How to make your gadget?

Question

Iron

Hello everyone. Now wearable gadgets are developing very well, and I want to make my own, or rather combine several into one set so that they complement each other. And here are a couple of questions:

• Will I have the right to buy their gadgets from manufacturers, connect them at home and sell them as something of my own?
  
• Who can help me in connecting gadgets into one whole? Some kind of engineer? I hope I don't need a whole plant
  
• If this is some kind of engineer, then how to get around that option so that when I told the idea to the engineer, he would not refuse me, but he would go and implement my idea?
  

Answer 1

• Will I have the right to buy their gadgets from manufacturers, connect them at home and sell them as something of my own?

Will.
Blue tape.
You need to bribe him or intimidate him, or better, both.