I can't just add the other Vin wire to the same 3V arduino pin, can I ? and the ground to the same ground? That would mean having the Vin and ground of each in parallel I guess. My arduino gets power from my computer, but will it be able to keep the 3V even when the circuit is now pulling twice as much power? What are my options?
and can't find documentation as to whether the groups of 3 pins that come off the midline of the shield are isolated or not. I assume so since there seems to be no other designation.