Arduino how to get more Power
ShiftBrites actually prefer to run on 5.5V to 9V. Most reliable results seem to be with 6 to 7 volts. Regulation is not too crucial, but switching power supplies work well and are smaller and lighter than transformer based supplies. Each ShiftBrite can draw up to 60mA, so multiply that by the number of ShiftBrites you have to determine the current rating of the power supply.

You definitely need to connect the grounds of all your supplies together. Just make sure the ShiftBrite V+ positive supply is not connected to the Arduino 5V supply if you are using different voltages! Actually, if you choose something like 7V you can power the ShiftBrite chain, and connect the same power to the Arduino VIN. The Arduino will regulate the power for itself.

This simple wiring is all done for you on the ShiftBrite Shield, you attach external power to the screw terminal and plug the ShiftBrite chain into the six pin connector: http://macetech.com/store/index.php?main_page=product_info&amp;cPath=4&amp;products_id=7