a controller with three push buttons controls three leds. (video link)
i use a controller with three push buttons (see above). the cables of the push buttons are connected to ground and to one digital pin each. three leds are connected to ground on their cathode, and through a 220 ohm resistor going to a digital pin each on the anode (see fritzing image).
here you can find the source code for this incredibly exciting project ;-). maybe it’s useful for someone…