The most elegant solution is just to buy an alarm clock or watch. They're cheap to buy (you may even be able to get a second hand one for free depending on where you lived), and would cut your electricity usage compared to running your MBP as an alarm clock.

With your phone, have you tried anything to save it after it was damaged by water? If you want a technical challenge, I'd suggest focusing on that. There's advice on the web on how to repair a phone after dropping it in water.