Mate rov underwater range finder

[Erik102696]

So for the mate completion this year we need to measure ALOT of stuff. But in past years we tried slapping on a tape measure on it. But I want to use a more eligent solution . But I also don't want to spend an arm and a leg.
Thanks

[scubersteve]

I will be quietly watching this thread...

[Technoviking]

can you waterproof a hunting range finder, or dismantle a shop bought one and squeeze it into a PVC housing with a window for the laser and receiver? or do the rules prevent you from purchasing a commercial unit?

[rossrov]

First thoughts are:
Do you need to be able to measure subject/object distance from ROV, or just know when the ROV is a certain distance away from the subject?
You need to be able to determine the size of subject.
What accuracy is required by the rules and does greater accuracy mean a greater score?
What other requirements does MATE have. Laser safety? Passive or active systems?

[Erik102696]

We have to measure the length of many different objects. For example we need to measure a "iceberg" that's made out of pvc. It has to be accurate to about 5mm. With lasers wouldn't refraction be an issue?

[rossrov]

I could describe in detail how to build something simple to do the job but that would kind of go against MATE's goals. So here are some more clues

http://en.wikipedia.org/wiki/Refraction

If you search the forum you will find a thread regarding this where Lasers are described. I posted my 2 cents worth there as well

viewtopic.php?f=14&t=595&p=5387&hilit=laser#p5387

A passive optical range and size measuring device could be made with mirrors based on the same principles linked to below. Distance then size can be calculated using basic trig. once the angles are known

http://www.google.com.au/search?q=Coinc ... 24&bih=643

http://nyfirearms.com/forums/long-range ... inder.html Scroll down the thread to diagram

The good thing about ROV stuff in a way is that distance is limited by water visibility. Shorter distances are easier to work with - precision easier than with long distance so you can get away with much rougher tolerances than the military or firearm enthusiast gear.

A Sextant as used in navigation could give you some ideas - it too uses coincidence principles, just a bit different

[Garry987]

I could describe in detail how to build something simple to do the job but that would kind of go against MATE's goals. So here are some more clues

http://en.wikipedia.org/wiki/Refraction

If you search the forum you will find a thread regarding this where Lasers are described. I posted my 2 cents worth there as well

viewtopic.php?f=14&t=595&p=5387&hilit=laser#p5387

A passive optical range and size measuring device could be made with mirrors based on the same principles linked to below. Distance then size can be calculated using basic trig. once the angles are known

http://www.google.com.au/search?q=Coinc ... 24&bih=643

http://nyfirearms.com/forums/long-range ... inder.html Scroll down the thread to diagram

https://theoptics.org/best-rangefinder-under-100/

The good thing about ROV stuff in a way is that distance is limited by water visibility. Shorter distances are easier to work with - precision easier than with long distance so you can get away with much rougher tolerances than the military or firearm enthusiast gear.

A Sextant as used in navigation could give you some ideas - it too uses coincidence principles, just a bit different

It this information true for today? I’ve got this project where we want to measure the depths of some areas that are covered in water. Basically, we want to find out how deep the puddles are, from a few centimeters to a few meters.

And I’ve got this Lidar-Lite 3 Laser Rangefinder that I could possibly mount on one of my drones .

Question is, is this a match ? Will the Lidar go all through water and give me my water depth, or rather reflect on the surface , or somewhere in between depending on some parameters ? Anyone ever tried this ?