Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Bruce Bell]

As far as the warm end of the temperature spectrum goes, I have used a
Crockpot without the crock and put a thermometer probe inside. when I
wanted it to stay at a specific temperature I threw a blanket over it and
shut it off.  I suspect you could get it to hold temperature better by
 simply controlling the voltage to it.
For the cold end perhaps, you could put the ceramic crock in the freezer
(roughly 0°F). It would warm slowly enough that you could perform testing
along the way.

On Mon, Sep 5, 2016 at 9:48 PM, Richard (Rick) Karlquist <
rich...@karlquist.com> wrote:

> As we all know, step #1 in making a clock is NOT
> to build a thermometer :-)
>
> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.  I
> have some crystals, oscillators, and other
> electronics I would like to characterize over
> temperature.  I know this reflector has discussed
> homebrew stabilization ovens; however, they
> have tended to have very long time constants
> (which makes sense for that application).  I
> need to be able to change temperature in a
> reasonable amount of time, and I don't need
> extreme stability.  Looking for any ideas,
> maybe in the "maker" spirit.  I think the
> size I need would be perhaps 1/2 the size
> of a shoebox.
>
> BTW, in case someone has a chamber to sell,
> let me know...
>
> Rick Karlquist N6RK
> ___
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Brooke Clarke]

Hi Rick:

I've used two types.
1. Most of the replies have been for controlled air temperature devices.  These are by far the most common but also they 
take a long time to change temperature.
2. Hot/Cold plates are much faster since the DUT is in close contact with the plate.  We used these with a PID 
controller and liquid Nitrogen gas.  Just toss a towel over the DUT and you have very fast cycle times.


I built a DIY version for heat only using a couple of flexible heater strips glued to aluminum blocks, a PID controller 
and a 10k thermistor embedded in one of the blocks.   The Steinhart-Hart thermistor equation is of the third order with 
respect to R but it is linear with respect to the coefficients making it easy to fit.

http://www.prc68.com/I/Sensors.shtml#Temperature

The unit is hiding from me, maybe it's photo shy.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.

 Original Message 

As we all know, step #1 in making a clock is NOT
to build a thermometer :-)

I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design.  I
have some crystals, oscillators, and other
electronics I would like to characterize over
temperature.  I know this reflector has discussed
homebrew stabilization ovens; however, they
have tended to have very long time constants
(which makes sense for that application).  I
need to be able to change temperature in a
reasonable amount of time, and I don't need
extreme stability.  Looking for any ideas,
maybe in the "maker" spirit.  I think the
size I need would be perhaps 1/2 the size
of a shoebox.

BTW, in case someone has a chamber to sell,
let me know...

Rick Karlquist N6RK
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Scott Stobbe]

It is amazing what is available for 10 - 20 dollars. Some of the LED
drivers have a dimming input on the low voltage side. Not sure of the
detailed implementation of a din temperature controller with 4-20 mA
output, but it might be as simple as tl431 shunt reference and a resistor
network to map 4-20 mA to the 1 - 10 VDC analog input of an LED driver
(there are a plethora available "Meanwell led driver" is one that comes to
mind).

On Tue, Sep 6, 2016 at 12:05 AM, jimlux  wrote:

> On 9/5/16 8:52 PM, Scott Stobbe wrote:
>
>> The bargain price mini coolers are often peltier cooled, they appear to
>> fall under the marketing term "thermoelectric mini-fridge". I can't think
>> of a project name, but I'm sure I've seen this done before using a mini
>> fridge.
>>
>>
> https://www.amazon.com/AGPtek%C2%AE-Digital-Temperature-Cont
> roller-Alarm/dp/B005NGL5AK
>
> Not used this particular one, but i have some that look quite similar, and
> work well.
>
>
>
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Oz-in-DFW]

On 9/5/2016 9:48 PM, Richard (Rick) Karlquist wrote:

> As we all know, step #1 in making a clock is NOT
> to build a thermometer :-)
>
> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.



> Rick Karlquist N6RK
Another thing I've done in the (distant) past is two cheap foam coolers
with a muffin fan between them.  fill one with dry ice and control the
fan for cooling.  This was the essence of the bench coolers when I
worked for Collins Radio in the late 70's. In that case they were
aluminum boxes with foam walls.  They had Edison based wire heaters with
porcelain forms.  OSHA nightmare, but worked for the task at hand. Used
simple bang-bang controllers.

There are cheap (~$25) Chinese PID controllers, but as I said, I use the
Pico-reflow controller.  Almost as cheap and a /lot/ more flexible.

Oz (N1OZ, in DFW)

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 



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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Bruce Griffiths]

Also avoids thermomechanical fatigue failure in the Peltier device.
 

On Wednesday, 7 September 2016 12:14 AM, jimlux  
wrote:
 

 On 9/6/16 1:19 AM, Adrian Godwin wrote:
> On Tue, Sep 6, 2016 at 4:24 AM, Bob Darlington 
> wrote:
>
>> Rick,
>>
>> I'm going from memory here.  My former business partner (now deceased) had
>> a "beer fridge" setup as an environmental chamber for our instruments.  The
>> trick for stability was to run the AC compressor all the time, and push
>> against it with heat lamps.
>
>
>
> I had a commercial environmental chamber  : it did exactly this.  The
> fridge unit could be controlled from an auxiliary output of the PID
> controller but the basic principle was to heat from ambient, or heat
> against the fridge for lower temperatures. Maybe Peltier systems can have a
> cleaner rollover for cooling, but gas-based coolers have far too much
> settling time / transients / hysteresis to be actively in the control loop.
>


One thing we just found when using a Peltier type device is that the 
stock controller typically PWM modulates the 12-24V supply voltage going 
to the TE device. This produces enormous current/voltage transients 
(many amps at 24V slamming on and off) at some audio frequency which is 
sufficient to disrupt your carefully designed quiet device

On our controllers (from TE Tech) you can use an external DC power 
supply that has a remote programming input (e.g. a unipolar power 
amplifier) and it just uses the H bridge to switch polarity to the 
Peltier.  This is MUCH quieter EMI/EMC wise.

The other issue is the condensation/frost when you go cold.

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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[jimlux]

On 9/6/16 1:19 AM, Adrian Godwin wrote:

On Tue, Sep 6, 2016 at 4:24 AM, Bob Darlington 
wrote:


Rick,

I'm going from memory here.  My former business partner (now deceased) had
a "beer fridge" setup as an environmental chamber for our instruments.  The
trick for stability was to run the AC compressor all the time, and push
against it with heat lamps.




I had a commercial environmental chamber  : it did exactly this.  The
fridge unit could be controlled from an auxiliary output of the PID
controller but the basic principle was to heat from ambient, or heat
against the fridge for lower temperatures. Maybe Peltier systems can have a
cleaner rollover for cooling, but gas-based coolers have far too much
settling time / transients / hysteresis to be actively in the control loop.




One thing we just found when using a Peltier type device is that the 
stock controller typically PWM modulates the 12-24V supply voltage going 
to the TE device. This produces enormous current/voltage transients 
(many amps at 24V slamming on and off) at some audio frequency which is 
sufficient to disrupt your carefully designed quiet device


On our controllers (from TE Tech) you can use an external DC power 
supply that has a remote programming input (e.g. a unipolar power 
amplifier) and it just uses the H bridge to switch polarity to the 
Peltier.  This is MUCH quieter EMI/EMC wise.


The other issue is the condensation/frost when you go cold.

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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Adrian Godwin]

On Tue, Sep 6, 2016 at 4:24 AM, Bob Darlington 
wrote:

> Rick,
>
> I'm going from memory here.  My former business partner (now deceased) had
> a "beer fridge" setup as an environmental chamber for our instruments.  The
> trick for stability was to run the AC compressor all the time, and push
> against it with heat lamps.



I had a commercial environmental chamber  : it did exactly this.  The
fridge unit could be controlled from an auxiliary output of the PID
controller but the basic principle was to heat from ambient, or heat
against the fridge for lower temperatures. Maybe Peltier systems can have a
cleaner rollover for cooling, but gas-based coolers have far too much
settling time / transients / hysteresis to be actively in the control loop.
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Neville Michie]

Constant temperature chambers are not hard to build.
I assume you want stability in the range 0.001 to 0.01 degC.
I have made a few of these chambers, about 1 cubic feet, out of 3/4 inch 
particle board,
it is not a brilliant insulator, but you want some heat loss.
Make a partition at one end with both ends open as a radiation wall.
Behind the radiation wall instal one or two tungsten filament lamps,
about 50 watts for heaters, these have low thermal mass and fast response.
Instal a computer sized fan, behind the wall to reduce any radiant output to 
circulate the air in the box.
You want a small hurricane. On the far side of the box from the partition place 
a small bead thermistor, 
glass encapsulated are good. In the air flow this should have a response time 
of a second.
A proportional controller sets the temperature. Air velocity of up to 1m/s will 
not disturb items being tested 
but ensures low temperature gradients.
The trick is to have fast response in heater and measurement and no hysteresis 
in the controller.

cheers,
Neville Michie




> On 6 Sep 2016, at 12:48 PM, Richard (Rick) Karlquist  
> wrote:
> 
> As we all know, step #1 in making a clock is NOT
> to build a thermometer :-)
> 
> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.  I
> have some crystals, oscillators, and other
> electronics I would like to characterize over
> temperature.  I know this reflector has discussed
> homebrew stabilization ovens; however, they
> have tended to have very long time constants
> (which makes sense for that application).  I
> need to be able to change temperature in a
> reasonable amount of time, and I don't need
> extreme stability.  Looking for any ideas,
> maybe in the "maker" spirit.  I think the
> size I need would be perhaps 1/2 the size
> of a shoebox.
> 
> BTW, in case someone has a chamber to sell,
> let me know...
> 
> Rick Karlquist N6RK
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Brent Gordon]

There are cheap GC (gas chromatograph) ovens on eBay.  They are 
well-insulated and give you fast, precise temperature control. Some of 
them are designed with a liquid nitrogen input for cooling.  Otherwise, 
you can use dry ice.  I saw one mentioned on one of the mailing lists I 
read, maybe this one, a few months ago.  I meant to buy one, but got 
side-tracked.  Unfortunately, I can no longer recall the brand.


Brent


On 9/5/2016 8:48 PM, Richard (Rick) Karlquist wrote:

As we all know, step #1 in making a clock is NOT
to build a thermometer :-)

I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design.  I
have some crystals, oscillators, and other
electronics I would like to characterize over
temperature.  I know this reflector has discussed
homebrew stabilization ovens; however, they
have tended to have very long time constants
(which makes sense for that application).  I
need to be able to change temperature in a
reasonable amount of time, and I don't need
extreme stability.  Looking for any ideas,
maybe in the "maker" spirit.  I think the
size I need would be perhaps 1/2 the size
of a shoebox.

BTW, in case someone has a chamber to sell,
let me know...

Rick Karlquist N6RK



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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Chris Albertson]

You don't need exact control of the temperature.  You just need a slow rate
of change and the ability to measure the temperature accurately.

I have used a picnic cooler with some water in the bottom and a very small
fish tank heater.  But this was for an experiment in a home biology lab not
an electronic lab.  Any insulated box with a largish thermal mass inside
will do.  Try sand in place of the water.  The neat thing about aquarium
heaters is their built in thermostat.

Or simp[lly place the DUT in an attic and let the day/night temperature
swing do the work for you.  My attic get blazing hot in the day and cool at
 night, the rate of change is not to fast


On Mon, Sep 5, 2016 at 7:48 PM, Richard (Rick) Karlquist <
rich...@karlquist.com> wrote:

> As we all know, step #1 in making a clock is NOT
> to build a thermometer :-)
>
> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.  I
> have some crystals, oscillators, and other
> electronics I would like to characterize over
> temperature.  I know this reflector has discussed
> homebrew stabilization ovens; however, they
> have tended to have very long time constants
> (which makes sense for that application).  I
> need to be able to change temperature in a
> reasonable amount of time, and I don't need
> extreme stability.  Looking for any ideas,
> maybe in the "maker" spirit.  I think the
> size I need would be perhaps 1/2 the size
> of a shoebox.
>
> BTW, in case someone has a chamber to sell,
> let me know...
>
> Rick Karlquist N6RK
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/m
> ailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Bob Darlington]

Rick,

I'm going from memory here.  My former business partner (now deceased) had
a "beer fridge" setup as an environmental chamber for our instruments.  The
trick for stability was to run the AC compressor all the time, and push
against it with heat lamps.  The lamps were controlled with an Omega PID
controller with an RTD hanging in the fridge.   Model was RTD-805 (I just
happen to have it here in my office).  It has a little metal bird cage
around the sensor.  I believe he had a small fan in there too, to circulate
the air.  I removed the electronics and have since sold the commercial
refrigerator.

The instrument he was using in the chamber was an SRS 830 lock in
amplifier.

This is where my memory gets fuzzy.  SRS comped him another 830 because he
taught them how to get 10x or 100x the performance out of it.  I wasn't
working with him at the time but heard the story 50x over the years about
how impressed the SRS folks were about what he did.  I wish I knew those
details.

A buddy of mine that is now at Life Sciences contacted me about how we did
this.  He had the fridge and heater, but was heating using a thermostat to
controller the refrigeration compressor as well as the heater.  This did
not work.

And forgive me if this is way too course for time nuttery.  Just trying to
thow my 2 cents in and worst case you guys will school me on methods that
work even better.   Now I'm using a Sun environmental chamber which is
significantly smaller and meets my needs.

-Bob


On Mon, Sep 5, 2016 at 8:48 PM, Richard (Rick) Karlquist <
rich...@karlquist.com> wrote:

> As we all know, step #1 in making a clock is NOT
> to build a thermometer :-)
>
> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.  I
> have some crystals, oscillators, and other
> electronics I would like to characterize over
> temperature.  I know this reflector has discussed
> homebrew stabilization ovens; however, they
> have tended to have very long time constants
> (which makes sense for that application).  I
> need to be able to change temperature in a
> reasonable amount of time, and I don't need
> extreme stability.  Looking for any ideas,
> maybe in the "maker" spirit.  I think the
> size I need would be perhaps 1/2 the size
> of a shoebox.
>
> BTW, in case someone has a chamber to sell,
> let me know...
>
> Rick Karlquist N6RK
> ___
> time-nuts mailing list -- time-nuts@febo.com
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> ailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Hal Murray]

rich...@karlquist.com said:
> I thought I would check the brain trust here to see if anyone has seen a
> hobbyist grade temperature testing chamber or kit or homebrew design.  I
> have some crystals, oscillators, and other electronics I would like to
> characterize over temperature.  I know this reflector has discussed homebrew
> stabilization ovens; however, they have tended to have very long time
> constants (which makes sense for that application).  I need to be able to
> change temperature in a reasonable amount of time, and I don't need extreme
> stability.  Looking for any ideas, maybe in the "maker" spirit.  I think the
> size I need would be perhaps 1/2 the size of a shoebox.

What temperature range do you have in mind?

You can probably get close to freezing using ice.  If you want to go below 
that, you probably need dry ice.

My straw man would be a box with two sets of fan+ducting blowing over a metal 
back with a micro running the fans: one for hot, the other for cold.

As Gary suggested, a (small) fan inside the box will speed things up.

-

Many years ago (pre ebay), my boss picked up a used refrigerator sized unit.  
The top half was the chamber with lots of insulation and lots of air blowing 
around.  The bottom half was the refrigeration.  It was way overkill for your 
needs, but if you have the space and power and you can find something like that 
you might find other uses for it.

We only used it a few times.  It was way overkill and noisy.

I poked "temperature test chamber" into ebay.  There were lots of expensive 
units.  I didn't see anything cheap enough to be interesting and I didn't 
consider shipping.



-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Oz-in-DFW]

As with most things here - it depends.

I have a converted wine cooler I use for some things.  Bought it for $20
at a flea market. It had blow a fuse on the power supply. This appears
to be a common failure. Won't handle much thermal load, but it's a
Peltier unit, so it will heat as well if wired correctly.  If I need
quicker cooling or lower temps, a couple of pounds of dry ice wrapped in
paper bags usually does the trick.  Heat usually isn't a problem.  I
have a stock of power resistors and many, many watts of power supply.

When I need really hot I use the toaster oven I use for reflow soldering.

I use the 'pico reflow' for temp control. 
https://apollo.open-resource.org/mission:resources:picoreflow  It's
Raspberry PI based and provides a lot of flexibility. I keep meaning to
do a board to collect all the control bits so I don't have to hand wire
them.  I'm looking at the Microchip MCP9600 for the thermocouple interface.

I had to do thermal shock for a project a few years back.  A CO2 tank
and a cheap foam cooler handled that nicely.


On 9/5/2016 9:48 PM, Richard (Rick) Karlquist wrote:
> As we all know, step #1 in making a clock is NOT
> to build a thermometer :-)
>
> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.

> Rick Karlquist N6RK
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> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
Oz (N1OZ in DFW)

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 



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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[jimlux]

On 9/5/16 8:52 PM, Scott Stobbe wrote:

The bargain price mini coolers are often peltier cooled, they appear to
fall under the marketing term "thermoelectric mini-fridge". I can't think
of a project name, but I'm sure I've seen this done before using a mini
fridge.



https://www.amazon.com/AGPtek%C2%AE-Digital-Temperature-Controller-Alarm/dp/B005NGL5AK

Not used this particular one, but i have some that look quite similar, 
and work well.



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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[jimlux]

On 9/5/16 7:48 PM, Richard (Rick) Karlquist wrote:

As we all know, step #1 in making a clock is NOT
to build a thermometer :-)

I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design.  I
have some crystals, oscillators, and other
electronics I would like to characterize over
temperature.  I know this reflector has discussed
homebrew stabilization ovens; however, they
have tended to have very long time constants
(which makes sense for that application).  I
need to be able to change temperature in a
reasonable amount of time, and I don't need
extreme stability.  Looking for any ideas,
maybe in the "maker" spirit.  I think the
size I need would be perhaps 1/2 the size
of a shoebox.


You might look at inexpensive thermoelectric cooler/heaters - depending 
on what temp range you want.


You could get a small electric icechest/heater and cobble up a 
controller.  They make ones that are designed to heat/cool something the 
size of a 1 liter coke bottle..



TE technology has a wide variety of TE coolers and 
controllers..Basically it's all about DC power supplies or power op amps 
in one form or another.


http://tetech.com/


You can buy inexpensive 1/8 DIN PID controllers for about $20 online..
They will take all manner of input sensor, thermocouple, PRT, 
thermistor, etc.


Look at the "homebuilt sous vide" folks.

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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Scott Stobbe]

The bargain price mini coolers are often peltier cooled, they appear to
fall under the marketing term "thermoelectric mini-fridge". I can't think
of a project name, but I'm sure I've seen this done before using a mini
fridge.

On Monday, 5 September 2016, Richard (Rick) Karlquist 
wrote:

> As we all know, step #1 in making a clock is NOT
> to build a thermometer :-)
>
> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.  I
> have some crystals, oscillators, and other
> electronics I would like to characterize over
> temperature.  I know this reflector has discussed
> homebrew stabilization ovens; however, they
> have tended to have very long time constants
> (which makes sense for that application).  I
> need to be able to change temperature in a
> reasonable amount of time, and I don't need
> extreme stability.  Looking for any ideas,
> maybe in the "maker" spirit.  I think the
> size I need would be perhaps 1/2 the size
> of a shoebox.
>
> BTW, in case someone has a chamber to sell,
> let me know...
>
> Rick Karlquist N6RK
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Bob Albert via time-nuts]

Better stock up on 60W bulbs.  They are becoming outlawed.
(Only kidding, a resistor works as well.)
Also, a foam drink cooler will give a more stable temperature.  You can make it 
leak a bit of heat to get the thermostat to cycle.  The hard part is the 
thermostat; they aren't cheap - even the low cost ones at the hardware store 
that work on low voltage.

Bob
 

On Monday, September 5, 2016 8:30 PM, Gary E. Miller  
wrote:
 

 Yo Richard!

On Mon, 5 Sep 2016 19:48:14 -0700
"Richard (Rick) Karlquist"  wrote:

> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.

When I did this for testing labs, I took a cardboard box, a 60w
incadescent light bulb, and a cheap thermostat.  Set the thermostat to
a bit above max ambient and you are good to go.  For more precise temp
control, put a fan in the box to prevent temperature startification.

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
    g...@rellim.com  Tel:+1 541 382 8588
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Re: [time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Gary E. Miller]

Yo Richard!

On Mon, 5 Sep 2016 19:48:14 -0700
"Richard (Rick) Karlquist"  wrote:

> I thought I would check the brain trust here to see
> if anyone has seen a hobbyist grade temperature
> testing chamber or kit or homebrew design.

When I did this for testing labs, I took a cardboard box, a 60w
incadescent light bulb, and a cheap thermostat.  Set the thermostat to
a bit above max ambient and you are good to go.  For more precise temp
control, put a fan in the box to prevent temperature startification.

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com  Tel:+1 541 382 8588


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[time-nuts] Hobbyist grade or homebrew temperature testing chamber?

[Richard (Rick) Karlquist]

As we all know, step #1 in making a clock is NOT
to build a thermometer :-)

I thought I would check the brain trust here to see
if anyone has seen a hobbyist grade temperature
testing chamber or kit or homebrew design.  I
have some crystals, oscillators, and other
electronics I would like to characterize over
temperature.  I know this reflector has discussed
homebrew stabilization ovens; however, they
have tended to have very long time constants
(which makes sense for that application).  I
need to be able to change temperature in a
reasonable amount of time, and I don't need
extreme stability.  Looking for any ideas,
maybe in the "maker" spirit.  I think the
size I need would be perhaps 1/2 the size
of a shoebox.

BTW, in case someone has a chamber to sell,
let me know...

Rick Karlquist N6RK
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