I'm using a duemilanove to control 4 relays. I've a typical relay board.. All 5v relays 2n3904 transistors
I basically used the design on this page except I'm using smaller resistors, like 200ohm I think. My relays require less current as well and are NC. www.glacialwanderer.com/hobbyrobotics/?p=9
I've also got it connected to a ethernet shield on my home network. The problem is that it seems like after I switch 2 or more relays the whole thing crashes. By that I mean the arduino completely resets, I gotta wait for the ethernet shield to reinitialize before it'll accept communication, etc.
I'm powering the unit with a 12vdc 1a source. It doesn't just crash on my code either. I ran standard firmata and after the 2nd relay was triggered it became unstable.... Sometimes it never crashes, sometimes immediate, sometimes a few minutes. Always after I've triggered at least 2 relays though. It's indiscriminate of which relay I'm triggering.
Any ideas what might be causing this? I can post more details on circuit if needed and/or the schematic.