At 03:29 AM 6/27/2007, you wrote:


> >-----Original Message-----
> >From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]
> >On Behalf Of Russell McMahon
> >Sent: 27 June 2007 07:06
> >To: Microcontroller discussion list - Public.
> >Subject: Re: [EE] Cheap solution for environmental chamber
> >
> >
> >
> >If you need to go VERY low then a Peltier device may not have enough
> >power. What is your target temperature range?
>
>If you need more delta T then stacked Peltiers =

>are a possiblity.  This is what we use for over =

>temperature testing in production (way faster =

>than the environmental chambers we used to use).
>
>Regards
>
>Mike

Last time I needed to go very low for one-off =

testing and didn't have access to a
commercial environmental chamber I just went and picked up some dry ice
(-79=B0C) for a few dollars, then balanced off the cold with a heater and R=
TD
temperature controller (no problem with that, as we made them).
Things like styrofoam coolers or even cardboard boxes lined with styrofoam
will do the chamber part if it's only temperature you're interested in
(but be careful to avoid fires...). It would be nice to have a full (humidi=
ty
and temperature) chamber, but they are generally huge and for our purposes
would spend most of the time sitting around empty (maybe they could keep
my lunch cold). For burn-in and high temperature testing/cycling, a
computer controlled benchtop lab oven works nicely.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the rewar=
d"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com




-- =

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