This works but because the MOSFET is only on 1/8th of the time, the LEDs are too dim for my liking.  Turning the LED PSU up from 5V to 9V helps, but I worry that if the MOSFET ever stop pulsing, then I'd burn those LEDs.  Resistors are 100 ohm. Shift registers are 74HC595, MOSFET is p-channel (FQP27P06).  There must be a better way... Current limiting circuit for safety? How?