Your first step should be finding someone with experience in hardware and getting their insight into the feasibility of your product. That person will need to give you a sense for how unique your product is compared to what already exists, if it can be made with current manufacturing processes or needs something custom, and how much it would cost you to develop a prototype and a final version ready for market. You may find that you can use existing processes or technology to create something simple on the cheap. Or, it might be really complicated and expensive, which means you may want to look elsewhere for product ideas since the path to market with hardware is typically quite a bit more expensive than with services or software. You really want to know what you are getting yourself into with your specific product before you spend money on developing a prototype.

I'd also suggest researching similar products (or products that have a foundation in similar hardware technology but are in different form) to see how much you can reverse engineer when thinking through how your product will be made. Look at their costs, price points, and demand, and see how they compare to what you want to build.

Best of luck!

Cheers,
Chris Justice