I want to build this project where an IR Transmitter and Receiver are capable of monitoring a rotating element, producing an output compatible with PIC A2D to integrate with PIC system.
Basically a modulated infra beam and detector detects the spokes (Black and White Strips) and pass the information to the PIC which calculates the RPM of the rotating object and displays it on the LCD.
You should use comparator between IR RX and PIC port. (That serves A2D) count the pulses, divide by time and scale it(depends on dia,no of slots, etc). You have the speed of motor. LCD interfacing is another Task.