Hello Alfer,
I will give you two agents I've checked out that may help you with your project (concept) please keep it touch with me, I'd like to correspond with you because I am an inventor too.
Be careful and do your research but also realize that at some point you will have to disclose your concept with someone. There are ways to do it and protect your concept at the same time.
Lambert & lambert is in Saint Paul MN you can call them at (651) 552-0880
Invention Marketing Help For Patents & New Ideas.
Harvey Reese is in Pennslavania you find him on the website he has a good book out 2nd edition called how to license your million dollar idea. It gives you all sorts of info about prototypes etc: I had the same problem as you, all of a suddent I figured it out how to make my concept work.
Philly4458