Hello. I am new to Arduino. I know my idea is possible, I am just seeking advice on what electronics to use. I want to setup a 'light beam' switch. Have a piece of glass or plexiglass about the size of a smartphone or tablet. I want to setup an LED light on one side and LDR on the other side. Is there an LED that will shine a beam about 6 inches and be detecable by the LDR? When the beam is broken by an object I can detect through the arduino etc? Also the glass may be lit up by other LED's placed behind it. Would that affect my switch?? Could I setup 2 'Beams' intersecting somewhere on the glass so touching that one spot ( breaking both beams ) would give me an invisible 'button' on the glass that could control other LED's
If I understand, you want light beams (invisible) that can be detected about 6 inches away, and upon interruption of the light beam, send a signal(s) to the arduino.
Yes, you can use infrared led(s) and sensors to make it invisible. 6 inches should be easy.
Google for “infrared pair emitter detector”
It seems you are talking about a "touch screen"; you want to shine the beams across the surface of the screen, not through it.
You will need to have the sensors at the end of some black tubing so that they are not affected by ambient light or the LEDs behind the screen.