Ask HN: How to scale up a hardware project for commercial application?

I made a functioning prototype of a Raspberry Pi project that I think has applications in a retail environment. I intend to demo this project for local stores in the coming weeks. As I do, I want to start thinking about the design of the product, the layout of its wiring, the construction of the housing, which consists of metal, glass, and plastic elements. I also want to start thinking about how to manufacture a completed design. What steps does one take, who does you hire, what resources do you take advantage of, in the process of turning a prototype into a product? Right now, the people involved are myself, with a smattering of knowledge on the hardware and software sides, and a software engineer, who has little knowledge of the hardware side. Who do you hire to consider the design challenges, and where do you find them?