know of a no-pressure timer?!

Hey I really need some help I have a 55 gallon drum and a great drip system set up and clones out at a guerilla grow. BUT the timer i bought needs at least 10 PSI and like an idiot I did not look at that fact. So now I need a watering timer that can be placed at the bottom of a 55 gallon drum with no pressure and work! anybody used anything that works. help would be great thanks

haha. even me bro, i was wondering how come no waters is coming out.