Using cable's shield as ground for Wire library

Using Arduino General Electronics
1

Hello,

I have 2x0.14mm shielded copper cable and I need several UNO boards to communicate together. I got several questions about it, that I hope some electronics pros could help me with.

First of all, is the cable suitable for communications based on Wire library?

Can I use cable's shield as ground, since Wire library requires 2 pins + ground?

If my setup wouldn't work, do you know any ways to communicate over 2 pins instead of 2 + GND?

I hope I've stated my questions correctly.
Thanks in advance, guys.

2

Yes. How long of a distance do you plan? I2C (Wire) is only intended for short distances.
Yes.
RS485 is better for long distances, altho it needs a Gnd wire also.

More here on Unbalanced vs Balanced signals.

MAXIM AN763 Guidelines for RS485 wiring.pdf (247 KB)

3

And an article for not having a common ground with RS485, more applicable to very long distances I think.

and a forum discussion as well rs485 - is shared ground required? - General Electronics - Arduino Forum

4

CrossRoads:
And an article for not having a common ground with RS485, more applicable to very long distances I think.
http://www.planetanalog.com/author.asp?section_id=483&doc_id=562062

and a forum discussion as well rs485 - is shared ground required? - General Electronics - Arduino Forum

Well, that's the first time I heard "don't connect all the grounds"... :o

5

CrossRoads:
Yes. How long of a distance do you plan? I2C (Wire) is only intended for short distances.
Yes.
RS485 is better for long distances, altho it needs a Gnd wire also.

No it doesn't. It is permissable to have a ground wire, but the standard is simply differential twisted pair.

6

CrossRoads:
Yes. How long of a distance do you plan? I2C (Wire) is only intended for short distances.
Yes.
RS485 is better for long distances, altho it needs a Gnd wire also.

More here on Unbalanced vs Balanced signals.
Google

Thanks, that was helpful. The distance isn't that long (up to 15 meters). I'd like to take your advice and use RS485, but it would require additional parts and it's quite to get them in my town. I guess, I'll stick on Wire, unless I'd manage to get some RS485 modules.