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On Wed, May 30, 2007 at 09:35:18AM -0400, Timothy J. Weber wrote:
> Peter Todd wrote:
> > Alternately if you have any other cheap suggestions for how to get
> > myself a nice dry atmosphere in a hermetically sealed enclosure I'd be
> > interested.
> 
> I have a project that's well-sealed - not hermetically, but splashproof 
> and perhaps submersible - and used in cold environments with high 
> humidity.  I use conformal coating, plus a small power resistor as a 
> heater on the board.  Evidence suggests the heater alone may be 
> sufficient.  I'm guessing as long as the inside temperature is higher 
> than the outside air, condensation won't happen (which is my concern).
> 
> Just another possible approach, depending on your requirements.

Unfortunately in this case the device is going to be battery powered,
so heaters are totally out, well, almost, plutonium powered heaters
would last long enough... :)

A conformal coating wouldn't work in my case as I have a display, and I
don't want condensation between the display and the (acrylic) walls of
the box. 

I am considering simply encapsulating the whole thing in off-the-shelf
polyester clear casting resin, but I recently had a device encapsulated
in resin fail. This project will be a lot more complex, and expensive,
so if anything fails I want to be able to open up the box it's in and
figure out why.

- -- 
http://petertodd.ca
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