A couple of days ago, developer Mr305 released the PSP Hardware Alarm Interface I v1.3.359 homebrew app for use among the homebrew community. This application enabled PSP owners to use their handhelds as an alarm clock, even if it was powered down.

The app was also compatible with units running on CFW 3.xx, giving it a distinct edge as compared to similar homebrews out there. The developer visited the QJ.NET Forums earlier to announce the release of this homebrew's source code.

Mr305 also put together the OpenAlarmLib v1 in case you're interested in developing similar apps as the Hardware Alarm Interface. You will want to keep Mr305's note in mind before downloading the source code (quoting the readme):

This is still an ON-GOING project and still supported by me (Mr305).

I do not ENDORSE nor SUPPORT any 'enhancements' or 'mods'; however you can freely make any changes AS LONG AS it's private and NOT shared to the public. Hope everyone understands this.

The dev does note that you can freely modify and release any updates to the Power Alarm Support Plugin. Full details on both the source code and dev library are available in each file bundle's readme. You may also want to visit Mr305's release thread at the QJ.NET PSP Development Forum to join in the ongoing discussions.

Download: PSP Hardware Alarm Interface I v1.3.359 SRC
Download:  OpenAlarmLib v1 Enhanced
Visit: QJ.NET PSP Development Forum