Timer 900 seconds

Hey guys, I'm working on a new project, a timer that will count from 0 to 900 seconds in real time! I'm using the Flip Flop principle to build it, their systems are complex, though the project is only 30% complete, because I be working on four other projects at the same time hope this magnificent stopwatch ready to estaja on 29/11/12! The systems are a redstone this riddle my work and I hope I have the conclusive without any error! If you also want to download this timer is only there on top subscribe and wait to get this great map! I hope you enjoy! = D