no, not gng paranoid, but....

Polytropon freebsd at edvax.de
Fri Oct 18 05:37:43 UTC 2013


On Fri, 18 Oct 2013 00:18:20 +0000, Gary Kline wrote:
> 	does anybody know of any hardware for FBSD for a closed-ckt camera?

I'd suggest using an ordinary CCTV camera. Used ones can be
obtained for few money, and they are usually still good. You
will probably want to use a B/W model because they tend to
have a better contrast even during darkness. (On the other
hand, you could always add an "invisible" IR lamp.)

Those cameras usually come with a BNC connector, it's a normal
asymmetric wire. Any compatible video grabber card or USB dongle
should work fine.

I've been using something similar in the past with the following
configuration: "Old-fashioned" CCTV camera in exterior housing,
BNC cable, BT-878 based TV card (Haupauge WinTV) on FreeBSD, and
mplayer. With mplayer, I could bring up a window showing the
video feed (I had mapped that to a key), and with mencoder it
was possible to record and encode the feed, or make stills at
defined intervals (every 2 seconds, once per minute and so on).
Compatibility? No issues here.

Of course, obtaining and installing PCI TV cards isn't that
easy anymore (with "modern" PCs). But there are several kinds
of USB dongles that act as a video grabber (they are often sold
under that name, "TV grabber" or "video grabber"). But as I
have no experience with them (PCI card still installed and
working!), I can't be more specific to recommend a brand and
model for this.

To extent the idea of grabbing stills: It would be possible to
obtain a "sample" showing "nobody at the door" and then have
mencoder obtain a still at the rate of, well, let's say every
5 seconds, and then compare it to the "predefined sample". In
case it does _not_ match, an audio signal could be emitted
(e. g. by playing an MP3 file) and if needed, start a 
continuous recording which can be deleted later on (if
nothing criminal happened at the door).

All this (!) works easily with FreeBSD.



> 	my wife's mother is still here and scared of her shadow. 

Add more lights. :-)



> im no
> 	fool [...well...:-) ] ... but I hesitate to swing open the front
> 	door if somebody unexpectly knocks.  the lens to see out is for
> 	somebody standing.  that's hard for me to do.

In addition to my idea explained above, there is a nice way to
avoid cabling: Some years ago, I bought a 2 GHz A/V link system
(for 15 Euro at a typical "el cheapo" store). The camera can be
connected to the transmitter device. It will be installed near
the door. The receiver device will then be connected to the TV
card or USB video grabber. The emitted power is few enough so
the signal will be fine indoors, but won't easily be interceptable
from the outside.



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...


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