Ixus70 operating temps - General Chat - CHDK Forum

Ixus70 operating temps

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Ixus70 operating temps
« on: 07 / August / 2008, 07:52:45 »
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I've been testing performance and battery life of an ixus 70 at low operating temperatures to simulate the conditions on a weather balloon.

I was running a script with the LCD turned off and taking a full res image every 30 seconds (no flash) until the camera switched off.

Here are the results...
Room temperature:
8 Hours, 21 Minutes
Room temp 19 degrees (c)
Camera Max 29 deg
Camera Min 19 deg

Freezer:
5 hours, 54 Minutes
Ambient Temp -21 degrees (c)
Camera Max 20 deg
Camera Min -10 deg (Not sure if it reads lower than -10 as it appears to stabilize here)

Note that with the freezer, the camera was left in there for another 6 hours after it turned off.  I can say with almost 100% certainty, the camera got down to almost ambient temp (maybe -20 deg).



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Offline PhyrePhoX

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Re: Ixus70 operating temps
« Reply #1 on: 07 / August / 2008, 08:18:05 »
did you measure all three sensors? none of them went below -10? maybe you should have put in new batteries after these 6 additional hours in the freezer, to make sure they cant show below -10?
anyways, this is very impressive!

Re: Ixus70 operating temps
« Reply #2 on: 07 / August / 2008, 08:43:49 »
did you measure all three sensors? none of them went below -10? maybe you should have put in new batteries after these 6 additional hours in the freezer, to make sure they cant show below -10?
anyways, this is very impressive!

I did all 3 sensors plus battery voltage.

I'll run the test again tomorrow with a "prechilled" camera and see how it goes.  I'm really keen to make sure these will run at low temps (-50 deg) before sending them on their way.

I'll supply the log after this 3rd test if anyone is interested

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Offline PhyrePhoX

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Re: Ixus70 operating temps
« Reply #3 on: 07 / August / 2008, 08:49:46 »
i guess maybe the current running through the cam will keep them warm for a while. good luck with your project. btw the pictures that came out were all pretty dark i guess, unless you have a magic freezer that has a lamp that doesnt switch off when the door's shut. what about condensation water? do you have them wrapped in something? what if it rains, the cams get wet and then the water freezes? like i said, good luck :)


Re: Ixus70 operating temps
« Reply #4 on: 07 / August / 2008, 10:28:24 »
I Left one turned off in the freezer for 4 hours.  My thermocouple showed -23 degrees (c) at the battery.

I turned it on and the temperatures were:
-10c
-10c
-10c

I'm guessing -10c is as low as the sensor goes (at least on an Ixus 70).

One thing I did find interesting is that at this temperature, the lens has trouble extending, but once it is out, it takes photos.
It also comes up with a trivial error "Change the battery" even though the battery voltage.

As for condensation, the camera is double bagged in ziplock sandwich bags.  I'm not taking it out of the bags until it's back up to room temp.  The LCD displays seem fine at this temp.

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Offline Hacki

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Re: Ixus70 operating temps
« Reply #5 on: 07 / August / 2008, 11:12:45 »

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Offline reyalp

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Re: Ixus70 operating temps
« Reply #6 on: 07 / August / 2008, 16:15:19 »
As for condensation, the camera is double bagged in ziplock sandwich bags.  I'm not taking it out of the bags until it's back up to room temp.  The LCD displays seem fine at this temp.
The ambient air in the camera and bags could still form condensation. If the cameras operating it'll probably be OK (since it's warm and the condensation should form elsewhere first) but some desiccant packs in the bag wouldn't hurt.

Hacki is right about battery performance. AFAIK, both NiMH and li-ion will stop working right around -20. The suggestion of insulating around the camera is good. With even a fairly modest amount of insulation, the heat generated by the camera should be enough to keep it from dropping that low.

One easy (but potentially messy) way to get form fitting insulation is to use expanding foam in a plastic bag.

You'll also get a lot more life out of the battery if it isn't dropping to the very limit of it's operating range.

edit:
BTW, here's another user working on high altitude flights:
A550 - Script both stills and video?
« Last Edit: 07 / August / 2008, 16:17:54 by reyalp »
Don't forget what the H stands for.

Re: Ixus70 operating temps
« Reply #7 on: 05 / November / 2010, 01:23:35 »

Hi,
-temp and time tagging-
I am hoping someone can help me with my similar problem.
I am planning to send my A430 up with a weather balloon.
I have a script that will take a picture ever few seconds, and I would like to tag these pictures with the temperature and time.
Do you have this script/ know where I could find it.
Thanks


 

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