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.
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.
I've owned a number of Subarus and let me tell you, even the non-performance models have a way of shaking things inside the house that you wouldn't believe until you experience it. My STI was capable of being loud, but oddly enough it was my wife's Outback (nearly silent if you stood next to it) that would shake pictures on the walls and make them start tapping.
Very true. My '13 WRX shakes pictures when I start it up in the garage, I have to immediately pull into the street so I don't piss anyone off while getting Google Maps and Spotify set up before I drive.
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.
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.
Mine isn't connected but, yep, could certainly see how that'd work. Whilst no fancy auto pilot yet, the AEB and radar cruise are very nice things to have in a car.
Motion detectors with microwave, especially residential sensors, don't use it as the sole detection method. It's always paired with passive infrared. Microwave interference doesn't really make any sense because he'd have to be tripping the infrared and microwave source at the same time.
Source: I wrote firmware for microwave/PIR motion detectors for a few years.
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.
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.
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)
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.
Well, putting it in reverse with the engine off but with electronics on would potentially let us rule out anything related to sound from the engine, and would mean it's more likely something related to electromagnetic waves or something else coming from the onboard electronics.
> For one thing, okay, we did that and the alarm didn’t go off. What did we eliminate?
Weird EM interference from electronics, ultrasonic backup sensors, Magic Stuff Related To Reverse #1.
> 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.
Maybe it was caused by Magic Stuff Related To Reverse #2, or maybe it turns out the system is actually powered when you thought it isn't.
Looking over your other comments in this thread, I feel like you're approaching the topic from a position of someone who's an expert in cars and electronics, and thus has almost everything important in their memory already. But in cases when one isn't an expert with a thing one's debugging, I'd err on the side of doing the tests that seem ridiculous, at least if they're cheap to do. Discovering that it's probably Magic Stuff Related To Reverse #1 is a fair result, and should then be followed by reading up on what else gets activated/actuated when one's car gets switched to 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 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!
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.
I'll add a related real life debugging tip I've seen play out at least twice in the real world:
If you can't get an alarm to shut-off or stop beeping, no matter what you try, then give serious thought to the possibility that there's a second alarm nearby which is the source of the noise.
About a year after I moved into my previous house, we heard that familiar chirping sound.
After 3 goddamn hours of searching, and having run to the store to buy 9-volts and replaced every goddamn battery in the house, we found a carbon monoxide alarm thrown INSIDE the return air duct of the HVAC unit...
Which is a reasonable place for one, as it will trigger from excess CO anywhere in the house when the HVAC is running. The problem is only obvious when you're not the original tenant who installed the thing.
The others were correct. It was the neighbors low battery smoke alarm.
I had high suspicion that it was that. But not hearing it thru neighbors door. And with how loud it was and the fact I could hear it thru my front door and not theirs. Made the hunt for it so much harder.
Just did this yesterday, and eventually found it was the neighbours one that was flat. It’s the 3rd time I’ve knocked on a neighbours door (different people each time) to ask them to take a battery out an alarm. I’d consider it a feature if they combusted after alarming for a day.
I am Deaf. In the night you would need to break into my flat, too, because the flash indicating the door bell is in the living room, not the bed room. Nobody and nothing disturbs my sacred nightly sleep.
My house has 6 fire alarms, when they beep there is NO way to tell which one it is making the noise 2/2 the combination of short beep and irregular beeping interval.
My solution is to just change all the batteries at once so i dont have to guess (and if you guess wrong you then you wont sleep tomorrow because of the beeping)
I wish there was some visual indicator to tell which one was faulty.
I believe they all beep because they want you to replace all the batteries.
I had this happen a few months ago except it wasn't a low battery alarm. It kept yelling "FIRE FIRE" but then turning off. Of course FirstAlert apparently doesn't indicate which alarm is causing it. They say the initiating one flashes a different pattern but I didn't find one. Ended up, after getting no sleep at all, replacing all 9 of them with nests. At least then if one fails I'll know which one.
Aren't Nest Protect alarms also linked? This harrowing video leads me to believe they are. It's a couple years old at this point though. (Turn your sound down, video is a poor soul trying to deactivate them.)
My smoke detectors made a boast on the packaging they featured a fool-proof low battery indication, without going into any details.
I bought half a dozen of them to install in our new house years ago, thinking the nightly find-the-beeping-^+=¥€ games were finally a thing of the past.
When one started beeping, I did the rounds, figuring I'd be back in bed in minutes. Well, I wasn't. Turned out the fool-proof indication was to have the normally green LED flash red instead.
Unfortunately as some who isn't colour blind and doesn't have any close friends who are, it's easy to forget about these concerns. I think attention to accessibility issues like this is one of the things that separates great designers from good ones.
That reminded me of an iOS quirk that thankfully has since been resolved.
A few years ago I used "Find my iPhone" to chase down my phone in the house, buried under some pile or another. Unfortunately I had earlier been using AirPlay to play music through remote speakers, so of course the emergency tone played through the speakers, not the device.
Had a near identical issue 3 years back in my apartment! After tracking the source (ear on walls, floor and just figuring out where it was) i ended up discovering it was an alarm in the mechanical room below my apartment. There was a crack in the heat exchanger and it was a CO alarm, the disturbing part (lost sleep aside) was that my complaint about the sound is what alerted the building to the issue, and worse yet, their solution was to consider it a false alarm as they couldn’t see anything wrong and air the room into the hallway to stop the sensor (worked for around 30 mins until in unit alarms started going off too).
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!
I think this one is even more evil, because it forces you search in the dark.
This in fact is a very popular around the world electronic kit for beginner hobbyists, because it's trivial to build and has only few components. I remember it from electronics magazines in Poland.
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.
Elsewhere in the thead I was
moaning about this design, as multiple times it’s been in flat in our neighbours house and I’ve been checking ours.
Can’t they just die quietly? If you aren’t checking them periodically anyway, you don’t know they they work.
They shouldn't, unless you want to risk dying with them :).
That said, everyone should check their alarms at least once. You should be able to find appropriate "testers" to purchase with alarms. I use CO alarms at the place I live in (gas-heated water), and each of them I tested with what I affectionately call "carbon monoxide in a spray can".
Back when Facebook used a "pop" sound when you get a message, I was able to imitate it well enough to make my friends in the same room check their computer for messages!
In the late 90's early 00's, we had a pet cockatiel that could perfectly mimic the sound of dial-up modem dialing. He would also do the tunes to TV theme songs and a few regular TV ads.
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".
The whole house hard wired smoke alarms are just SO FUN when they start to fail. The one that is failing immediately sets all of them off, but only once at 3AM every night for two weeks. So you get woken up by a brief ear piercing alarm from around the whole house and have no idea which one it is.
I had a battery powered one that randomly triggered in the small hours. I'm very sensitive to loud high-pitched sounds, so I woke up with a fright that must have aged me 20 years. Tore that thing off the ceiling, nearly pulling a chunk out with it. Landlord was very unhappy with me doing that, but it was right over my bed.
If I'd had a baseball bat or wooden sword, I'd have smashed that thing free like a piñata!
Your observation of the unhappy timing is probably related to the temperature. Cold batteries have lower voltage across their terminals, triggering the chirp.
(You can troll people into thinking you have magical powers, rub the batteries of a just-failing calculator/scale/wristwatch in your hands and you'll get another ten minutes of use out of them)
(Un)fortunately there are things that are written down in standards, like the LED blinking behavior, that the manufacturers can not change if they want to legally sell the devices.
You can get a smoke alarm with 10 year battery life to reduce the likelihood of this happening. When all are purchased in one batch, you can then pretty much replace them all at once -- if first battery goes, next ones are soon to follow.
I got some unconventional looking ones from Jalo Helsinki [1] for my house. They work well and look good. However, I know some people working at Jalo, so my opinion is biased. There are several other long battery-life smoke alarms on the market from different manufacturers to choose from.
You could also just buy the Lithium 9V batteries instead of Alkaline and put in your regular smoke detector - same result https://www.amazon.com/dp/B01684J7P0
If it runs on a standard 9V battery, then a very good option!
Newer and smarter smoke detector chips are designed for 3V lithium-manganese dioxide batteries.
In theory, you can. However, the standards also mandate that the "annoying" function has to work at least few months after the battery is low. Adding an extra LED there will consume too much power.
20 years ago, in my first graduate job, we were issued pagers. One day my friend lost his - and it was on silent mode. We really didn't want to tell the company that it had disappeared.
Then we remembered that, at a certain time - I recall it being reasonably late at night - the device would emit a single, short, beep. I don't remember why, but even on silent mode, that beep would sound.
At five minutes to the hour - because this thing's clock wasn't synchronised, and we didn't know how accurate it was - we all positioned ourselves around the house. Silent as a mouse we waited, until - yes! - there it is, somewhere upstairs.
Now that we knew that it was actually in the house, it was just a matter of finding the thing. It was in his pants pocket - but they way they were folded in the wardrobe, the pocket wasn't where you'd expect it to be if you did a casual "pat the pockets" to see if it was in there.
I might be mildly evil, but I have deliberately caused a situation like this once in my life. I lived in an apartment with someone above and below me. At some point a woman moved in above me and my gf, paying way more than I did (par for the course in SF at the time). She was a super bitchy lawyer, and pretty shortly we started getting complaints that we were making too much noise at night. Keep in mind she was above us, so it wasn’t us walking around. She complained she could hear us talking and typing — but we were both really quiet people, and it’s not like I had a loud keyboard or anything. It was annoying and she wouldn’t stop complaining.
Eventually I decided to move out, for other reasons. My last act after everything was out of the place was to buy a cheap battery powered alarm clock, sat on a high shelf in a bedroom closet in a hard to see spot, programmed to go off at 2am every night for 5 minutes.
I had something along these lines happen to me years ago. It was sound-related, but didn't turn out to be electronic.
I was renting in a century-old house that had been converted into apartments. Every night, around midnight, this very high-pitched hum would start, and continue until almost dawn. None of the other residents ever heard it when they were around. While the exact timing varied, the time during which it happened overlapped with my sleep schedule (I was working a late tech support shift at the time) and it kept me awake. Earplugs didn't really seem to help.
There didn't seem to be any obvious source. I did exhaustive work to try and track it down - even got the permission of the owner and my fellow tenants to try shutting off the power at the breaker box in the middle of the night to see if that helped. (It didn't.)
It wasn't always constant, but it was around enough and preventing me from sleeping enough that I was going slowly insane. I had my ears checked for tinnitus - nope, I had and still have darn good hearing. I started reading about the Taos hum, looking into resonant frequencies, and finally stumbled across the answer.
The noise started a little while after everyone in the building went to bed. It stopped shortly after they got up in the morning. It was the sound of the century-old plumbing system at full pressure. If I just left a tap open a trickle, and the noise went away along with my sleep-deprivation.
One day, years ago, I was working from home and I heard the intermittent "beep!" my uninterruptible power supplies make when they're unplugged and running on battery. I checked all of my UPS's, then turned off all of my equipment, but still every few seconds, "beeep! ... beeep!" It seemed to be coming from underneath my computer desk.
Eventually a spark of inspiration hit me, and I reached up and pulled the cord on the window blinds behind the computer desk. I found myself nose to beak (through glass) with a startled mockingbird. "Beep?" it said, and flew off.
Of what little I read of the reddit thread, there must not be many gear heads in there that debug software, too. I say that only because there is a lot of “it’s probably...”
but no “try this, which will eliminate $FOO. Next, $BAR, which eliminates $FOOBAR.”
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.
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.
I was a noobie computer programmer in my first job. After being there for a few months my mouse started to have issues. It stuttered and refused to move correctly.
So I'd take the little grey ball out and clean it and it'd be OK again. But the next day it'd do it again.
So I ended up with the cleanest fucking mouse on planet earth. Yet every so often it'd stop working... on parts of the screen. Other parts it'd work. I ended up using the keyboard a lot.
The mouse would work fine all day some days. Some days it would work fine until about 2PM then it may or may not work.
Eventually I figured out that when the sun shone through the window it created a beam across my mouse mat. When the mouse was moved into the beam it would stop working. So I took it to bits and discovered that the ball would roll a little disc, that disc had little holes in it, there was also an LED and a photodetector. So the mouse was counting the blips in light to determine the movement in the mouse. I guess the cheap plastic was allowing the bright sunlight to bleed through the case causing the photodetctor to go bonkers.
A secondary thing about that cheap as shit PC was you could hear the video card render the screen. It'd buzz when the screen was mostly blue, when it was white it would be silent.
Ha, my mouse scroll partially stopped - turns out it's a rotary encoder like you describe, some of the gaps get blocked with dust and the mouse stops scrolling, a bit, still scrolls but seems intermittent (like a software issue), was a couple of days before I opened it up as I was looking for a fault in logs and such.
Of course opening a mouse up and not breaking it is quite hard, they're made to break and be replaced. Current bugbear is Logitech keyboard stand pieces that appear only to be there to break and thus require keyboard replacement - again it seems a design with a penny's more of plastic would be almost invincible.
I recall a story on reddit's talesfromtechsupport a printer would stop working at a certain time of day. I think it was near a skylight or something weird. I have no idea what it was about but your story jogged my memory but not enough to remember it all.
Wait, you had a buzzin when the video card is active as well? Was yours dependent on the refresh rate on the video card? (I haven't found any other mention of a similar problem elsewhere, and mine has been doing that for a few years now.)
I can hear a small buzz when something is rendering as well. Turns out that in my case it was coming from the VGA cable making interferences in my loudspeakers cable.
Here's my odd story. Years ago, my wife and I were sleeping over at my parents house and we were awoken by garbled conversation from the clock radio. I sleepily checked it out and saw that the radio was turned off. Thinking that the on/off switch was broken, I just unplugged it. The garbled conversation continued. At this point I wondered if my parents house was built on top of an ancient burial ground...
Talking to my father in the morning, he indicated that his neighbor had taken up Ham radio and he was having to put filters on various devices to reduce interference. To this day, I wonder if his spotty wifi in the house is related to his neighbor turning his system...
It seems like a bit of a stretch, but in theory - depending on the details of the radio, and the power being emitted by the neighbor's station - you might be able to get some audio from a "powered off" radio. Maybe it's doing something like what happens when a crystal radio[1] absorbs enough power inductively to generate its audio.
Something like this happened when I was a kid and it scared the heck out of me. Suddenly there was this loud garbled voice booming from the stereo speakers. I thought it was the devil or something. Turned out to be the radio enthusiast who lived next door. There was a big antenna in their backyard, so they were probably broadcasting with some power. Plus my dad had the whole Hi-Fi rigged up with lamp cords.
I knew someone who lived two blocks from a radio station, and they would get interference everywhere, there would be staticky top 40 music coming from the phones, from clock radios, from the stereo. It would come and go. They would complain, the radio station would fix something, but in a few months it would be back.
I had to debug my home this summer and I think it makes a good story. I have been renting this appartment on the ground floor for one year, and for environmental and economical reasons, I decided to try to reduce my electricity bill, which was quite large for the size of the appartment. An obvious culprit was the Canadian winter in a poorly isolated place, but I was also wondering about why in summer I had around 22-23 kWH of electricity consumption every day. I have no A/C, so I figured it was either my electronics or the appliances or a combination of both.
I bought an electricity usage monitor plug and started to measure every electricity consuming stuff, but couldn't account for more than 3 or 4 daily kWH. Then I went in vacation for one week, turning off almost everything in the house, and the electricity consumption, that I can check every day, had barely moved. Something was consuming at least 20kWH every day in my home and I didn't know what it was.
At the same time in prevision of the winter, I bought a thermal IR camera to spot isolation problems. I started to play around with it, and discovered a fairly large hot spot in the bathroom, on the bottom of the bathtub. Touching it with the hand, it sure felt warmer than you would expect from a baththub. Maybe it was some hot water? But the water heater was on gas and my gas bill was fairly normal. The hotspot would also not go away after hours. Then I remember a visiting friend remarking weeks ago that my bathroom was warmer than the rest of the appartment.
To test my suspicions, I tried to play with the electricity meter of the appartment. After some experiments, I found out a switch that would turn off the mysterious heat source. The baththub started to cool down and the power usage displayed went down to 0. My theory was validated! Something under my bathroom was drawing around 800W constantly every hour of the day and every day of the week and that was making my appartment so hot in summer and my bill so large.
At this point, the only thing I could do was contacting my landlord and detailing my findings. It turned out he had installed a dehumidifer in the basement the year before to dry out the air and fight a moisture problem, but he had configured it to a very low setting, like 30% humidity and that was making it work constantly. The dehumidifer was installed just below my bathtub and its operation was heating it at the same time. Since it was an old home he had bought out a few years before, he didn't know where the basement was drawing its electricity from. Well now he does.
He reimbursed me the electricity and changed the settings of the machine and then my electricity consumption went to almost nothing... until november came and the cold of the last weeks of fall started to hit Montreal, but that's another story.
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.
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.
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.
There are no explicit "parking" sensors (it's not going to beep if you're about to back into something) but all but the base model have blind spot and reverse cross-traffic sensors. I can't find any explicit mention of the trim from OP. It's quite possible he's incorrect in saying he has no sensors.
I have a 2016 WRX with what should be the same exhaust. When you start the car, it starts with a high 2000-2200RPM idle and drops from there. If it needs to warm up, it will sit around ~1800rpm which is exactly where the stock exhaust makes the loudest drone.
So simply starting the car and letting it idle should result in it hitting all the revs that trying to reverse would (unless OP is awful at driving stick and way overrevving it here).
I find it way more likely there's a sensor interference issue than it's an exhaust issue based on the other information. My second guess would be some IR from the halogen running lights / fog lights / other lights in the car interfering with a motion sensor.
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).
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.
Seems like the neighbors home security system should have a log of which sensor is tripped. Once you know that it should be pretty easy to figure out what is going on.
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):
> 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
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.
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.
Maybe they had the kind that grows in the wood and not in the shop? ;) When you pick berries it is normal to store them frozen to have through the winter
> 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.
Indeed. Several years ago, I was working on a 2.4GHz device, and we noticed that occasionally, the microwave in the office kitchen would disrupt things. A quick check with a 2.4GHz band spectrum analyser showed what was going on:
The company being as cheap as it was, I simply began using the microwave as a deliberate noise source for testing the device's operation under adverse conditions, placing a few mugs of water in the microwave for a few minutes, and deliberately setting my channel to collide with the microwave.
When I lived with my brother and played a lot of WoW I would get disconnected almost every night at around the same time, and usually in a Raid which was quite annoying.
Eventually I tracked it down to microwave usage. Whenever the microwave was in use, I lost WiFi.
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
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!
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:
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!
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.
It's not that they use different frequencies (in a lot of places, they've actually recycled GSM frequencies for increased LTE bandwidth) but that they use a different form of modulation (than TDMA) that doesn't cause the same interference
I remember old feature phones which had a fancy light on the back, which started blinking whenever a call was about to come through. Was a pretty nifty feature when you were expecting calls ['twas a time when I used to give "missed calls" for a callback].
Before UMTS came online and brought higher frequencies etc, i seem to recall novelty shops had a rack of objects one could attach to a phone. These would all light up when a call came in. There was apparently enough juice in the signal that the antenna in the object could drive a LED.
Yup. It doesn't take much to make an SMT LED shine - just a milliamp or two, and an interesting property of that kind of inductive coupling is that, up to a limit, you can couple a higher voltage out of a given signal by increasing the number of turns in your winding. And if you couple out more than the forward voltage of your LED junctions, you can convert the surplus into enough current to visibly light the LEDs as they conduct. So with the right kind of boost circuit - in this application probably just an inductor, although I could be wrong here, analog isn't my forte - driving the LEDs, and a bare-die CMOS shift register that sips a few microamperes for the animation, you can pretty easily produce the kinds of effects I remember seeing back in the before time too - and still miss to this day!
RFID works by the same principle, incidentally - in this case, the energizing signal comes
from a primary winding in the reader housing, and the secondary in the card powers a little CMOS chip that in cheaper models just modulates the voltage drop over the winding to return a constant code, and in more expensive models receives a challenge nonce signaled by the card reader and modulates the winding to return an encrypted response. It's a really interesting application, and an impressive but often overlooked early example of "IoT" style smarts done well.
My friend's chinese motorcycle had this light built in on the gas tank. It's really helpful because you can't hear your phone ringing/vibrating while riding. AFAIK, this stopped working after transition to 3G.
The same thing happens with a Motorola RAZR V3 GSM quad-band cell phone (a flip phone). I have that on video as well though I didn't upload it. I haven't tested any other phones.
Probably GSM. They do that, make interference before the phone rings. Put it by some computer speakers turned on full blast with no sound playing. You'll here the GSM morse code.
I would guess it's probably your phone's speaker. As the call coming in, the phone fires up the speaker for ringing. The speaker induces a current.
GFCI works by detecting the difference in the current flowing between the hot wire and the neutral wire. It needs to work very fast (to avoid the human touching the wire getting electrocuted) so any slight difference in current would trip it off. The current induce by your phone's speaker probably causes enough difference in the current to trip it off.
You can run an experiment by turning off your phone's speaker for incoming call. See if the speaker is the culprit.
The timing sounds like RF interference. I worked in TV a while back, and we were not allowed to have any cell phones (even silenced) on set - they would introduce this crackling sound into lightly-shielded cables near them. The interference would kick in about a second or two before the ringing started, because there's probably some handshake/setup before the receiving phone decides it's actually an incoming call.
In that case too, sending calls didn't trigger the interference, and neither did picking up the received call.
My layman understanding of the old GSM network is that cells have a control channel that is used to set up calls (and initially also transfer SMS, before it became popular enough to DOS the cells) and then a bunch of channels for handling the actual calls.
It may well be that the control channel's initial "wakeup" transmission is done at a very high power to ensure the phone receives it clearly, and then after some back and forth the two adjust their power levels and move to a different channel for the actual call.
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.
I lived in an apartment in Fl and during the month of August and into September, every afternoon my cable would cut out for several hours. Happened every year for the three years I was there and only during that part of the year. Could never get Comcast to get a tech out there during the correct time frame, but they had a box mounted on one wall and that time of year it got direct sunlight and I suspect heat was to blame.
I worked for a cable ISP helpdesk once and during a particularly hot summer I vividly remember an on/off outage where we'd be getting regular updates from the field guys along the lines of: "We opened the doors and it works now." and "It failed again but we got a fan from the neighbors and that seems to help!"
Many years ago I had an optical mouse that would act erratically in the afternoons (just wouldn't register movement). It seemed to be ok if I squeezed it while I was using it so I figured it was a connection somewhere. Eventually I realised that it was the afternoon sun streaming in through the plastic seam and somehow stopping the sensor.
Reminds me of a wireless mouse I had that would intermittently become stuttery, but would usually fix itself whilst I tried to troubleshoot. I eventually realised that my laptop was between the mouse and its receiver, and any higher than normal utilisation of WiFi would interrupt the signal. Moving the receiver to the other side of the laptop completely resolved the issue.
Just curious, but what was the ultimate "fix" you landed on? Did you simply move the machine out of the path of the sun? Add a visor or something to the screen or window? Add something to cool the device down when it overheats? Switch to a different device entirely?
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.
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.
In the 90s I was working a summer job as a forest fire fighter, and one morning the radio kept constantly beeping on one channel. Nobody could figure it out until a couple of hours later we got a call about a fire on a hillside on the other side of town. It turned out there was a radio repeater on the hill and the fire had burned through its power line, so it was beeping to tell us it was running on batteries.
At one time I lived in an apartment building just outside of Seattle that had public retail space in the lobby. To allow residents and their visitors in after hours, a fancy touch screen was installed where you could enter an apartment number and it would phone the apartment where someone could then punch a number and unlock the door. Standard stuff.
Except that the touch screen could be activated by rain. In Seattle.
There was a small cowl over the apparatus to keep regular rain off, but if there was any wind at all, it was very easy for drops to be blown onto the screen and it would start phoning apartments in the middle of the night.
Amazingly, this was among the building's least troublesome faults.
I was working in a place that used to be a food store. Talked to the former owner, they had a big problem with all the freezers turning off during the nights and when they came to work all food was unfrozen and had to be thrown away. Turns out the timer to the sign outside was connected wrong and also turned off the freezers in the night. I do understand them, the electricity wiring in that building was not fun to work with... The place had been several different stores, all adding to the cables and connections over the years.
I setup several emergency call beacons at a college (push a button, and 911 is immediately dialed, and a big blue light on the pole strobes, to help police find you). After 2 weeks of random alerts for a single beacon, we eventually determined it was the sun hitting the face of the device, expanding the button a bit. Rotated the face of the device 90 degrees, and never had an issue again.
Reminds me of a story an old coworker told me. He was working as a repair tech back in the days when computers had tape drives. He was called out to a military base where they had just moved their computer one floor up, because the tape drive kept glitching. It would start up fine but then error out some seconds later, seemingly at random. After staring at this for quite some time he finally decided to stretch his legs and wander to the window. And what did he see, but a radar antenna rotating around. The glitches happened every time the antenna was pointed in his direction. On the lower floor it was out of the beam so there wasn't any problem.
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.
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.
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.
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?
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.
Reminds me of someone having trouble getting their Tesla to charge after the power company installed "smartmeters". The reason was that the model they had picked was one that used the power lines to transmit the readings, and the added noise tripped the Tesla's sensitive charging circuit.
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.
315 comments
[ 3.2 ms ] story [ 260 ms ] threadWe live in a crazy world.
Without knowing the details of the alarm system it is hard to have an educated guess.
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.
Source: I wrote firmware for microwave/PIR motion detectors for a few years.
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) (...)
[as someone else already said]
Weird EM interference from electronics, ultrasonic backup sensors, Magic Stuff Related To Reverse #1.
> 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.
Maybe it was caused by Magic Stuff Related To Reverse #2, or maybe it turns out the system is actually powered when you thought it isn't.
Looking over your other comments in this thread, I feel like you're approaching the topic from a position of someone who's an expert in cars and electronics, and thus has almost everything important in their memory already. But in cases when one isn't an expert with a thing one's debugging, I'd err on the side of doing the tests that seem ridiculous, at least if they're cheap to do. Discovering that it's probably Magic Stuff Related To Reverse #1 is a fair result, and should then be followed by reading up on what else gets activated/actuated when one's car gets switched to reverse.
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!
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.
If you can't get an alarm to shut-off or stop beeping, no matter what you try, then give serious thought to the possibility that there's a second alarm nearby which is the source of the noise.
After 3 goddamn hours of searching, and having run to the store to buy 9-volts and replaced every goddamn battery in the house, we found a carbon monoxide alarm thrown INSIDE the return air duct of the HVAC unit...
I had high suspicion that it was that. But not hearing it thru neighbors door. And with how loud it was and the fact I could hear it thru my front door and not theirs. Made the hunt for it so much harder.
Next day, enraged, we tried again. Eventually we found it in the bathroom trash can.
The designer apparently thought that emitting a single beep every five minutes or so would be an awesome low battery indicator.
I didn't know what kind of thing was making the beep, naturally, which was unhelpful.
It took about a month of me slowly going mad before I finally found the thing at the back of a desk drawer.
My solution is to just change all the batteries at once so i dont have to guess (and if you guess wrong you then you wont sleep tomorrow because of the beeping)
I wish there was some visual indicator to tell which one was faulty.
I had this happen a few months ago except it wasn't a low battery alarm. It kept yelling "FIRE FIRE" but then turning off. Of course FirstAlert apparently doesn't indicate which alarm is causing it. They say the initiating one flashes a different pattern but I didn't find one. Ended up, after getting no sleep at all, replacing all 9 of them with nests. At least then if one fails I'll know which one.
Manufacturers can get away with it because even if they screw up, an angry customer doesn't really affect their sales in any meaningful way.
https://www.youtube.com/watch?v=BpsMkLaEiOY
I bought half a dozen of them to install in our new house years ago, thinking the nightly find-the-beeping-^+=¥€ games were finally a thing of the past.
When one started beeping, I did the rounds, figuring I'd be back in bed in minutes. Well, I wasn't. Turned out the fool-proof indication was to have the normally green LED flash red instead.
Did I mention that I am colour blind?
A few years ago I used "Find my iPhone" to chase down my phone in the house, buried under some pile or another. Unfortunately I had earlier been using AirPlay to play music through remote speakers, so of course the emergency tone played through the speakers, not the device.
http://www.goldmine-elec-products.com/prodinfo.asp?number=C6...
This in fact is a very popular around the world electronic kit for beginner hobbyists, because it's trivial to build and has only few components. I remember it from electronics magazines in Poland.
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.
That said, everyone should check their alarms at least once. You should be able to find appropriate "testers" to purchase with alarms. I use CO alarms at the place I live in (gas-heated water), and each of them I tested with what I affectionately call "carbon monoxide in a spray can".
If I'd had a baseball bat or wooden sword, I'd have smashed that thing free like a piñata!
(You can troll people into thinking you have magical powers, rub the batteries of a just-failing calculator/scale/wristwatch in your hands and you'll get another ten minutes of use out of them)
You can get a smoke alarm with 10 year battery life to reduce the likelihood of this happening. When all are purchased in one batch, you can then pretty much replace them all at once -- if first battery goes, next ones are soon to follow.
I got some unconventional looking ones from Jalo Helsinki [1] for my house. They work well and look good. However, I know some people working at Jalo, so my opinion is biased. There are several other long battery-life smoke alarms on the market from different manufacturers to choose from.
[1] https://www.jalohelsinki.com/product-category/smoke-alarms-1...
20 years ago, in my first graduate job, we were issued pagers. One day my friend lost his - and it was on silent mode. We really didn't want to tell the company that it had disappeared.
Then we remembered that, at a certain time - I recall it being reasonably late at night - the device would emit a single, short, beep. I don't remember why, but even on silent mode, that beep would sound.
At five minutes to the hour - because this thing's clock wasn't synchronised, and we didn't know how accurate it was - we all positioned ourselves around the house. Silent as a mouse we waited, until - yes! - there it is, somewhere upstairs.
Now that we knew that it was actually in the house, it was just a matter of finding the thing. It was in his pants pocket - but they way they were folded in the wardrobe, the pocket wasn't where you'd expect it to be if you did a casual "pat the pockets" to see if it was in there.
Eventually I decided to move out, for other reasons. My last act after everything was out of the place was to buy a cheap battery powered alarm clock, sat on a high shelf in a bedroom closet in a hard to see spot, programmed to go off at 2am every night for 5 minutes.
I was renting in a century-old house that had been converted into apartments. Every night, around midnight, this very high-pitched hum would start, and continue until almost dawn. None of the other residents ever heard it when they were around. While the exact timing varied, the time during which it happened overlapped with my sleep schedule (I was working a late tech support shift at the time) and it kept me awake. Earplugs didn't really seem to help.
There didn't seem to be any obvious source. I did exhaustive work to try and track it down - even got the permission of the owner and my fellow tenants to try shutting off the power at the breaker box in the middle of the night to see if that helped. (It didn't.)
It wasn't always constant, but it was around enough and preventing me from sleeping enough that I was going slowly insane. I had my ears checked for tinnitus - nope, I had and still have darn good hearing. I started reading about the Taos hum, looking into resonant frequencies, and finally stumbled across the answer.
The noise started a little while after everyone in the building went to bed. It stopped shortly after they got up in the morning. It was the sound of the century-old plumbing system at full pressure. If I just left a tap open a trickle, and the noise went away along with my sleep-deprivation.
Eventually a spark of inspiration hit me, and I reached up and pulled the cord on the window blinds behind the computer desk. I found myself nose to beak (through glass) with a startled mockingbird. "Beep?" it said, and flew off.
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.
I was a noobie computer programmer in my first job. After being there for a few months my mouse started to have issues. It stuttered and refused to move correctly.
So I'd take the little grey ball out and clean it and it'd be OK again. But the next day it'd do it again.
So I ended up with the cleanest fucking mouse on planet earth. Yet every so often it'd stop working... on parts of the screen. Other parts it'd work. I ended up using the keyboard a lot.
The mouse would work fine all day some days. Some days it would work fine until about 2PM then it may or may not work.
Eventually I figured out that when the sun shone through the window it created a beam across my mouse mat. When the mouse was moved into the beam it would stop working. So I took it to bits and discovered that the ball would roll a little disc, that disc had little holes in it, there was also an LED and a photodetector. So the mouse was counting the blips in light to determine the movement in the mouse. I guess the cheap plastic was allowing the bright sunlight to bleed through the case causing the photodetctor to go bonkers.
A secondary thing about that cheap as shit PC was you could hear the video card render the screen. It'd buzz when the screen was mostly blue, when it was white it would be silent.
Of course opening a mouse up and not breaking it is quite hard, they're made to break and be replaced. Current bugbear is Logitech keyboard stand pieces that appear only to be there to break and thus require keyboard replacement - again it seems a design with a penny's more of plastic would be almost invincible.
Ubuntu doesn't print to Brother printers on Tuesdays.
site:reddit.com/r/talesfromtechsupport printer stopped working skylight
Even worse than that I had already saved the post when I read it the first time.
Moved the VGA away from the RCA, no buzz now.
From what I heard this is not uncommon.
Talking to my father in the morning, he indicated that his neighbor had taken up Ham radio and he was having to put filters on various devices to reduce interference. To this day, I wonder if his spotty wifi in the house is related to his neighbor turning his system...
[1]: https://en.wikipedia.org/wiki/Crystal_radio
https://www.youtube.com/watch?v=GHSuInSkHtA
Listening to the tranmission using the arc the tower generates to ground!
https://www.youtube.com/watch?v=lMuJKsUjD_o
I knew someone who lived two blocks from a radio station, and they would get interference everywhere, there would be staticky top 40 music coming from the phones, from clock radios, from the stereo. It would come and go. They would complain, the radio station would fix something, but in a few months it would be back.
He was probably onto something.
http://www.zdnet.com/article/coat-hanger-wire-is-just-as-goo...
I bought an electricity usage monitor plug and started to measure every electricity consuming stuff, but couldn't account for more than 3 or 4 daily kWH. Then I went in vacation for one week, turning off almost everything in the house, and the electricity consumption, that I can check every day, had barely moved. Something was consuming at least 20kWH every day in my home and I didn't know what it was.
At the same time in prevision of the winter, I bought a thermal IR camera to spot isolation problems. I started to play around with it, and discovered a fairly large hot spot in the bathroom, on the bottom of the bathtub. Touching it with the hand, it sure felt warmer than you would expect from a baththub. Maybe it was some hot water? But the water heater was on gas and my gas bill was fairly normal. The hotspot would also not go away after hours. Then I remember a visiting friend remarking weeks ago that my bathroom was warmer than the rest of the appartment.
To test my suspicions, I tried to play with the electricity meter of the appartment. After some experiments, I found out a switch that would turn off the mysterious heat source. The baththub started to cool down and the power usage displayed went down to 0. My theory was validated! Something under my bathroom was drawing around 800W constantly every hour of the day and every day of the week and that was making my appartment so hot in summer and my bill so large.
At this point, the only thing I could do was contacting my landlord and detailing my findings. It turned out he had installed a dehumidifer in the basement the year before to dry out the air and fight a moisture problem, but he had configured it to a very low setting, like 30% humidity and that was making it work constantly. The dehumidifer was installed just below my bathtub and its operation was heating it at the same time. Since it was an old home he had bought out a few years before, he didn't know where the basement was drawing its electricity from. Well now he does.
He reimbursed me the electricity and changed the settings of the machine and then my electricity consumption went to almost nothing... until november came and the cold of the last weeks of fall started to hit Montreal, but that's another story.
That way they can see debug output of what happens when he hits reverse.
> What does your neighbor think of this lmao
> > I don't have time to stay around because I tend to lag for work and have to leave as soon as I do get to my car.
How ... convenient.
[1] https://www.reddit.com/r/cars/comments/7k12fs/neighbors_hous...
I have a 2016 WRX with what should be the same exhaust. When you start the car, it starts with a high 2000-2200RPM idle and drops from there. If it needs to warm up, it will sit around ~1800rpm which is exactly where the stock exhaust makes the loudest drone.
So simply starting the car and letting it idle should result in it hitting all the revs that trying to reverse would (unless OP is awful at driving stick and way overrevving it here).
I find it way more likely there's a sensor interference issue than it's an exhaust issue based on the other information. My second guess would be some IR from the halogen running lights / fog lights / other lights in the car interfering with a motion sensor.
Because me being a sysadmin for the past 14 years would go directly to the logs and see my client timing out.
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...
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.
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):
> 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
Reminds me of "Trolling for Taillights"!
http://www.cs.cmu.edu/~hgobioff/public/random_stuff/traffic
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.
> 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.
Or frozen blueberries, but why would anyone buy frozen blueberries.
Because 'fresh' blueberries out of seasons cost 3 times as much and taste like nothing much.
Smoothies.
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.
As for the S2000, I guess water coincidentally changes the frequency of the leaked radio waves to match the car alarm?
https://i.imgur.com/S1Luizd.jpg
The company being as cheap as it was, I simply began using the microwave as a deliberate noise source for testing the device's operation under adverse conditions, placing a few mugs of water in the microwave for a few minutes, and deliberately setting my channel to collide with the microwave.
Eventually I tracked it down to microwave usage. Whenever the microwave was in use, I lost WiFi.
https://www.snopes.com/autos/techno/icecream.asp
> Maybe you neighbor is setting off his alarm on purpose just to mess with you haha!
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://news.ycombinator.com/item?id=11935275
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
I'd love to hear comments about the possible cause.
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!
https://youtu.be/jBu1ILbIKZo
RFID works by the same principle, incidentally - in this case, the energizing signal comes from a primary winding in the reader housing, and the secondary in the card powers a little CMOS chip that in cheaper models just modulates the voltage drop over the winding to return a constant code, and in more expensive models receives a challenge nonce signaled by the card reader and modulates the winding to return an encrypted response. It's a really interesting application, and an impressive but often overlooked early example of "IoT" style smarts done well.
GFCI works by detecting the difference in the current flowing between the hot wire and the neutral wire. It needs to work very fast (to avoid the human touching the wire getting electrocuted) so any slight difference in current would trip it off. The current induce by your phone's speaker probably causes enough difference in the current to trip it off.
You can run an experiment by turning off your phone's speaker for incoming call. See if the speaker is the culprit.
In that case too, sending calls didn't trigger the interference, and neither did picking up the received call.
It may well be that the control channel's initial "wakeup" transmission is done at a very high power to ensure the phone receives it clearly, and then after some back and forth the two adjust their power levels and move to a different channel for the actual call.
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.
Many years ago I had an optical mouse that would act erratically in the afternoons (just wouldn't register movement). It seemed to be ok if I squeezed it while I was using it so I figured it was a connection somewhere. Eventually I realised that it was the afternoon sun streaming in through the plastic seam and somehow stopping the sensor.
https://www.snopes.com/horrors/freakish/cleaner.asp
Except that the touch screen could be activated by rain. In Seattle.
There was a small cowl over the apparatus to keep regular rain off, but if there was any wind at all, it was very easy for drops to be blown onto the screen and it would start phoning apartments in the middle of the night.
Amazingly, this was among the building's least troublesome faults.
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 :)
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.
It was too cheaply made to have an interference suppression capacitor across the supply leads, is how. Bet he got it from Harbor Freight...
If his garage is angled, he could try neutralling out to the street before starting the car.
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.