Depth Transducer (30M Depth) for Arduino

Using Arduino Sensors
1

Hello,

I am looking for advise on what depth transducers are available to be used with Arduino for an upcoming project to measure tidal levels in one location.

The sensor will be placed on /in a floating device at water surface level in a small harbour and the depth values then sent via serial comm to another Arduino ~3 metres away (there is wifi available).

I have used the Bar30 pressure sensor and this is not suitable for my needs as I want the device to on the surface.

I have read previous posts on this topic but there does not seem to be any finished/successful projects to date. Whilst I my budget is not unlimited, I am willing to invest in the correct transducer and interfaces to get this up and running.
Any help or suggestions are welcome!
Thank you

2

To be "used with Arduino" just requires that it has an interface that's present* on the Arduino, and uses signals that are within the Arduino's specifications - eg, 5V or 3V?

What Arduino are you using? In particular, is it 3V or 5V?

Arduinos commonly support UART, SPI, and I2C - and many more.

* Or can be added with a shield.

3

If you want to measure water depth from a floating platform, an ultrasonic transducer like those used in a "fish finder" would probably be easiest. Search "fish finder transducer".
One hit:
https://www.hodgesmarine.com/navigation-electronics/fish-finders/fish-finder-transducers.html

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4

Are you going to allow it to float away? IF anchored, how will the depth vary with the movement at anchor? What will you use for an anchor? Can it be used as a reflector for either sound or light?

5

One way is to have a pile (or piles) driven into the river/sea bed, and a platform which can move up & down on these piles; eg,

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In that case, perhaps you could use markings or suchlike on the piles?

6

Hi all, firstly thank you for everyone's quick responses. For some additional background I am an artist about to go to The Bay of Fundy, Maine, and I want to use the large tidal range in the harbour to trigger a motor movement in my studio that is across the path from the harbour.

@awneil I have Arduino Uno, 5V, but I understand what you have said that I will need a specific shield to convert the data depending on what type of transducer I get

@JCA34F thank you for the link, this ST40 transducer is ST40 compatible which follows NMEA protocol...and then I will need a converter to send the depth value to Arduino?

@Paul_KD7HB It will be anchored in the harbour with an anchor and heavy enough rope that when the tide goes out the rope will sink (opposed to it floating) The tidal range is nearly 20 metres, resulting in pressure issues for any electronics placed at that depth.

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7

hi @awneil the tidal range is ~20 metres which will require an awful lot of material for a vertical pile :open_mouth:
ideally the device would be inside a buoy anchored and omit the depth values to me onshore.
I am also not 'married' to the Arduino Uno if you think an RPi / similar would be 'easier' ...

8

R4 or R3/2/1 ?

If the sensor has an interface directly supported on the Arduino, you won't need to add a shield.

9

An Arduino should be fine.

How will you power it? That becomes far more of a challenge with RPi!

10

Sorry they are all R3 , I'm open to suggestions for powering it...

I was planning on using a battery pack but have also been looking into using solar panels.
Trying to figure out the best transducer option / sensor first

11

Find a place with ZERO currents and perhaps that will work.

12

Why not use the tide table? A navigational tide table keyed to your location on the bay should be quite accurate, in both height and timing.

13

So you're making a high-tech one of these:

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"Tide Gauge" would seem to be a good search term ...

14

Yes, I am attempting to make a high tech version of this, and asking for advise from the forum on what transducer and/or interfaces people think would be best

15

I have used tide tables in multiple of my projects before through api keys, for this project I want to gather the data from a device that I have set up on location myself so that people can observe the device outside and the output in my studio first hand

16

Would anyone be the wiser if you have an interesting looking "sensor" outside (that does nothing) and use tide table data as the "output"?

:slight_smile:

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18

From looking at those, "Tide Gauge" would seem to be a good search term ...

Also, rather than depth, could you set up something above the water to measure height of the water? That could be done ultrasonically, I think ...

19

Yes I could definitely set up a device with a sensor that came out from the pier and calculated the distance to the water less the distance to the sea bed.
The harbour is famous for the largest tidal range in the world so that is why I am quite determined to have the movement of the actual sea drive the information :slight_smile:

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20

no, they most likely would have no clue, but i would, and I'm a divil for punishment, hence the determination!

21

So it is:

Sounds like an ideal place for some tidal power generation ... ? :thinking:

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