PJDL is a communication protocol I work on since 2010 that uses a single wire to connect up to 255 devices and can even operate using the human body as a conductor, here is the video of its operation: <a href="https://www.youtube.com/watch?v=GWlhKD5lz5w" rel="nofollow">https://www.youtube.com/watch?v=GWlhKD5lz5w</a>