At sometime or another you may run out of pins on your Arduino board and need to extend it with shift registers. This example is based on the 74HC595. The datasheet refers to the 74HC595 as an "8-bit serial-in, serial or parallel-out shift register with output latches; 3-state." In other words, you can use it to control 8 outputs at a time while only taking up a few pins on your microcontroller.
The 74HC595 IC chip has eight parallel output data pin (pin 15 and pin 1 to 7),one serial input pin(Pin 14) and two control pins-( pin 11(clock pin) and pin 12(latch pin)).
In this project We will use 74HC595 to light up 8 LED one by one.
Step 1 - connect 74HC595 with Arduino
DS (pin 14) to Ardunio DigitalPin 11 (blue wire)
SH_CP (pin 11) to to Ardunio DigitalPin 12 (yellow wire)
ST_CP (pin 12) to Ardunio DigitalPin 8 (green wire)
Step 2 - add 8 LED lights
Step 3 - Download HC595.ino sketch file and load it into Arduino. The eight LEDs will loop lighting one by one.
Project Demo Video: