Some good readings about hardware startups and starting a hardware business:
“It’s a simple question: Why are you starting a company?
It’s hard to answer. Either because you don’t know or you are embarrassed about how simple the reason is.
The good news is you can get away without have a clear why for a very long time. Most people will never ask you, instead they will focus on what you have built.
The bad news is down the road then the deck is stacked against you, when you are exhausted from the journey, and when you are wavering between a crappy and a really crappy decision, not having a clear why make you a leader without a compass.”