This is a 12-step rotary encoder with a nice \'clicking\' feel. It\'s breadboard friendly, and has a pretty handy select switch (by pushing in on the knob). The encoder is different from a potentiometer in that an encoder has full rotation without limits. The unit outputs [gray code](http://en.wikipedia.org/wiki/Gray_code) so that you can tell how much and in which direction the encoder has been turned.
This unit does not come with a knob, but a working knob is related below.
**Documents:**
* Bildr example showing [how to use an encoder in Arduino](http://bildr.org/2012/08/rotary-encoder-arduino/)
* Rotary Encoder [Tutorial and Arduino Project](https://www.circuitsathome.com/mcu/reading-rotary-encoder-on-arduino/)
* Example [Arduino Project](http://www.sparkfun.com/datasheets/Components/RotaryEncoder.pde)
* Example [Cooking Timer](http://www.eran.io/rotary-encoder-based-cooking-timer/)
* [Datasheet](http://www.sparkfun.com/datasheets/Components/TW-700198.pdf)