Compound daily interest

Hey,

Looking for a formula that gives me the abilty compound daily interest for R.R.S.P's. I would like the ability to start with a principle and add biweekly to the principle.

I.E

100$ + 15 days of compound interest @ 8% a day + 150$ biweekly increment = $ yearly total with the abilty to change the principle (100$), the biweekly increment (150$) and the interest rate (8%)

Anybody have any clue how i would do this? Any help would be appreciated.