Quadrature Encoders
Rotary and Linear Encoders Explained
Introduction
Rotary encoders tell mechanical devices where they are. We forget that machines need us to provide this information to function correctly and the quadrature encoder, for a better name, does the job.
Project Description
What I've tried to do here is showcase several examples of rotary encoders as well as linear encoders that use the quadrature principle to work.
Examples of this sort of encoding can be found in menu driven displays that use a detent rotary that is used for selecting menu items to include a button to select that item. Then the encoder is used to set a value for the menu item. Push the button again and the value is set and an indicator puts you back in the main menu list.
More sophisticated rotary encoders are found attached to DC motors with varying degrees of accuracy to determine angular position or as a feedback device in a closed-loop servo system.
Linear encoders that use the quadrature technology are found in every printer or plotter to gain accurate position for a print head. It's a simple and economical way to get the job done.
The most common varieties of quadrature encoders are mechanical switches, optical reticles, or Hall effect sensors to produce the standard two quadrature signals. The signals are used to interrupt a computer and provide position and direction of motion. In addition, the processing can reveal speed by counting pulses read per unit time. As you might surmised, rotary or linear encoders are an essential element in machine design. I hope this project sheds some light on how they work.
Rotary Encoders
Intro Video:
Design Video:
Code Video:
Demo Video:
Linear Slider:
Design Video:
Demo Video:
LCD Motor Control:
Summary:
Rotory or linear encoders both use quadrature signals to define direction and count that can be used for angle or distance, etc. This data can be use in a factory automation program. LCD displays can be use as a interactive menu to control motors and actuators.