Cave Sonar/Distance measuring

[Winmit]

Hi,

does anyone have some experience with underwater measuring devices. I want to be able to measure a bit better when making maps. Tried with a fish-finder, but the beam angle is very wide 45+ degrees, which makes it very inaccurate in narrow places. Started researching for a DIY thingy with arduino in example, but the only sensor I managed to find was with 11degrees angle. I think its will not be as easy as expected task and for sure someone more experienced have already researched the topic. Any inputs on the topic? Lets ignore the fact that at the end we don't need a detailed map up to the centimetre...

 

[Underwater Tourist]

SLAM and LiDAR Cave Mapping

I've been holding off on this post for a couple of months now, but I've been working on mapping caves using visual-inertial SLAM. There's still a ton of work to do, but I'm getting there with the process and it's only getting better over time. I could practically write a thesis on it all, but to...

scubaboard.com

not sure if this thread is helpful

 

[Simpel]

Maybe this?
Echotest

 

[InWay2Deep]

For simple line distance I think most people use the MNemo (MNemo | Cave survey data acquisition | Ariane's Line) or count knots. I've also heard of a 'Sonar Gun' (looks like of like a flashlight) but no idea where to get one.

 

[Winmit]

Simpel - i have tried exactly with such. The angle is wide and it bounces top/bottom. In narrow places gives false distances.

 

[PfcAJ]

I’ve done a bit of LRUD measurement with this thing

Handheld Digital Depth Sonar

The Handheld Digital Depthsounder or LPS-1 is simple to use. Just put it in the water, point and push the ON button. The depth or distance is digitally displayed for 10 seconds before automatically shutting off, with no risk of battery drain. A must for the outdoor enthusiast! Take the compact...

store.vexilar.com

Seems fine.