The first program we will be writing to get started with Arduino will be Blink LED. The Blink LED program is a physically computed program similar to a common beginner program known as 'Hello World!'.
An LED is an electronic component and stands for Light Emitting Diode. It is a small light which has a very low power consumption. The Arduino has one built in LED which is internally connected to digital pin 13.
First, we are going to declare a global variable name to digital pin 13. This is so we can use an alias name instead of 'pin 13' throughout our code. We need to also define the data type for this variable which will be an Integer. An integer can be read and write or just read-only. For this variable, we would like it to be read-only, and this would be called and constant integer.