Cicadas are so loud, fiber optic cables can ‘hear’ them | Hacker News Reader

Cicadas are so loud, fiber optic cables can ‘hear’ them

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220 pointsnixass80 comments

Fiber cable can actually be a very good sensor. Some light gets reflected back from the most minute bends of the cable. By sensing reflections and comparing them with previous reflections you can see whether the cable has experienced any new bends. By timing the arrival of reflections you can calculate exactly where the new bends are. By sensing the intensity of reflections you can calculate how sharp the bend is.

And this is not a research project anymore. Well, the fiber the article talks about is a research project, but there is a company called luna innovations that sells production fiber sensors that operate in commercial environments. There are underground fibers that sense whether someone steps in a restricted area. There are fibers stuck to pipelines that sense whether someone is trying to drill a hole in the pipeline to steal some oil (or any other vibrations or ruptures). There are fibers glued to the undersides of bridges that sense whether the bridge vibrates and bends too much.

It is a very useful sensor, because you can essentially get sensing along a large area without paying for multiple sensors and trying to figure out how you are going to power them, how they are going to communicate back, etc.

The electronics for extracting data from the fiber are complex but they do not have to be out in the wild in the area being sensed, they can be safely housed at one end of the fiber.

I’ve had a fiber line for residential internet buried in my yard. At one point it stopped working and a tech was able to pinpoint the exact location that it had a slight kink using a device that measured the reflection. They just dug up that section with hand tools to unkink it.

Yup-- an optical time domain reflectometer.

Though TDRs are in common use for copper cable, too. You send the pulse down the line and get a reflection back. They're a little worse than optical ones because there's more uncertainty of the speed pulses travel down a random network cable than a piece of optical fiber.

They make some really cool in-line OTDRs these days, but the one we use was about $10k I believe and it's had a broken screen for years. Still works if you plug a mouse in!

Does varying twist rate contribute to that uncertainty? I imagine that a cable with a high twist rate is slower because the twist means the individual conductors are longer (maybe just by a couple percent) than one with a lower twist rate. And if the test equipment isn't configured for the pinout scheme being used (A vs B) then it might not even be pulsing a single pair at a time (each pair has a different twist rate) although perhaps that issue is automatically avoided.

> Does varying twist rate contribute to that uncertainty?

Yes, but beyond the effect that you're saying. The distance between conductors affects speed down the cable. Tighter twisting also changes the distance and the amount of dielectric around, which also varies speed of propagation.

These effects can be massive; a typical cat 7 cable has a velocity factor of 80% of the speed of light, varying by a couple of percent; a cat 5e cable more is often more like 65%. If you launch a pulse into a mess of mixed wiring to find out where something is unplugged or cut, you could be off by 20% or more.

How does a cable develop a kink while it's buried?

I don’t know, but it happened relatively quickly (within a few days) of initial installation. I suspect either settling soil or animal activity.

> or animal activity

more likely tree roots hugging it

A professor I knew would measure temperature and gas species along the entire length of a fiber at refractory temperatures.

Fibers are incredibly accurate devices

All of modern technology owes its origin to measuring light precisely. Optics is an ancient science. It's quite low tech, surprisingly so.

I worked for a local IT contractor in a small Midwestern city 10 years ago. We had a handheld Fluke TDR device in the truck, for locating fiber breaks.

I wouldn't be surprised if the Fluke cost as much as the truck.

"If you drop your DVM and it still works, it's a Fluke."

We use similar sensors in test flow loops to see how prototype electrically heated nuclear fuel rods jiggle.

It's insane how cool humans are to be coming up with this insane stuff.

> there is a company called luna innovations that sells production fiber sensors

Luna is the current front, but acquired the technology from Optasense [0] relatively recently. There is a good timeline of Optasense commercial development in the fibre optic sensing domain at [1], going back to 2007, when Optasense was spun off from QinetiQ, which was itself the commercial spin-off (in 2001) from the UK's Defence and Evaluation Research Agency. This timeline illustrates the wide range of application areas, including pipeline and railway monitoring, border surveillance, drilling seismology, deep sea and others.

[0] https://www.optasense.com/

[1] https://www.optasense.com/about-us/company-background/

I know of several compagnies in europe that do geophysical monitoring of dikes levees and dams with optical fibers

Indeed and fiber cables are used to sense distant earthquakes as well. They are a very good sensor network.

And as a bonus you can transmit symmetric gigabit internet over all of your sensors!

A few years ago I went to a party in Brazil during cicada season. The event happened in a country club, surrounded by coffee farms stretching over the hills around us, and fencing the club itself was a line of tall eucalyptus trees. The stage was huge, maybe three thousand people dancing under the tent. The sound was as always insanely loud, four massive stacks, two main and two delays. A huge wall of subwoofers, maybe 10 meters wide.

As you walked from under the tent to the corners of the country club, under the eucalyptus trees, the cicadas would slowly become audible, then loud, then completely overpower the soundsystem, which blew my mind at the time, considering we weren't really that far away from the speakers.

In a way even though the cicadas are themselves extremely loud, it created a little chill sound bubble around the event, because their sound somehow still feels like nature, and was definitely more pleasant than the leftover sounds of far away speakers.

This fall I was in Iowa and had to pick up a coworker at the airport in Des Moines. I was sitting in the cellphone lot and as the sun started to set this crazy noise started picking up. It sounded like it was almost... spinning in a circle around the airport. The direction seemed to be constantly moving. For a while I thought it was one of those noise generators that were meant to annoy teenagers. We got back to Ames and I started hearing the same noise in the hotel parking lot. I have no idea what compelled me to think "cicadas" but as soon as I googled it I confirmed that that's what it was. Crazy crazy little creatures!

Had a similar experience around dusk earlier this year when I started thinking that I was having vision problems. I kept seeing all of these weird little sparkles of light out in a corn field. Sure enough, fireflies!

You want loud? Try Coqui frogs in Hawaii. Loud enough to keep people from being able to sleep. Loud enough to make them literally go insane. Loud enough to make people commit suicide, or at least accidentally drive their cars off the road due to lack of sleep.

A single tiny 22 millimeter frog can emit a sound of 91 decibels. Now, ask yourself what happens when you get a bunch of them together.

Apart from fireflies and mantises, cicadas are one of my favorite insects.

The sound of cicadas is a hallmark of summer. Whether you're inside or outside, it envelops the senses and recalls the nostalgia of endless childhood summers and adventure.

I'm looking forward to Brood XIX [1] hatching next year in Atlanta. It should me amazing.

I'm hoping to see the synchronous fireflies [2] next year. Together with the total solar eclipse, there's a lot of good nature and science to take in.

[1] https://en.wikipedia.org/wiki/Brood_XIX

[2] https://www.firefly.org/synchronous-fireflies.html

[3] https://science.nasa.gov/eclipses/future-eclipses/eclipse-20...

Definitely relate to this - quintessential summer sound and almost relaxing at this point. They’re some dumb insects though, run into anything and everything.

How do their noise compare to crickets?

Subjectively: cicadas are louder but far less annoying.

I enjoy the sound of crickets and cicadas (which are much louder) except for the one particular kind of cicadas we get occasionally in Texas that make a singular unwavering high pitched ambient buzzing sound, like the whine of an old tv cranked to 11, coming from everywhere. It's a horribly unpleasant sound, but thankfully they don't stick around long. The other cicada sounds are nice.

Crickets chirp (mostly a single kind of chirp) while Cicadas grind. The grinding lasts for half a minute or so, and they rhythmically pulsate the frequency, ending in a descending slowing of the grinding. Like a long WEEEEhoooWEEEEhoooWEEEEEeeee...

Cicadas sound like a defective transformer.

For clarification, are you meaning an electrical transformer or a Transformer robot? Because I can imagine both being possible lol

Or a multi-attention head with skip connections

Something like comparing a whisper to a jet engine, at least when there is a big brood.

https://housegrail.com/how-loud-is-cicada-in-decibels/

The cicadas can't be heard any more where I live.

When I was a kid they were so loud your ears buzzed.

It makes me very sad that we have ruined the eden that was the earth.

We haven’t completely ruined it. Build native habitat in your yard, be vocal about your concerns, donate to land preservation and get involved in your local politics and you can make a huge difference.

Yes but we get a new iPhone every year! The Internet can write poems for us! We have electric cars! Who needs God’s green Earth when we can have…stuff! /s

In so many parts of the world that part of Cyberpunk is already true: _everything_ is human made, even the plants and animals are purpose bred. You can live a life where the only natural thing you ever see is the grass between street pavement.

>It makes me very sad that we have ruined the eden that was the earth.

Are you the Platitude Man? I think I just died of cringe.

I saw them for the first time in West Virginia in the summer 2016!! It was freaking surreal, the noise, the smell of dead ones, you'd imagine they made some places slippery to walk on!! They look very intimidating but were very harmless!!

You are welcome to join us in Northern Virginia in the summer if you’d like to experience the halcyon days of cicadas you remember.

On the plus side, they compete with my tinnitus and make it far less noticeable.

I heard them once in a Maryland suburb of DC: there were so many that it was just a constant whine in the background, unlike what I've heard elsewhere.

Thankfully I was just passing through or it would've given me a headache.

While you usually will hear a few cicadas every summer, they are all normally on a 13 or 17 year cycle. You may simply live in an area that is in the middle of a cycle. when that 13 or 17 year mark hits, you will likely hear them everywhere again. You can look up the "brood" cycle for your area online.

There are also plenty of annual cicadas in North America, which I assume you are talking about NA with the 13 and 17 year brood cycles. While not nearly as loud as the broods, annual cicadas have always been a sure sign of the seasons. I have always considered the end of summer when the cicadas stop singing. They become such a constant background noise that it is easy to forget that they are even there if you have lived in the area for awhile.

Cicadas ruin my sesame seeds for my burger king so I'm find with that

Sounds (heh) like a improvement to me, tbh.

But who am I to condemn these loud bugs to extinction just because I don't like them? Instead I choose to live where they don't occur (California).

Wonder what else you could use this sensing capability for ...

It sounds like you can turn any arbitrary underground fiber into a microphone with a certain sensitivity.

Yes, you can. This was first used by the Navy to record / detect submarines, many decades ago.

You can also use the cable for distributed temperature sensing (some of my research used this).

https://en.wikipedia.org/wiki/Microphone#Fiber-optic

They’re definitely used to detect earthquakes and such.

FibreSense have commercialised hardware and software that does just this in an insane amount of detail, it’s very cool

https://fibersense.com/

Not affiliated, just a fan

Sounds interesting but the bloated website and nonconsensual cookies make it hard to want to learn more

Lots! https://lunainc.com/solutions

Gyroscopes, accelerometers, and magnetic field sensors

There’s a network under Melbourne [0] that’s in use for research what’s possible for city scale sensing. Seems to be an option for seismology, traffic, rainfall, drainage etc.

[0]: https://www.rmit.edu.au/research/centres-collaborations/mult....

I was listening to a YouTube ( I think it was 60 minutes of all things ) where volcanologists are burying them deep down in icelandic volcanoes to help detect when volcanoes might blow. Sensing the underground magma movement..

No kidding about cicadas being loud. We were in the south of France earlier this year and it's incredible how much of the soundscape is dominated by the cicadas. I have no idea if it was just a couple or a couple billion, but it seemed to just come from everywhere above us

Some people don't like the sound of cicadas but I love them. My little piece of paradise on earth is on the french riviera and it is full of italian stone pine trees [1] and there are lots of cicadas.

I go there since I was kid and I actually lived there for a while (my kid went to school there). Many of our little family movies (the ones we now all film with our phones) have noisy cicadas in the background.

At times there has been years without cicadas (I think due to a terribly harsh winter and the weird/long cicadas lifecycles) and I was dearly missing them.

It's become a Pavlovian conditioning to me: I hear cicadas in a movie and I want to be there!

[1] https://en.wikipedia.org/wiki/Stone_pine

First time we traveled to Texas when I was a young lad, and we heard cicadas, they were very close to us and I thought it was a vacuum cleaner.

Cicadas make different sounds, in my area hard to confuse with anything else. Here’s a video(1) with various samples of cicadas. Was any of these sounding like a vacuum cleaner?

(1)-https://m.youtube.com/watch?v=thbgObpfoNs

When you have no concept of insects being able to make that much noise, the brian just maps it to something else. When you're familiar with them, you can pick out the patterns in the frequencies and the ebb and flow, when you're first exposed to it it's just generic _loud_.

That was exactly it.

I was staying just outside Toronto (/suburban GTA) this summer; it was a few days before I stopped assuming the sound was construction (sawing). Extraordinary, nothing like it (as far as I've ever known anyway) in the UK. Crickets can be 'loud' (more so in France IME) but these cicadas were in a different league.

It was that sound but it was right next to my head, camouflaged by the tree it was occupying. I had no idea what it was and didn’t detect its visible presence. I assumed it was many feet away. Wasn’t for days that I understood it was an insect.

We used to call them locusts in Texas. I still miss it. Yes, I know they aren’t locusts. We’re all suburban tv babies sharing the same accent these days.

They were called locusts in my area as well. Wasn't until college zoology that I learned we were calling them the wrong thing.

Anyways, I had a dog that would watch from the back porch and when he saw one flying low across the back yard would run out and catch it out of mid air. The things would be flapping and croaking about until they were crushed mid-swallow. It was a gross but impressive feat to behold.

I grew up calling them zeezer-bugs. Or cicadas if you wanted to be fancy.

My grandmother in N TX called them that too. They're cicadas and they're damn loud. Since 1980, all grasshopper species remaining in N America are too rare now to enter a gregarious phase.

New Zealander checking in - our February (summer) is insane if you're close to certain types of bush. Deafening. Not sure if it was in the article (paywalled) but the little mofos can get up to 100db. There's a good couple of weeks I avoid the bush for sure.

We had a big year for them in 2021 in Australia. I was testing an Apple Watch at the time and since exercise was one of the reasons at that time to be allowed out I went for bush walks in my local area.

In quite a few areas the noise was so loud the watch informed me I was going to damage my hearing if I remained in the area.

When I first heard them, I thought some power lines were damaged.

(slightly) less pop science version: fiber optic cables are so sensitive, they can even detect the sounds of cidadas.

Remember, keep Cicadas away from your hard drives.

I worked with Fiber Bragg grating [1] technology in the 2000s, exploring its applications in diverse fields. This included biomedical applications, where a fibre optic cable inserted inside a catheter measured temperature and pressure at specific points within a person's body. And in deep oil drilling, where the same fibre optic cable could extend kilometers down a well.

[1] https://en.wikipedia.org/wiki/Fiber_Bragg_grating

Neat, but I think it’s a bit gross to use the same cable for a catheter that you used in an oil well.

We did this at Pure Technologies (now Xylem) running fibre cables over infrastructure to listen for wire breaks in underground pipes, and on bridges to listen for micro-fractures in the concrete structure and steel cabling.

The analysis and install was called "AFO Analyst" [0].

[0] https://www.xylem.com/en-us/products--services/pipeline-asse...

It turns out that when you Google "cicada", there's a speaker button near the Wikipedia card in the top right corner which allows you to play the sound of cicadas from within the search results page.

So a transducer? Hmmh I think I remember a potential usage in oil pipelines as pointed out by someone above.

Puts the expression "cable leaks" into perspective lol /jk

Anyway, interesting.

Random goofball aside, but cicadas erupted at my graduation from Princeton 1987 and it was so loud a couple times it truly was hard to hear each other.

> It could lead to a new way of monitoring insects.

Hm!

56k dialup, here we go again. I still have a external USR 56k

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