stan2004 posted:
While brainstorming is useful, I think the sky's-the-limit, kitchen-sink approach can bog down. So while I am a proponent of clearly identifying the what before choosing the how, if the what is so open-ended as to be ill-defined then maybe the hammer-nail approach deserves a look.
Agreed.
Not only the "what" but also the "who."
If you are serious about making this a product, exactly who is the market? A person who understands fiddling with Arduino hardware and sketches is going to build his own because it is so easy. If it is intended to be a product for most model railroaders any necessary "fiddling" is going to be an issue.
Based on long experience in industrial control systems I suspect you will find the programming the easy part, the nuts and bolts of the I/O and the documentation will be the big choke point.