Single wire communication

Thread Starter


Joined Jun 9, 2019
Hi All,

Is it possible for two arduinos to communicate over a single copper line(with no common ground) like a simplex telegraph or something.

John P

Joined Oct 14, 2008
For half-duplex operation, pull the wire. For full duplex, pull it from one end and twist it from the other. Is that a brilliant idea, or what?


Joined Jan 17, 2007
If you were to mount both arduinos on a common metallic chasis, then you could use said structure as your ground reference/return.

John P

Joined Oct 14, 2008
Roman Black, who used to be an active member here, presented a scheme that he called Blacknet. If you take the option he called "ghost power", you'd have a multi-processor bus that uses a power/data line that normally sits at 12V, but gets pulled low to send a zero by any unit that's transmitting. Which obviously only one unit at a time can do! Each processor has a diode-capacitor-regulator setup to provide its power, so it clearly can't carry high-density data; the line needs to spend most of its time high in order to charge the power supply capacitors at the remote stations. The description of Blacknet is still on line: