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evilengineer_bcet
05-09-2005, 06:16 PM
hi, :cry:
i am keenly 8O 8O intersedted in making a underwater probe robot.an hexapod or bipod just wont do.but i am pretty skeptical about how to waterproof it below 50 mtrs.
any robo dude wants to help..?
call on 09888221375...or email at er_harshvardhansharma@rediffmail.com :D :D :D :?

vikas
05-09-2005, 11:19 PM
thatll be a little tricky one ( whats the objective ... be a little more specific ) ...

BTW do you have the equipment to test such a thing at such depths ?

ice
05-10-2005, 10:15 AM
hmmm...jst worried abt the pressure ur bot will have to take at those depths...

i got a link for you here
http://www.huv.com/

specialises in underwater machines..

pkshima
05-10-2005, 10:23 AM
Well whats the problem.
we all know what waterproof means.
to make one well you have to somehow cover it all up.
use plastic/fiber. tough enough to bear the pressure which exists at that depth in water.

how to cover it up is an implementation issue not a design issue.
just do it. Its nothing more difficult than that. Also it will have to swim i guess as it would be VERY difficult to walk in water especially that deep.
So you use a propeller kind of thing thats there in submarines.
Use the motor from a water pump. maybe submersible pumps beacuse they are very well waterproofed and they also have the propeller kindda thingy in them. I am not sure but I think they must be.
Also, submersible pumps should be VERY EASILY available in punjab.

For further info, I would suggest reading "how submarines work" and how "(submersible) water pumps work"

Also, please dont request pple to email the reply directly to you as this forum would like to preserve the reply for others to see. Just click the
"Notify me when a reply is posted" checkbox to be alerted by email when someone replies.

vidur
05-10-2005, 01:02 PM
Your submersible will deal with upto 5-6 atm. pressure. at
You'll also have to use a long umbilical cable for communications(if unmanned)...almost all submersibles use one

YOu'll also need ballast tanks like that of a submarine

At 5 atm i dont know how good a fiberglass structure would be. A carbon composite of metal hull would be good

For thrust use DC motors through a stuffing box built into the hull. or a seperate pod.


Payload like robo arm,cameras ,sonar are all on your imagination & how deep your pockets run

You can also relieve the stress on the hull by slightly decreasing the air pressure insde the hull as it descends into the water


Need more hlp...

lemme know

evilengineer_bcet
05-10-2005, 06:08 PM
dear robotics india dudes,
i am really indebted to all of you for such a quick response.see:
i can share my design part with any one who's interested.
being a mechie ,i am more concerned bout the torque and dexterity.
stepprs are fine but not for pickin up something as big as a lost mesh gear part..!!!...or a hevy uncountious auntiji..!(just in case..)
i mean 50 mtrs or more and good strenth.
ya i have the submersible KIRLOSKAR 7 h.p motor D.C...
but the problem is pressure...
insulation is ok ...yes submarines use a trck wire...but r/c interface like in the UT-900 sub series is gr8r.
sensors.....sensors could be used in the nosecone, including a chemical sensor, a small digital camera, or a hydrophone...
so all dudez who get a idea can share it ASAP...
major part being the design asopect of the casing,,...
fiberglass not strong enuff...i am considering..DURALMIN..fighter plane material...(dad's in army)..might work out..!!!..do keep suggestions open
and thanks once again...to all techies. :lol:

evilengineer_bcet
05-10-2005, 06:19 PM
more tech details are:
at the top is a 3.7 volt 100 mAh lithium polymer battery.
The bottom circuit board has an Analog Devices ADXL202 at the front, an Atmel AVR Mega-168 microcontroller in the middle, and three Vishay SI9988 h-bridge chips at the back. The top circuit board has a Honeywell HMC1053 3-axis compass chip on it.
any other intricasies you wanr to discuss do inform.

anyone from DCE..?
:roll: sameer mehta..? :lol:

vidur
05-10-2005, 06:29 PM
Dont go for R/C

You wont want to lose a sub, beacause your data link is very unreliable....blue water is definately unreliable

Imagine what happens if your RF link collapses for even a few seconds

TRUST ME....Use an umbilical cord.

evilengineer_bcet
05-11-2005, 06:45 PM
hi,
yaar the problem with a umblical cord is degress of freedom,
it constraints your motion..
if by the way u know some guys who have worked on it i would love to be in contact with them. :lol:

regards

harshvardhan sharma
mechanical engineer

vidur
05-11-2005, 07:46 PM
Thats why submerisble operators are trained before they use it in the field.

All the commercial submersibles use cords...

but if you can make the radio work underwater....WHICH IS VERY DIFFICULT INDEED....i only know of VLF/LF bands...which have inherent channel capacity problems


by the way...what kind of radio you're using...Sea water is pretty salty & hence conductive. That's why I dont think Radio will work underwater, unless you have a bouy antenna sticking out of the water, which is as good or bad as using an umbilical cable

Please think twice be4 making a unreversible decision

ice
05-11-2005, 10:12 PM
My suggestion would be : use an umbilical cord...You will need alot of channels [like motors,cameras,pumps..]..to control.

You can always use a radio later.
Look at all the deep sea missions..they were never radio controlled.
an example would be the ROVs used for xploring the Titanic,seen the movie "THE ABYSS",theres an underwater bot in tht too.

IMHO..Build your machine first..test it out with the umbilical.My bet is tht u will stick to the umbilical.

sumandeep1984
05-12-2005, 10:03 AM
Wow .... lots of real cool info on Underwater Vehicles

vikas
05-12-2005, 12:47 PM
what about ultrasonic communication ??? ... like the whales communicate ( just givin ideas :D ) . i belive the data transfer rate will be really low .

pkshima
05-12-2005, 12:58 PM
Whales/dolphins wont like it.
and so green-peace wouldnt let you do that I guess :wink: :lol:

vidur
05-12-2005, 08:11 PM
Ultrasound obviously has many problems


Prob1: Obviusly Channel Capacity...Carrier freq is 40KHz ...you'll be lucky if you get 1000bps...so forget cameras...on the payload

Prob 2: I dont know of a mechanism to modulate ultrasonics apart from ON-OFF.

Prob 3: Diffraction. Since sound is much slow, communication protocols will be something like what satellites use ....NOT USEFUL for Real time ..Also large wavelegnth means you'll not get a good range...I guess 200 m maX

Prob 4: i dont really know how much power you'll need to pump in to the transmitter.


moral of the story....ULTRASOUND is not worth it yaaar!

:-)

vidur
05-12-2005, 08:22 PM
Whales/dolphins wont like it.
and so green-peace wouldnt let you do that I guess :wink: :lol:

Even if you do it...the whales might probably think it is one of their own kind!!!!!!!

:lol: :lol: :lol: :lol: :lol: :lol: :lol:

docel
01-08-2006, 02:34 AM
HI,
june , july, aug, sep, oct, nov, dec, jan. 8 months.
Did any one make anything??

Will be nice to see some discussion here.