Contactless Measurement of Angular - Speed

The control technology has been improved to enormous scales so far. People are trying to
apply control over everything they do, so that the level of accuracy and efficiency
increase. The simplest form of control could be a control of a rotating shaft. We might
want to keep its speed stable at some rps (rounds per second). This can be achieved in
numerous methods. Regardless of any method chosen, the first step to achieve this goal
would always be being able to measure the speed and then to apply control measures to
it.
In this project, I aminvestigating contactless measurement ofangular speed of a rotating
shaft. My main objective is to demonstrate how to measure the angular speed of a
rotating shaft contactlessly. Contactless measurement of angular speed is particularly
critical when dealing with load-sensitive devices such as mobile antennas.
I am achieving the contactless measurement through using IR (infrared) emitter-detector
circuitry. The IR pair generates pulses, which are galvanized by the rotation of the shaft.
Slots on a disk mounted to the shaft permits light transmission between IR emitter and
detector, which are placed on both sides of the disk. Hence, when the disk rotates it is
possible to get stream of pulses from the circuitry.
I used a PIC microcontroller to accept the pulses and obtain the angular speed in terms of
rps. This value is then displayed on 7-segment LEDs.
Lastly, this project involved a lot of microprocessor concepts. I tried my best to present
concepts involvedas comprehensible as possible. I expectthe reader to have no difficulty
while reading it.