This sketech creates a volume control knob from a rotary encoder to work with a computer. The sketch has been tested on an Arduino Leonardo clone named the LeoStick, from Freetronics. The sketch is known to work on Ubuntu 12.04 LTS and Mac OS/X 10.7.5. The volume up down functions, but not the mute function, have been tested to work on a Nexus 7 tablet running KitKat (4.4.2) using a USB-OTG cable. This sketch is based on the work of Digistump Digispark forum poster Bluebie, for the initial sketch and wiring diagram. A prerequisite for this sketch is making the modifications detailed on the blog post of Stefan Jones: http://stefanjones.ca/blog/arduino-leonardo-remote-multimedia-keys/