Re: [PSUBS-MAILIST] Joysticks

[Lew Clayman <lew_clayman@yahoo.com>]

--- 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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