Introduction: Arduino Binary Clock
It has an "arduino brain" to show us what time is it in a binary way. The first row of leds are the hours and the second one indicates the minutes. You will have to add up to be on time. It can work with a 9v battery or with an AC/DC adapter.
http://www.youtube.com/watch?v=DfyoCdWcFcM
Participated in the
Clocks Challenge