water pressure sensor

So I have a couple of questions. First of all, could you use a barometric pressure sensor underwater? Second question is if no to the first question, are there any water pressure sensors that could be used? It has to use I2C protocol.

Thanks in advance!

KF7QAZ

I2C works only for very short connections (a few cm), so any underwater sensor that uses I2C communications would have to be packaged with an MCU to read it out.

jremington:
I2C works only for very short connections (a few cm)

There is more than one I2C standard.
The oldest one can do several meters if you use the right wire and pullup resistors.
Leo..

Are you trying to measure water pressure in a pipe, depth or level in a tank or container, is the tank top open?

In a pool, For a MATE competition

I would use a “bubbler” arrangement, drop a piece of tubing to the bottom of the pool, connect your low pressure sensor to the top end, about 4 inches below the sensor tee in a small air pump (like an aquarium pump) to keep water from coming up the tube, between the pump and drop tube, insert another tee and connect a small “bleeder” valve open to atmosphere so you can adjust the bubble rate, you only need an occasional bubble to keep the drop tube clear of water.
How deep is the pool?

Its about 20 ft deep but my team doesn't want any airlines to go down to the machine, were trying to keep the overall size and weight as low as possible. So we already have a ROV (underwater robot) down there and it'll have a arduino on it we'll need a pressure sensor, I was looking at the pressor sensor combo from OpenROV but it to much, at over $100. There's also one from sparkfun, but its still pretty spendy at $60. If there is nothing else then we could use the sparkfun one, but I was looking for something cheaper.

So you know that there are water pressure sensors but they are not cheap.

I believe that you can build a water pressure sensor putting a barometric sensor in a case that can shrink with water pressure (not too much) but then you have to calibrate it. Check for proper ranges.