Step 8: Laser Driver Board
The drawings below are a little different than what I have wired but should work. You could also put this all on one board, this was the biggest board I had on hand.
The Laser driver board takes 9V from a wall wart power supply to drive the relay and the LD33V 3.3V Voltage Regulator that powers the laser. The TIP120 transistor switches the relay which switches the ground of the laser to turn it on or off.