Need timer help

First let me say Hi.
I need to build a timer that will power 110v motor at the same amount on and off. I have found a few diagrams to build one using a 4541 Programmable Timer chip but the fastest it will go is .5sec and I was trying to find a way to go from .1sec to maybe 30sec in .1sec increases. If anyone can point me in the right direction it would be greatly appreciated.

Thank you
Ed

Is it an AC motor? Why would you want to do this?

yes it is an AC motor. I am building a wave generator for my Aquarium and I need to be able to change the speed that the pump turnes on and off so that it will make a smooth wave in the tank.

Ed