rayholt:
I am looking to create a sensor device that can detect and edge of a paper. For example say we have a plain surface with a 1mm black line and if a piece of paper was to cross this line then an LED should flash.
There are multiple ways to detect this.
- detect a lessening of reflected light
- detect thickness of the paper
- detect loss of signal from IR (or other) xmit/rcv pair
What is it you're actually wanting to sense? What's the significance of the black line?