MDFB2013 - updating the fastest CHDK motion detection script

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Offline blackhole

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Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #40 on: 12 / April / 2014, 03:43:26 »
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Using anti-fog inserts are very effective such as these:  http://www.ebay.com/itm/8-Anti-Fog-Inserts-for-GoPro-Hero3-Hero2-Hero-by-NoFog-/181051646529?pt=LH_DefaultDomain_0&hash=item2a2784e241
It's a little too expensive, this is the same thing but cheaper.
http://www.ebay.com/sch/i.html?_trksid=p2047675.m570.l1313.TR0.TRC0.H0.Xsilica+gel&_nkw=silica+gel&_sacat=0&_from=R40

Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #41 on: 12 / April / 2014, 09:35:43 »
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Using anti-fog inserts are very effective such as these:  http://www.ebay.com/itm/8-Anti-Fog-Inserts-for-GoPro-Hero3-Hero2-Hero-by-NoFog-/181051646529?pt=LH_DefaultDomain_0&hash=item2a2784e241
It's a little too expensive, this is the same thing but cheaper.
http://www.ebay.com/sch/i.html?_trksid=p2047675.m570.l1313.TR0.TRC0.H0.Xsilica+gel&_nkw=silica+gel&_sacat=0&_from=R40

Yeah, those desiccant pack look pretty small.  The other ones I linked to are very thin.  They tend to fit into very tight spots between the camera and case.

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Offline ahull

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Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #42 on: 12 / April / 2014, 10:15:44 »
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Using anti-fog inserts are very effective such as these:  http://www.ebay.com/itm/8-Anti-Fog-Inserts-for-GoPro-Hero3-Hero2-Hero-by-NoFog-/181051646529?pt=LH_DefaultDomain_0&hash=item2a2784e241
It's a little too expensive, this is the same thing but cheaper.
http://www.ebay.com/sch/i.html?_trksid=p2047675.m570.l1313.TR0.TRC0.H0.Xsilica+gel&_nkw=silica+gel&_sacat=0&_from=R40

Yeah, those desiccant pack look pretty small.  The other ones I linked to are very thin.  They tend to fit into very tight spots between the camera and case.

FWIW You often find even smaller desiccant strips/bags in scrap hard disks, along with a tiny air filter. If you have one in your junk box it might be worth a look,  and of course while you are dissecting it, don't forget to remove the Neodymium magnet(s).   

Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #43 on: 12 / April / 2014, 10:35:27 »
FWIW You often find even smaller desiccant strips/bags in scrap hard disks, along with a tiny air filter.
Dessicant bags absorb water vapour from the air.  As they clearly can't have infinite capacity to do so, how do you "dry" them out and store then after they have been exposed the normal moisture in the atmosphere for a while?
Ported :   A1200    SD940   G10    Powershot N    G16


Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #44 on: 12 / April / 2014, 11:15:51 »
FWIW You often find even smaller desiccant strips/bags in scrap hard disks, along with a tiny air filter.
Desiccant bags absorb water vapour from the air.  As they clearly can't have infinite capacity to do so, how do you "dry" them out and store then after they have been exposed the normal moisture in the atmosphere for a while?

When folks make there own anti-fog paper towel inserts, they simply dry them in an oven for a short time and can usually reuse them.  Your ordinary desiccant pack is made of silica gel.  According to Wikipedia, silica gel can be regenerated by heating it 250 F for a couple hours.  I myself wouldn't try it.  It's cheap enough to buy plenty of them.

When I was a telecom tech, we used to have huge bags of silica gel.  If you took a hand full of the stuff and poured water on it, the silica would get so hot you couldn't hold it.  It could absorb a good amount of water though.

I think if you store them in a Ziploc it will keep them fresh until needed.  I keep desiccant pack in all of my ammo boxes to keep it dry and they can last a good while if not exposed to fresh air often.

Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #45 on: 12 / April / 2014, 11:49:18 »
When folks make there own anti-fog paper towel inserts, they simply dry them in an oven for a short time and can usually reuse them.  Your ordinary desiccant pack is made of silica gel.  According to Wikipedia, silica gel can be regenerated by heating it 250 F for a couple hours.
Basically boiling the water out?  I guess that you'd need to immediately put them in a sealed container while they cooled to avoid reabsorbing all the water they lost.

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I myself wouldn't try it.  It's cheap enough to buy plenty of them.
Unless it's Saturday afternoon and you need fresh bags for a launch on Sunday morning  ;)

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When I was a telecom tech, we used to have huge bags of silica gel.  If you took a hand full of the stuff and poured water on it, the silica would get so hot you couldn't hold it.  It could absorb a good amount of water though.  I think if you store them in a Ziploc it will keep them fresh until needed.  I keep desiccant pack in all of my ammo boxes to keep it dry and they can last a good while if not exposed to fresh air often.
Have you ever seen any with an "indicator" (i.e. color change) that indicates if they are wet or dry?
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline ahull

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Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #46 on: 12 / April / 2014, 12:14:10 »
FWIW You often find even smaller desiccant strips/bags in scrap hard disks, along with a tiny air filter.
Dessicant bags absorb water vapour from the air.  As they clearly can't have infinite capacity to do so, how do you "dry" them out and store then after they have been exposed the normal moisture in the atmosphere for a while?

There is lots of duff info out there in interweb land regarding drying them out, like "5 mins in the microwave and you are good to go". The general ideas is heat them above 100C for a period, determined by their weight, long enough to dry them out. I suspect for tiny packs like these, heating them for an hour or so would do the trick. Not sure that microwaving them will work, but you could try that too.

If you want the scientific answer, weigh a new pack, soak it in water for an hour or so, weigh it again, the diffetence is the amount of water it can absorb.

Next, heat it to a suitable temperature to drive out the moisture (the silica gel will be fairly robust, not sure about the bag, so don't get crazily hot, maybe stick below 120C), weigh it every 15 mins till it returns to 90% or so of its original weight, and there is your answer.

Alternatively, given the low cost of these little guys, if you can't be bothered with all that trouble, and aren't worried by the "landfill factor" buy some more. 

EDIT: Some reasonable instructions for drying out similar packs here.

Note, the instructions I linked to are on deg F not deg C, don't mix them up or you will probably set the packs on fire. 240F is around 115C if I am not mistaken.  240C on the other hand.. is 464F, and will make for very crispy bacon  :D
« Last Edit: 12 / April / 2014, 12:24:56 by ahull »

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Offline blackhole

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Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #47 on: 12 / April / 2014, 14:05:13 »
Ohh guys, this is not the launching of the Space Shuttle. Looks like the only solution is hermetically sealed vacuum housing.With so many problems, life is too short and does not have enough time for recording. :D


Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #48 on: 20 / July / 2014, 06:52:42 »
Used this script last night with a Powershot SX210 and got this picture.
Many thanks

And the local tv weather report just used it and gave me a name check, woohoo!
« Last Edit: 21 / July / 2014, 17:20:23 by simon.moore.92317 »

Re: MDFB2013 - updating the fastest CHDK motion detection script
« Reply #49 on: 28 / July / 2014, 10:11:55 »
I'm having trouble with this script. I don't seem to understand it at all. I have the reaction mode set to fast,  I've tried threshold from 10-100 and it still doesnt pick up the lightning in an evening light. When I wave my hand in front of the camera then it goes off. Also, I don't get how the picture comparing thingy works. The display goes black randomly I think, not after 7ms like I have set it.

 

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