I actually have an 8 channel relay boardhttp://www.amazon.com/dp/B006J4G45G/ref=pe_175190_21431760_M3T1_ST1_dp_1
but this picture illustrates what I am looking at doing. I am another person that doesn't know enough about this environment to even know where to look for answers. I hope that you can help.
I read that this board allowed for electrical isolation from the Arduino board only if it has its own 5V power source. Also, since many cables come in 8 wire configurations, I thought that I could move the VCC (5V) and the ground lines to an external power source.
My thinking was to break open a wall wart and connect it to a 3 pronged plug, which includes a ground. I'm not completely sure about wiring here because the relay board requires a VCC and a ground wire and the wall wart typically has just the 2 AC plugs.
I also thought that I would use a USB cable or a phone type jack and cable but I don't know if they would carry enough current to do the switching. perhaps some other cable would be better.
Can anyone please help me with this?