[ale] OT: Video Motion Sensor

[meuon at geeklabs.com (Mike Harrison)]

> to determine/measure a potential threat.  Does anyone know of 
> software/projects/devices that do this sort of thing?

http://www.acroname.com/robotics/parts/R15-SONAR2.html

Video's a pain.. Ultrasound would do that in the dark..

The robotics guys use things like:

http://www.acroname.com/robotics/info/examples/polaroid-3/polaroid-3.html

But you may need something with a lot more range.