How to program a state change functionality. 'State change detection' is a method to see when a button is pressed or released. You can use it to fire a different action each press of a button.
For example the "Play/Pause" button on a cd-player behaves like that. The first press is play, the next press is pause, the next play again etc. Depending the state the action is different ( play > pause, pause > play ).
Level : beginner with Arduino. ( Basic knowledge of programming principles like if/else and variables ).
Download the code examples from http://kasperkamperman.com/blog/