Underwater pressure sensor

Hello this is my first post I’m new here

I’m currently working on a prototype project for my company and I would like some feedback or recommendation on the sensors I’m looking at

Objective: The objective is to analyze the pressure waves and differences induced by objects moving through water. I’m hoping to be able to isolate signatures of various rotating blades and fishing lures moving through the water by the pressure differences they induce in the water

Sensors: IF YOU HAVE ANY SENSORS YOUD RECCOMEMD PLEASE DO

I’m looking at these two: https://www.bluerobotics.com/store/sensors-sonars-cameras/sensors/bar02-sensor-r1-rp/

Pros: less margin of error and slightly more accurate however the resolution is less than the next sensor I’m considering, I believe I will require the higher resolution

https://www.sparkfun.com/products/12909 This sensor has higher resolution but it seems to have a higher swing in its accuracy in the data sheet

Do you think either of these sensors will be able to measure pressure waves given off by spinner blades and fishing lures passing by in a test tank? Is there a completely different type of sensor you would recommend or a different model?

Any feedback from anyone with experience with these sensors or underwater pressure sensors would be appreciated im trying to assess the feasibility

A "pressure wave" moving through water is a sound wave. The velocity of the pressure wave is about 1500 m/s.

You would need an underwater microphone to detect that.

I have a sensitive hydrophone on the way that’s the primary way I plan to measure this, I wasn’t sure if a pressure sensor could sense the displacement of the water as well

Certainly not an I2C sensor (actually just about any sort of digital pressure sensor). They are VERY slow.

LureLabs: I have a sensitive hydrophone on the way that’s the primary way I plan to measure this, I wasn’t sure if a pressure sensor could sense the displacement of the water as well

The water displacement is a + and - value. Are you measuring both?

Paul

What is it that you are trying to measure, or optimize?

Unless the tank is designed to have acoustically dead walls, you will likely encounter many difficulties with standing waves and other interference phenomena.

Do you have a style of sensor you would recommend that is faster besides I2c?

First off I do prototyping and model building and I’ve been assisting and partnered with someone with some pretty innovative ideas. We do have a special tank designed for the testing that should limit the acoustic interference to a reasonable degree

What I am trying to measure is some sort of signature from the spinner blade and lure we are designing that we can compare to others. We are making our lures out of a non traditional material as well and we want to compare the performance, motion signature and acoustics to the traditonal lures available.

I have gathered a good amount of data from the bioacoustics of baitfish and pressure signatures given off during baitfish feeding from research papers and I’m hoping to improve our design to come into or match these patterns as closely as possible

Paul,

I’m not sure how I would go about measuring both values but I have considered this, I wasn’t sure if I had a single sensitive pressure sensor if it would just record the slight variations in water pressure given off by the blade

Maybe if I had two sensors one on each side I could measure the positive and negative values

I think a hydrophone is your only option for detecting an acoustic signature.

What range of frequencies is relevant?

Digital sensors might be able to detect pressure variations on the order of 100 Hz, depending on resolution. The sensor sold by bluerobotics has an ADC conversion time of about 17 ms on the highest resolution setting, for a maximum audio frequency of about 26 Hz (Nyquist limit), not counting the data transmission time.

400-700hz is the main range we are targeting, it seems like this is out of range if even the digital sensors

The blue robotics time and range is much too low then.

Do you have any tips on amplifying a hydrophone signal?

Also could I use a sensitive accelerometer to capture the vibration of the lure and plot the data if I cleverly attached it to not disrupt its natural pattern?

I have a sensitive hydrophone on the way

Start with that. This is already an extremely ambitious project.

Ok thank you for all your help I appreciate you taking the time