose IDs happened to have a leading 0-digit. Our software couldn't
handle a situation we had setup for it.

But yes, I do agree with the general sentiment of "communicate via something
internal, not something user-supplied".

------
lb1lf
Is 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 assistant. (Stupid sensor thinking IR, ultrasound
or RF sure-fire sign of break-in)

c) Remove fuse for reverse light. (Stupid motion detector confusing light for
potential intruder)

d) Rev it up a little before shifting into reverse. (In case a resonance is
the cause)

e) Roll out of the driveway in neutral. (Would be surprised if this triggered
anything - if the car's movement was the cause, alarm wouldn't go off
immediately upon shifting into reverse, only when it moved)

f) (...)

~~~
Namrog84
> 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 direction. But also
just loud enough to be annoying after hours and hours. I spent several hours
trying to pinpoint it. Including putting my head up agaisnt numerous neighbors
doors to see if it was coming thru the walls.

I ended up downloading a dozen different audio apps for phone. And found only
one that gave out an accurate enough histogram of dB volume level. Most
weren't good enough. I needed to differentiate between 2 and most were
sensitive enough of reading. I was able to triangulate the direction thru
several patient iterations.

Turns out it was coming thru the wall.

Be careful what you wish for. Because you might end up with something
arbitrarily dumb and annoying!

~~~
mdip
Off topic to the discussion, but you hit on something that struck a nerve with
me so I'm going to go with it . . .

Oh good God, this happens to me _every_ time one of my smoke alarm batteries
starts to go. I have 6 smoke detectors and an older home where they're not all
wired/battery back-up but rather all battery powered.

The "chirp at 90 second interval" thing is the _worst_ design in the universe
and it bites me every time. If I didn't know any better -- since there is no
clock device and these things are not networked in any way -- I'd swear they
are also programmed to only start chirping between the hours of 2:00 AM and
4:00 AM. I've lived here 10 years. I have _never_ had one of these fail in the
morning, middle of the day or afternoon; only in the middle of the night.
Hunting down the _one_ of the _six_ devices that is failing with its way-too-
infrequent chirp that's so high-pitched, only a dog could figure out where
it's coming from, is made _extra_ fun when you're in the fantastic mood that
being awoken from a pleasant dream in the middle of the night and have the joy
of hunting it down in your boxers in a cold house.

How much more complicated would it have been to _also_ include a visual
indicator. The things have an LED on them that _continues_ to blink as the
battery dies. Why not _also_ have it either stop blinking (to conserve
battery) or blink faster -- _anything_ to make it easier to identify which of
the infernal, identical, devices is in need of a 9-volt.

Thankfully, they're due for replacement this year. Now I have to research
which of the models that are available handle this circumstance with a little
more intelligence (that don't cost a hundred bucks a pop). This is such an
easy-to-solve problem -- I don't want a "smart smoke detector", I want a $25
one that A) detects smoke and B) reports when it needs other attention in a
way that is useful. Heck, I'd pay an extra $10 for the latter feature even
knowing it would cost them no more than the "dumb chirp" method.

There was a very bad house fire a few miles from me about a year ago and the
person who lived there died in their sleep while the fire raged. The rumor was
that the home had a bunch of smoke detectors without batteries in it and it
was spread through our neighborhood as a "cautionary tale". I'm willing to bet
there's a story of being woken up in the middle of the night for a battery
change chirp in there somewhere.

~~~
azernik
Vaguely related - I once met a parrot that had learned to imitate _that exact
chirp_. Maddening.

~~~
logfromblammo
I know a caique that learned how to imitate a ringing telephone. They had to
replace all the phones in the house with a different model, because they were
constantly looking at dark caller ID panels that didn't ever say "your
parrot".

------
fauria
Time to revisit the 500 miles email...
[http://web.mit.edu/jemorris/humor/500-miles](http://web.mit.edu/jemorris/humor/500-miles)

~~~
INTPenis
Funny how he went about troubleshooting. I guess it was a long time ago and
they didn't enable logs to save disk space.

Because me being a sysadmin for the past 14 years would go directly to the
logs and see my client timing out.

------
chrissnell
When we were kids (dating myself here), my friend had a TV with a remote
control back when almost nobody had a TV with a remote. You would push the
channel-change button on it and the channel knob (!!!) on the TV would
mechanically turn and the channel would change. Well, apparently, the remote
used an almost-audible high frequency to signal a channel change and when his
dog ran through the living room, the dog's tags would jingle and change the
channel on the TV.

~~~
Kiro
> the dog's tags would jingle

What does this mean?

~~~
bagels
I presume, the dog was wearing a collar with some metal tags that bounced off
of one another, making sounds of similar frequency to the ultrasonic remote.

------
eco
My guess is that the backup camera has an IR light to assist with nightvision.
Some security cameras support triggering alerts if they get too much IR light
because blasting them with an IR floodlight is a common way to blind a
security camera.

~~~
valine
Maybe its a backup sensor? The sensors on newer cars make radar detectors go
nuts. It’s hard to say without knowing anything about the neighbors security
system.

------
diggum
Shortly after a big upgrade to the application I worked on, we started to get
bug reports on our forum about a pretty ugly bug where a modal window would
get “stuck” after clicking OK. The window would no longer respond to users but
the application would act as if it were still up, and the only way out was to
kill the process and lose all the unsaved work.

Understandably, the complaints got louder and angrier as no one on our
engineering or prerelease teams were able to reproduce it, but easily half the
bug reports were all about this issue and identical. After 2 weeks of trying
every configuration of video card, OS, and any other alchemical recipe we
could think of, my partner on the test team stumbled upon the license crack
online while searching for anyone else having this problem but not having
reported it to us directly.

As a brief respite from this ongoing madness, he decided to install the crack
on a clean machine and aee how it worked so we could report it. Lo and behold,
the problem reproduced on the first try. This whole time, indignant, angry
users who were actively threatening our team and vowing to never use another
product from our company had been bested by a poorly written crack.

Before exposing the secret, I asked dozens of the most vocal and vicious
reporters to please email me a particular log file, and give me contact
information where we might get in touch with them as we were close to cracking
the case. (Pun intended, and this was before we had very clear rules around
personally identifiable information, but even with the policy at the time,
these weren’t our customers so I felt less anguish about it.). I received all
of it and more, invited them to share their experiences on the forum threads,
and then tactfully but clearly explained exactly why they’d seen this problem.
I offered to work one on one with anyone who felt my accusation was in error,
but not one single affected user replied or followed up after that message.

~~~
AndrewStephens
I was a junior developer on a heavily used utility that was frequently
pirated. The company tried a few strategies to deal with this but one of the
best was incredibly sneaky.

This was before validating license keys over the internet was really possible
so a lot of people just used our application with a key from a public cracking
site. Of course, we also knew about this list of cracked keys and our
application would pretend to accept them. But if you actually tried to use the
application, it would appear to be doing something for several minutes but
fail with a mysterious error inviting the user to submit a log file to
support.

Of course, the log file was secretly marked to indicate that it had come from
a pirated copy and the customer would get a polite call from the sales team.

It worked out pretty well, a lot of customers didn't know they were using
pirated software (or so they claimed; somewhat plausible given the nature of
the utility) and were happy to pay and the sales team got a lot of solid
leads. Evil vanquished, good prevailed, and I got paid.

------
m52go
Got 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.

~~~
mizzao
Why would someone microwave blueberries?

~~~
Anderkent
Making sauce or heating up a muffin, I guess?

Or frozen blueberries, but why would anyone buy frozen blueberries.

~~~
dragonwriter
> Or frozen blueberries, but why would anyone buy frozen blueberries.

Because they are available and inexpensive year-round, and they defrost well
and are good in many applications. Outside of the peak of local season, its
the best way to buy blueberries.

------
yogrish
Reminds me of "story of a car that wouldn’t start every time its owner bought
vanilla ice cream". [http://www.kepner-tregoe.com/blog/help-my-car-is-
allergic-to...](http://www.kepner-tregoe.com/blog/help-my-car-is-allergic-to-
vanilla-ice-cream-a-study-in-problem-solving-part-ii/)

~~~
9935c101ab17a66
That story is so incredibly far-fetched, and further comprised by the not-so-
subtle product plugs liberally sprinkled at every turn.

~~~
sundarurfriend
It sounds like it was written or told by an engineering person and then
mangled into this BusinessExecutive™-speak by some marketing person.

And the story doesn't have that big a payoff to justify that either.

All the plugging did was make me slightly annoyed and averse towards the brand
and that bloody catchphrase.

~~~
1wd
The story has apparently been recounted and rewritten many times since at
least the "June 1978 issue of Traffic Safety magazine".

[https://www.snopes.com/autos/techno/icecream.asp](https://www.snopes.com/autos/techno/icecream.asp)

~~~
magic_beans
That makes the biz-speak story posted on the KT website all the more
distasteful.

------
post_break
When I worked at an NOC for a fairly large ISP they told me a story of an
intermittent outage that occurred randomly on weekends. Something was
injecting insane amounts of RF interference on the lines. They tracked it down
to the node, then the neighborhood. And then finally they found the culprit.
What was knocking the network out of whack? It was some guys edge trimmer. The
motor in it was injecting crazy signals somehow. The ISP bought him a new
trimmer and promptly took pictures of this one and destroyed it. Never had an
issue with RF again.

~~~
lucaspiller
On a related note it’s interesting how electric shavers (which could easily
suffer from the same issue) are allowed on aircraft, but mobile devices need
to be in flight mode. Are the frequencies of RF noise from an electric motor
in a different range, so they don’t cause issues with aircraft?

~~~
throwanem
The problem with electric motors is back EMF, not so much RF - motors don't
spin that fast. (Switch-mode power supplies _do_ switch that fast - into the
hundreds of kilohertz - which is why cheaply made and thus poorly suppressed
ones do tend to produce radio noise that you can hear, in harmonics at least,
in the lower AM band. It'd be rare to find a tool motor that spins much over
30K RPM, and even that's on the high end.) So the noise is too low frequency
to qualify as RF, but you're still dumping inductive voltage spikes into the
supply, which can destabilize other equipment on the same circuit or one
nearby - in this case, while the neighborhood concentrator might not have been
(probably wasn't) on the very same circuit as the trimmer, it probably was on
the same transformer, or else the circuits ran parallel in a conduit somewhere
and the noise was getting capacitively coupled into the concentrator's supply.

This wouldn't be a problem with a battery-powered trimmer because it isn't
connected to the aircraft's hotel supply - or if it is, it's through a wall
wart, which will contain a transformer and at least some suppression
circuitry, which will dissipate any EMF that makes it out of the tool. And in
general, the way you suppress this kind of inductive noise is with capacitors
and chokes, which any reputable manufacturer of a line-powered motorized tool
will include in the design. But there are a lot of disreputable manufacturers
out there, too.

------
justjash
I guess this could be fun depending on how much you liked your neighbors.

I had something like this happen once that was interesting. We had recently
got a Simple Human automatic soap dispenser and had it sitting in the kitchen
by the sink. I was bored and started playing with a small RC helicopter and
kept hearing a weird noise but didn't know where it was coming from.

For whatever reason, every time I would throttle up on the controller it would
trigger the the dispenser to dispense soap as if someone had stuck their hand
under the sensor. I ended up finding a large puddle of soap in the sink and
then it clicked as to what the noise was.

~~~
bonestamp2
Was it one of those cheap RC helicopters that uses IR for control and the IR
blaster on the remote was triggering some kind of IR sensor on the soap
dispenser that is normally trigger by a nearby hand?

~~~
justjash
Yep, just a cheap RC helicopter from Amazon with IR controller.

------
drtillberg
The comment from im_from_detroit [1] seems on-point, possibly ultrasonic sound
from a backup sensor on the car being received by an ultrasonic detector in
the house.

[1]
[https://www.reddit.com/r/cars/comments/7k12fs/neighbors_hous...](https://www.reddit.com/r/cars/comments/7k12fs/neighbors_house_alarm_triggers_when_i_put_my_car/drbfqge/)

~~~
alkonaut
Op mentions later there are no sensors. So either a light/shadow thing or a
sound/vibration thing.

~~~
jsmthrowaway
Engines sound deeper when you put them in gear, if he’s driving a muscle car
or something, though I’d expect coming home in the evening would do it too in
that case.

~~~
emodendroket
It's a WRX.

------
patkai
Is there a way to vote this as the funniest HN submission of the year? I
started laughing and when I thought "what will happen when the vague concept
of the Internet-of-Things becomes a reality" I can't stop. I always loved
Subarus, but now I want one.

~~~
theandrewbailey
I don't think there's a funniest submission competition, but I marked it as a
favorite.

------
alister
Along the same lines, I had a hell of a time tracking down the reason my
washroom GFI (ground fault interrupter) tripped on random occasions; i.e., the
electric outlet would lose power and need to be reset.

It turned out that an iPhone _receiving_ a phone call tripped it -- even
before it starts to ring! Making a phone call didn't do anything. Here's a
13-second video:

[https://vimeo.com/247730625](https://vimeo.com/247730625)

I'd love to hear comments about the possible cause.

~~~
beala
I can often tell that I'm about to receive a text message because my poorly
shielded computer speakers will start buzzing. I assume it's caused by a
transmission from my phone's radio inducing a current in the amplification
circuit.

I would guess this is what's happening with your GFI. Even though you're
receiving the call, your phone is probably transmitting too (sending back the
equivalent of an ACK or something). The current induced causes a difference
between hot and neutral and the GFI trips. It's surprising that it can induce
a strong enough current! I'm not sure what wattage cell phone radios operate
at.

Edit: Ah missed the detail about outgoing calls not causing it. That is very
strange! Perhaps a cell phone engineer can shed some light on that!

~~~
SOLAR_FIELDS
I’m guessing car manufacturers have caught onto this. I drove a year 2000 car
whose speakers would know I was about to receive a text/call several seconds
before receiving it. I don’t think I’ve been in a model later than 2008 that’s
had this problem. The noise, like the AOL dialup modem beeps, are one of those
things that become cemented in your brain and immediately recall themselves as
soon as you think about them. I heard the short succession of beep patterns in
my head as I read your comment.

~~~
robocat
2G GSM?

[https://youtu.be/jBu1ILbIKZo](https://youtu.be/jBu1ILbIKZo)

~~~
digi_owl
Makes a guy nostalgic for beach summers when the boombox would overlay that
because someone left their phone to close to it.

------
acranox
I don’t know why, but my thought was the same as the third most voted comment
in the thread too. The collision avoidance system, which I would have guessed
was ultrasound, but the guy on reddit says it’s microwave. Either way, that
could be picked up by some kind of sensors in a house alarm system.

We live in a crazy world.

~~~
derekp7
I don't know, I would tend to side with the theory that the car engine sound
at the specific RPM and power output matches the resonance frequency of one of
the house windows. Resonance can creep up in many phenomena.

~~~
to3m
But the engine speed doesn't change until you lift the clutch. So if this were
due to the RPM, putting it in reverse while stationary surely wouldn't do
anything in particular.

~~~
acranox
If it’s an automatic, putting into reverse will change the engine RPM.

------
sidedishes
Reminds me of this story where a car was 'allergic' to vanilla ice cream:
[https://news.ycombinator.com/item?id=13347852](https://news.ycombinator.com/item?id=13347852)

~~~
bshacklett
There's also the case where an email seemingly had a physical distance limit :
[https://www.ibiblio.org/harris/500milemail.html](https://www.ibiblio.org/harris/500milemail.html)

------
balabaster
The curse of the 500 mile email and the car that won't start because it's
allergic to vanilla icecream. ;)

\-
[https://www.ibiblio.org/harris/500milemail.html](https://www.ibiblio.org/harris/500milemail.html)

\-
[http://www.cgl.uwaterloo.ca/smann/IceCream/humor.html](http://www.cgl.uwaterloo.ca/smann/IceCream/humor.html)

------
mrmondo
Used to set off car alarms all the time when I had ‘quite hotted up’ Type R
Integra years ago, never house alarms though I think.

I’m willing to be the guy/gal next door has those broken window alarm strips
installed, one part of the strip is loose and when the cars RPM drops as the
clutch is let out while in reverse it slightly vibrates the window causing the
contact to short (or break) and thus the house alarm goes off.

Good fun :)

~~~
dawnerd
Very likely. My neighbors son has a loud as hell car and it definitely rattles
my windows even when in idle.

------
rurp
Last year a co-worker frantically came over to tell me that text was
disappearing from her computer screen. I walked over to her desk and watched
as she began to type an email. Sure enough, the characters she entered went
away one at a time. I glanced down at the desk and gently lifted a headset
that was resting on the "delete" key of the keyboard.

------
tgb
What I would pay to hear this on Car Talk. Sigh.

~~~
pcurve
_sigh_. I know...

Skip to 18:50 and listen on for couple minutes.

Love the caller complaining about his brother in law.

[https://play.podtrac.com/npr-510208/npr.mc.tritondigital.com...](https://play.podtrac.com/npr-510208/npr.mc.tritondigital.com/NPR_510208/media/anon.npr-
podcasts/podcast/510208/543083891/npr_543083891.mp3?orgId=1&d=3191&p=510208&story=543083891&t=podcast&e=543083891&siteplayer=true&dl=1)

~~~
macintux
That's great, and thanks, I had no idea about the implications of the oil
light.

~~~
pcurve
I really miss his infectious laugh. He saw humor in everything.

------
2_listerine_pls
This comment made me laugh:

> Maybe you neighbor is setting off his alarm on purpose just to mess with you
> haha!

~~~
brailsafe
That would be some next level mindfuckery

------
geekamongus
Reminds me of when my dad had strewn ham radio antennae between trees in our
backyard when I was a kid. For a few days, any time he started doing his Morse
code, the neighbor's garage door would start going up and down.

~~~
digi_owl
Makes me think of early days of wireless keyboard, where the same model would
always broadcast on the same frequency.

Made for some fun times at LAN parties etc.

Even read about a pair of keyboard that managed to reach several kilometers,
even though the locations had line of sight blocked by a hillside.

------
dbrgn
Added to my "Stories from the Internet" collection :)
[https://dbrgn.ch/stories-from-the-internet.html](https://dbrgn.ch/stories-
from-the-internet.html)

~~~
ivanbozic
Nice, I love reading about these things.

------
webignition
Two related things-that-should-not-be-related bugs that I have encountered:

The WiFi on my girlfriend's laptop would fail when an HDMI cable was plugged
into the laptop. Changing the channel on the router "fixed" it but we never
could figure out the ultimate cause.

I can pause my Roku box using the Kodi remote app on my phone. This occurred
when I inadvertently used the wrong remote to pause the Roku. It appears only
to work if the Raspberry Pi running Kodi has gone into some sort of standby
mode, possibly making the Kodi remote app send a wake signal which is
interpreted by Roku as the pause signal.

~~~
digi_owl
No engineer, but i suspect the WIFI and hdmi stuff is RF related. Someone did
a poor job on the laptop wiring and the HDMI is leaking noise into the WIFI
antenna or something.

Seem to recall reading about similar issues related to WIFI and USB3.

As for the remote app stuff, i guess it's time to break out the packet
sniffer.

------
sirwitti
My first thought was parking assistance which might trigger a sensor in the
other house.

------
drawnwren
I drive a modified car, this is obviously the glass break sensors in the
house. My car sets the sensors of other aftermarket car alarms off as I drive
around because of the exhaust frequency. I imagine the same thing is happening
here.

~~~
jasonmp85
I didn't realize anyone would actually admit to driving such a public
nuisance.

~~~
drawnwren
Not only are you being rude, you're providing no value to the conversation.

------
IndrekR
To me (an electronics engineer) it sounds like your neighbor's alarm did not
pass EMC immunity tests quite ok... and at the same time the car's tests were
passed with way too thin margin.

Or it could be that one of the alarm inputs is in high impedance, but then it
should trigger to way more than just putting a car in reverse. Little bit of
site surveying with portable spectrum analyzer may reveal something. Or
playing around with wide-band emitters -- which may be illegal.

Then again -- it may be something else. Good hint would be to know what sensor
is triggered exactly. Usually alarm control panels tell that.

------
pishpash
Yeah, no I don't think we're ready for the internet of things.

------
molteanu
I have this weird "turn on your laptop and your phone cannot see the wi-fi
anymore" bug, or whatever this is. I've tested this with different phones,
same issue. So, I'm turning on my phone wi-fi and it all works well. As soon
as I start my laptop, the wi-fi goes off, it is not seen by my phone. The
laptop is cable-connected. Sometimes all is fine so this is kinda random.
Maybe on cloudy days it works (as remyp says of his ipads), haven't checked.

~~~
pishpash
Sounds like your laptop's wifi module is introducing unwanted interference.

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pryelluw
My brother had a 1991 Ford Mustang 5.0 with a flowmaster 3 inch exhaust system
(no cats). It would set off alarms at a specific RPM in 2nd gear (under slight
load). He enjoyed annoying people with it (my brother was a hardcore car guy).

View this YouTube video to get a good idea of how the car sounded (my
brother's was a bit louder):
[https://youtu.be/cNWv5WpamPc](https://youtu.be/cNWv5WpamPc)

------
jstanley
Interestingly, 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.

~~~
spydum
Garage door openers frequently operate at 433MHz, very likely your neighbor
was hitting the button as they left?

~~~
jstanley
Good thought, but they don't have a garage.

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danschumann
This reminds me of "emails won't send beyond 200 miles".

If his garage is angled, he could try neutralling out to the street before
starting the car.

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udaciousmark
This makes me wonder if anyone has thought to add microphones yet to the array
of sensors an autonomous car uses. Things like "my neighbors alarm keeps going
off when I go into reverse" and "there is an ambulance somewhere I cannot see
yet" sound mighty useful (well, at least the latter example), but very hard to
incorporate.

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markwillis82
I currently have an issue with my iMac (also happened with the MBP) and iphone
8 (also happened with the previous iPhone 5S) that if I have bluetooth enabled
on my phone and unlock it... my bluetooth mouse stops responding on the iMac.
Interestingly my phone and iMac are not paired and nor is the mouse and phone.

Very frustrating

------
simonjgreen
I used to have a Mazda whose alarm went off every time I used particular
2.4ghz remote control within 10ft of it.

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djsumdog
I've owned two WRXes (05 and 07) and stock, they do have quite a lot of bass.
:-P I usually take the train to work every morning, so thankfully I haven't
triggered a neighbors car alarm. Yet considering the sound that comes out of
the stock muffler, I can see how this happens.

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joeyspn
Some time ago I posted a weird issue I noticed with my neighbour. HN solved
the mistery in minutes... =)

[https://news.ycombinator.com/item?id=11935275](https://news.ycombinator.com/item?id=11935275)

~~~
jventura
Yours remind me when I was also a radio aficionado many years ago, one night
my upstairs neighbor called me because each time I pressed the button to talk,
my voice would come out from her TV. I was basically ruining her favorite soap
opera!

------
scelerat
I'm having a waking dream of Click and Clack (RIP) discussing the phenomenon.

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emilssolmanis
I half expected this to be another IoT thing. The car broadcasting some form
of wireless signal when it switches gears for some app integration, and the
alarm picking that up.

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sliverstorm
Not particularly mysterious, but I got quite a jump one day when I keyed up my
50w VHF mobile in the garage and instanly every single fire alarm in my house
went off.

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evanslify
Maybe the car owner has some sort of parking sensor, uses radio and thus
interferes with neighbor’s house alarm system?

------
m3kw9
Maybe the rear lights has something to do with it, could be a faulty light
oscillator for led if you are using one

------
jjuel
Sounds like a great question for Car Talk!

------
nouveau0
Reddit is literally leaking

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petar_prog
Someone 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).

~~~
alister
> _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.

~~~
_Nat_
Alternative hypothesis, for the sake of example -

Someone's just really be into practical jokes. Possibly the neighbor whose
alarm keeps going off, or possibly a third-party who found an easy way to
trigger the alarm.

But, my first thought on this thing triggering when he backs up is a rear-view
sensor that uses a projection to get data. Apparently the 2018 version of his
car has radar sensors that go off when backing up
([https://www.subaru.com/engineering/safety.html](https://www.subaru.com/engineering/safety.html)):

> Rear Cross-Traffic Alert uses radar sensors to help warn you of traffic
> approaching from the side as you are backing up, utilizing an audible
> warning and flashing visual indicators in your side mirrors and Rear-Vision
> Camera display

~~~
DonHopkins
I wonder if backing up would set off other people's radar detectors.

Reminds me of "Trolling for Taillights"!

[http://www.cs.cmu.edu/~hgobioff/public/random_stuff/traffic](http://www.cs.cmu.edu/~hgobioff/public/random_stuff/traffic)

------
api
It's the future.

