an Attempt at Simple Toucam Cooling (with RESULTS)

[ballaratdragons]

I am fed up with getting Amp Glow in the corner of my pics when doing Long Exposures, but I know that cooling decreases it.

So I have made a very basic cooling device for my Toucam.
It is a small fan from an old computer attached (temporarily) to the back of the Toucam. I know I can fit Peltier Cooling inside the Camera, but this is a test of a very simple method anyone can do if it works. Plus it's cheap :D

The 1st Test:
I tested its performance today for creating cold air. The Air temp outside was 8 degrees during testing. I switched on the fan and held it close to my hand. Within 1 minute my hand was starting to sting badly from cold!!!

The 2nd Test:
I strapped the fan to the Toucam and ran it for 3 minutes. Then I removed the fan and felt the Toucam body. It was extremely cold to touch!!!

So far so good.

Now all I need is a clear sky and I can test it on Long Exposures. The temps at night are dropping to around 1 degree here at the moment, soon to be in the minus region, so I am hoping the fan will make the camera go down to somewhere around -5 degrees or lower.

If it all works, I will mount it properly to the camera body instead of by the Rubber Bands I am using now.

I will do a report on its performance when I get some sky. :thumbsup:

[matt]

Great work, Ken:thumbsup:

Excuse ignorance, but isn't the best the fan can acheieve only the same temp as ambient temp, given it's only blowing ambient air onto the ToUcam?

If it's 1 degree ambient, how can the fan achieve -5 without some other form of heat transfer?

You'd need active cooling - peltiers - to get below ambient.

[ballaratdragons]

Matt, it is called 'Chill Factor'. Bowing cold air makes air even colder.

Motorcycle riders are all too familiar with it.

[matt]

Hmmm. Didn't think it worked that way. Seem to recall Bird posting comments about this somewhere.

Anyhoo... go Ken!!!:thumbsup:

[bojan]

Ken, chill factor is about how fast heat is transferred from warmer body to moving air that sourrounds it...
http://www.learner.org/exhibits/weather/act_windchill/
So, blowing wind will only cool your camera faster, until the same temperature is reached.
For anything lower, you need peltier (active cooling).

[ballaratdragons]

:sadeyes:
It appears that you guys are right.

I just googled the scientific side of Wind Chill and it seems that it doesn't make the air colder, it just takes heat away faster :(

Well how come the Toucam body was very very cold to touch. Much colder than the Ambient air today? :shrug:

[Doug]

Ken, I think that allthough wind chill has to do with faster heat transfer, it might tend to work for you but not as well as hoped.
With no latent heat of vaporisation to aid cooling such as with the human body, wind chill will not be as obvious. Increasing air preasure locally over the body of the toucam should aid in some heat transfer, but not much.
my 2c worth

Doug

[Doug]

Ken, I think the ambient air temp is not sensed very quickly by the body. that is why you can go outside for a short while before the cold gets to you; but staying out side for an hour or two and you begin to feel uncomfortable?

[bojan]

And all this discussion is very easy to quantify in scientific terms, by menas of a thermometer :-)

[Doug]

Yup tis true! Ken you might like to google 'wet-bulb thermometer'

[leon]

Ken, not getting into the chill factor debate, would the fan on the camera itself cause vibrations, and upset the image quality, i would be interested to know. :shrug:

Leon :thumbsup:

[ballaratdragons]

Dunno yet Leon, I haven't tested it yet. But I did feel the Toucam while it was running and there was no vibrations felt.

[ballaratdragons]

Noun 1. wet-bulb thermometer wet-bulb thermometer - a thermometer with a bulb that is covered with moist muslin; used in a psychrometer to measure humidity


:shrug: What about it?

[Doug]

Oh...nevermind. But say Ken, you could test your idea using a cover over the OTA couyldn't you? no stars but any amp glow will be there anyway no?

[middy]

Correct. This is because air is actually a good insulator when it comes to heat. Contrast this with a metal surface which will feel very cold when you touch it because metal is a good conductor of heat.

The metal object and the air are actually at the same ambient temperature but the metal 'sucks' the heat from your fingers very fast so it feels cold to the touch. The air takes your heat away a lot slower which is why, as Doug says, you can stay outside a while before feeling the cold.

...... so endeth todays Physics lesson. :)

[ballaratdragons]

That's a very good point Doug! Why didn't I think of that :doh:

[Garyh]

Hi Ken, not knowing much about the toucams I can`t say if this is right, but with your DSLR`s cooling the ccd/camera makes little difference with actual amp glow which is not temperature related. Only noise is temp related. Your cooling idea should help with the noise a little as any heat created by the ccd/curcuit board shall be removed and kept at ambient not 5c higher than ambient...Why don`t you go for the amp off modd?
cheers Gary

[ballaratdragons]

Reults from tonights test of the fan cooling (or lack of)

Terrible results :sadeyes:

[Astroman]

shame it didnt work Ken. might be time to chill it :)

[Lester]

Could try an ice block on the rear of the camera.

[ballaratdragons]

Coz I know nothing about electronics.
I read some sites about how to do 'Amp Off' and I was turned off the idea on every site. It was actually way over my head in the 1st few paragraphs. It is way beyond my capablilities. Same with Peltier cooling. Too complicated for me.

[bloodhound31]

Last year I rode to work at 100 kph on a minus 7 degree celcius morning in Canberra.

The wind chill factor brought me down to minus 21 degrees.

I will never forget that morning. It was the day I broke th seat because the thing was frozen and it shattered...

true story!

Baz.

[Omaroo]

Hi Ken

I can't see exactly what you've done here, but are you attempting to cool the actual CCD chip, or just the back of the case? I tend to think that the insulative qualities of the plastic - as well as the air gaps within the camera - will serve to utterly insulate your efforts from where it counts - the CCD itself.

I'm looking at cooling my ToUcam as well. From what I have read you need to literally remove the CCD array from the PCB by extending the contacts via ribbon cables. At that point you can mount the CCD on a cold "finger" of billet aluminium, with a thermal transfer paste between them to make thermal conductivity more efficient. Then you use a peltier device to cool the finger and a fan to cool the peltier.

Looks like a big job, but I'm willing to give it a go....

Cheers
Chris

[ballaratdragons]

Yep Chris, aware of the difficulty getting the cold thru the case. But I'm not electronically minded to pull the guts out.

I have read heaps on how to do Peltier cooling but I like my camera working. If I got inside it and tried to do anything it's the last time the Toucam would work. :scared:

[JohnH]

You could try mangling one of these :

http://www.thinkgeek.com/gadgets/electronic/7f5a/

[ving]

hehe john, thats interesting. it cools to 45 deg F. is that cold enough?

[ballaratdragons]

7.2 degrees Celsius!!! That is about 10 degrees warmer than the ambient temp :lol:

I could use it as an EP warmer during winter :rofl:

[bojan]

It will be much lower than that... Peltier generates temperature difference.
And if this thing is powered from higher voltage (USB provides 5V, 500mA only) you may have quite good cooler actually.
Much better than fan only :-)

[ving]

and about 15 degrees C. colder than i like to be out in :P