is it enough time?
Depends on how adept you prove to be writing code. Reading a PIR isn't difficult. Triggering an MP3, with the appropriate shield, is easy. Without a shield, it's plain impossible.
Borrowing someone else's code is not going to do you any good, unless it is for the SAME hardware you have, arranged the same way. The odds of that happening are pretty slim.
Even if if did, what would you have learned? Why are you taking this class, if it isn't to learn?