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.
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!
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.
Good luck with any future cases and can't wait to see what upgrades you make!
Perhaps intoxication + a muscle spasm caused him to floor the gas at some point? Maybe his leg fell asleep while driving?
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-02/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-03/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-04/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-05/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-06/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-07/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-08/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-09/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-10/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-11/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-12/
https://suanto.com/2024/06/06/the-time-I-built-an-ROV-13/
But we got an email from a (unrelated) user saying it's good, so I've put it in the SCP (https://news.ycombinator.com/item?id=26998308).
ROV = remotely operated vehicle btw
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.
There is a guy that has been using one of the off the shelf ones in the lakes around seattle (https://www.youtube.com/@rctestflight/videos), 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.
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.
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.
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.
"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).
They also used an ArduRover powered catamaran and the same brand Sonar, but made a smaller deployable ROV.
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!
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.
1: https://www.iti.uni-luebeck.de/en/research-areas/mobile-robo...
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 :-)
The way to do it is have a boat with GPS tow your sensor array.
What you are describing would be called a UUV (unmanned underwater vehicle) or AUV (autonomous underwater vehicle).
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!
(1) https://tamim.io/professional_projects/nerds-heavy-lift-dron...
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.)
[1] https://suanto.com/2024/06/06/the-time-I-built-an-ROV-06/
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.
https://www.otherhand.org/home-page/search-and-rescue/the-hu...
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!)
The Hunt for the Death Valley Germans (2012) - https://news.ycombinator.com/item?id=40568151 - June 2024 (2 comments)
The Hunt for the Death Valley Germans (2012) - https://news.ycombinator.com/item?id=34676129 - Feb 2023 (147 comments)
The Hunt for the Death Valley Germans - https://news.ycombinator.com/item?id=32871761 - Sept 2022 (3 comments)
The Hunt for the Death Valley Germans (2012) - https://news.ycombinator.com/item?id=23582417 - June 2020 (75 comments)
Hunt for the Death Valley Germans (2015) - https://news.ycombinator.com/item?id=19263057 - Feb 2019 (38 comments)
The Hunt for the Death Valley Germans - https://news.ycombinator.com/item?id=12019567 - July 2016 (61 comments)
The Hunt for the Death Valley Germans - https://news.ycombinator.com/item?id=9723065 - June 2015 (1 comment)
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.
His latest post is from a year ago: http://perryscanlon.com/MSJinfo_phpBB3/viewtopic.php?f=1&t=6....
Most of us only wish we could tell stories like that as a result of the technical work we do.
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.
still a massive accomplishment imo!
This would make for a great TV series ;-)
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.
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.
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.
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.
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 "
EDIT: also https://gist.github.com/klaaspieter/12cd68f54bb71a3940eae5cd...
r/rov: https://www.reddit.com/r/rov/
Bioradiolocation: https://en.wikipedia.org/wiki/Bioradiolocation
FMCW: https://en.wikipedia.org/wiki/Continuous-wave_radar
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) https://scholar.google.com/scholar?cites=8297460493079369585...
Citations of "Wi-Fi signal analysis for heartbeat and metal detection: a comparative study of reliable contactless systems" https://scholar.google.com/scholar?cites=3926358377223165726...
/? does WiFi work underwater? https://www.google.com/search?q=does+wifi+work+underwater
https://scholar.google.com/scholar?cites=1308760257416493671... ... "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" https://scholar.google.com/scholar?cites=1710768155624387794... :
> 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: https://www.google.com/search?q=baywatch+s09e01
"I didn’t know it back then but it all started while I was reading Hacker News in February 2019"
