Infrared tripwire

Infrared trip-wire http://www.ownthenight.com/catalog/i20.html. Emits a IR pulse at 880Nm which will be seen by the Watec 0.003 CCD camera fitted to a UAV drone. Fly the drone over a patrol route taking pictures at a hight of 200m by night to detect a farm or other perimeter intrusion.
Instead of a physical wire activating the beacon, trigger the flashing beacon with a normal IR beam alarm system described at 
Infrared leds
Category:Sasecurity
Category:Infrared
Category:Trip wire
Category:Infrared beacon
Category:Perimeter control