Ethernet sharing on arduinos?

Hi. I am an arduino noob/virgin… go easy lols

I am looking to expand on the artnet - dmx nodes that can be built where it is recommended to use 1 arduino per dmx output for the best resolution.

In the end i´d like to create a finnished “product” mounted in a box with 2, 3 or 4 dmx universe outputs.

What I´m trying to work out is at what stage the processing is done on the arduino. They say that using just one arduino with 4 universes will cause it to crash, I think it was an overflow issue…
ANYWAY…

To prevent a spaghetti of cabling and having to hide a network switch inside the box (and power it) as well, is there a way to share one network sheild with say 3 arduinos so that they all read from the same sheild but each arduino will convert just its dmx universe?

Or will it just need one sheild per arduino?

What do you mean by dmx google thinks its a rapper!.

Mark

DMX 512 is a serial signal used in professional lighting..

basically the idea is arduino takes an ethernet signal, and spits out a data signal I want for lighting (on another shield)

I don't know what Artnet is or what a DMX universe is, but it sounds as if you have reached the limits of what can be done on one Arduino. I suggest you need to be clear which Arduino this is based on and what resource is the limiting factor on that Arduino. There are alternative Arduinos and clones with more I/O pins and more memory, and also more processing power - it may be possible to avoid the complexity and cost of multiple Arduinos if you can fit everything onto one.

Agreed, I´d love to fit everything onto one and Just have a nice small package with less interconnections (that can go wrong during a concert etc).

IF I take the lazy option and just copy someone else´s project, I am restricted to the uno (for one output) or the mega for more
BUT as you implement more outputs you reduce the frame rate of each output.. clearly the arduino is just stretched "too thin" over so much work.

http://www.deskontrol.net/blog/arduino-based-dmx-artnet-node/

Basically I am trying to work out if I can build, say a mega with ethernet shield and dmx output shield..
then take "whatever it offeres" from the ethernet shield and pass it to another arduino (uno for example) with just the dmx shield..

Am I just asking too much from the system or is this something that can be done?

I don't think it would be practical to share the Ethernet connection - you'd need to have one Arduino accessing the Ethernet and relaying messages to the other ones. However, you'd need to consider the workload imposed by that extra communication on each of your Arduinos - you might avoid one problem only to cause another. Can you find out a bit more detail about what's limiting the scalability of the current solution? If it's purely processing speed, it may be possible to optimise the code or adopt a faster processor.

To be honest I havnt gotten into any of the REAL details as yet as i´m still bouncing about the many possible ways of doing this..
eg.
-create lots of individual units,
-one large case with individual units plus a network switch and power distro.
-use one as 2 universes with reduced framerate but be careful to use it in a specific situation where that is not an issue...

thats why I wondered about this idea, I didnt know if it were a viable option to even start investigating or not. From the sounds of it no.

I have orded a selection of arduinos and ethernet shields so I can start playing around...
I dont intend on using that exact project I linked, as for starters not having opto-isolation on dmx outputs is just NOT an option when doing concerts with generators etc etc its really not uncommon for a light to have a fault and send mains down what is a 5v signal wire...

Thanks for all your help!