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Topic: communication between arduinos (Read 944 times) previous topic - next topic

ljarrald

hi, i have a project where i will have one main arduino (probably an arduino mega) and then about 2-4 slave arduinos (these can be any type as i have not bought them yet. it could even be a picaxe chip!) they need to communicate between each other (master to slave, slave to master) but i can only use two wires for communication.
i have never really properly programmed an arduino before, nor have i used serial coms before so any help would be greatly appreciated!
should i convert th 'rx' and 'tx' from each chip to another protocol like rs-485?

please help!

- luke

pieturp

What's the length of the cables? If, say, a meter or so, you definitely want or need something like RS-232. Or maybe RS-485 if it's even further. If it's less, you could stay on TTL levels.

For RS-485 you need three wires; A, B and Ground, also named Hot, Cold and Ground.

Are you absolutely sure you only have "two wires" for communication? I don't know your setup and/or goals with your project. No information about cable lengths and your specific application needs, makes things a bit difficult to, eh, predict?

graynomad

We need to know the distances and speeds involved.

In general I would suggest RS-485, unless you really mean 2 wires ie 1 signal and 1 GND, in which case I might suggest LIN or just an open-collector home-brew system.

More info please.

______
Rob


Rob Gray aka the GRAYnomad www.robgray.com

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