Water depth by pressure? Alternativ to MS5540C & MS5541?

Other Hardware Sensors
1

Hey together,

I just working on a little sensor buoy project from me. I want to log the water depth from leaks.
Know somebody a absolute pressure sensor from (0)-3/5 bar with I2C? MS5540C can't work in 10-15m depth. And from the datasheet the MS5541 has with +-0.5m fluctuation. For me it would be interesting to record a level change of 3cm (0.03bar). I actually only want to get the relative fill level of the lake out. But if the sensor would not be too expensive (best under 10€) I would attach it to the buoy chain to give other sensors their depth.

I would be very grateful for any idea. I know that the MS5541 has a lot to offer. But with 0-30bar it is a bit too far away from my maximum pressure 5bar and with 25€ or more a bit too expensive.

Thank you very much and many greetings

Timo

Edit:
MS5541C
pressure: 0-14bar (0-130m)
accuracy: +20mbar -50mbar => +20-50cm
resulution: 1.2mbar => 1,2cm
Cost: 17€

Sounds good but maybe somebody knows a sensor in range of 0-5bar witch is a little cheaper and have the same or better accuracy/resulution :slight_smile:

2

It is unlikely you will find cheaper. I usually end up using pressure sensors in the $50-$60 range to get the performance I want.

3

Try this link: MEMS-based Pressure Sensors | NXP Semiconductors. They have a large varity even some amplified ideal for an arduino analog input. I have used them they are great and stable. I use one in the air line for my outside fish pond, about 1 meter deep. As the water level varies the readings change accordingly. It has been operational for five years and the readings are consistent. I never calibrated it for depth. The pump etc is in the house the air line is about 25 meters long.
Good Luck & Have Fun!
Gil

4

Most cheap silicon pressure sensors are only rated for dry air. That means they will not survive long in damp environment. However there are pressure sensors designed for piped fluids, that's most likely what you want.

An absolute sensor will be affected by barometric pressure so not be hugely accurate, a differential sensor needs an air pipe to somewhere high up for the reference, and this better be safe for damp conditions too.

An absolute sensor can always be compensated for barometric pressure if you have a barometer sensor somewhere (or even from the web!)

5

Have a look at the MS5837

It can do better than 3 cm, is designed for underwater use and can withstand water for a long time, but its accuracy stands and falls with your measurement of the local atmospheric pressure (you have to compensate for this!).

They're not cheap, but offer a pretty good performance for their price.