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Measuring Depth of water with lasers

pseudoabdul

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Long story short I am trying to develop a way to measure the depth of water, potential with lasers.

The water will be up to 1m deep in a 10m hole. It maybe be full of dirt and other stuff that would make it cloudy. I'm wondering how well lasers penetrate dirty water and if its just a matter of more power.
 



CurtisOliver

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Just use a water depth marker like everyone else.

 

CurtisOliver

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A laser isn't really going to work either in those conditions.
Why do you need to be able to measure the water level quickly?
For cost, you could use a laser distance tool and a float on the surface of the water.
What is your application, and what sort of water hole is it?
 
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Radim

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Try use sound instead of light. Sound depth meters are used on boats and are pretty accurate. If the water is dirty, the light won't work well.

You need to describe more your need. Is bottom variable? Why you could not use static water meter and just read it (even with some electronics on it using conductivity of water)? Without close description people here cannot propose suitable solution. Lasers are not needed everywhere (but here we are able to use them everywhere :D).
 
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steve001

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Long story short I am trying to develop a way to measure the depth of water, potential with lasers.

The water will be up to 1m deep in a 10m hole. It maybe be full of dirt and other stuff that would make it cloudy. I'm wondering how well lasers penetrate dirty water and if its just a matter of more power.
Have you googled? Your not the first person in the world to want to do this. You'll find articles.
 

pseudoabdul

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Have you googled? Your not the first person in the world to want to do this. You'll find articles.
Yes I have. The only thing close to this is shallow water bathymetry, but it is hard to scale down that practice. I've spent many hours on this before coming here.
 

Radim

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Yes I have. The only thing close to this is shallow water bathymetry, but it is hard to scale down that practice. I've spent many hours on this before coming here.
I think ultrasound might work well and much better than laser as laser will be stopped by dirt water fast. The point is not only to get through to bottom, you need to get back the reflected radiation. If bottom changes its albedo, it might be very hard to receive some signal back (one black stone for example and you loose it). To penetrate dirty water you need IMO IR (to have larger wave than particles - but as EM radiation is slower in water, the wavelength will be shorter than in air) and IR is absorbed by water - so it won't work, the same it would be for maser (microwave "laser"), but this will be likely expensive. You might also consider some short radio wave to do that - but this might be quite tricky (not accurate enough).

Still ultrasound looks the most suitable to me - you use the medium (water), where sound spreads very well, and short wavelength should give you a good accuracy.

Inspire yourself in current technology and how ultrasound is used to see what's happening in pregnant women - people are composed mostly from water - there is a reason why ultrasound is used (penetrates good, does not ionise as x-ray - crucial for developing fetus, and short wave gives you good resolution).
 

steve001

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Yes I have. The only thing close to this is shallow water bathymetry, but it is hard to scale down that practice. I've spent many hours on this before coming here.
To my knowledge no one here has any practical know how. I think you'll have to rely on the articles and use them as a starting point.
 
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Rivem

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While it is possible to use lasers for this type of measurement, the instrumentation required to do so is far out of reach for consumers. You'd likely spend at least tens of thousands trying to make something like this.

Sonar is the best choice for something along these lines as consuner "laser" measuring devices are actually sonic rangefinders.

Honestly though, you're really over complicating this way too much. People have been measuring things in this same situation for hundreds of years very simply. Any person that's certified a modern well has done it.

Read here: Well Water Pumps. Measuring your well specs.

Edit: Just to be clear, the ultrasonic solution is simply called an ultrasonic level meter. I've worked with ones made by a company called Flowline. I believe Davis makes some as well. They're used to measure water depth and distance to water in large tanks. More expensive than it needs to be, but that's along the line of what you're interested in.
 
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Encap

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Are you related to Paula Abdul?

 
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paul1598419

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If you know where the bottom is, you can use a float to detect the amount of water present for next to nothing. Everyone wants to do something with lasers for the wow factor. It just isn't practical or necessary.
 
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Benm

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I'm a bit confused as to what you want to measure as well.

If it is the water level at some static point (in a river, a well, lake etc) just driving a pole into the bottom and putting a scale on that would be the simplest solution by far.

If you want to measure water depth, such as from a boat so you can assure you'll not run into sandbanks and such, ultrasonic solutions are the industry standard, and work pretty well in murky water as well (but not always when the floor is really muddy so the transition between murky water and dilute mud is vague).

These things are available commercially for $100-ish (for the the display system and transducer in one package), fairly reliable and not that hard to install. Range is usually limited to something like 50 meters, but then again, if you need a depth of over 50 meters you don't generally care about $10.000 more or less on equipment to secure your vessel worth millions not running aground ;)
 

CurtisOliver

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You could perhaps use one of these..

New 40/60/80/100M Laser Distance Meter Digital Level Area Range Finder Handheld | eBay

iT SHOULD get you a measurement from the
sensor to a detected bounce back surface.

Specs:-
Range: 0.2 feet to 130 feet
Accuracy: 0.01"
Price: $19.50 USD with Free Shipping


Jerry
If you know where the bottom is, you can use a float to detect the amount of water present for next to nothing. Everyone wants to do something with lasers for the wow factor. It just isn't practical or necessary.
Posted the same idea. Seems the most cost effective and logical way IMO.
 




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