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Ixus 160 shutting down at 56 degrees C

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Offline Sdack

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Ixus 160 shutting down at 56 degrees C
« on: 02 / April / 2018, 00:11:09 »
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I've had several of these Ixus 160s running steadily for days in shaded positions but now I have an off-grid situation which will likely put one in the full Sun on a 6 pack of 18650 rechargable batteries for the first time. 
My first power duration tests, using Utimate Intervalometer,  http://chdk.wikia.com/wiki/Ultimate_Intervalometer
have been stumped by the camera shutting down after just over 1,500 images.  The 32 GIG SD card has plenty of space left and the battery pack is barely depleted.  The Ultimate.log shows that the temperature rose to 56 degrees C (134 F), which makes me suspect overheating.
The unit is encased in a small weatherproof worklight case.

The LCD display is set to go off shortly after the script starts taking one image every 10 seconds.
Anyone got any suggestions to debug.. aside from encasing the whole worklight unit in a second layer of insulation and Sun protection
Cheers
Sdack

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Offline reyalp

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Re: Ixus 160 shutting down at 56 degrees C
« Reply #1 on: 02 / April / 2018, 00:43:21 »
The Ultimate.log shows that the temperature rose to 56 degrees C (134 F), which makes me suspect overheating.
Is that sensor or optical temp? IIRC people have reported sensor temps higher than that. (edit looking at the ultimate source, this is optical temp, so yeah, that's pretty high. Logging sensor temp as well might be useful)

When it shuts down, does it end up with the lens out, or retracted?
Have you checked for a romlog?
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Anyone got any suggestions to debug.. aside from encasing the whole worklight unit in a second layer of insulation and Sun protection
I'd suggest a reflective (on the outside) shade with an air gap. You might also be able to improve how well heat is rejected. If the worklight enclosure is metal, put a heat conductive path from the camera or hot components on the PSU to the inside of the case.

Another thing that might be useful is do do a controlled test to see whether camera temperature alone triggers a shutdown at this temperature. Batteries on board protection circuits or the power supply might also have shutdown thresholds.
« Last Edit: 02 / April / 2018, 00:51:41 by reyalp »
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Offline Sdack

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Re: Ixus 160 shutting down at 56 degrees C
« Reply #2 on: 02 / April / 2018, 01:17:18 »
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Is that sensor or optical temp? IIRC people have reported sensor temps higher than that. (edit looking at the ultimate source, this is optical temp, so yeah, that's pretty high. Logging sensor temp as well might be useful)
Yeah, It's pretty sweaty here this week, 27C and very humid, feels like the last blast of Summer!
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When it shuts down, does it end up with the lens out, or retracted?
Should have mentioned this - Retracted which seems to point to a camera initiated shutdown.
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Have you checked for a romlog?
Will do that after the current test which is running  keeping the camera just inside the shade
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I'd suggest a reflective (on the outside) shade with an air gap. You might also be able to improve how well heat is rejected. If the worklight enclosure is metal, put a heat conductive path from the camera or hot components on the PSU to the inside of the case.

Another thing that might be useful is do do a controlled test to see whether camera temperature alone triggers a shutdown at this temperature. Batteries on board protection circuits or the power supply might also have shutdown thresholds.
Good ideas all.

FYI the battery pack is outside the case, and was in the shade when the shutdowns occured.

Thanks for your help on this Reyalp.
I will look into adding sensor temp but I'm a bit daunted at the idea of poking around in such a complex script.
Sdack

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Offline reyalp

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Re: Ixus 160 shutting down at 56 degrees C
« Reply #3 on: 02 / April / 2018, 02:17:23 »
Should have mentioned this - Retracted which seems to point to a camera initiated shutdown.
Agreed.
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I will look into adding sensor temp but I'm a bit daunted at the idea of poking around in such a complex script.
Sdack
The line that logs it
Code: [Select]
                printf("%s V: %d.%3.3d T: %d ", shotstring, bvolts/1000,bvolts%1000, get_temperature(0))
You could change it to something like
Code: [Select]
                printf("%s V: %d.%3.3d T: %d Ts: %d ", shotstring, bvolts/1000,bvolts%1000, get_temperature(0),get_temperature(1))
Don't forget what the H stands for.


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Offline Sdack

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Re: Ixus 160 shutting down at 56 degrees C
« Reply #4 on: 02 / April / 2018, 02:57:49 »
Thanks for that,
Now getting a sensor temp as well as optics.

I had spent a while searching the ultimate.lua file for "temperature" without success but your line lead me straight to it. 

Alas, the heat of the day today is over now and my last test only reached an optical temp of 42 degrees,  however a quick test with the updated script shows a sensor temp of 50, for an optical reading of 38 degrees.  Some difference !
I will see what I can do to keep the Sun at bay with reflective surfaces and air gaps etc.

I have another, newly built, Raspberry Pi controlled, rig in a sealed enclosure in which I installed a fan but when I tested the cooling effect at a high temperature (50+ IIRC), it didn't make any difference at all.  I guess it was just pushing the hot air around inside the case, like a fan forced oven.  I've been musing on creating a tube between the rear of the fan and a spare cable gland entry point at the bottom rear end of the case, in the hope that it will draw fresh air inside.
Cheers
Sdack

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Offline Sdack

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Re: Ixus 160 shutting down at 56 degrees C
« Reply #5 on: 03 / April / 2018, 04:03:28 »
OK,

Another sunny day, another test.

First logged image taken

Day 1 Tue Apr  3 11:25:42 2018 V: 4.310 T: 27 Ts: 33 IMG_5293.JPG tv: 1/400 f: 3.2 ISO: 94 bv: 789

Last successful image taken -

Day 1 Tue Apr  3 14:48:02 2018 V: 4.320 T: 54 Ts: 80 IMG_6507.JPG tv: 1/400 f: 9.0 ISO: 94 bv: 1119

The numbering didn't start at zero but it's actually the 1,215th image, they're being shot every 10 seconds, which I guess doesn't help the sensor to lose any heat because it's constantly doing stuff.

This is the first sensor temp that achieved 80 degrees, so it feels a prominent demarkation point for shutdown in the system

Cheers
Sdack

Re: Ixus 160 shutting down at 56 degrees C
« Reply #6 on: 03 / April / 2018, 08:46:01 »
Last successful image taken
What does this mean? Does the cam stops working or did you stop?

The numbering didn't start at zero but it's actually the 1,215th image, they're being shot every 10 seconds, which I guess doesn't help the sensor to lose any heat because it's constantly doing stuff.
I think for the temperature there is no different if you take every 10s or 60s a picture. The problem is that the cam is always reading sensor data. This heats the senor. I would probably help, if you change between shoots to playback mode.
5 Minutes live view heats the sensor more than just one picture with a exposure time from 60 Minutes.
This is the first sensor temp that achieved 80 degrees, so it feels a prominent demarkation point for shutdown in the system
I thought maximum temperature is around 90C…
https://chdk.setepontos.com/index.php?topic=12942.msg129769#msg129769
https://chdk.setepontos.com/index.php?topic=12303.msg121438#msg121438

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Offline reyalp

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Re: Ixus 160 shutting down at 56 degrees C
« Reply #7 on: 03 / April / 2018, 13:00:46 »
I think for the temperature there is no different if you take every 10s or 60s a picture. The problem is that the cam is always reading sensor data. This heats the senor. I would probably help, if you change between shoots to playback mode.
The sensor is also turned off when Canon power saving display off kicks in, but the minimum timeout is 10 sec. Finding a way to trigger this from CHDK code would be nice. (maybe some clues in https://chdk.setepontos.com/index.php?topic=12754.0)
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I thought maximum temperature is around 90C…
I wouldn't be surprised if this is different for different models. Round numbers like 80, 90 seem likely.
« Last Edit: 04 / April / 2018, 00:14:24 by reyalp »
Don't forget what the H stands for.


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Offline Sdack

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Re: Ixus 160 shutting down at 56 degrees C
« Reply #8 on: 03 / April / 2018, 23:23:24 »
OK.. I'm going all N.AS.A. on this now..









Sadly it's not quite as hot today.. there's a slightly cooling breeze which could favour the test, however, I'm testing anyway!



This is of course a prototype.. the production model will be somewhat slicker (in my mind's eye at least)

Hey Reyalp, if there is an inbuilt shutdown protection in the camera at 80C, would that appear, and be accessible, in the software?  ie. could we override it, if necessary?

In the next week or so I have to shoot the harvest of a hemp field and, to get a good angle, the camera will be stuck at the top of a pole, 6 or more metres off the ground and I won't know if it's shutdown til the end of the day, by which time, of course. it's a bit late.

I would use my Internet connected rig for this but it's far too heavy for the pole.  A scaffold would work but there's no budget and the field in question is on a 20 degree slope anyway.

Cheers
Sdack

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Offline reyalp

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Re: Ixus 160 shutting down at 56 degrees C
« Reply #9 on: 04 / April / 2018, 00:14:03 »
Hey Reyalp, if there is an inbuilt shutdown protection in the camera at 80C, would that appear, and be accessible, in the software?  ie. could we override it, if necessary?
Given that the camera seems to do a clean shutdown it seems like it has to be software controlled, but I haven't ever noticed any relevant code or strings, so developing an override quickly seems unlikely.

It might be relatively simple to spoof in hardware by cutting or adding a resistor to the line that connects the thermistor on the sensor board to the mainboard.

That said, I'd guess the limit is there for a good reason. At a minimum, messing with the reported sensor temperature would affect some of the hot pixel or noise reduction logic.

The obvious brute force approach to cooling your enclosure would be to drill a bunch of holes and add a fan.

A more dust, weather and critter resistant approach might be to use a heat pipe or heat sinks, with a fan on the outside if needed.
Don't forget what the H stands for.

 

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