Radar doppler sensors for non contact water Speed measurement

Hi Guys,

Just as a general question: do you have experience with radar doppler sensors that can be used for water speed measurements? The Doppler Sensors are great because they can be used for non contact measurements. I have seen a few low cost devices but I think those can Just detect the motion and no speed. It would be great if you can recommend a device.

Thank you!

I guess that you have to let ships float in the water, so that solid objects can reflect the radar waves.

There is also the problem that flow may not be of constant velocity across the flowing stream or at different depths - so a point measurement across a stream is likely to be inaccurate .

Unless this is an open channel a conventional flow meter will give a better result. There are other pressure drop techniques for water flow measurement in open channels ( google) or methods based on water properties .

Actually, it is ultrasonics, not radar.

Hello Guys,
There are already commercial products for non contact water speed measurements:
https://www.ott.com/en-us/products/water-flow-3/ott-svr-100-2406/

These are a bit pricy I guess. The principle is doppler radio (with a couple of GHz), not ultrasonic. I thought there might be some cheaper modules around.

mbobinger:
Hello Guys,
There are already commercial products for non contact water speed measurements:
https://www.ott.com/en-us/products/water-flow-3/ott-svr-100-2406/

These are a bit pricy I guess. The principle is doppler radio (with a couple of GHz), not ultrasonic. I thought there might be some cheaper modules around.

Did you note the very first sentence in your link? "OTT SVR 100 is a simple, non-contact, compact surface water velocity radar sensor". It only monitors the "surface" of the stream. Wind may blow the surface water in reverse of the stream flow.

Paul

You could experiment with the very inexpensive HB100 X-band radar module ($8 on Amazon). Not sure it will work for your application - it operates at about 10 GHz, whereas the sensor you linked to operates at 24 GHz - but it may be worth a try.

Some additional electronics are required to connect the HB100 to an Arduino. You can "roll your own" supplementary electronics or you can buy the HB on a breakout board (e.g., $40 from Parallax).

This website has what seems like reasonable advice (unverified by me): Arduino Intrusion Monitoring system | by Ben Fraser | Medium

You would need to convert the measured frequency (such as from the mentioned freqMeasure library) to water surface velocity. That could be tricky, but it would be fun to attempt...