Need help finding a lever/valve mechanism for a school project

I'm trying to help my son with a school project. He wants to build a candy dispenser. It will be gravity fed, fall through a tube, then come out the bottom of the tube. At the tube, he wants some kind of lever or valve to let the user open and close it to dispense candy.

We looked at some plumbing valves, and they do the trick, but they're all somewhat hard to manage easily with one hand. Any suggestions? He's not picky about how much candy comes out at once, or exactly the type of lever/valve. I did some searching online, and came up empty.

Any suggestions? Is there a site somewhere that sells things like this for home inventors?

Thanks!

Submitted March 30, 2015 at 04:33AM by BigMax http://ift.tt/1NveCzk