I know it was a long time ago, but that is how Edison got most of the patents attributed to him. He came up with an idea and had his lab techs do the hands on. Then he took creditI dont think you owe him anything, all he did was have an idea. You did all the work in design & construction. Having an idea is easy, puting it into practice is the hard part.
No, you don't need to do that if you weren't paid for your service (if so, questions of who 'owned' the work would come into play if he got a lawyer). Depends on how well you know him. I'd cut a friend in for a bit of the profits only out of being a nice guy.No, he didn't pay me anything. What's to make him sign the paper though? Or were you suggesting I pay him to sign it?