GPIO Current Output

I want to control transistors with the GPIO ports. I’m planning on using a shift register to control them (I need to control 8), and I’m going to supply power to the shift register from a separate source than the beagleboard, would the current output of the GPIO pins be enough to use as the data input for the shift register?

Also, having a separate power source powering the shift registers and the beagleboard controlling them wouldn’t be a problem, right?

You can copy the schematic of the board, where it drives the LEDs on the board. It uses transistors.

As to the last question: