I have to thank one author of a rotary encoder decoder (Ben Buxton). While his code seemed overly complex to my untutored eye, for example creating a new data type, it did show Arduino-novice me two ...

At the heart of the device is a AD9833 waveform generator; with the Arduino, rotary encoder, and 16×2 LCD providing an interface to control it over SPI. Unfortunately, the AD9833 doesn’t have ...