I am building a task lamp for my product design class at Otis College of Art and Design, and I need to power an LED at 6.5volts, and a usb output plug at 5volts. is it possible to power these from one arduino? if so, what board would work best?
Sure - Connect a 7.2V supply to the barrel jack and bring 6.5V from the Vin pin on the power header to the LED and use an Arduino (Uno) output to control a transistor to connect the 'negative' lead of the LED to Gnd. (Or 7.5V if you can live with 6.8V and adjust your current limit resistor)
http://www.dipmicro.com/store/DCA-07510
If the USB is only providing +5 & gnd, connect those to the power header pins.