1 knob, 6 functions.

This tiny, super cheap media controller works with all devices that supports USB Media Controls - computers, tablets, phones etc. Tested so far with Windows 10 & Android 6.

A single knob performs the following:

• Play - press knob
• Pause - press knob again
• Volume up - turn knob right
• Volume down - turn knob left
• Previous track - press AND turn knob left
• Next track - press AND turn knob right

You can also replace the actions of the knob with pretty much any key press you want. See Changing functions further down this page.

There are several one-knob media controllers out there, but I've found no version that allows you to change tracks without dedicated buttons (like my larger Arduino Pro Micro-based Media Controller has). And none so cheap and easy to build.

The only components needed are a Digispark (Micro USB version) Arduino microcontroller and a KY-040 rotary encoder, which can be had for about 1€ each on eBay/Ali. A few wires to solder and that's it - hardware is done!

I'm also including the Arduino source I wrote which includes (or links to) pinouts, libraries , instructions and pretty much everything you need in order to program the controller.

I made several different knobs that you can choose from. The encoder has a standard D-shaped 6mm shaft so there are a multitude to choose from if you want to buy or get one from elsewhere.

Update 2018-07-03
Pinout diagram added.
Software updated to version 2.0, courtesy of IAmOrion, aka James Tanner. Basically rewritten from scratch - fixes a problem when changing direction, includes debugging mode and opens the possibility for much more advanced functions. Settings are now all in a separate Settings.h file. All code can be found in The_Knob_Arduino_code_v2.0.zip.
See the Comments section for even more versions with added functionality from IAmOrion (triple-click, anyone?).