1100D Set-Point Cooling with Peltier TEC and Air Cooling - v3

[dp297]

well i am getting my 550d modified by jtw astronomy and they mentioned that under operating conditions at40c sensor temp a 60w system would provide a -5c constant temp

[dp297]

well i am getting my 550d modified by jtw astronomy and they mentioned that under operating conditions at40c sensor temp a 60w system would provide a -5c constant temp

[dp297]

Would u suggest something different?

[Gina]

My experiments showed that a 60W Peltier TEC was too much. The amount of heat to be removed from the image sensor is only a few watts so you don't need a powerful TEC and in fact quite the opposite, a lower power one works better. My experiments and findings are detailled in a couple of very long threads elsewhere in the forum.

[dp297]

Here? ()

[Gina]

Here? (http://stargazerslou...g/page__st__540)

Yes, that's one of them

This thread describes fitting the cold finger that apply particularly to the 1100D and the various difficulties :-

• http://stargazerslou...0d-sensor-chip/
  

There is also some with water cooling:-

• http://stargazerslou...-water-cooling/
  
• http://stargazerslou...-water-cooling/
  
• http://stargazerslou...-water-cooli
  

Also an attempt at cooling the whole camera

• http://stargazerslou...ole-1100d-dslr/
  

[drhemlock2]

trust gina's findings she is the guru of trying to use the DSLR and to get it cooler that i have found, not that i am an expert but she is very scientific and tells you as it is. i have been following her for a while and getting ready later on as i get a 1100D to mod. i have grown way to fond of my 300D to attack her in such a way. i plan to use her for WF astrophotography a dual system like gina's. it is good to try new things even if they fail at times i am finding out.

doc

[Gina]

I now have the CPU coolers I ordered and can see which will be most suitable. Then I can get on with finishing off the cooling system and box. ( I also have another but it turned out to be heavier than my last one.) One of these three is 50mm square and the other two 60mm square. First is very light at 92g second is 152g and the third, all copper, is a huge 488g. First thoughts are that the second will be the one. The copper one will no doubt be very efficient with many thin copper fins but it's very heavy.

[Mik3]

I've been thinking about doing this to mine, I was thinking about taking the sensor out the camera and housing it in a small aluminium box and cooling that. The only problem is trying to extend the ribbon cable.

[Gina]

Yes, that cable has a lot of connections. Also, you would have a job getting the sensor exactly at right-angles to the light path. Leave it where it is and slide in a cold finger behind it - between it and the PCB.

[mindburner]

hi Gina. I'm back at this myself again after failing miserably with my well made but ultimately non heat conductive box.

I love the idea of the cold finger and I can see that you have it working nicely in another thread.

I plan to do something similar, but I was wondering if it's possible to keep the back on the camera and cut a slit for the cold finger plate to exit, then mount the peltier, HS & fan on the outside. Cooling won't be just as good as an enclosure but hoping for -15 deg below average.

I may invest in a spare 1100d body just in case I hammer my current one

[Ags]

You guys... If I was an 1100D I would be afraid, very afraid! :-)

[Gina]

hi Gina. I'm back at this myself again after failing miserably with my well made but ultimately non heat conductive box.

I love the idea of the cold finger and I can see that you have it working nicely in another thread.

I plan to do something similar, but I was wondering if it's possible to keep the back on the camera and cut a slit for the cold finger plate to exit, then mount the peltier, HS & fan on the outside. Cooling won't be just as good as an enclosure but hoping for -15 deg below average.

I may invest in a spare 1100d body just in case I hammer my current one

I tried the approach of feeding the coldfinger out through the side of the camera but it wasn't very successful. With the extra heat path the temperature loss was appreciable. As I recall something like 10C. I'll see if I can find it in the appropriate thread. Without special insulation the external part of the cold finger would get covered in a thick layer of frost. This again reduced efficiency due to latent heat of freezing.

Why do you want to keep the back - all required functions can be controlled by USB?

[Gina]

You guys... If I was an 1100D I would be afraid, very afraid! :-)

[mindburner]

hi Gina

spent the night catching up and refreshing myself with the latest on this project. I resurrected my coolbox but temp drop was only 10 deg and that's in the box. The camera would only get say 5-6 deg , maybe 8 at a push

So the coldfinger bent around the back in the U shape seems the best solution as you say.

I was tempted to just remove the LCD display screen and have the finger visible and maybe enough space to mount the TEC/FAN combo. I'm not after extreme cooling (yet but 15-20 deg below ambient would be great.

I was thinking this on the back with PAPST fans would be the trick. IF I have to loose the rear buttons, then a custom box like you have looks great

If I could ask a question or two ...

How exactly did you secure the cold finger to the rear of the CCD sensor?

Is it screwed down? I ordered 0.7mm copper plate

Did you ever get a solution to the date/tiime set or SD card format issues from software so that all the rear buttons etc. can be removed?

I have not taken the camera apart yet so it's not obvious to me so far.

This is a fantastic project, the work you have put in is well appreciated.

I have just got a nice Atik OSC camera with smooth noise, but I miss the big sensor, so a less noisy version is definitely attractive

Its a pity the CCD sensor assembly ribbon cable could not be extended in some way so that just the sensor, in a custom mini box could be at the scope and the camera guts seperate

[Gina]

hi Gina

spent the night catching up and refreshing myself with the latest on this project. I resurrected my coolbox but temp drop was only 10 deg and that's in the box. The camera would only get say 5-6 deg , maybe 8 at a push

Sounds about right. I shall be rewriting my cooling threads abbreviating as I go like I'm doing with my obsy build, cutting out all the false trails and blind alleys. This will deal with version 3 that I'm working on at present with with the earlier camera mods taken from other threads. I may do a separate thread dealing with the various methods of cooling briefly and how I came to the decisions resulting in the latest version.

So the coldfinger bent around the back in the U shape seems the best solution as you say.

Yes.

I was tempted to just remove the LCD display screen and have the finger visible and maybe enough space to mount the TEC/FAN combo. I'm not after extreme cooling (yet but 15-20 deg below ambient would be great.

I was thinking this on the back with PAPST fans would be the trick. IF I have to loose the rear buttons, then a custom box like you have looks great

I have another working cooling system not using a Peltier TEC but just a CPU cooler on the cold finger brought out to the back. This method gives about 12C reduction in sensor temperature but cooling it to a couple of degrees above ambient. This reduces the noise almost four-fold.

How exactly did you secure the cold finger to the rear of the CCD sensor?

Is it screwed down? I ordered 0.7mm copper plate

The springiness of the copper strip was all I used.

Did you ever get a solution to the date/tiime set or SD card format issues from software so that all the rear buttons etc. can be removed?

I have not taken the camera apart yet so it's not obvious to me so far.

You don't need to format the card but you can do it from Windows via the USB - it behaves just like any USB device. I found the date/time didn't affect using the camera from software (EOS Utility and APT).

This is a fantastic project, the work you have put in is well appreciated.

Thank you I'm very happy to pass on any knowledge and experience I can obtain

I have just got a nice Atik OSC camera with smooth noise, but I miss the big sensor, so a less noisy version is definitely attractive

My thoughts entirely. I'm retaining my DSLR capability for the time being anyway.

Its a pity the CCD sensor assembly ribbon cable could not be extended in some way so that just the sensor, in a custom mini box could be at the scope and the camera guts seperate

Yes, that would certainly make for a smaller cooled sensor unit but then would cause other headaches. For instance, the sensor needs to be very accurately aligned at right angles to the light path so that focus is maintained over the whole area. Not impossible but pretty difficult. A few people have tried extending the connections to CMOS sensors, particularly with webcams but found the extra length causes problems with extra capacitance and cross coupling plus pickup of interference. It's not an easy project, there are so many connections. I don't know of anyone who has tried extending the connections on a DSLR between the image processor PCB and the main board - those connections may be less sensitive to extra capacitive loading and cross-talk. I imagine they would be digital data lines rather than partly analogue but I have no knowledge of the camera internal workings and I would guess Canon keep that secret.

[mindburner]

Many thanks for the info Gina. Started on my own cooling mod and a new post, Took the back off today and fitted the cold finger. I have ordered some pain table silicone PCB protector from RS components, so that should reduce moisture issues on the circuit boards.

Plus some pipe lagging tape, which I will cut to size and insulate the exposed parts of the cold finger/bracket.

The little copper heat sink and fan I have seem great now. Temps from 25 ambient to -1 deg

I'm just a bit worried about condensation so will be enclosing the whole lot, in a sealed box as you have done

[Gina]

Sounds good

[badgerchap]

Thanks for this Gina, has given me some ideas as to how to proceed.

You really can tell you used to work in a lab you know this reads just like a lab diary!

Awesome report, thanks again.

[Gina]

Thank you And I apologise for my replying sooner - this project got shelved. But I may be resurecting it - I shall be looking again at trying to get at the sensor surface and remove the Bayer CFA layer.

[Gina]

I see I didn't post the front view so here it is.

With a "de-bayered" sensor and hence mono camera, I may well use a different case and see if I can make room for a filter wheel.

[mindburner]

after leaving this for a while due to having the Atik OSCI have decided to have another go with my Canon 1100D. This time with a much smaller peltier and fan. I mean the one of the Atik is tiny right.. I can get 15 degrees of cooling which if fin. I was getting much cooler results but condensation is the BIG issue with any of these cooling projects. Misty sensors do not good astro pics make. Heating the sensor is a real pain and already has cost me one motherboard. Sealing the sensor chamber is a good way to go but night on impossible with this camera minus the front filter.

Gina your set pint cooling is great. I must have a look at this more closely and try and get it working with mine as it would allow me to run the camera above the dew point and avoid the dreaded condensation.

A few pics of the new mod

[Gina]

Thank you

I'm planning a new properly sealed casing with smaller air space and looking into flushing the air space with a dry inert gas such as nitrogen but so far I've had no success finding any nitrogen gas suitable for this purpose. I guess almost any gas would do as long as it's completely dry. Maybe a compressed air can as used for blowing dust off - I presume this is dry air. OTOH I see that Atik use desiccant in their CCD cameras. If they can't get the sensor in a complete dry environment and sealed what chance do I have?

[Gina]

Version 2 of this project used local control of cooling mode, temperature etc. with a control box on the pier (I had decided controls and display on the camera itself was impractical due to the awkward angles the camera might end up with). Now I'm thinking it would be much better if the control were to be on the computer (in the warm room). This would not only be more convenient but would also dispense with another box and all the associated wiring. The Arduino could be placed inside the camera casing as could the 12v to 7.5v switch mode voltage regulator. This would mean the camera would only need the standard 12v power and USB connections (same as commercial cameras).

[mindburner]

Version 2 of this project used local control of cooling mode, temperature etc. with a control box on the pier (I had decided controls and display on the camera itself was impractical due to the awkward angles the camera might end up with). Now I'm thinking it would be much better if the control were to be on the computer (in the warm room). This would not only be more convenient but would also dispense with another box and all the associated wiring. The Arduino could be placed inside the camera casing as could the 12v to 7.5v switch mode voltage regulator. This would mean the camera would only need the standard 12v power and USB connections (same as commercial cameras).

That sounds like a great plan. I must study the way the set point cooling (as opposed to set pint cooling )works and have a go at that. Keeping the camera from going too cold seems to be a good compromise between the excellent lower but hassle filled temps and the higher, not much better than un-modded temps.

Would you happen to have a bit of info on the set point cooling system. It's maybe in the previous posts. I was hoping to get something basic that would say keep the sensor at around 5 deg. I was toying with the idea of using something like this temperature controller to switch off the power via a relay. It's messier than the Arduino but i'm pretty clueless when it comes to this device.

Great post as usual Gina BTW