I am looking for a light sensor like is used in a garage door system to detect if an object is between a light source and light sensor.
I need something to put in my back yard to detect if someone is breaking through a particular path. It is like a light activated trip sensor , used for home security awareness, but I cannot figure out what this device is called so I can find it online to purchase.
Any ideas?
Thanks
Background: Just had some people crawl through my back window a couple of weeks ago and steal some stuff with house full of people, nobody heard them. I want more situational awareness. I also have other more effective means now of dealing will them too.