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Motion Detection

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Motion Detection
« on: 16 / November / 2011, 17:57:20 »
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Hello guys,

I'm a nature photographer, and I discovered the CHDK in searching for motion detection.
I need a compact camera, that I can leave in the woods, pointed to some feeders, so I can monitor what species come and eat from it.

All the models supportted cameras listed in http://chdk.wikia.com/wiki/CHDK can do this? Or motion detection is only available for some models?

When I'll boot with the hack, and run the motion detection mode, the LCD must be on all the time? Or is it possible to suspend it to prevent battery drain?

I'm looking forward for your answers.

Best regards.

Re: Motion Detection
« Reply #1 on: 16 / November / 2011, 18:26:14 »
All of these cameras are supported :  http://mighty-hoernsche.de/

Turning off the backlight does not save much power.

You can turn off the sensor but I don't think you want that !

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Offline Lebeau

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Re: Motion Detection
« Reply #2 on: 16 / November / 2011, 18:30:29 »
From what I know, motion detection is largely supported, I don't know exception but the best would be to find a used model, to check against CHDK specifications, and to make your choice concerning power supply and consumption.

From what I know, motion detection checks within viewport internal memory, not within the liveview LCD, so you can turn it off and would reduce consumption but also reduce night luminescence. An other concern for your wildlife application is the flash consumption, if used.

May be some other members have made a "hunting" setup with battery pack and solar recharging system ? As power supply, my A650is uses 4x1.5v AA or external adaptative transformer (A650is need 4.3 volts external supply and my transformer is able to supply a bit more, like 5 V which is not a thermal issue).

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Offline reyalp

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Re: Motion Detection
« Reply #3 on: 16 / November / 2011, 20:23:51 »
From what I know, motion detection checks within viewport internal memory, not within the liveview LCD, so you can turn it off and would reduce consumption but also reduce night luminescence.
The viewport used for motion detection is the same used for live view. So as Microfunguy said, you can turn off the backlight, but this actually saves very little power. The display must be on as far as the camera is concerned, otherwise there is no viewport buffer to detect motion in.

As far as support goes, all ports in the autobuild support MD (alphas might not). However, only some of them support fast MD. Unfortunately, there is no list of which ones do, or any easy way to tell. Sometimes the cameras notes.txt or wiki page will say. You can look in platform/<camera>/sub/<fw version>/lib.c (e.g. http://tools.assembla.com/chdk/browser/trunk/platform/d10/sub/100a/lib.c ) and check if vid_get_viewport_live_fb returns NULL or not. If it returns NULL, then fast md is not implemented. If it doesn't return null, then something is implemented but that doesn't necessarily mean it's implemented correctly.

Fast MD may not be needed for wildlife, it would depend on the kind of wildlife and the shooting situation. It's pretty essential for lightning.
Don't forget what the H stands for.


Re: Motion Detection
« Reply #4 on: 17 / November / 2011, 11:23:29 »
I thank you all...
That means that even with a modest Canon Powershot A550 the motion detection would work? I don't need very sharp pictures, only enough to identify the species, and later photograh them with my DSLR.

Quote
As far as support goes, all ports in the autobuild support MD (alphas might not).
Or alphas are the models like A550?

I don't need fast MD... A shot with 1/60s should be enough...

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Offline Lebeau

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Re: Motion Detection
« Reply #5 on: 17 / November / 2011, 11:38:50 »
From what I know, motion detection checks within viewport internal memory, not within the liveview LCD, so you can turn it off and would reduce consumption but also reduce night luminescence.
The viewport used for motion detection is the same used for live view. So as Microfunguy said, you can turn off the backlight, but this actually saves very little power. The display must be on as far as the camera is concerned, otherwise there is no viewport buffer to detect motion in.

Wow ! I learn every time I come here :) Liveview off has no buffer :( I didn't know but now ... thanks

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Offline zeno

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Re: Motion Detection
« Reply #6 on: 17 / November / 2011, 11:39:49 »
Alpha builds are unofficial ones still in progress. All the cameras listed here - http://chdk.wikia.com/wiki/CHDK - are either proper official builds or beta versions (listed as such) that may still have one or two outstanding issues.

The A550 is a well-established official build.

Fast means a fast response to movement, i.e. how quickly the shutter is clicked after something moves in front of the lens. It's nothing to do with shutter speed.
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Offline reyalp

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Re: Motion Detection
« Reply #7 on: 17 / November / 2011, 16:23:19 »
Or alphas are the models like A550?
Alpha would be builds with an _ALPHA suffix on the autobuild server, or unfinished development builds from the forum
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I don't need fast MD... A shot with 1/60s should be enough...
The fastest md is around 100ms between motion and shot starting.  The ones without vid_get_viewport_live_fb will vary between the low value to up to 3 (or maybe 4 ?) times that.

The a550 does have vid_get_viewport_live_fb.
Don't forget what the H stands for.


Re: Motion Detection
« Reply #8 on: 18 / November / 2011, 09:44:55 »
The a550 does have vid_get_viewport_live_fb.

EXACTLY how is this location found on various cameras ?

Re: Motion Detection
« Reply #9 on: 18 / November / 2011, 10:52:30 »
EXACTLY how is this location found on various cameras ?
@microfunguy :  I suspect that when you ask for an EXACT way to find the location,  you want a 100% sure process.  But as you probably suspect, I'm pretty sure there is not one - each camera is a little different.  So its mostly trial and error based on looking at what was done for other ports.  If it could be reduced to a formula,  philmoz would probably already have added it to his new sigfinder.

The best ports to look at are always the ones from cameras released at the same time as yours ( dpreview has timelines) and at ports where the developer put in good comments.  The G12, sx30, and sd900 come to mind - hopefully somebody else can post some good examples too.

Ported :   A1200    SD940   G10    Powershot N    G16

 

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