AC Motor Speed Control and RPM Count

Abstract

A digital tachometer is a digital device that measures and indicates the speed of a rotating object. A rotating object may be a bike tire, a car tire or a ceiling fan, or any other motor, and so on. A digital tachometer circuit comprises LCD or LED read out and a memory for storage. Digital tachometers are more common these days and they provide numerical readings instead of dials and needles. This device is an embedded system; it is built using a microcontroller, an alpha-numeric LCD module and an infrared system to detect the rotation of the fan whose speed is being measured. The infrared system generates the pulses from the fan which will be sent to the microcontroller and the pulses will be counted; the reading is displayed on the liquid crystal display (LCD module) in revolution per minute (RPM). It is a low cost digital tachometer that can display exact speed reading based on how fast an object is rotating.it adopts the Use infrared transmitter and receiver as the technology behind the speed detection. It can be used in various applications. It can measure the speed of rotating objects (examples of rotating objects include: a bike tire, a car tire, a ceiling fan, or any other motor) in the most accurate form possible. In automotive, it is used as a gauge showing the speed (RPM) of the engine shaft that is driving the transmission, usually in thousands of rotations per minute.