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Solution to the underwater video transmission problem

R/C Submarine modelers

Solution to the underwater video transmission problem

Postby Andreas_dk » Thu Jan 15, 2009 3:31 pm

Allright, are you ready for a scientific wonder!

I have developed a way to transmit video under water without using radiowaves. It is based on ultrasonic transducers, a hydrophone and a laptop for calculations.

The project is only in its infant stage, but I am getting on with it. Maybe it will be finished in about a year. At the moment the system will ahve a resolution of 176x144 (Q-CIF) and use 9-bit colors (512 different colors) and a 2 pictures per sec. I now it sounds pretty ugly, especially the 2 pictures per sec, but then here is the bonuses about the system:

- Its 100% legal, uses now radiowaves only highfrequence sound
- It will have a range far above what can be achieved with radio transmitters.
- the transmitter can be small
- the transmitter will run 6 volt, maybe 9 volt.
- Maybe I can implement the transmitter to send some data about speed, depth, batterylevel etc. too

- Low picture rate and low resolution
- Might have problems in waters with smooth and hard shore (Like swimmingpools) as a result of strong echoes.
- Pretty expensive maybe around 200-300 dollar (if you don't have a laptop then you need that too)
- You might need a laptop with a pretty good graphics card (To do the math)
- The receiver and laptop must do a lot of math to create the actual picture, thereby using your laptop battery very fast
- Range dramaticly reduced when above water.
- The project is long from finished and I might discover some problems I can't solve at the moment.
- It will take at least a year before I have a working version.

At the moment I am working on how to create the computer interface with microcontrolers. I have found a suitable camera and some possible ultrasonic transducer.

Now what I would like to know from you fellow sub builders is:
Would I have a market for this nifty wireless camera?

Andreas DK
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Postby aquadeep » Wed Jan 21, 2009 1:11 pm

Sounds like a very interesting system and has potential market value.

My only concern besides the cost would be the posible harm the ultrasound waves may do to the fish and other wild life?
The Navy is in hot water over those wales and there new hipowered sonar system. :(

There is a company that has developed a system that uses satalites and repeaters to relay telemitry to divers and vedeo link and its live.
Hate to know the cost of that baby!

Great research you are doing and keep us posted I am very interested !

Dave amur Ship Yard :D
"I like submarine comanders ,they don't have time for bull!!" and
"Don't tell me it can't be done!"

President Roosevelt

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Postby Sub culture » Wed Jan 21, 2009 3:21 pm

Thinking laterally, maybe this could be used to control the sub too. It would negate the problems with brackish or salty water.
'Why are you staring at an empty pond?'

Want to dive your boat in crystal clear water? Then you had better Dive-in-
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Postby Ramius-II » Sat Feb 07, 2009 5:59 pm

Hi Andreas! :)
What you are developing sound interesting. The primary reason with radio transmission is that most people use the wrong frequency for transmission! 2.4 GHZ is the resonant frequency of water thus once the antenna is in the water all you end up doing is warming the water around the antenna! The second part is that the antenna systems being used are a straight "whip" or 1/2 of a "dipole" antenna with no antenna "gain" or ability to direct the signal upward rather than in a transmission pattern the looks more like a ball, going up, down, sideways, etc. A coaxial antenna will give a minimum 3 db of gain (every 3 db is twice the power). What you may consider in finding a way to shift the transducers frequency as now, if I understand correctly, you are trying to ship video via Amplitude Modulation aka AM or what is called "Ancient Modulation". If you can cause a shift in the transducers frequency then you would working with FM or "Frequency Modulation" which has significant advantages. 6 MHZ would give you enough "bandwidth" for video and maybe more! Just an idea, hope it has value for you.

Best, Ed
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