[HH] web cams as security cameras

[Shankar Viswanathan]

On Thu, Aug 11, 2011 at 12:57 AM, Tom Metro <tmetro+hhacking at gmail.com> wrote:
> I noticed one of these:
> http://www.microcenter.com/single_product_results.phtml?product_id=0332677
>
> selling for $15 in the latest Micro Center flyer (price not reflected on
> their site for some reason).

This seems very interesting. Anyone know if this is supported by stock
Linux kernels?


> I would expect to see several limitations with using web cams as
> security cameras:
>
> -The lens angle for a web cam may be too wide or narrow when you
> position the camera 10 feet away from your area of interest, instead of 2.
>
> -As above, focus may be off, but the lens may already be designed be
> focused at "infinity" for anything that is more than a foot away.
> (Looking at a large JPEG of the camera, it looks like it has a manual
> focus ring and the markings F/#2.4 f:80mm-infinity.)
>
> -The "night vision" LEDs appear to be visible white, rather than IR,
> which diminishes their value for security applications. If the camera
> needs visible light, then you might as well just use general lighting,
> and you likely would need that in a security application where you need
> to illuminate a larger area. No specifications for the minimum light
> level required by the camera.
>
> -This is a wide aspect ratio HD camera. The extra width may or may not
> be useful in a security application. The slightly cheaper 800 x 600
> resolution model might be better.

One thing I have heard about using webcams as security cams is
reliability. Consumer grade webcams aren't generally designed for 24/7
operation, I'm assuming the thermals aren't designed to dissipate heat
properly, causing long-term reliability issues.


> I know there are some people on the list that have experimented with
> using web cams as security cameras. Have you had success using higher
> resolution web cams to produce a better image than what you'd get from a
> $200 IP cam? If so, what did you pair it with? ShevaPlug?

An ex-colleague uses a standard Logitech USB webcam connected to a
SheevaPlug (running Debian) as a security cam for his basement. He
uses the 'motion' package to do motion detection and has it setup to
email him a snapshot if it detects motion and uploads the recording to
a remote server. He's quite happy with the results, with two caveats:
 1. He has a separate timer to turn on the light at night so that the
webcam can 'see', and similarly turns it off sometime in the morning.
Both these 'light on' and 'light off' events get detected by the
webcam as motion, triggering a recording. He's had to hack some
scripts to prevent this from being flagged as an alarm.
 2. His house is on a corner lot, and there is a window in his
basement that has a view of the side street. Any large vehicles
passing by on the street during the daytime also triggers the motion
detect. He hasn't figured out how to stop this.


-Shankar