Marklar who is a senior member over at the Arduino forums converted a junked radio into a fantastic RGB LED controller. When he looked inside an old radio to salvage some IR parts he spied a Rotary Encoder, these are a bit tricky to setup for the first time but they are great when you are done. For those who aren’t sure what a rotary encoder is, be sure to watch the video that Chris Savage did.
Via: Make
“The concept here is that multiple sets of buttons can be read by a separate analog inputs and can work either in tandem or stand alone. I do not want to use the memory to store values in an array, so I want to use code to determine the button value instead of a commonly used array look up table. For this reason I use a callback function to return the button based on the analog value. A callback is also used when a valid button is pressed. This allows the code to put into a library and only the base mechanism used.”