Get a patent. A provisional patent lasts for I believe 1 year, and its cheap (I think about $250). Only a couple quick papers to fill out as well. After a year, you'll need a non provisional patent which is much more expensive and will require you to hire a patent attorney. As soon as you file for the provisional, you can claim "patent pending" which is usually enough to keep people away. PM me if you want more info. I am going through the process right now as well.