I see myself in this position al of the time with my ideas. My main suggestion is to do as much research you can and really pinpoint what you don't know exactly. Once you have this, you can look up the appropriate articles, books, even Wikipedia to get a decent sense of what you need. You can also ask industry professionals and not risk too much disclosure since you have a specific question.
You created a new bathroom fan that automatically turns on when the humidity of the apartment is significantly lower than the bathroom. You wouldn't need too many details (besides aesthetics, general function, etc.) but a few questions you would Google include:
-What sensor measures humidity? hygrometer
-How to combine different electronic systems?
-How would i calculate humidity displacement?
Olugbenga "Tumi" Oredein Jr.
O-Zone Product Development