For a project that I'm building, I need an object detector that signals when something "cross" the virtual wall of light.
I create a virtual wall using a laser and two mirrors (one in front the other). The laser goes to the front mirror, it reflects the light back to the other mirror that is behind the laser, and it reflects back the light and so on. An the end, a photorresistor sense the laser light. When an object cross thru the light, the photorresistor change and a comparator signals that something is passing thru the virtual wall.
The problem is the photorresistor that it is sensible to natural light and of course the laser... it is dangerous for the eyes (an accident can happen). Another problem is with the mirrors, they need to be complete aligned to each other.
I want to change it to infrared light and a IR detector.. like those used in remote controls. But I need some IR leds with a small apperture to create a virtual wall.
Do anyone has some ideas, facts, experiences, suggestions and so on about what to do ? Is it a good idea ? Any led reference for it ?
Hern=E1n S=E1nchez Medell=EDn, Colombia