Sometimes I'll get a feeler e-mail about someone who wants to work with me, and they start off right away by saying "if you're interested, let me know and I'll get an NDA out to you right away."
I don't mind working under an NDA (under certain conditions), but some things about being hit up by it right away like that scare me:
- Once I sign this NDA, if I subsequently complete or publish a project which is remotely similar to this person's idea, there is a legal document which could cause grief for me. This is why music labels and publishing houses have rules about unsolicited material.
- If the person e-mailing me is doing so as the classic "garage inventor", the assumption of an NDA feels to me like an assumption of asymmetry of relationship- they value their idea more heavily than my ability to make that idea a reality, and that spells trouble. The fact is, ideas AND engineering chops are both a dime a dozen. What's TRULY rare is the wherewithal to bring an idea to fruition in the right place at the right time.
- I believe in open source hardware and software. An NDA is pretty much an acknowledgment from the get-go that this project will never see the light of day, EVEN IF there is no "secret sauce" in the project. If it's good enough to steal, it'll get stolen whether I post details on the net or not.
Don Lancaster has a lot to say about patents (and being an engineer in general- if you're not familiar with his work it certainly a little browsing of his copious online archives certainly won't harm you any) so I'll not do more than touch on it. In short, all a patent does is give you license to sue someone if they rip off your project. If your project is good enough for a Chinese manufacturer to decide to rip it off, they'll make enough money to brush off your lawsuit. If not, you have nothing to fear because nobody will waste their time with your fiddling small change. The key is not to get overly self important about the matter- it's easy to waste a lot of time and money on patenting something.
Finally, how I actually view projects that make it through the filter to be considered:
Broadly, I divide commission projects into two groups- one-offs and product development. A one-off is something like that bathroom hassler that I posted a couple of weeks ago- probably something REALLY fun, where the client is not concerned with bringing something to production, the overall effort is like to be pretty small, etc. Those I usually negotiate terms on a by-project basis- I ask that they buy extra parts so I can keep some goodies at the end (I make them fully aware of the fact that some of the hardware is part of my payment), or get a little in-kind service (I've done projects for food, laser cutting, and soon, golf driving range access).
Product development is a bit different. For that I'm more likely to look for hourly rate plus development costs. Part of the reason for that is because the process is more in depth and difficult- a one-off is basically a jumped-up hobbyist project, whereas product development requires some real knowledge beyond just slapping something together. Another part is that, if things go well, they stand to benefit a lot from my work and so a steeper up-front cost is reasonable- it's an expense of doing business.
You'll find that a lot of people that come looking for help developing a product have no interest or ability to pay for it- but that's okay, because it's my day job to do that sort of stuff and the one-offs are more entertaining and enjoyable anyway.