Why Rotary Encoder?

One of the main functions of a controller for audio is to control volume. Typically, volume is controlled with a potentiometer on the analog audio signal. But we want to use a controller to control another device that will control the volume. For example, controlling the digital volume capabilities of a modern DAC such as the Wolfson 8741 or audio volume chips such as TI PGA2320

A rotary encoder is a device that will keep on turning (there is no maximum or minimum) producing a signal with "clicks" indicating clockwise motion or counter-clockwise motion as shows in the following diagram


Why use a rotary encoder instead of a potentiometer? A rotary encoder will allow you to:

• Use a preset volume level every time you turn on your stereo system (without having to turn a knob to a preset position)
• Use an IR remote and a knob on the same system (without having a motor move the knob)
• Change the sensitivity of the adjustment in software
• Add a volume offset in software