A simple Larson Scanner based on 74HC595 Shift Register
An Arduino UNO is used to interface the 74HC595 shift register which sequentially lights up the LEDs connected to output pins QA - QH
A user-defined function shiftWrite is used to write to the internal register of shift register sequentially from QA to QH on the rising-edge of clock and then latch it to the output on the falling edge of the clock.