Introduction: How to Make a Hopper Clock in Minecraft 1.5 +
Here is how to make a Hopper Clock in Minecraft 1.5 (or a slight variation of it should) unless they drastically change the way Hoppers work when 1.5 comes out.
Follow me on Twitter: http://www.twitter.com/Aerophite
I'm on Facebook too!: https://www.facebook.com/pages/Aerophite/109858952517740