[HH] motion-activated hardware hackery

[Tom Metro]

Federico Lucifredi wrote:
> I am wondering if anyone has played with motion-activated cameras,
> for security use or for child monitoring.

Software or hardware-based motion detection?

I have tried out the software-based motion detection built-in to a
variety of Linux-running IP cameras. They all performed lousy. Typically
they'll trigger when lighting conditions change (i.e. cloud passes in
front of the sun), so unless you have a purely artificially lit area,
you'll have problems. Reduce the sensitivity to avoid these problems and
you'll miss legitimate motion.

To solve this I ended up wiring up a traditional hardware passive IR
motion detector to my cameras. A number of inexpensive cameras have
external trigger inputs which you can use to trigger emails (or
whatever) just as if the internal motion detector fired. Way more reliable.

Panasonic's IP cameras, which are a bit dated now, were notable for
having built-in passive IR motion detection hardware. Given how little
cost this would add to the camera (maybe $2 or $3), it's hard to see why
all cameras don't do likewise.

ACTi has some more modern (megapixel resolution) cameras with built-in
PIRs, like:
http://www.acti.com/product/product_info.asp?PID=F633BFB5-A26E-41C9-BFD5-FB307E987659

but (so I've read) they took a common boneheaded approach of putting a
web UI on their Linux-running camera that only works with IE (about 2
web browsers behind current trends).

I hear that the motion detection software in ZoneMinder is decent, but
haven't personally experienced that. I imagine if you are using beefy
enough image processing hardware on a central server that you can make
software-based motion detection work well. Personally I like the idea of
offloading processing to the individual cameras so you can scale up to
multiple cameras without needing to upgrade the central server.

 -Tom