LED Table Connection issues (I2C)

Using Arduino Interfacing w/ Software on the Computer
1

Heho!

Recently I finished my LED-Table Project (the hardware stuff at least) and it looks pretty nice to me.
I'm using a selfmade RGB Matrix with an rainbowduino.
I've downloaded the neorainbowduino firmware, which means that I use my Arduino(Diavolino in my case) to send I2C Signals to the rainbowduino to control the leds.
It works fine, but at some random point (10 secs, to 5 mins) the connection is disrupted and the animation on the table stands still. In Processing(controlling the animation) appears a lot of "Serial Device not responding (32ms)"...
The only way to get it back to work is restarting the processing sketch.

Now my question is: Is this a problem of my I2C connection (cable too long,...) or rather something with the arduino or processing coding?
(note that I patched the wire library to run at 400k Hz and a bufferlength of 98, as said in the neorainbowduino firmware)

Thank you so far,
greenfly

2

Now my question is: Is this a problem of my I2C connection (cable too long,...) or rather something with the arduino or processing coding?

This is hard to say as you haven't said how long your I2C run is, how it is wired, (mesh or chain) what pullups you have and where they are nor have you posted any code.

3

Hm... this is a little tricky, cause I would not like to post the entire library/firmware here, but I will look for the important parts.
The actual cable measures 2.5m (0.75mm^2 diameter), not using any pullups, but maybe they are already in the rainbowduino pcb as it has dedicated I2C inputs... (I'll look that up too).