Well, it depends on what exactly your design entails. Some hardware devices can be prototyped on pre-built development boards/platforms typically made available

Well, it depends on what exactly your design entails. Some hardware devices can be prototyped on pre-built development boards/platforms typically made available by the core chip manufacturer. If you need to build a demo to raise money, this is most realistic option if it at all works for you. In case the "device" is such that it cannot be demoed without custom hardware, then you have no choice but to contract design and prototyping partners - there are a number of those. Again, depending on the quantity you may hope to sell one day, it might be best to contact a sales/business development representative of the company that produces your core chip (the central processor/SoC, etc - typically the component thats going to cost the most on your BOM). Such manufacturer can usually put you in touch with a "recommended" design partner who can spec your hardware, design it, produce prototypes of it, and even help you with software development. Such a partner is very useful as frequently (though not always) hardware prototypes take more than one "re spins" to get everything right. (edit: also, the design partner usually can get you a lot better rates for the chips on your BOM via their contacts. ) I used to work for such a company (not in the US, though most of our clients were based in the US) and led dozens of such concept-to-prototype-to-production projects. I am well versed with the process. I might be able to give you better help if you ask more specific questions.