#Summarized

Introduction to Arduino Programming using Arduino IDE

Introduction to Arduino

• Arduino is an open source microcontroller platform used for sensing digital/analog inputs and controlling digital outputs
• Being open source means the hardware design is freely available to the public to use and modify without restrictions
• No patent or copyright violations when modifying the Arduino for personal projects

Arduino UNO Hardware Overview

Pin Layout

Board Layout

Key Interfaces

• 14 digital I/O pins: numbered 1-13
• 6 analog input pins: labeled A0-A5
• 6 PWM pins: marked with the ~ symbol
• Communication protocols: USART (Tx/Rx pins), I2C, SPI

Pin Details

Arduino IDE Basics

Overview

• Arduino IDE is the software used to program the Arduino UNO
• Uses the Arduino programming language (a variant of C++)
• Programs written for Arduino are called "sketches"
• Download link: https://www.arduino.cc/en/main/software

Setup Process

1. Connect Arduino UNO to computer and note the COM port number
2. Open Arduino IDE
3. Select Tools > Board > Arduino/Genuino UNO
4. Select Tools > Port and choose the correct COM port

IDE Interface

Programming Workflow

1. Write your sketch in the Arduino IDE
2. Click the Verify button to check for errors
3. Click the Upload button to compile and transfer your sketch to the Arduino UNO

Arduino Sketch Layout/Structure

Basic Structure

Arduino programs (known as "sketches") follow a specific structure:

#include <header file>
 
// Global variable declaration
type variable = value;
 
void setup() {
    command;
    command;
    // ...
}
 
void loop() {
    command;
    command;
    // ...
}

Core Components

Arduino sketches are executed line-by-line from top to bottom and consist of four main parts:

1. Header Files
   • External library files that provide additional functionality
   • Included at the beginning using the #include directive
   • Example: #include <Servo.h> for servo motor control
2. Global Variables
   • Variables declared outside of any function
   • Accessible throughout the entire sketch
   • Used to store data that needs to persist across function calls
3. setup() Function
   • Runs exactly once when the Arduino powers on
   • Used for initialization tasks:
     • Setting pin modes (input/output)
     • Initializing serial communication
     • Setting initial states
   • The bootloader specifically looks for this function at startup
4. loop() Function
   • Contains the main program code
   • Executes repeatedly until power is disconnected
   • Core of most Arduino applications
   • The bootloader jumps to this function after setup() completes

Example: LED Blink

// This sketch blinks an LED connected to pin 2
 
// Global variable declaration
int pin = 2;  // LED connected to digital pin 2
 
void setup() { 
    pinMode(pin, OUTPUT);    // Set pin as an output
    digitalWrite(pin, LOW);  // Ensure LED starts in OFF state
}
 
void loop() {
    digitalWrite(pin, HIGH);  // Turn LED ON (HIGH = 1 = 5V)
    delay(1000);             // Wait for 1 second (1000 milliseconds)
    digitalWrite(pin, LOW);   // Turn LED OFF (LOW = 0 = 0V)
    delay(1000);             // Wait for 1 second
}

How It Works

1. A global variable pin is declared and set to 2, specifying which pin controls the LED
2. In setup():
   • pinMode(pin, OUTPUT) configures pin 2 as an output
   • digitalWrite(pin, LOW) ensures the LED starts in the OFF state
3. In loop():
   • The LED alternates between ON and OFF states with 1-second intervals
   • digitalWrite(pin, HIGH) sets pin 2 to 5V (ON)
   • digitalWrite(pin, LOW) sets pin 2 to 0V (OFF)
   • delay(1000) pauses execution for 1000 milliseconds (1 second)

Basic Arduino Programming Commands

Working with Variables

Declaration

Variables must be declared before use:

datatype variable_name;

Example:

int pin;  // Declares an integer variable named 'pin'

Variable Names

• Can contain letters, numbers, underscores, dollar signs
• Must start with a letter
• Are case-sensitive
• No length limit

Data Types

Data types define value ranges and memory usage:

Variable Scope

• Global variables: Declared outside any function, accessible everywhere
• Local variables: Declared inside a function, accessible only within that function

Math Operations

Standard Operators

• + (addition)
• - (subtraction)
• * (multiplication)
• / (division)
• % (modulo/remainder)

Compound Operators

Shorthand for math assignments:

count += 1;  // Same as: count = count + 1;
x -= 5;      // Same as: x = x - 5;
y *= 2;      // Same as: y = y * 2;
z /= 4;      // Same as: z = z / 4;

Advanced Math Functions

Serial Monitor

A terminal window in Arduino IDE for:

• Sending messages from Arduino to computer
• Receiving messages from computer to Arduino

Key Commands

Serial.begin(9600);          // Initialize at 9600 baud rate
Serial.print("Message");     // Print text
Serial.println("Message");   // Print text with newline
Serial.print(variable);      // Print variable value
Serial.println(variable);    // Print variable value with newline

Example output:

Time Delays

Commands

delay(ms);              // Pause for milliseconds
delayMicroseconds(us);  // Pause for microseconds

Example:

delay(1000);              // Wait 1 second
delayMicroseconds(1000);  // Wait 1000 microseconds (1 ms)

Comparison Conditions

Numeric Comparisons

Return TRUE or FALSE:

Compound Conditions

Combine multiple conditions:

• && (AND): Both must be true
• || (OR): At least one must be true
  Examples:

(x == 1) && (y > 5)    // TRUE if x is 1 AND y is greater than 5
(x >= -10) || (y != 0)  // TRUE if x is >= -10 OR y is not 0

Boolean Conditions

• Non-zero values = TRUE
• Zero value = FALSE

Conditional Statements

if Statement

if (condition) {
    // Code executed if condition is TRUE
}

if-else Statement

if (condition) {
    // Code executed if condition is TRUE
} else {
    // Code executed if condition is FALSE
}

if-else if-else Statement

if (condition1) {
    // Code executed if condition1 is TRUE
} else if (condition2) {
    // Code executed if condition2 is TRUE
} else if (condition3) {
    // Code executed if condition3 is TRUE
} else {
    // Code executed if no conditions are TRUE
}

Loops

while Loop

Repeats until condition is FALSE:

while (condition) {
    // Code to repeat
}

do-while Loop

Executes at least once, then repeats until condition is FALSE:

do {
    // Code to repeat
} while (condition);

for Loop

For counted iterations:

for (initialization; condition; update) {
    // Code to repeat
}

Example:

for (int i = 0; i < 10; i++) {
    // Repeats 10 times with i from 0 to 9
}

Custom Functions

Definition

returnType functionName(paramType paramName) {
    // Function code
    return value;  // Return a value of returnType
}

When to Use

• For repeated code blocks
• To organize code logically
• To create reusable components

Example

int calculateArea(int width, int height) {
    int area = width * height;
    return area;
}

Usage:

int roomArea = calculateArea(10, 20);  // Returns 200