So I asked something like this before. But I need a way to detect when a person goes into the room and out. I need one sensor that can do that. Basicly I just need a way to know if someone went from left to right or from right to left (in an 5cm area). I am trying to do something like this with IR sensors (two IR emmitters and two sensors) but the arduino is a little too slow to handle that fast movements - I am just measuring the time difference between the sensors.
So can I can get something that sends a digital pulse for one direction and different pulse for other direction?