It's possible a CHDK bug could appear only under certain shooting conditions (lighting, focus, camera chosen exposure settings, chdk override/script exposure settings). Some pattern might emerge if you logged what the script is doing.
Mmmh, that sounds interesting. It sounds unlikely to me but since I have relatively little experience with CHDK I suppose it is possible the camera is crashing because of some pattern. The script logs the shots and some simple data but I'm not sure what you want to have logged in order to find out more?
The ROMLOGs you've posted are all in a task that CHDK doesn't hook, but memory corruption or other problems caused by CHDK code could trigger that. Looking at what specific checks in the Canon firmware trigger the asserts might provide some clues.
I have no idea what you mean, could you emphasise?
EMI might not be out of the question if there is a strong enough source nearby. Maybe it needs an AFDB?
Finally got use for my Tin Foil Hat! No but seriously, maybe I can try to make something that can shield the camera to test.
_______________
I just thought I'd share my thoughts on trying to trouble shoot this.
If you can run the camera with a "do nothing but shoot" script, as suggested above and sill see the issue, it is probably an environmental or hardware issue.
If the camera and "do nothing" script is then run in a different location, away from the potential trouble sources, and it still crashes, it may be a hardware problem.
If you have access to a 2nd camera that runs CHDK try that in the original location. This would help eliminate the hardware as the source. You can pick up an Ixus 40,50,60, 70 or similar which will run CHDK for a few bucks on ebay to test this theory.
I like your analytical exclusion method approach ;-) I'm pretty sure it's not script dependant since the exact same equipment works fine in other locations.
Buying a second camera has certainly come to mind. This was really my last resort solution though.
_______________
Just a thought, but presumably these cranes run on three phase and have sliding power contacts running on taught wires or bus bars.
These frequently spark due to poor maintenance and dust build up. You get lots of spikes on the earth in the vicinity of this equipment (most likely including the Beam). Perhaps the beam needs a decent earth cable back to the supply to nail things down a bit.
Seen this sort of problem cause false trippings on rcd devices countless times. And literally had to get earth jumpers installed throughout a unit because of interference to IT equipment including freezing some years ago.
I know equipment these days is pretty immune, but we arent talking about new cameras here and i'm not sure the immunity standard of a camera would be that good anyway.
Also dont mount too close to any steelwork, take care of battery / cable position too, try to keep everything a couple of inches clear.
Prob non of the above but these are all things i have seen in the past
Yes, they run on three phase but no, there are (as far as I can see) no sliding power contacts but rather cables that follow the trolley (taut wires?). I therefore am not sure how electricity enters the steel construction, but with so many high power devices around I don't exclude it.
I placed another camera on another side, but also close to one of the beams and it started to show the same problem! There is definitely something "spooky" about that area...
_______________
Can't really tell from the picture how the external supply is configured. If that little wire I see exiting to the left of the camera in the photo is the 3.4V feed to the camera, then running that any length in the environment describe above is sure to cause issues.
The external supply is simply a ACK-DC90 clone from eBay. I have 4 of them and all of them work "flawlessly" unless I mount them in that "spooky" location.
Moreover, I have tested a LiPo battery which has previously worked perfectly but the camera crashed within 30 minutes. This LiPo battery has a very short cable length to the camera.
_______________
I would use a 12 to 24v supply to the camera location, and the use a step down reggy to 3.15v close to the camera.
Always tightly twist your DC cables as this helps to limit noise.
reccomend a LM2596 dc-dc buck convertor as the reggy. I have used these to supply full dslr for a long time with no probs.
Running the 12 to 24v supply as AC to the camera location may also help reduce noise (just remember to rectify with full wave. ( the LM2596 are good for about 35v input).
Lastly watch your cable volt drop, i am assuming you may have a decent run here so you should be using a heavy gauge wire right up to the reggy,
suggest 24/0.2 wire to reggy then 7/0.2 to the camera max 300mm.
I actually have some LM2596's lying around. However, I think the power supplies I have are fine, there's nothing wrong with them.
Forgot to add.
you should also use a "ferrite", just behind the power plug irrespective as to whether you are using an ac adapter or external batteries in a noisy environment.
There are generally two types one is a ring and requires you to loop your cable through it a couple of times, the other clips on in 2 halves.
Typical good quality usb leads always have the,
The white original cannon usb cables have them and the older ones can be unclipped from the cable with a knife tip if you want to get your hands on one for test purposes.
That's a good idea! Will try that. It doesn't protect against any interference that radiates straight to the camera. Perhaps I should build a shield around the camera? Tin foil should do...