Rotary Encoders Cedric Pinder Major: Computer Engineering

What is a Rotary Encoder? Wikipedia A digital electronic device used to convert the angular position of a shaft or axle to a digital code. Layman’s Term Is a mechanism that converts a shaft (rotary) angle into an electrical signal.

Terms Gray code- is a binary numeral system where two successive values differ in only one digit. Detent- is a catch or lever that locks the movement of one part of a mechanism.

How is this possible?

When the rotary encoder is turned How is this possible? When the rotary encoder is turned Why Gray code & Binary’ Rotary encoders are subject to wear and tear due to the turning of the shaft. In due time the opening and closing timing of the internal switches won’t be in-sync. If the switches are not in-sync, then incorrect position codes will be generated at the output of the logic devices connected to the encoder. So, since Gray code only changes by one bit at a time and we can only close or open one switch of a rotary encoder at a time than this eliminates the problems.

Oscilloscope’s Results Clockwise Counter clockwise

Are they other encoders? Absolute encoder- is a device that reports the shaft angle within a 360° range. An absolute encoder does not lose its position after a power-down and provides the absolute position upon power-up without requiring a home cycle or any shaft rotation. Incremental encoder- is made up of 2 major parts: the disk and the sensor. The disk of an incremental encoder is patterned with a single track of repeating identical lines near the outside edge of the disk. The number of line pairs on the disk determines the encoder resolution (CPR). Optical encoder- is a sensor that uses light to sense the speed, angle and direction of a rotary shaft. A linear encoder reads a linear strip instead of a disk to provide the same information for linear motion.

How is this beneficial to you? This can be used in your final project for: Volume and Tone Control for Audio Visual Equipment. Tuner for Communication Units Mode Selection for Measurement

Technical Specification Encoder 360 degree, 12 detents,pulses per revolution Voltage 5 Vdc Current 1 mA

Circuit Diagram

References & Further information technical documentation- http://rocky.digikey.com/WebLib/Panasonic/Web%20data/EVE%20G,H,J,K,L.pdf http://www.usdigital.com www.dictionary.com www.wikepedia.com Embedded Design with the PIC18F452 Microcontroller, pg. 108-110 http://www.circuitcellar.com/library/print/0303/millier152/2303017.pdf

Contact Info Cedric Pinder Phone: 814-217-2611 E-mail: cmp241@psu.edu