I'm trying to create a circuit for a IR emitter/detector pair so that when the beam is broken it will read as a HIGH on the arduino digital pin. I'm very noob to electronics, I'm a programmer and am more into the program development on the arduino and have no electronics background.
I have fashioned my circuit after this example of a tach/rpm counter. http://arduino.cc/forum/index.php/topic,94690.0.html
I have that circuit working using the LED so that if I break the beam then the LED will light. But instead of lighting the LED, I want to run that signal to one of the digital inputs to the arduino.
I want to use digital pin high/low, as oppose to analog pins, because I'm actually wanting to use multiple sets of IR emitter/detector pairs and run them into a parallel/serial shift register (74HC156) so that I can feed many sensor signals into the arduino. My understanding is that the shift register will want high/low signals and won't work with analog levels???
I have my programming working with the 74HC165 and tested with multiple push buttons and received the signals; now I want to replace those buttons with the IR emitter/detectors. I'm getting fluctuating and constants signals, I believe, because the IR is always sending some level of voltage on the signal pin which I presume causes continuous high signals?
So, can the IR emitter/detector pair be used as I am wanting, in the scenario I've described? And if so, how would the circuit be set up?
Thanks for tips/comments.