I built an ROV to solve missing person cases

1031 points3
0xFEE1DEAD6 hours ago

Although it has already been said close to 137 times, this is the best read I've had this year, although that's likely an understatement. I love the hacking spirit and how they always settle on the simplest solution, whether from a technical standpoint or an investigative one.

Great job, and I'm glad they got the recognition they deserve. Shout out to the Finnish police as well for not letting their ego interfere with information brought to them by a couple of random amateurs. This should be the norm, but sadly it isn’t.

nstart11 hours ago

Joining the chorus to say that this is one of the greatest articles I’ve read. I love everything about it. From the hacker spirit to the investigative reasoning to the little observations made during the process like what could be considered a weapon according to regulations and how Covid affected costs of different items and when to consider o ring size in the planning. Love love love it.

My favorite line had to be this though.

> The first prototype didn’t look like much but the mental effect was enormous. Now there was at least something to show and improve.

worthy of being printed and framed.

lemonlime0x3C332 days ago

This was incredibly well written and the project itself was super cool to see come together. I worked on building UAV's in University but seeing the unique challenges with dealing with water from a signals perspective was really intriguing.

Good luck with any future cases and can't wait to see what upgrades you make!

udev19 hours ago

Except for not defining what an ROV is.

nervousvarun3 hours ago
lemonlime0x3C3319 hours ago

that is fair, I did a lot of robotics research in University so I may be a bit biased :p

not_good_coder19 hours ago

I am here trying to find this out.

not_good_coder19 hours ago

Remotely Operated Vehicle

kleiba18 hours ago

(it is mentioned in the article, but only after a few pages in)

throwaway815231 day ago

The article doesn't say so, but some web search and translation makes it sound like the second missing person may have died by suicide. When they first found the sunken car, they wondered (presuming that the car had gone off the road by accident) how the heck the car had ended up so far out into the water. The answer might be that it didn't fall off the road, but rather was driven off at high speed on purpose, with the express intention of making it hard to find afterwards. :(

0xDEAFBEAD4 hours ago

>The taxi driver later said that there wasn’t anything unusual about Juha or his behavior. He just seemed to have sat in an uncomfortable manner, like he had hurt his back. He also said Juha might have been a bit tipsy.

Perhaps intoxication + a muscle spasm caused him to floor the gas at some point? Maybe his leg fell asleep while driving?

Natsu17 hours ago

I liked how they used logic to narrow things down to just what was verifiable and only ended up searching a few spots in the end. It makes me feel like the police should work with them to solve other missing persons cases.

spaceship__sun12 hours ago

Yeah it's first principles reasoning, just like coding and manufacturing lol!

andrelaszlo2 days ago

This is amazing. A Finnish man gets curious about a missing persons case. He does some great detective work, and builds an ROV with side scanning sonar and video. The outcome, with some help from his brother, is just spectacular. I couldn't stop reading!

bemmu1 day ago

It's absolutely brilliant.

Everyone has watched a TV show where a case is slowly being solved, but who actually considers that oh yeah, I could actually become the person who searches for a random missing person case, instead of watching it on Netflix?

And the amount of McGyvering involved! How many people would have given up at one of the steps? Oh it requires coding in C++ for Arduino, sure, I'll just do that. Oh, it requires me to contact manufacturers to manufacture something, which I have never done, and I don't even know how to use a 3D modeling program. Sure, I'll just learn how to do that and then actually have it made. Pretty sure the give-up rate there would be very high!

If this were TV, people would hardly consider it plausible. And they did it, for real. And all out of just pure curiosity!

Natsu17 hours ago

I'm surprised someone hasn't made a miniseries out of this yet. It'd make a good one.

spaceship__sun12 hours ago

This is giving post-scarcity civilization vibes...

jumploops1 day ago

This is the best thing I've read on HN in months.

Hats off to the author and his willingness to combine his curiosity and skillset in such a rewarding way. We need more people like him.

cryptonector2 days ago

TFA is nothing short of amazing and absolutely deserves attention.

The author (and his brother) built (from scratch!) a side-scan sonar remote controlled boat and an ROV (a remote controlled submersible) with a camera and a light, and with this they found TWO missing persons' cars under water. Real products of these sorts would have cost enormous amounts of money, but they built their own for the cost of parts and labor (sure, lots of labor). They did this on a lark.

sleepybrett2 days ago

You can buy similar off the shelf, the way these diy projects go it may have been cheaper in the long run, but more power to him. It can be hard to drop 5 grand on a kitted out submarine when you think you might be able to do it for 2k in parts in your own labor, but in my experience that 2k in parts starts to creep up as you accidentally destroy things, determine that the things you bought and can't return won't quite work, etc.

There is a guy that has been using one of the off the shelf ones in the lakes around seattle (, he's also built a bunch of other rc stuff including a few autonomous boats that he takes into the lakes as well as the sound.

Natsu18 hours ago

Yeah, this was a good read and definitely the kind of material I come to HN to read.

thecatspaw2 days ago

Thanks for giving it a second chance. I read all of it, and it was very interesting indeed

emmelaich1 day ago

In the video in part8, at 0:30s there's something that could be a hand. I hope it wasn't a hand. There's no comment in the text of what it might be.

lxgr2 days ago

Would be great to be able to read all of these as a single article! (I'm intrigued, but I'm not saving 13 blog posts to my read-it-later app. Even stitched together, it wouldn't be the longest in my list by a long shot.)

dang2 days ago

I agree and sometimes email authors to ask if they would compile (or should I say link?) a multipart article into a single piece before we put it into the second-chance pool. But even I was afraid of how long this one would turn out to be.

aidenn02 days ago

For articles like these, I use shiori; it's a webclipper that saves html to an sqlite database. Then you can concatenate them with a single sql statement. If the final product is particularly long, then I use calibre convert the result to an epub to read on my phone and/or ereader.

lnyng1 day ago

One of the best articles I have read for years. It's easy to underestimate how difficult it is to make things "just work" in the first trial. I really envy the author's ability to plan for known and unknown situations. Marvelous job!

deanresin2 days ago

> So where was he going? I saw two possibilities: either to Tikkakoski to visit his ex-girlfrind he was on the phone with or; just to drive around with a new powerful car, to shake off the heated phone call.

I don't understand how suicide isn't at the top of the list here. He was obviously very upset emotionally. He didn't care for his belongs other than his phone. He didn't care to steal someone's car or answer for it. He never shows up anywhere.

aetherson2 days ago

I think very few people commit suicide by driving a car into a river.

deanresin2 days ago

People have committed or failed suicide attempts in probably any way we can imagine.

aetherson2 days ago

Certainly. But some are much more common than others, and if you're playing the odds, as you must in these kinds of events, we can say that it's much more likely for an inexperienced driver to have an accident on pitch black wet roads, than that they attempted suicide in this unusual way.

trinsic218 hours ago

Why would he bring his phone though?

bigiain12 hours ago

Mine lives in my pocket. I pretty much bring it everywhere I go.

deanresin12 hours ago

To send last messages before he kills himself? Call for help if he backs out?

HanClinto2 days ago

Absolutely fantastic read. The author got nerd-sniped HARD by these missing-person cases and his approach and accomplishments are inspiring, to say the least. Very well done!

rblatz1 day ago

For the first case I kept wondering why they needed so much complicated technology. The water they’re searching isn’t all that deep a cheap canoe and a long pole with a go pro, and a magnet on a rope would have been equally effective, cheaper, and faster. But for the second case that they needed the be able to search a much wider area and the tire tracks likely wouldn’t have been visible in on a camera. Really cool project though.

For the ROV I was wondering why not build something heavier than water but have it on lines attached to buoys, then to go up/down you just climb or down the ropes. Not as maneuverable but not certain if it’s significantly less maneuverable.

jumploops1 day ago

> For the first case I kept wondering why they needed so much complicated technology.

"It's always in the last place I looked"

I think we're seeing the first few guesses for where the car might be, but according to the author, there was a 40km distance between the cabin and the girlfriend's town.

Hindsight is 20/20, but I wouldn't put it past the author to commit beyond 3 search sites, some of which may require deeper and larger bodies of water (like the second investigation did).

flaminHotSpeedo1 day ago

Also by my interpretation it sounds like the author welcomed the excuse for a project

nickmcc1 day ago

The team at CPSdrone (3D printed submersibles) made a very similar project to hunt for and identify a sunken plane:

They also used an ArduRover powered catamaran and the same brand Sonar, but made a smaller deployable ROV.

fusslo2 days ago

I love these long-form build logs.

I just started reading, and I am making the faux-pas of commenting before finishing.

But, I'm wondering what the challenges are of automating the ROV to map a body of water's floor in a pattern. like a grid pattern, or whatever is most efficient.

At first I was thinking currents would cause displacement. but can't we sense the current moving us in undesirable ways and correct with thrusters?

And then I thought.. do lakes have currents? Do they have tides? can a ROV sense the boundary of a lake?

just further down the rabbit hole, realizing how little I've learned about the natural environment!

tetha1 day ago

Lübecks university has several projects[1] using swarms of robots for automatic cartography, water measurements and such.

Autonomous accurate navigation under water is quite complicated, because after a certain point you need to start relying on local sensors because nothing reaches you anymore. But local sensors tend to be weird, because a straight line underwater is not necessarily a straight line - you are most likely drifting -- and detecting drift isn't easy. From a local observer, the water around you isn't even moving. That was a fun team to talk with.


fusslo23 hours ago

so cool; thank you for the link

jarofgreen1 day ago

Lakes can have currents.

I wonder if pedantically speaking the definition of lake would include non-tidal in many countries but ....

A) humans use names sloppily and if it's an important detail I wouldn't assume a lake is non-tidal without checking.

B) non-tidal bodies of water might still change height over the year, for example after a heavy rainfall.

Mainly I'd question the need to automate it. It's difficult, and in many cases the cost of a human to drive it is tiny compared to all the other costs you need to pay so just do that (as in the article - those weren't automated). Also, driving them can be fun :-)

eythian2 hours ago

Rarely (as far as I know), lakes can be tidal in their own way. For example Lake Wakatipu changes by about 10cm every half an hour.

rkangel16 hours ago

Note that ROV stands for Remotely Operated Vehicle - it is not autonomous, it is controlled by a person.

What you are describing would be called a UUV (unmanned underwater vehicle) or AUV (autonomous underwater vehicle).

relaxing2 days ago

My brother in christ we cannot even keep a robot on land rolling in a straight line without an external source of ground truth.

The way to do it is have a boat with GPS tow your sensor array.

fnordpiglet1 day ago

I throughly enjoyed reading the entire story. However I found it strange he sort of ended with “they searched for the car and asked us to leave.” The first one they got thanked profusely. But at no point did the author ever claim to have definitively found the car or the body. It’s humble but almost oddly so. Anyway great story.

klausjensen1 day ago

Finnish people are typically quite humble and don't invite a lot of attention.

jonah1 day ago

He did say there was a front page article about that case.

fnordpiglet1 day ago

I know. But a natural conclusion would be “they found the car with his body inside it” or something similar. There was never a clear affirmation of success or detail of what success looked like. It’s ok! Just weird.

throwaway815231 day ago

The news coverage discusses it a bit. The police identified the body by DNA analysis, which presumably took a while after the car had been located. Reading between the lines, I think there may be some details that the author didn't want to get into. The victims have living relatives who don't need the gruesome specifics to be dragged out.

neontomo2 days ago

Without a doubt the most interesting article I've read here. If they didn't sink in a car, am I correct to assume the bodies would have surfaced eventually?

resolutebat2 days ago

Highly unlikely, since I presume all car windows would have been closed (winter in Finland is COLD) and they would have been strapped in with seatbelts. It's difficult to escape from a submerged car even in the best of circumstances, and being suddenly plunged into near-freezing water in the black of night is far from that.

neontomo1 day ago

While your reply is interesting to me, what I actually was asking was, "if these people died in circumstances that did NOT involve a car, but in the water, would the bodies have been found eventually because they float to the surface?"

recursivecaveat21 hours ago

Apparently bodies sink initially, float temporarily for a while due to bloating, then return to the bottom again after some decomposition. So you could easily miss the window if there are not good conditions to beach it I guess?

noman-land2 days ago

I didn't expect to read this whole piece but it was completely gripping. Outstanding work and a really great write up.

tamimio2 days ago

I loved the project!! I also like how “messy” the room is, reminded me of my room (1) when I was working from home years ago.

I haven’t read the whole thing but I will, however, I did go through the technical details, some notes:

> This model didn’t have a long enough range on the analog sticks

I see you are using Radiomaster tx16s, pro tip: You can use ELRS 2W model on BOTH transmitter and the receiver, don’t use the typical receiver unit, use another transmitter and flash it as a receiver, and you would have 2W on both sides, preferably 900mhz not 2.4ghz, and you would’ve hundreds of kilometers of range and strong obstacles penetration.

For the camera and the tether, technically you can get rid of the tether and use wireless comms, but probably what you did is the best for bucks solution.

Overall, looks great!


jonah2 days ago

I took the comment[1] on the analog sticks to be referring to the game controller pictured directly above:

I'm guessing that the range of resistance values over the full swept range of the sticks was small, and so getting precise enough values/smooth enough change out of it wasn't possible. (Assuming these things basically have X and Y potentiometers for each stick.)


bigiain1 day ago

> I'm guessing that the range of resistance values over the full swept range of the sticks was small

My assumption was they meant the distance of movement on those small joysticks was too small, so the precision problem wasn't measuring the resistance, but in accurately moving the sticks to the right place to get the desired control input when they only have tiny amounts of travel.

rrr_oh_man2 days ago

Access denied - The owner of this website ( does not allow hotlinking to that resource

tamimio2 days ago

Sorry my bad, I added an exclusion rule, thanks.

jonah2 days ago

The quest he mentions as inspiration - Tom Mahood's "The Hunt for the Death Valley Germans" - is a fascinating read and worth your time.

I first read it seven years ago and similar to the author, it inspired me to join my local Search & Rescue team which has been incredibly rewarding. I highly recommend doing that to anyone who wants to combine a love of the outdoors, specialized skills, serving the community, and helping people in their worst moments. (And doesn't mind getting up at 3am in pouring rain and going out and pushing through dense underbrush for hours!)

conscion23 hours ago

If anyone is unable to access the site, it's available on the WaybackMachine

dang22 hours ago


The Hunt for the Death Valley Germans (2012) - - June 2024 (2 comments)

The Hunt for the Death Valley Germans (2012) - - Feb 2023 (147 comments)

The Hunt for the Death Valley Germans - - Sept 2022 (3 comments)

The Hunt for the Death Valley Germans (2012) - - June 2020 (75 comments)

Hunt for the Death Valley Germans (2015) - - Feb 2019 (38 comments)

The Hunt for the Death Valley Germans - - July 2016 (61 comments)

The Hunt for the Death Valley Germans - - June 2015 (1 comment)

lnwlebjel2 days ago

Is there a fitness test for SAR? Do you train to stay fit enough for it?

jonah2 days ago

Yes. It varies from team to team. Ours is a 4.1 mile hike (with 2,500+ ft. Elevation gain) carrying a 25 lb pack in under 2 and 1/2 hours.

I'm also a volunteer firefighter and the "pack test" level of Work Capacity Test for wildland firefighters is 3 mi on flat ground carrying a 45 lb pack in 45 minutes.

It is pretty important to be in shape as you are often carrying a lot of gear and don't want to bonk and cause an issue that would jeopardize yourself, your teammates, or the mission.

Edit: to answer your second question, my wife and I hike recreationally just about every weekend and the team often hikes during trainings and does a weekly casual hike as well.

lnwlebjel2 days ago

Thanks for this info. This is something I've been thinking about doing in a few years (once the kids are further along). Seems like a very cool thing to do.

jonah2 days ago

Feel free to email me if I can answer any questions.

ramcle23 hours ago

By the way, does anyone know why the site stopped being updated in 2019? Besides Death Valley Germans there were other interesting articles in there, about other Search & Rescue endeavors, Area 51, an interesting take on Bob Lazar etc. I hope the author is OK and in good health.

burkaman22 hours ago

I don't know why he stopped updating his site, but I believe he is fine and posts to this forum sometimes:

His latest post is from a year ago:

anitil2 days ago

It's been a long time since I read that, and I still think about it from time to time. I suppose it's time for a re-read

ghaff1 day ago

As someone who has spent a fair bit of time around Death Valley, it really helped to illuminate how someone with no point of reference about the environment could really get themselves in trouble.

tired_star_nrg2 days ago

why is it asking me to sign in to read this?

nmstoker2 days ago

It was fine when I read the first five or so installments, then I got a random authentication request, which I couldn't see the cause of, but seems like it may have been triggered when I chucked an image. My guess is that during the time I was viewing the site, the owner decided they would lock it down to people who were authenticated. Shame as I was just getting to the point of progress!

bfLives2 days ago

It’s accessible via the Wayback Machine, fortunately.

jonah2 days ago

Curious. Maybe it was hugged to death and he or his ISP locked it down to cut down on bandwidth. Or maybe decided he didn't want a bunch of people reading it right now?

nosrepa1 day ago

The site was posted here and probably other social media in the last day or so. More than likely it's to prevent the site from getting hugged to death.

Dylan168071 day ago


netsharc2 days ago

Ouch, I'm sort of annoyed that the author was inspired to be long-winded and have 16 or more parts to his story. I'm up to part 2 and there's a fear of disappointment that it'll be a boring waste of time. (In comparison to the Death Valley Germans story, which was captivating!)

jonah2 days ago

I just finished the ROV series of posts. It was sufficiently captivating. I enjoyed his narrative - I can see that he was inspired by Mahood's writing style as well as his quest.

noman-land2 days ago

It's really good. Keep reading.

ac2u2 days ago

While I'm sure they did this to try to combine their talents and interests with altruism, what they got out of the end of that was both of those but also a legacy.

Most of us only wish we could tell stories like that as a result of the technical work we do.

sircastor1 day ago

I recall that the guys who started OpenROV did so because they wanted to explore a flooded cave that was rumored to have stolen gold in it.

sircastor22 hours ago

For anyone that is interested in the background of that:

noisy_boy2 hours ago

Just make a netflix documentary already. Amazing material.

timzaman1 day ago

These articles are the reason i check hacker news every day. What an amazing find, thanks for sharing - I love these articles, especially since Tom Mahood's website has been kind of dried up (otherhand).

IncreasePosts2 days ago

Awesome story! The first case had me thinking "These nerds are wasting their time...why not just a gopro on a long stick". But hearing about the details of the second story, it would have been impossible without the sonar and ROV!

rblatz1 day ago

Ha, same I even posted basically the same thing higher in the thread.

NKosmatos1 day ago

Loved the writing style, the technical description, the links to info and also the actual missing person cases.

This would make for a great TV series ;-)

shokhie1 hour ago

Awesome Read.

spathi_fwiffo2 days ago

I would suggest defining any acronyms in the title of an article in the introduction section of the article.

Had to get to PART 6 to answer my first question: What is an "ROV"?

"The solution was to use an ROV, Remote Operated Vehicle "

goshx23 hours ago

I agree. I couldn't find the reference on the first few pages, so I pasted the URL to chatGPT and asked what is an ROV to get the context based on the article

hi-v-rocknroll1 day ago
codeulike1 day ago

Yeah that really should be in the first paragraph or two, at least

drcongo1 day ago

Once I got to the end of the first page without finding out, I selected the "ROV" in the title and three-finger-touched my trackpad and it told me the answer. One of the little Mac niceties I'd struggle without.

martyvis1 day ago

On my Android Pixel you only need to highlight the text and a definition pops up which can then be swiped further up for other search options

scrozier2 days ago

It is my futile mission in life to help people understand that initials, acronyms, and abbreviations are real barriers to communication.

m4632 days ago
KennyBlanken2 days ago

Musk is always good for the 'hot take' that on the surface seems smart...but turns out it isn't, because he thinks that talking with an engineer in a specific area makes him qualified to talk like them. And then it turns out that he does the very thing he complains about.

For the latter, check this long list of acronyms used in Telsa vehicles (yes, A/C is obvious....keep scrolling down):

What the fluff is a "Brick Monitor Board"? I'm a car nut and I know a lot about EVs, and my best guess: it's a submodule of the battery management system that monitors a group of cells, which I think the only reason I know to guess that is because I've watched youtube videos of tesla packs being repaired or torn down. IBST? Turns out that's the vacuum pump for the brake servo, and "I" means "electronic."

For the former, he was probably ranting about this because he's always struck me as a little insecure about being better than NASA (not really that hard) and thus is annoyed by NASA's fetish for backronyms...which I think it inherited from the military due to sleeping in the same bed for three quarters of a century, but also their convenience.

During all phases of a mission, there are often times where comms need to be fast (for example, when the flight director or whoever does it, asks each subsystem person if they're go for launch - there's a lot of those subsystem people and the "are you OK with us proceeding" happens multiple times just during the lead-up to launch. It's a lot faster to have the following conversation:

"ECS?" "Go." "TACNAZ?" "Go." "DONUT?" "Go."

If you're the astronaut, you don't want to be shouting "Electronic Cookie Stabilizer failure!" over the radio during an emergency, and anyone on the channel with you probably knows every acronym relating to the mission by heart..

resolutebat2 days ago


mindslight2 days ago

Funny, because I'd say that jargon is a facilitator of communication between knowledgeable people. It can always be looked up by those with the interest but not the knowledge. I end up doing this all the time, and appreciating reading dumps of domain knowledge and perspective. Meanwhile, writing everything for a lowest common denominator audience creates real barriers to communication - both destroying communications bandwidth, and also encouraging experts to retreat to less visible forums.

scrozier2 days ago

It would take the author a few seconds to type "remotely operated vehicle" (or whatever it stands for), and therefore save hours of time for people who need to look it up. Not to mention...I almost skipped the article because I didn't know what ROV stood for. Lost audience.

Your argument is that lots of experts on remotely operated vehicles would scoff at the article because it didn't use their "inside" jargon? First off, how many people would that be, compared to the number of people who love a good mystery and a good gadget, but have no idea what an ROV is?

As to bandwidth, you only have to spell it out once. Simple practice: I built a remotely-operated vehicle (ROV) and solved some cold missing person cases.

The author of this piece doesn't strike me as someone who relishes communicating in cryptic acronyms, so my guess is that it was just thoughtless. He hadn't yet seen my screed on the subject. :-)

I'm sure there are those who love communicating in cryptic code. They tend to congregate in like-minded cliques that don't much care about communicating outside their tightly-defined world. So be it. But if you want to be read and understood by a wide audience, spell it out.

mindslight1 day ago
mcculley1 day ago

HTML has a handy tag for abbreviations and a way to link to definitions. It is a shame that so few bother to use it.

klondike_klive2 days ago

Sorry buddy, you might be SOL

ryanisnan2 days ago

They mean the Roman god personifying the sun, FYI.

aidenn02 days ago
tw0419 hours ago

The author clearly reads HN or used to. I’m curious if he plans on pursuing this further. Sounds like the last investigation wrapped in 2021 and he may have even gotten a cash injection to upgrade some of his kit. The last update kind of leaves you hanging!

r00fus16 hours ago

If the author wants to crowdsource the funding of the next operation (if needed) this story would be an amazing push. I sure would donate to solving more cases!

trinsic218 hours ago

I'm pretty sure he said that in the article.

b33j0r2 days ago

This is sort of an aside, I hope no one hates it.

I’ve spread myself so thin over the years that I find it hard to get excited about things.

If this is your mission, don’t quit. Do it. Second chances are consolation prizes, and a noble cause may only present once.

lemonlime0x3C331 day ago

I hope you can take a break, burn out is real and it is important to take care of yourself! It is never too late to work on something you care about :)

bestest1 day ago

i don't usually read long articles, especially paginated ones. but this one got my attention and I don't regret it. such a nice mix of tech and suspense mystery thriller. thanks!

sandos1 day ago

Agreed, I was thinking "what if the could have made those guesses right away?" Would have been trivial to see the tracks leading down into the water compared to building a ROV!

hoseja1 day ago

I'm not even that impressed by the DIY tech but by the incredible detective insight this man seems to have to just guess three likely sites and be correct and not having to search half of Finland.

mzs2 days ago

recent HN discussion on an earlier SAR that was the spark for this glorious mad Finn:

mparnisari19 hours ago

Does anyone have the Google maps location where these two cars were found? Trying to see if they are visible there

y-curious2 days ago

An incredible read! Thank you so much. It even has the famous Finnish humility downplaying his huge achievements

Fauntleroy2 days ago

Posts like these really get down to the essence of Hacker News for me. Doing amazing, previously impossible things through sheer nerdy effort. What a deeply impressive story!

MuffinFlavored1 day ago

> “ROV” stands for remotely operated vehicle

mparnisari2 days ago

Amazing read! These ROVs should be massed produced and distributed to the police everywhere..

westurner2 days ago

/? underwater infrared camera:




mmWave (60 Ghz) can do heartbeat detection above water FWIU. As can WiFi.

mmwave (millimeter wave), UWA (Underwater Acoustic)

Citations of "Analysis and estimation of the underwater acoustic millimeter-wave communication channel" (2016)

Citations of "Wi-Fi signal analysis for heartbeat and metal detection: a comparative study of reliable contactless systems"

/? does WiFi work underwater? ... "Environment-independent textile fiber identification using Wi-Fi channel state information", "Measurement of construction materials properties using Wi-Fi and convolutional neural networks"

"Underwater target detection by measuring water-surface vibration with millimeter-wave radar" :

> UWSN (Underwater Sensor Network)

I'm reminded of Baywatch S09E01; but those aren't actual trained lifeguards. The film Armageddon works as a training film because of all of the [safety,] mistakes:

jojobas11 hours ago

Fascinating but sad reading. Don't drink and drive.

danw19792 days ago

This series of articles is genuinely thrilling to read. What a fantastic and truly worthwhile bit of detective work. Very well written up.

he00011 day ago

This was absolutely captivating! Better than any book I’ve read lately!

octernion2 days ago

having built autonomous ROVs in college, i'm absolutely astonished at what this person accomplished essentially on their own. they are so finicky and piloting them is a whole skill set on its own.

and, what perseverance; it really did read like a detective story and what a good job distilling the cases down to their basics.

what a cool read and an absolute triumph of an accomplishment.

sleepybrett1 day ago

There is quite a bit of open source info out there on how to build these things these days. I think the quadcopter/'drone' boom kinda opened up the market for rc hobbies in general. I've seen guys with UHF fpv setups on planes fly for miles and miles and maintain signal. With purpose built antennas they can go even further. The legality is .. suspect at best, but shrug.

octernion23 hours ago

yeah, fair enough. we had to build virtually all of the software from scratch, including like, IPC. i wasn't involved as much with hardware but it does seem to be much more out there these days.

still a massive accomplishment imo!

sitkack2 days ago

Excellent writing. The next ROV should have a magnetometer.

aredox2 days ago

The technical details are in part 4 and 6.

edm0nd2 days ago

OP should have not felt bad about contacting family members and done it to yield more information to help them in their cases.

DaveTheSane20 hours ago


more_corn22 hours ago

This is so cool. I hope he kept at it.

KennyBlanken2 days ago

Frankly, my takeaway here is that police detectives in Finland are poorly trained and not very good at analytical thinking.

In the first case, if they'd reasoned things out like the author did, they could have simply had someone walk alongside the road that he was likely to be on, they would have seen pretty obvious evidence of damage to the ground / foliage, gone for a closer look, and seen all the broken car bits.

Add to that the author getting the cold shoulder when he called the police and said "hey, can you send a detective over, I found a car in the water and it matches the vehicle in the missing person case nearby", and they basically told him to fuck off - and then finally showed up when the fire brigade pestered them a second time.

trymas1 day ago

Hindsight is 20/20, though I was asking similar things since almost the beginning. If the car went off the road - there must have been signs for it. Broken shrubs, trees, car parts, etc.

Especially for the first case, where OP found Citroen car parts on the side of the road 10 years after the accident.

My only guess - in the middle of forested Finland - police force is small and most likely overworked.

suddenclarity1 day ago

We don't know what was said between the author and the police. As stated in the article, it's a cold case where the search had been going on for years and they had several witnesses claiming to have seen the car in a different location.

Finding a car isn't that uncommon. I know one youtuber doing these kind of things found three cars at the same location when searching for a missing person. In Sweden we have one talked about waterfilled hole with at least 17 cars but no one wants to deal with it due to the costs and environmental issues if you start pulling them.

poulpy1231 day ago

And now I have a new obsession: building an boat or underwater ROV with a camera and a sonar