Lidar Lite 2 suitable for water depth use?

[woland]

Hi
I am looking at replacing sonar with LiDAR. Could you tell me if the lidar lite 2 would work in water depths up to 10m?
I am hoping to be able to work out lake depths. Some of the lakes are quite murky which is my main concern
Thank you

[km6vv]

Unlikely to work, depending on the color (IR?) of the LASER, it’s light would be absorbed quickly.

SONAR is the appropriate tool. Sound is not affected by murky waters.

Alan KM6VV

[cadcoke5]

I would imagine that even minor cloudyness would be a problem. The additional window that the LADAR must look through would also be another issue.

-Joe

[scharette]

Hi,

As our community members so expertly mentioned, lake depth measurement using a LIDAR-Lite will most probably fail. The only real use for LIDAR in general with liquids would be to measure the level of a liquid (how high the liquid surface is), such as in a tank or other container of fixed size.

For a lake depth measurement application, sonars are indeed the right tool.

Sincerely,

[woland]

@scharette

Hi,

As our community members so expertly mentioned, lake depth measurement using a LIDAR-Lite will most probably fail. The only real use for LIDAR in general with liquids would be to measure the level of a liquid (how high the liquid surface is), such as in a tank or other container of fixed size.

For a lake depth measurement application, sonars are indeed the right tool.

Sincerely,

Thank you very much. Which one would you recommend for lakes which are no deeper than ten meters and also which product is most easily waterproofed?

Thanks again

[scharette]

Hi,

Many sonars will do what you need, but we do carry quite a few of the MaxBotix brand that have full outdoor environment shielding (usually IP67) available.

The simplest use-case is to have the sensor place above the water surface and sending its pulses straight down. This usually produces two received signals, one from the water surface and a second (echo) from the bottom of the river/lake/container/etc. Of course, you should use the 2nd reading, not the first one.

Simply choose one that fits with your distance, resolution, interface and outdoor environment requirements. For example, the RB-Max-65 should have a range of up to 10 m.

We have contacted the manufacturer to obtain more details. We will post again on this thread when we receive a reply.

Sincerely,

[scharette]

Hi,

Here is what the manufacturer had to say about this idea:

@manufacturer

The MB7386 could certainly be used to help measure the depth of a lake. However, they are not depth finders. Our sensors need to be placed a known distance above the lake bed for instance 12 meters. Then a reading of 2 meters to the water’s surface indicates that the lake is 12 meters minus 2 meters (10 meters) deep. Unless you know the distance between the sensor and the lake bed, you cannot calculate the depth with our sensors.

Of course, this is not exactly the answer we expected. We have inquired about underwater use (since the device is rated IP67) and what kind of results such a use would produce (if possible) and we will post again once we have more details.

Sincerely,

[scharette]

Hi,

Here are more details from the manufacturer concerning the use of this sensor underwater directly (for your lake dept measurement application):

@manufacturer

[font=arial, sans-serif][highlight=#ffffff]Underwater use is a non-supported/non-warranty use of the MaxSonar-WR and WRC sensors. That being said, we have had many requests for this type of sensor. For this reason, we have provided the information below as a courtesy. The information covers frequently asked questions regarding underwater use. Additionally, we have shared the brief results of previous users who have tried our sensors in an underwater environment.[/highlight][/font]
[font=arial, sans-serif][highlight=#ffffff]Again, underwater applications are not covered under warranty.[/highlight][/font]

[font=arial, sans-serif][highlight=#ffffff]The links below show a couple of end users that have published results regarding the use of our sensors underwater.[/highlight][/font]
designspark.com/blog/coconut-pi-individual-components-development-for-an-auv
youtube.com/watch?v=Z3vIcjI8Lmc

[font=arial, sans-serif][highlight=#ffffff]The MaxSonar-WR and MaxSonar-WRC sensors are IP67 rated and can be submerged (up to one meter) but the sensors are not designed to range underwater. The primary reason is because of the change in the density and speed of sound through the water medium. We have had many requests to explore this type of ranging, however, we have decided not to go in the direction of underwater ultrasonic sensors at this time as it is outside our current company scope. Periodically, we will continue to reevaluate adding a product that is designed for underwater use.[/highlight][/font]

[font=arial, sans-serif][highlight=#ffffff]The sensor is rated IP67 meaning it can tolerate submersion in water up to 1 meter deep (and we believe it could tolerate IP68 three meter submersion or even more). This said, the sensor is not designed to operate when underwater.[/highlight][/font]

[font=arial, sans-serif][highlight=#ffffff]We have had several customers that have tested the sensors underwater, however, we have received minimal feedback that included range data. Of the data received, the reported distance was incorrect (i.e. speed of sound was different), but the sensor was reported to operate (send and receive the sounds). The reason for successful operation underwater was because of the higher output power, and excellent packaging. Even so, the sensor was not designed or calibrated to operate underwater.[/highlight][/font]

[font=arial, sans-serif][highlight=#ffffff]If you purchase the MB7070 version of the sensor, and use the analog envelope output, you could can use the waveform and look for the underwater reflections in the waveform detected by the sensor. This would require an AD converter that sampled at regular intervals and then this data would show the distance to the target. Some users have reported that they used the Analog voltage output with success (wrong distance reported, but they were able to use the measurements with look-up values).[/highlight][/font]

[font=arial, sans-serif][highlight=#ffffff]-Do I have to seal the back side of the sensor where the pinout is?[/highlight][/font]
[font=arial, sans-serif][highlight=#ffffff]Yes, the front side of the sensor is IP67 rated, however the user is still required to seal the pin out section of the sensor.[/highlight][/font]

[font=arial, sans-serif][highlight=#ffffff]-Will the sensor be damaged if submerged beyond 1 meter?[/highlight][/font]
[font=arial, sans-serif][highlight=#ffffff]We have not tested this parameter of our sensor.

Ok, so it seems this will work. You could possible have the sensor slightly underwater (under the surface of the lake, facing downwards) and take measurements that way. The video linked above shows a simple way of sealing the sensor. You could alternatively also use thread seal tape and a pipe to connect to the sensor’s back, therefore preventing water from coming in.[/highlight][/font]

We hope this extra information helps!

Sincerely,
[font=arial, sans-serif][highlight=#ffffff]
[/highlight][/font]

[woland]

Thank you very much!! Very useful information. Do you have a link to where I can buy the sensor on your website?

Thanks again!

[scharette]

Hi,

Here is a copy of the links we gave earlier:

@scharette

We do carry quite a few of the MaxBotix brand that have full outdoor environment shielding (usually IP67) available.

@scharette

Simply choose one that fits with your distance, resolution, interface and outdoor environment requirements. For example, the RB-Max-65 should have a range of up to 10 m.

The RB-Max-65 is a good choice for your application since it is rated IP67 and it has a maximum range of 10 m.

Sincerely,

[JoshYang]

Hello,

I am also interested in measuring underwater depth.
Do you have any updates on your applications or any suggestions?

Thank you very much for your information.

Josh