Measuring Pulley RPM with Infrared Diodes and an Oscilloscope HD

This video just shows you a demonstration of a infrared diode transmitter and receiver being used in association with an op amp to measure the rpm of this lathe pulley. There are 5 spokes on the pulley so the math is quite simple. You divide the oscilloscope frequency by 5, then multiply it by 60 to get the rpm of the pulley! The infrared diodes serve as the sensor. The op amp serves as a pulse squaring device. The LED is an indicator. The purpose of this was to determine the speed of the lathe chuck!