Course: 06. Arduino Foundations

Arduino - What and Why

Select activity Understanding Arduino
🧠 Section 1: What is Arduino and Why Use It?

Imagine if you had a small, friendly brain that could listen to the world around it, make decisions, and control things like lights, sounds, or even motors. That’s exactly what Arduino is — a tiny brain for electronics!

🤖 What is Arduino?

Arduino is an open-source electronics platform that helps you build cool electronic projects. It’s made up of two main parts:

Hardware: A small circuit board called a microcontroller (like Arduino Uno)

Software: A simple program on your computer to write and upload code

You can connect sensors (like temperature or light detectors) and actuators (like motors or lights) to it and write instructions in code to control them.

🌍 Where Do We See Microcontrollers?

Microcontrollers like Arduino are everywhere! You’ve already seen or used them, maybe without even realizing:

Washing machines that decide the water level

Microwaves that beep after the timer ends

Remote-controlled toys

Traffic lights that change based on time or cars

All of these have small computers inside — those are microcontrollers!

🔧 Why Use Arduino?

There are many reasons why Arduino is loved by hobbyists, students, and even professionals:

Easy to Learn: It’s beginner-friendly

Affordable: One board costs less than a meal!

Lots of Examples: Tons of free projects and tutorials

Global Community: People from India, USA, Africa, Europe — everyone uses Arduino

🎒 Real-Life, Everyday Examples

Example	Is it Arduino-powered?	How Arduino Helps
Automatic plant watering system	✅	Senses soil moisture and turns on water pump
Smart dustbin	✅	Detects hand with sensor and opens lid automatically
Temperature-controlled fan	✅	Reads room temperature and adjusts fan speed
Pedestrian crossing button	✅	Reads button press and changes signal timing

💡 Aha! Thought

Did you know? Some students in rural parts of India use Arduino to build automatic irrigation systems for farms — saving water and time! All using simple components and a small microcontroller.

📦 What You’ll Learn Next

Now that you know what Arduino is and where it’s used, let’s look at the board itself! What are all those pins, and how do they help in building real-world projects?

Select activity Buy Arduino
🛒 Note: Which Arduino to Buy and Where to Find It

To get started, you don’t need anything too fancy. The most popular and beginner-friendly board is the Arduino Uno. It’s used in almost every beginner tutorial and works with most sensors and motors you’ll use in early robotics projects.

💰 How Much Does It Cost?

Original Arduino Uno: Around ₹2,000 – ₹2,500 (India) or $25 – $30 (USA)

Compatible or Clone Boards: Around ₹500 – ₹800 (India) or $8 – $12 (Global)

Tip: Clone boards work just like the original but are more affordable. Perfect for learning!

🛍️ Where to Buy

India: Amazon.in, Robu.in, Kits'n'Spares, MakerKart

USA & Worldwide: Amazon.com, SparkFun, Adafruit, Arduino.cc

📦 What Else Might You Need?

USB cable (usually comes with the board)

Breadboard and jumper wires

LEDs, resistors, and basic components (can be bought as a kit)

If you're just starting out, look for a starter kit that includes the Arduino Uno, cables, sensors, and a few basic parts. It saves time and money, and you get everything in one box!

Arduino comes in many shapes and sizes! While the Arduino Uno is the most beginner-friendly board, there are many other versions made for different kinds of projects — from wearable tech to powerful robots.

🧩 Why So Many Models?

Each Arduino model is designed for a specific purpose — some are smaller, some have more memory, and others can connect to the internet or Bluetooth. Let’s take a look at some popular ones:

📊 Comparison Table: Popular Arduino Models

Arduino Model	Main Features	Best For	Size
Arduino Uno	Standard board, 14 digital pins, 6 analog inputs	Beginners, general projects	Medium
Arduino Nano	Compact size, breadboard-friendly, USB-C option	Space-limited projects	Small
Arduino Mega	More pins and memory, 54 digital I/O pins	Large robots, 3D printers	Large
Arduino Leonardo	Acts like a keyboard or mouse, USB built-in	HID projects (e.g., custom keyboards)	Medium
Arduino MKR WiFi 1010	Built-in WiFi and Bluetooth	IoT (Internet of Things) projects	Small-Medium
Lilypad Arduino	Washable, made for sewing into clothes	Wearable electronics	Very Small

📦 Fun Fact!

The Lilypad was one of the first Arduinos designed specifically for wearable technology — you can sew it into jackets or bags and make them glow, beep, or react to movement!

Select activity What to Choose

🎓 What to Choose?

As a beginner, it’s best to start with the Arduino Uno. But as you grow, you’ll love exploring others depending on the project. Bigger robot? Try a Mega. Want to build a smart home device? MKR WiFi 1010 could be your pick!

Arduino Board - Uno

Now that you know what Arduino is, let’s dive deeper and explore what the Arduino board actually looks like. If you’ve never seen one before, don’t worry — by the end of this section, it will feel like a familiar friend!

Select activity Arduino Uno
🖼️ Meet the Arduino Uno

The most popular Arduino board for beginners is called the Arduino Uno. It's like the “first bicycle” of robotics — simple, safe, and powerful enough to get you rolling.

(Insert labeled image of Arduino Uno here)

🔌 Key Parts of the Arduino Board

Each part of the board has a special role to play. Let’s break it down:

USB Port: This is where you plug in your computer. It gives the board power and lets you upload your code.

Power Jack: You can use this to power the Arduino with a battery or adapter when it's not connected to the computer.

Digital Pins (0–13): These can be used to turn devices ON or OFF like LEDs, or read signals from buttons.

Analog Pins (A0–A5): These are used to read values like temperature or light intensity — anything with a range.

GND (Ground) Pins: These are used to complete a circuit, like the “return path” for electricity.

Reset Button: Press this if you want to restart the program on your board.

Microcontroller Chip: This is the brain of the board. It follows your code and makes things happen.

📘 Real-World Analogy

Think of Arduino as your home’s electric control center:

The USB is like the power switch.
The digital pins are like switches that turn on lights or fans.
The analog pins are like dimmer knobs that measure how much light or heat there is.
The microcontroller chip is like your brain deciding when to turn things on or off!

🎒 Quick Comparison Table

Arduino Part	What It Does	Everyday Example
Digital Pin	Reads or sends ON/OFF signals	Turns an LED light ON or OFF
Analog Pin	Reads sensor values (0–1023)	Measures light level in a room
GND	Completes the circuit	Like the neutral wire in your house
Reset Button	Restarts the board	Like rebooting your phone

💡 Aha! Thought

Here’s something fun: If you touch the analog pin while the board is powered on, you might trigger random values — your body acts like a sensor too! How cool is that?

📦 What You’ll Learn Next

Now that you’ve met the Arduino board, it’s time to learn how to bring it to life! In the next section, we’ll look at how to set up Arduino on your computer and run your first program — the famous "Blinking LED."

Arduino IDE and First Code

Before you can bring your robot to life, you need a way to talk to your Arduino board. That’s where the Arduino IDE (Integrated Development Environment) comes in. It’s a free software that helps you write code and send it to the Arduino.

Select activity Installing Arduino IDE
🛠️ Step-by-Step: Installing Arduino IDE

Go to arduino.cc/en/software

Download the version for your computer (Windows, Mac, or Linux)

Install and open the software

Once installed, you’ll see a clean editor window — this is where the magic begins!

🔌 Connecting Your Arduino

Plug your Arduino board into the computer using a USB cable

In the IDE, go to Tools → Board and select Arduino Uno (or your board)

Then go to Tools → Port and choose the correct port (it usually shows “Arduino Uno” next to it)
Select activity First Program
💡 Your First Program: Blink an LED

The classic first program for Arduino is called “Blink” — it turns an LED on and off. Here’s what the code looks like:

void setup() { pinMode(13, OUTPUT); // Set pin 13 as an output } void loop() { digitalWrite(13, HIGH); // Turn LED on delay(1000); // Wait 1 second digitalWrite(13, LOW); // Turn LED off delay(1000); // Wait 1 second }

🚦 What’s Happening Here?

setup() runs once when your Arduino turns on. It prepares the pin.

loop() runs over and over again. It turns the LED on and off every second.

pin 13 is connected to the onboard LED on most Arduino boards.

✅ Try It Out!

Click the checkmark button to verify the code, and then click the right-arrow button to upload it to your board. If everything goes well, the LED on your Arduino should start blinking every second. Congratulations — you just made your Arduino do something!

🎉 Fun Tip

You can change the number in delay(1000) to blink faster or slower. Try delay(200) for fast blinking, or delay(2000) for a slow blink.

Input/Output – Buttons and LEDs

Now that your Arduino is set up, let’s dive into one of the most fun and satisfying parts of learning electronics – making things blink and react!

Select activity Input and Output
💡 What is Input and Output?

Input: Something that sends data to your Arduino (like a button or sensor).

Output: Something that the Arduino controls (like an LED, buzzer, or motor).

When you press a button (input), the Arduino reads that action and can respond by turning on an LED (output). This is the basic idea behind all robots: Sense → Think → Act.
Select activity Programming Language
💬 About Arduino Programming Language

When you write programs (called sketches) for Arduino, you’re using a simplified version of the C/C++ programming language. Arduino’s creators made it easy to use for beginners by hiding the complex setup that traditional C++ usually needs.

Here’s what you need to know:

Language Base: Arduino code is based on C/C++.

Structure: Every Arduino sketch has two main parts:

setup() – runs once when the board is powered on or reset.

loop() – runs again and again, allowing continuous behavior.

Functions like digitalWrite() and delay() are pre-defined by the Arduino library to help you interact with hardware easily.

So while you are technically programming in C++, you won’t need to write complicated code like you would in full C++ applications. Arduino keeps it simple and beginner-friendly!

Why this is important: Learning Arduino gives you a head-start in understanding how real-world electronics and programming work together – and it builds a great foundation if you want to explore full C/C++ programming later.

🧪 Hands-On Example: Blinking an LED

This is often the very first program for anyone using Arduino. It’s like saying “Hello, world!”


int ledPin = 13;

void setup() {
  pinMode(ledPin, OUTPUT);
}

void loop() {
  digitalWrite(ledPin, HIGH);
  delay(1000);
  digitalWrite(ledPin, LOW);
  delay(1000);
}

This code turns the LED on for 1 second and off for 1 second in a loop.

👆 Using a Button as Input

Now let’s add a button so you can control when the LED turns on.


int ledPin = 13;
int buttonPin = 2;
int buttonState = 0;

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT);
}

void loop() {
  buttonState = digitalRead(buttonPin);
  if (buttonState == HIGH) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }
}

This program checks the button’s state. If it’s pressed, the LED turns on. Otherwise, it stays off.

Select activity Real-Life Connections
🔍 Real-Life Connections

TV remotes: Button input → signal output

Elevators: Button input → motor starts

Microwave: Press a button → turntable spins

🛠️ Troubleshooting Tips

Make sure your LED is connected in the right direction (long leg to positive).

Use a 220-ohm resistor with the LED to prevent burning it out.

If the button doesn’t respond, check the wiring and that you’re using a pull-down resistor (or enable INPUT_PULLUP).

With just one input and one output, you've built a basic interactive system. This is the core of every robot you'll ever make!

Button + LED

🚦 Our First Interaction – Button + LED

Now that you’ve seen how to writre a code to blink an LED, let’s make things more interactive! In this section, we’ll build a simple circuit where pressing a button will turn an LED on or off. This introduces how inputs (like buttons) can control outputs (like LEDs).

Select activity You’ll Need
🔧 What You’ll Need:

Arduino UNO (or compatible board)

Breadboard

1 LED (any color)

1 Push Button

1 Resistor (220Ω for LED)

1 Resistor (10kΩ for button pull-down)

Jumper wires
Select activity Step-by-Step Instructions
🧩 Step-by-Step Instructions:

Connect the LED:

Connect the longer leg (anode) of the LED to digital pin 13 via a 220Ω resistor.

Connect the shorter leg (cathode) to the GND rail on the breadboard.

Set up the button:

Place the button on the breadboard across the gap so it straddles the middle.

Connect one leg of the button to 5V on the Arduino.

Connect the opposite leg to digital pin 2 and also to GND via a 10kΩ resistor (this is called a pull-down resistor).

🔌 Circuit Diagram:

💻 Sample Code:

int ledPin = 13;
int buttonPin = 2;
int buttonState = 0;

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT);
}

void loop() {
  buttonState = digitalRead(buttonPin);

  if (buttonState == HIGH) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }
}

Bringing It All Together

🚀 Bringing It All Together – Run, Test, Debug

Now that everything is wired and coded, it’s time to test your first interactive Arduino project!

Select activity Step by Step
✅ Steps to Run:

Open the Arduino IDE on your computer.

Select the correct board: Tools > Board > Arduino UNO.

Select the correct port: Tools > Port (usually something like COM3 or ttyUSB0).

Copy and paste the sample code into the IDE.

Click the Upload button (right arrow icon).

Wait for the message Done uploading in the status bar.

🧪 How to Test:

Press the button on the breadboard.

If the LED lights up while pressing and turns off when released – 🎉 it works!

If not, don’t worry — that’s what debugging is for.

Your set-up will look something similar, do check the PIN's ID and change the code accordingly.
Select activity Debugging Tips
🛠️ Debugging Tips:

Check if the LED is placed correctly — long leg to pin 13, short to GND.

Make sure resistors are connected as shown in the diagram.

Use the Serial Monitor (under Tools) to print out the button state:
void loop() { buttonState = digitalRead(buttonPin); Serial.println(buttonState); // helps see if button is working if (buttonState == HIGH) { digitalWrite(ledPin, HIGH); } else { digitalWrite(ledPin, LOW); } }

Double-check pin numbers in code match your connections.

This is your first hands-on mini project, and it’s okay if you need a few tries. Learning to build, test, and debug is part of becoming a real robotics maker!

Summary and Quiz

Congratulations! You have completed your journey through the basics of Arduino. You now understand what Arduino is, how to set it up, connect components like LEDs and buttons, and write simple programs to make things happen in the real world. These skills form the foundation for building real robots and interactive systems. Let us test your understanding with a quick quiz before we move ahead!

Select activity Quiz

Quiz

Section outline

🧠 Section 1: What is Arduino and Why Use It?

🤖 What is Arduino?

🌍 Where Do We See Microcontrollers?

🔧 Why Use Arduino?

🎒 Real-Life, Everyday Examples

💡 Aha! Thought

📦 What You’ll Learn Next

🛒 Note: Which Arduino to Buy and Where to Find It

💰 How Much Does It Cost?

🛍️ Where to Buy

📦 What Else Might You Need?

🧩 Why So Many Models?

📊 Comparison Table: Popular Arduino Models

📦 Fun Fact!

🎓 What to Choose?

🖼️ Meet the Arduino Uno

🔌 Key Parts of the Arduino Board

📘 Real-World Analogy

🎒 Quick Comparison Table

💡 Aha! Thought

📦 What You’ll Learn Next

🛠️ Step-by-Step: Installing Arduino IDE

🔌 Connecting Your Arduino

💡 Your First Program: Blink an LED

🚦 What’s Happening Here?

✅ Try It Out!

🎉 Fun Tip

💡 What is Input and Output?

💬 About Arduino Programming Language

🧪 Hands-On Example: Blinking an LED

👆 Using a Button as Input

🔍 Real-Life Connections

🛠️ Troubleshooting Tips

🚦 Our First Interaction – Button + LED

🔧 What You’ll Need:

🧩 Step-by-Step Instructions:

🔌 Circuit Diagram:

💻 Sample Code:

🚀 Bringing It All Together – Run, Test, Debug

✅ Steps to Run:

🧪 How to Test:

🛠️ Debugging Tips: