I am trying to design a project that Arduino would have connected water and salinity sensor, would be packed in a special box be droped into ocean up to 500 meters. What sensors should I use and how should they be conencted. I assume that I would need professional equipment, not chineese stuff from ebay. Hardware needs to be able to work under 50*C and up to 50bar


Budget is about up to 400 pounds for sensors. Resolution of pressure 0 to 100 bar Resolution of salinity doesnt matter so much. Few percents of mistake, just to measure it somehow

  • What sort of resolution and accuracy do you need? How long is the deployment? Any communication?
    – Dave X
    Mar 16, 2016 at 13:07
  • pessure about 1bsi accuracy and accuracy of salinity doesnt matter. just something that measure quite properly under these conditions.
    – Mateusz
    Mar 16, 2016 at 13:11
  • I'm unfamiliar with bsi, it seems like 500m of saltwater would be a pressure of 5 MPa or 750 psi. The arduino can interface electrically to most things, but for advice on selection of an uncommon, special sensor, you might do better in an engineering forum.
    – Dave X
    Mar 16, 2016 at 13:25
  • oh I meant bar, sorry. 50 bar, 5MPa
    – Mateusz
    Mar 16, 2016 at 14:06
  • You may find Robotics Stackexchange useful for questions like this. Mar 16, 2016 at 15:40

1 Answer 1


I suggest that you look for a sensor from Honeywell. The problem is that the pressure is very high for a board mounted sensor and the atmospheric pressure is varying. The board mounted sensors measure a maximum of 10 bar. It is not clear what accuracy you require. Is there a connection to the surface? If so you should measure differential pressure between the seabed and the surface. Can you be content with a maximum depth of 100 m?

I don't think salinity varies much offshore so it might not be worth measuring.

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