In this tutorial i am going to teach you how to increase(add) digital IO (Input-Output) Pins of Arduino uno. Their are normally 14 (0-13) Digital Pins on Arduino 6 (0-5) Analog pins on Arduino uno. Some times your application needs more digital pins than available on the Arduino board. For example you want to connect an lcd and a 44 keypad with arduino you want to use lcd in 8-bit Mode. Now 14 pins are not enough to connect both the lcd and keypad with arduino. You need some extra pins to carry out the task.