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.

I have what might be the exact opposite story.

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.

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).

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.

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.

This is some brilliantly satisfying pure evil.

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.

When the battery is weak, fire alarms have a tendency to chirp in the middle of the night because lowered temperature affects the battery negatively.

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.

[1] https://www.jalohelsinki.com/product-category/smoke-alarms-1...

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.

Can you seriously not add a "Change Battery" LED next to it?

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.

Vaguely related - I once met a parrot that had learned to imitate that exact chirp. Maddening.

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".

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.

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!

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".

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!

This seems like a particularly evil variation of that idea:

http://www.goldmine-elec-products.com/prodinfo.asp?number=C6...

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.

We had a fire alarm going off due to low battery once. We searched the house for 3 hours trying to find it. Gave up, slept through the beeping.

Next day, enraged, we tried again. Eventually we found it in the bathroom trash can.

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.

It's amazing that people can just tolerate or not be aware of things like this.

My nemesis was one of those round stick-on LCD clocks that used to be popular.

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 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.

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.

Did I mention that I am colour blind?

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.

Oh, it isn't all bad - now I get to kick my wife out of bed to find the offender, instead.

The smoke detectors in my house are supposed to do that, but many times I've found one chirping and the light is nice and green.

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.

This who thread had me feeling twitchy. How did any of these product designs make it to market?

They weren't (probably still aren't) regulated enough.

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.

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.)

https://www.youtube.com/watch?v=BpsMkLaEiOY

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.

Which app did you use

So what was it?

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.

Not him but I'd bet 5 bucks it was a smoke alarm with depleted batteries.

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.

Wonder if a full battery with a resistor in series would prolong the agony.

Or a NiCd in place of an Alkaline battery.

Here is $5. You are right.

And what was the app?

I forget now. Was over a year ago now. It was just one that allowed me to zoom in on a specific point in the past 60 seconds of sound in real time to see an exact dB reading for a very specific and tiny spike.

To my ears it always sounded the same volume. And to some apps. It wasn't considered loud enough to be read in a meaningful way.