Do you make stuff with knobs on?

If you feel like trying out something a bit sexier than knobs and buttons here are some good resources for making capacitive touch inputs.

AN1102 - Layout and Physical Design Guidelines for Capacitive Sensing - Application Notes - Details

http://www.atmel.com/Images/doc10752.pdf

Or just go for the ghetto route and use a pencil...

Make a Touch Sensor with a Pencil Drawing - YouTube

If you prefer learning in video/animation form

Capacitive sensor, Theory, application and design - YouTube


Projected capacitive touch sensors, theory and design guides - YouTube

A simple 6 button circuit:

justDIY Project Log » Interface

A slider and spinner example:

AVR Capacitive Touch Sensor Slider and Spinner - YouTube