Wow! Thanks so much for the replies! In answer to the question, I just need the servos to go one direction, it doesn't matter which one. The speed it's been going is fine for me, it's not so important, just something in the medium range. I want each servo to start moving when you shine a light on it. The servos are are attached to a flower mechanism that opens and closes:
There are 15 of these in an icosahedron, it's supposed to be a virus.
I love your idea about making it go faster when the light is brighter, but right now I just need to make it go at all by next weekend! I can think about making it technologically cooler later.
I'm about to try the little program one of you posted, thanks for that!