Underwater Exploration Vessel

[Dileepa]

We are a group of mechanical engineering students from Sri Lanka. We are developing an underwater exploration vessel. As we are not very familier with electronics we need some help regarding the depth control.

Our sub has a neutral bouyancy and we are using an electronic pressure sensor to measure the depth and a thruster to control the depth. If you people have any circuit diagrams please help us.

All types of Ideas are wellcome

 

[ericgibbs]

hi,
The electronic pressure sensor you are using, is it a 4-20mA or a 0 to 5V type.? Is a differential or absolute sensor?.

What depth ranges will you be working to and what depth resolution ?

You should also consider fitting a depth below the RSV, ie seabed clearance.

Regards
EricG

 

[Gayan Soyza]

We are a group of mechanical engineering students from Sri Lanka. We are developing an underwater exploration vessel. As we are not very familier with electronics we need some help regarding the depth control.

Our sub has a neutral bouyancy and we are using an electronic pressure sensor to measure the depth and a thruster to control the depth. If you people have any circuit diagrams please help us.

All types of Ideas are wellcome

Hi are you CINEC students,or other?mmm not an easy task you choose.I'm not much familliar with these pressure sensors.but some few ideas which my ship has.in simply
Its having some transponders sending some waves (audio,laser,etc..)to the bottom of the sea and reciveing & calculating the depth in a small computer in the engine room.this system is built in with many ships.

Other old method is taking soundings.

 

[Dileepa]

Pressure sensor details

hi,
The electronic pressure sensor you are using, is it a 4-20mA or a 0 to 5V type.? Is a differential or absolute sensor?.

What depth ranges will you be working to and what depth resolution ?

You should also consider fitting a depth below the RSV, ie seabed clearance.

Regards
EricG

Sorry for taking so long to reply. The sensor we are using is a 0-5v type and the depth we are talking about is 30m. It is a differential pressure sensor and has a resolution of 0.267v/psi.
How ever the sensor we already have is a 15psi one. We are looking forward to buy a new one.
We didn't quit understand what is depth below RSV. Please explain.

Thank you.

 

[Dileepa]

Hi are you CINEC students,or other?mmm not an easy task you choose.I'm not much familliar with these pressure sensors.but some few ideas which my ship has.in simply
Its having some transponders sending some waves (audio,laser,etc..)to the bottom of the sea and reciveing & calculating the depth in a small computer in the engine room.this system is built in with many ships.

Other old method is taking soundings.

No, we are students of mechanical engineering department, university of moratuwa.
Your idea is suitable for ships, but we are concern about the water head above the vessel, not the depth of water. Anyway we can use your system with a memory to calculate the head provided the sea bed is uniform which is very unlikely.
Do you have any idea about the price of that unit?

 

[ericgibbs]

hi dileepa,
We didn't quit understand what is depth below RSV. Please explain.

As you have already stated the seabed is not always uniform, in fact unless its a dredged area its most likely not uniform.

The Remote Submersible Vehicle RSV, will I expect be capable of moving in three dimensions.
Depth being considered as the third dimension, you may know the depth of the RSV below the water surface, but how will you know how
much clearance you have below the RSV to the seabed??

Your 15 psi pressure sensor will only work down to 10mtrs water depth.
You will need at least a 3 bar sensor for 30mtrs.
[the 0 to +5v sensor is good choice]
As its a differential sensor, will the RSV be at atmospheric pressure?

edit:
In case you are not aware.
In the screened cable from the sensor there is also a hollow plastic tube, this is the atmospheric pressure tube for the sensor
diaphragm and should open to atmospheric pressure.


Eric

 

[baftab]

you want to measure the depth of your subamrine or its distance from the sea bed??

 

[Hero999]

You'll probably also need a temperature sensor because the water pressure at a given depth will also depend on the temperature.

 

[Dileepa]

you want to measure the depth of your subamrine or its distance from the sea bed??

We want to measure the depth of the submarine.

 

[ericgibbs]

hi Dileepa,

We know you want to measure the depth of the submersible.

Use a 3 bar,[ 30mtr] differential pressure transducer, with an output voltage range of 0 thru +5volts.
[it will require to be powered from +12v to +24v]

If you intend connecting the cable of the sensor to the surface/boat ask the supplier for a 40mtr cable.

Connect the output from the transducer into the analog input pin of a PIC and convert the adc value into a depth value.
[ connect a noise filter on the output of the sensor, before its connected to the PIC]

Please post a diagram on how you will connect the pressure sensor and PIC/etc

Are you asking for circuit diagrams on how to connect the sensor, process and display/output the depth ?

Eric

 

[Dileepa]

hi Dileepa,

We know you want to measure the depth of the submersible.

Use a 3 bar,[ 30mtr] differential pressure transducer, with an output voltage range of 0 thru +5volts.
[it will require to be powered from +12v to +24v]

If you intend connecting the cable of the sensor to the surface/boat ask the supplier for a 40mtr cable.

Connect the output from the transducer into the analog input pin of a PIC and convert the adc value into a depth value.
[ connect a noise filter on the output of the sensor, before its connected to the PIC]

Please post a diagram on how you will connect the pressure sensor and PIC/etc

Are you asking for circuit diagrams on how to connect the sensor, process and display/output the depth ?

Eric

If you already have those diagrams, YES!
You all can contact me on dileepa_rathnayake@yahoo.com