From GameBrew - a wiki dedicated to Video Game Homebrew.
Wecker DS is an alarm clock that wakes you up with an mp3 file, which wecker is German and means alarmclock.
It was participated in the Drunkencoders Compo in 2009.
Download and extract archive, DLDI patch .nds file.
Prepare a mp3 file, name it wakeup.mp3, and copy it with .nds file to the root directory of the card.
Left - Adjust minutes
Right - Adjust hours