Building a surveillance system
 

Hiya.
I'm currently in the business of attempting to build a custom surveillance system using sensors (such as a shock sensor, not motion) and cameras to take photos when triggered.

I'd really like to get some advice on how to achieve this via linux.
1. What do you think would be the best way to interface a sensor with a PC? I was thinking the parallel port. Write a perl script to listen for incoming signals.

2. I need to use a small form factor camera, such as a webcam or those professional pinhole cameras. What kind of software is out there on the linux platform to interface with cameras? What i've read so far is that i'll need the L4V drivers to interface with specific camera chipsets.


Any information would be greatly appreciated.

As far as #2, you might want to take a look at the LQ.org Hardware Compatibility List for various cameras -- most of them explain what software they used as well. It shouldn't be terribly difficult to wire something up to a parallel or even serial port, in regards to a shock sensor, and have the script call a graphics program to take a snapshot. I'll bug a security guy here in the office and see if he has more specific advice.

I don't think webcams would be up to this task mostly because if they use a USB interface, then their range is limited in that the USB cable cannot be longer than around 1 meter or so (and should probably be shorter) otherwise it won't receive enough power and won't be able to communicate efficiently or reliably. I'm assuming that a surveillance system will have cameras that are far away from the computer they interface with. I would use a camera that outputs though a coaxial cable and then a capture card (plenty are supported in linux).

The sensors as long as they are simple will certainly work on a serial or parallel port, but you'll have to do some 'hacking' to get there, just messing with it till it works properly.

I just saw an article on linux.com about a program called zoneminder. It looks like exactly what you are looking for.

Ah very nice, thanks for the replys thus far!
H_TeXMeX_H you raise a very good point, USB cameras would be too short! Well thats good, that cuts out some of the hardware research i have to do heh.
So really i'm going to be looking for a capture card, and if i'm not mistaken, any camera supported by the capture card? (IE, will not need drivers for the camera as its interfacing with the card, not linux. True?)

If so, then thats simple enough. Then it now just leaves the application that does the recording.
Thanks for your suggestion snowman81, but i'm actually looking for an application that captures video/pictures when triggered (via the sensors) and writes then straight to the HDD. I do not actually require a GUI, or want to rely on one at all.
ZoneMinder may actually do this, as i haven't fully checked it out. But any other suggestions are welcome!

As long as the camera outputs to coaxial, then just hook it up to the capture card and capture. Depends on the camera I suppose in that it must output to coaxial.

There was a thread on this topic not too long ago.. at least in regards to the software side.

http://www.linuxquestions.org/questi...ghlight=motion