I want to make a [Real Time Walky Talkie for Riding] using a SmartPhone so I can talk with people behind me that I pillion. And this is all the part:
The problem is, if I have all of it on my hand and assemble it, how can I make the SmartPhone deliver my voice (or at least echo it for both at the same time, and there is no sender or receiver) to the other side of earphone's passenger? Any software engineer here? Or electrician? I need their perspective on this project.