RE: [PSUBS-MAILIST] Joysticks

["Atul Patel" <apatel@elt-inc.com>]

Thanks for all the great responses.  I'm continuing my research and hope
to have a plan in place soon. 

I'm definately going to go the desktop route with the cabling coming out
of a watertight box.  I really like the conduction idea for heat
dissaption.  

I can't wait till I start putting the pieces together :)


-----Original Message-----
From: Lew Clayman [mailto:lew_clayman@yahoo.com]
Sent: Tuesday, November 20, 2001 8:39 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Joysticks


--- Paul B <paul_victor@hotmail.com> wrote:
> I'm afraid a watertight laptop would cost too much, if it is possible
at 
> all. You have over 80 keys on the keyboard to make watertight. And
then you 
> have your com ports, lpt port, usb, pc card adapter and so on..
> 
> And it's hard to make a waterproof case for it, because if there's not

> enough air to cool it down, it may overheat, lock up and there goes
your sub 
> control..

It's certainly possible, if perhaps fiduciarily challenging... there are
mil-spec computers and machines made for nasty industrial locations. 
Waterproofing the keyboard is pretty easy, you use a continous plastic
membrane: the action on the keys is pretty poor, but it works, as do the
even-lousier pressure-membrane keyboards, cheap variants on which are
used on
kiddie toys (may you never be so afflicted).  Waterproofing the ports is
no
harder than waterproofing anything else that opens, you have a fitted
cover
with a rubber seal.  I'm not sure how they handle heat dissipation, but
I'm
guessing conduction, not convection.  Can't be that hard.

Another "solution" is to use old, cheap, used machines.  They might
fail, but
who cares?  This of course only works if you have a manual control
system that
doesn't need the computer, or in some other use where the computer is
inessential.
 
> If I had to make the whole thing safe from electric shock, I would
take a 
> laptop with external battery and make something like a watertight
emergency 
> power off switch on the external battery itself. Maybe some sort of 
> automatic relay, activated by water?

This should work, too.

-L

=====
"It's never happened in the World Series competition, and it still
hasn't."
             - Yogi Berra
=====

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