In this tutorial, we'll cover the basics of Arduino programming, focusing on variable types , functions , function return types , and constant declarations . We will use simple examples to demonstrate how each concept works. 1. Variables in Arduino Variables are used to store data that your Arduino program can use. There are different types of variables based on the data they store. Common variable types: int : Stores integer values (whole numbers). float : Stores decimal numbers. char : Stores a single character. boolean : Stores true or false . String : Stores a sequence of characters (text). Example: int ledPin = 13 ; // Integer variable to store LED pin number float sensorValue = 0.0 ; // Float variable to store sensor value char myChar = 'A' ; // Char variable to store a character boolean isOn = true ; // Boolean variable to store true/false String myText = "Hello" ; // String variable to store a string 2. Constants Constants a