Distance sensor for 0-5 cm range

I am trying to build a robot arm that I can control with the motion of my own hand. I want to measure the distance between my fingers and use it to control the gripper but I can't find any distance sensors have too high of a minimum range. Anyone got any suggestions?

You might consider some flex sensors. This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!

Thank you for your suggestion and I can see how I could use something like that but I don't want to use a physical sensor. I was thinking about something more in the lines of laser sensor but the ones I can find usually have a minimum range of 5 cm. Do you know of any light or sound based sensors with a minimum range low enough for the distance between two fingers?