mcreefer:
Also in the bildr guide connects the source to the gnd pin on the arduino. Could I ground to something else? I would think that grounding them all to the arduino gnd would be a bad idea.
The current limitations on the I/O pins are because of their direct connection to the microprocessor IC chip. The GND pins on stock Arduinos don't have this concern because while the ground loop is connected to the microprocessor IC, it's also connected to the ground of the power supply (which the current should be flowing to, not the IC). Technically there is a maximum current limit for a female header pin, but it's rather unlikely you'd exceed it with many Arduino projects. 