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[on:]

Hello, i'm new in the community, i search information about creating a kind of network with more arduino. I use "arduino Mega2560" for the master (or the server?) and arduino uno for the slaves.
I think about ethernet, with ethernet shield, but it's expensive because i have to use one shield for each arduino and a ethernet switch
I need a full duplex connection, for send information from the master to the slaves and receive status and other information.
The rs495 is good, but isn't full duplex.

Excuse for my english if there are some errors, but i'm italian.

Bye, Marco

[Reply #1 on:]

Hi Marco,

a cheaper solution with reasonable performance is to use I2C :

- http://arduino.cc/en/Tutorial/MasterWriter + http://arduino.cc/en/Tutorial/MasterReader -

you can extend it to 126(?) devices.

[Reply #2 on:]

Hello, i'm new in the community, i search information about creating a kind of network with more arduino. I use "arduino Mega2560" for the master (or the server?) and arduino uno for the slaves.
I think about ethernet, with ethernet shield, but it's expensive because i have to use one shield for each arduino and a ethernet switch
I need a full duplex connection, for send information from the master to the slaves and receive status and other information.
The rs495 is good, but isn't full duplex.

Excuse for my english if there are some errors, but i'm italian.

Bye, Marco

The million dollar question is how far apart are the devices?

[Reply #3 on:]

Excuse for my english if there are some errors, but i'm italian.

So is one of my Arduino boards, but it's not nearly as polite and understandable as you are. 

Lefty

[Reply #4 on:]

The rs495 is good, but isn't full duplex.

It can be full- or half-duplex, it's just a matter of how you do it.

How many slaves? How far apart?

______
Rob

[Reply #5 on:]

Hello.
I answer at all yours questions:

The max distance between the boards is 5 meters, but it have to work at longer distance, like 10 / 20 m
Number of boards is not up to 10.

I can't use I2C because the cables are near motors (for the noise (electrical noise)).

Can i use ethernet connection for more arduino, without any PC?

Thanks, Marco

[Reply #6 on:]

Can i use ethernet connection for more arduino, without any PC?

I think so, but I thought you wanted full-duplex.

RS-485 will do full- or half-duplex and cost a lot less.

______
Rob

[Reply #7 on:]

maybe i use rs485... connecting the control pin of the MAX485 to an output of arduino, i can control the direction of messages (TX or RX).. Is it right?

Maybe is the better choice...

Thanks, Marco

Ps: now i do some experiments...

[Reply #8 on:]

NRF24L01+ 2.4GHz 2Mbs modules can be bought in a low power version from China for around £1.30 each. The high power versions, with external antenna, cost about £7.50 each.

Used with the NRF24 and NRF24 Network libraries from maniacbug they may be suitable for your requirements.

The low power ones are certainly cheap enough to buy a few to try out.

[Reply #9 on:]

maybe i use rs485... connecting the control pin of the MAX485 to an output of arduino, i can control the direction of messages (TX or RX).. Is it right?

Maybe is the better choice...

Thanks, Marco

Ps: now i do some experiments...

If you use but one twisted pair then only half-duplex is possible and a need to switch converter chips from send to receive mode is required in your software. However if you run two twisted pairs then true full-duplex is possible and the converter chips are 'hardwired' to send and receive modes.

Lefty