The Grate Experiment

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sparky
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The Grate Experiment

Post by sparky » Thu Feb 23, 2006 5:34 pm

I have a little project I am working on here .

and so far this is what i have come up with its still just a theroy actuly but I hope to test it soon.

I want to check my dive computer for to see if it is giving me true readings or not.

So The theroy is to place the computer in to a clear container and full of water by preasurising the container with compressed air I should be able to simulate depth i just need to figure out how much air to add to the deal to simulate say 60' for example.

by adding more air i should be ably to make the dive comuter think it is at any depth I can simulate by adding that much more air to preasurise the container .

What do you think should this work. =D>
or not?](*,)
Sparky
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Tangfish
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Post by Tangfish » Thu Feb 23, 2006 5:39 pm

My only question is.....if you have a compressor, why aren't we using it?!!! #-o

Seriously though, you can look at basic dive tables, Pressure vs. depth. 1 ATM is regular atmospheric pressure. Pressure approximately doubles for every 10 meters of sea water. :salute:

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DiverDown
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Post by DiverDown » Thu Feb 23, 2006 5:57 pm

I dont think thats gonna work sparky!!!! im no math wiz but thats gonna take alota freakin pressure..... \:D/ not to mention is water even compressible??
Who run barter town?

Scubak
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Post by Scubak » Thu Feb 23, 2006 8:03 pm

Sparky,
You need to go diving and quit worrying about the dive computer....
You really, really need to get in the water... :bounce: :bounce:
Kirsten
"Let's go diving!"

da_jab
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Post by da_jab » Thu Feb 23, 2006 9:07 pm

Well well, as an engineer I can't keep my fingers out of this one. ;)

I guess Sparky is worrying if his computer tells him the right things.

As for starters, water(liquid) don't compress, so the idea of having a container with water and compressing it with air doesn't work. If water would compress, it woud get thicker whlie going deeper and there wouldn't be a sport called diving I guess, which would be a major bummer.

So, what do we know about gas and it's behaviour from the OWD course? Right, as pressure(depth) increases, the gas(air) compresses, remember that empty plastic coke bottle trick? Now, what is a dive computer anyway? A device with a pressure sensor, cpu, display, battery and a bunch of software that does calculations according to time and the pressure(depth) data from the sensor.

Now, the key to bust this myth is (hehee, now I'm sounding like Adam and Jamie from the Mythbusters :) ) how to get the computer pressurized to a certain pressure that equals certain depth?

Well, actually it's quite easy. How we are treating DCI/DCS? In the recompression chamber ofcourse, so easiest way would be to take the computer to a local hospital that has this equipment, hop in with the computer, take a ride and see what it gives you.

While, that might be a little over for your budget so how to make a small one by yourself? Well I don't know much about mechanical engineering but I'd assume that maybe you could take an old scuba tank, cut it in half and mount a very thick glass window to it, put in the comp, add some air slowly and see what happens.

Back here the dive computer manufacturer Suunto test drives all the new computers down to 100m (300 something ft) and the old ones that are sent in for repairs and battery change. I have to say that I like them a lot, their service is something extraordinary. They fix and sometimes even change old computers to new ones that are sent in for maintenance, even after the warranty period has gone. Ofcourse there must be a real defect in the comp. but they do that and that is what I call service! :)

So something around these lines I guess but if you ever make that testing tank and bust your comp. please don't blame it on me. :)

So stop worrying and get diving!

.Janne

Ps. If you still have doubts, then buy a second one for backup, that is what I do, since water and electronics don't mix. :)
What works, works!
--Sheck Exley

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Dave
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Post by Dave » Thu Feb 23, 2006 9:56 pm

See what you've started Sparky!!! Just joking (of course) I am impressed with Janne's reply but think you better go with Scuba K's suggestion. If you get in the water just compare what your computer registers while your dive bud is at the same depth. Chances are both computers will read alike and if not I am sure you could get three together, in fact so far there are three of us diving Sunrise,,,,do I hear FOUR ???
btw, got the tin today I'll let you know how that goes this weekend,,
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wallyc72
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Post by wallyc72 » Fri Feb 24, 2006 4:00 pm

Global Manufacturing http://www.gmcscuba.com/ makes a Instrument Test Chamber. It cost's $1,799.00. and is designed to take the pressure. So your idea would work. But the chamber has to be able to take the pressure.

Wally
www.tacomascubacenter.com
http://www.uemis.com/

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sparky
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Post by sparky » Fri Feb 24, 2006 6:09 pm

Damn : :withstupid:
I was hopeing I was on to something here.

Thanks Janne you just had to burst my bouble didnt you. ](*,)
here I thought I was going to be a millioneare and be able to dive all day while you poor working stifs strugled through #-o that is just my luck.


No but realy
I have compared it to my dive buds computer only 1 foot differance between his computer and mine and I was on the down side of the slope from him at the time .

My concern is when Jay and did our weekend dive in the hood canal I made 3 dives but my Mares Toutur dive computer only loged 1 dive

funny thing is on dive #2 and #3 of the weekend it was showing me Depth dive time and water temps just like always any one ever heard of this.? And what would cause this I know I had fresh batt in the darn thing
I just bought some the night before our trip to the Hood Canal.


As to the theroy about diving and see what my computer tells me I would love to but I have to work tomorrow we are pumpping 100 plus yards of concrete maybe next weekend. I hope I hope :fish:
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Scubak
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Post by Scubak » Fri Feb 24, 2006 6:59 pm

Sparky,
I have always kinda checked my dive computer with my buddies...just to sort of see...what numbers come up., in the different modes.
I dive a Suunto and love it. I started with their Solution and in 6 years it still works and I found one up in the San Juans with only 54 dives on it...put a new batt in, cleaned it up and it acts as my backup.....plus...you're going to have to go the way and get a bottom timer and wetnotes to plan all your dives.
Wish we were diving tomorrow...
I am bummed so I am gonna work on my dive gear a bit tonight.
Kirsten
"Let's go diving!"

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sparky
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Post by sparky » Fri Feb 24, 2006 7:27 pm

Scubak:
I wish I was diving tomorrow to Hon:

I was realy looking foward to meeting every one, I am shooting for next weekends Dive.

I am still a little bumed out about my computer, I just had it serviced about six month ago and the shop that did it for me went out of business so we are looking for a new Mares service senter.

i am actuly thinking about contacting them my self to see what they say about this

hope you have a good time tomorrow post lots of pictures and a nice dive report for us working slobs.
:-({|=
Sparky
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Learns from his mistakes

A Wise Man
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Dave
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Post by Dave » Sat Feb 25, 2006 8:27 am

Will do Sparky!!!
\:D/
[Sparky wrote:
hope you have a good time tomorrow post lots of pictures and a nice dive report for us working slobs.
:-({|=
Sparky[/quote]
TAKE only pictures,,, LEAVE only bubbles...

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rcontrera
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Re: The Grate Experiment

Post by rcontrera » Wed Jul 19, 2006 4:05 pm

sparky wrote:So The theory is to place the computer in to a clear container and full of water by pressurizing the container with compressed air I should be able to simulate depth i just need to figure out how much air to add to the deal to simulate say 60' for example.


Just skip the water and only use air pressure. Your container will have to be able to hold about 30-40 PSI to get down around 60'.

While 30 PSI doesn't sound like much, if you have, say a 6" lid on container of air and it decides to come apart, it is going to send that lid flying! I had a pressure pot that we used to use for testing camera housings, gages, watches, etc and it was made of 1/2" thick aluminum with a 3/4" lexan window. We could test down to 300 FSW. One of the guys didn't lock all the lugs down on the lid one time and it blew apart a 1/4" steel bolt and sent the lid flying!

Be careful!

Just my $.02

Ray

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Post by Diver_Dave » Thu Jul 20, 2006 5:41 pm

Scubak wrote:Sparky,
You need to go diving and quit worrying about the dive computer....
You really, really need to get in the water... :bounce: :bounce:
Kirsten


I will agree w/Kristen u need to get in the water.....
D.D.
Sitka,Alaska
Finding things under water....

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