Re: [Gphoto-user] Getting a hook from shell mode to do motion detection?

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Hi,

If you want to do this all with one camera you might be better of writing
a program using libgphoto2, either in C or Python.

FWIW, I did something similar to Tomas btw.

Setup:

- Cheap Webcam
- Canon EOS 1000D with AC adapter.
- Laptop

Then I ran the "motion" tool using the webcam.

The "motion" tool has hooks where it can callout to shell scripts.
I wrote a simple shell script that ran gphoto2 --capture-image-and-download 
and hooked it to the motion detection hook.

It needed some checking that it does not run it twice (because
if there is motion it would trigger faster than capturing)
and it runs the disk full quite quickly with DSLR sized images.

Ciao, Marcus

On Sat, Dec 30, 2017 at 02:06:13PM -0500, Alan Corey wrote:
> I've been thinking about this.  I plan to write in C, and between
> system() and popen() and pipe() and etc there's probably a way to do
> it.  From a console you type shell and give commands, then you can
> type more commands.  But I'm not sure how a program would do that: as
> a file descriptor or a pipe (or a socket) (dbus?)?  Gphoto as a
> process stays running, you just need a programmatic way to communicate
> with it.  The looping and branching wouldn't happen in Gphoto's shell,
> that would be more like a low level server or driver.  I could of
> course modify my copy of the source but I'd rather not do that.  I was
> about to experiment a bit until I found my oldschool loadjpeg function
> evidently doesn't work under Linux, I need to make a Turbo Jpeg
> equivalent.  Or maybe I still need some dev file or header.  Wacky, it
> doesn't know jpeg_CreateDecompress or what a size_t is?  I wrote it
> under OpenBSD a couple years ago, it's been reasonably portable until
> now.  Loading a straight uncompressed RGB binary would be optimum but
> I need to decompress jpegs.  Don't know yet if I can send to stdout.
> 
> I ran across motion last night but didn't bother to install it.  I
> think it's strictly V4L so it's low quality just because the cameras
> are.  I've got a 640x480 USB webcam that does V4L but I'd rather not
> use it.  My motion detection scheme comes partly from a D-Link IP cam,
> that also only does 640x480.  I'll probably be running this on a
> Raspberry Pi, and I've got a few of those cameras, but I'd rather not
> use them.
> 
> The standard Gphoto --capture-preview or the shell equivalent gets me
> a 320x240 jpeg which, if I decompress and compare in C, not something
> awful like Python, should be fast enough.  I'd rather not use 2
> cameras.  I'm from the Nikon camp, new to Canons for this project.
> For $20 used I got a 7 MP camera that not only works with Gphoto but
> also shoots RAW, most low-end Nikons won't do either.  I'm not
> sticking my D5200 DSLR in a birdfeeder.
> 
> Shell mode is good for this because there's only 1 start-up time, the
> delay between pictures can be much lower than if you call Gphoto in a
> loop to start from scratch each time.  1 frame per second might be
> adequate but I'm aiming at 10.  CPU time on a Pi 3 comes cheap since
> it runs on a watt or two.  So I don't need to compare 320x240 images
> but if I can do it efficiently I can live with it.
> 
> On 12/30/17, Tomas Alonso <tal...@gm...> wrote:
> > El Viernes, 29 de diciembre de 2017 17:39:08 Alan Corey escribió:
> >> I want to set up a wildlife camera, so I've read a few articles about
> >> it.  I've been practicing with an old Canon PowerShot S70 and it seems
> >> suitable.  What I'd like to try to do is use the preview images for
> >> motion detection.  I need to mask out some areas to avoid false
> >> activations from clouds passing over, that sort of stuff, and probably
> >> some averaging to account for the sun rising and setting.
> >>
> >> For speed it seems advisable to work in Gphoto2's shell mode but I'm
> >> trying to figure out a way to provide input from an external program.
> >> I want to do capture-preview in a loop: get a preview, run my compare
> >> program, get another preview.  If the compare sees something go into
> >> another loop grabbing big images for some amount of time, then back to
> >> previews.
> >>
> >> I did help in shell mode but I don't see anything listed that looks
> >> like it would work, like being able to detect the presence of some
> >> file I could use a a semaphore.  There aren't any branch (or loop)
> >> instructions either.
> >>
> >>   Alan
> >
> > Hello Alan,
> >
> > For other needs related to security I'm also interested in doing something
> > equivalent. I thought my first try would be
> >
> > http://www.chriswpage.com/2009/05/setup-an-advanced-webcam-security-system-with-ubuntu-8-04-and-motion/
> >
> > using the motion program under Linux. It allows to launch scripts when
> > motion
> > is detected, but you need a webcam for motion detection and a camera for
> > good
> > quality shots. That's (and the fact I own a Canon 40D) why I'm not sure at
> > all
> > about the webcam approach.
> >
> > I have high programming skills and experience with gphoto so to implement
> > this
> > myself will not be a problem. If you can't find a solution for your case
> > just
> > send me the exact gphoto commands you use for your camera to enter shell
> > mode,
> > take a preview, and take also a big image in auto mode or whatever you use
> > (including the file names generated in your computer after executing those
> > commands).
> >
> > Can't promise to do it for a given date but likely it will take few weeks.
> >
> > Regards,
> > Tomas.
> >
> >
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> 
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