Day 40 – Night Session: IoT – Arduino Basics & Use Cases – ECET 2026

In ECET 2026, IoT (Internet of Things) is an emerging topic. Understanding Arduino basics is very useful because Arduino boards are widely used in IoT prototypes, projects, and smart systems.

📘 Concept Notes

🌐 What is Arduino?

• Arduino is an open-source microcontroller platform used to build electronics projects.
• It consists of:
  • Arduino Board (e.g., Arduino Uno): Hardware with microcontroller (ATmega328P).
  • Arduino IDE: Software used to write and upload code.
• Commonly used for IoT, robotics, automation, and prototyping.

⚙️ Key Features of Arduino

1. Open-source hardware & software – widely available.
2. Simple coding environment (C/C++ based).
3. Multiple I/O pins (digital & analog).
4. Supports sensors & actuators (temperature sensor, servo motors, etc.).
5. USB programmable – easy for beginners.

📐 Arduino Pin Details

• Digital Pins: 0–13 (input/output).
• Analog Pins: A0–A5 (analog input).
• PWM Pins: Digital pins with “~” symbol (e.g., 3, 5, 6, 9, 10, 11).
• Power Pins: 3.3V, 5V, GND.

🔋 Basic Formula – Voltage Divider (used with sensors)

If:

• Input Voltage =
• Resistors = ,

Then output voltage across :

👉 This formula is used when connecting sensors (like LDR) to Arduino analog pins.

🛠 Example Arduino Code – LED Blink

int led = 13;  
void setup() {  
  pinMode(led, OUTPUT);  
}  
void loop() {  
  digitalWrite(led, HIGH); // LED ON  
  delay(1000);  
  digitalWrite(led, LOW);  // LED OFF  
  delay(1000);  
}

int led = 13;  
void setup() {  
  pinMode(led, OUTPUT);  
}  
void loop() {  
  digitalWrite(led, HIGH); // LED ON  
  delay(1000);  
  digitalWrite(led, LOW);  // LED OFF  
  delay(1000);  
}

📊 Real-World IoT Use Cases of Arduino

1. Smart Home Automation – controlling lights/fans via mobile apps.
2. IoT Weather Station – sensors for temperature, humidity, rainfall.
3. Smart Agriculture – soil moisture detection and automatic irrigation.
4. Wearables & Health Monitoring – pulse sensors, fitness trackers.
5. Smart Cities – street light automation, parking systems.

🔟 10 Expected MCQs – ECET 2026

Q1. Arduino Uno is based on which microcontroller?
A) PIC16F877A
B) ATmega328P
C) ARM Cortex M3
D) Intel 8051

Q2. Which pin numbers are PWM pins in Arduino Uno?
A) 0–7
B) 2–9
C) 3,5,6,9,10,11
D) A0–A5

Q3. Arduino IDE uses which programming language?
A) Java
B) C/C++
C) Python
D) Assembly

Q4. Output voltage formula of a voltage divider is?
A)
B)
C)
D)

Q5. Analog pins in Arduino Uno are labeled as:
A) A0–A5
B) D0–D5
C) P0–P5
D) AD0–AD5

Q6. Arduino follows which data transfer protocol for uploading code?
A) SPI
B) UART (Serial)
C) I2C
D) CAN

Q7. Which is NOT an application of Arduino in IoT?
A) Smart Home
B) Smart Agriculture
C) Web Browser Development
D) Health Monitoring

Q8. Default clock speed of Arduino Uno is:
A) 8 MHz
B) 12 MHz
C) 16 MHz
D) 32 MHz

Q9. Arduino is best suited for:
A) High-end gaming systems
B) Large-scale servers
C) Prototyping IoT devices
D) Operating system design

Q10. Which pin provides 5V power in Arduino Uno?
A) A0
B) GND
C) 5V
D) Vin

✅ Answer Key

🧠 Explanations

• Q1 → B: Arduino Uno uses ATmega328P microcontroller.
• Q2 → C: PWM pins = 3,5,6,9,10,11.
• Q3 → B: Arduino IDE supports C/C++ code.
• Q4 → B: Standard voltage divider formula.
• Q5 → A: Analog pins = A0–A5.
• Q6 → B: Code uploaded via UART serial communication.
• Q7 → C: Web browser development is not related to Arduino IoT.
• Q8 → C: Arduino Uno runs at 16 MHz.
• Q9 → C: Arduino is mainly for prototyping IoT devices.
• Q10 → C: 5V pin provides regulated 5V supply.

🎯 Why Practice Matters

• Arduino basics help in understanding IoT hardware questions.
• ECET often asks direct pin numbers, microcontroller type, and simple formula-based questions.
• Also useful for practical projects and interviews.

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