UNIT – 3: Programming with Arduino Uno

 

UNIT – 3: Programming with Arduino Uno

1. Arduino UNO Board Block Diagram

• Key components:

  • ATmega328P Microcontroller

  • Power Supply (USB/adapter)

  • Digital I/O Pins (0–13)

  • Analog Input Pins (A0–A5)

  • Reset button

  • USB port (programming)

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2. Sketch Structure

// Structure of Arduino Program
void setup() {
  // initialization code, runs once
}

void loop() {
  // main code, runs continuously
}

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3. Data Types & Built-in Constants

• int, float, char, boolean

• Constants: HIGH, LOW, INPUT, OUTPUT, true, false

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4. Operators

• Arithmetic (+, -, *, /, %)

• Comparison (==, !=, >, <, >=, <=)

• Logical/Boolean (&&, ||, !)

• Bitwise (&, |, ^, ~, <<, >>)

• Compound (+=, -=, *=, /=)

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5. Control Statements and Loops

• if, else if, else

• for loop, while loop, do-while loop

• switch-case

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6. Functions

• User Defined: custom functions created by programmer.

• Library Functions:

  • I/O Functions: digitalWrite(), digitalRead(), analogRead(), analogWrite()

  • Char Functions: isAlpha(), isDigit()

  • Math Functions: abs(), pow(), sqrt(), random()

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Short Questions – UNIT 3

1. What is the purpose of setup() in Arduino?
   👉 To initialize variables, pin modes, and libraries (runs once).

2. Which Arduino function is used to read analog input?
   👉 analogRead()

3. What is the data type for storing decimal values?
   👉 float

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MCQs – UNIT 3

1. Arduino Uno is based on:
   a) ATmega8
   b) ATmega16
   c) ATmega328P ✅
   d) ATmega32

2. Which loop runs continuously in Arduino?
   a) setup()
   b) loop() ✅
   c) while()
   d) for()

3. Function to generate random number:
   a) rand()
   b) random() ✅
   c) randint()
   d) getRandom()

UNIT – 3: Programming with Arduino Uno

1. Draw and explain the block diagram of Arduino Uno board.

Answer:
The Arduino Uno has an ATmega328P microcontroller, digital I/O pins (0–13), analog input pins (A0–A5), power supply, USB interface, oscillator, and reset button. It acts as the central brain of IoT projects.

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2. Explain the structure of an Arduino sketch.

Answer:
Every Arduino program has two main functions:

• setup(): Runs once, used for initialization.

• loop(): Runs continuously, executes the main logic.

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3. Describe Arduino data types with examples.

Answer:

• int (integer numbers)

• float (decimal numbers)

• char (characters)

• boolean (true/false)
  Example: int x=10; float y=5.5;.

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4. Explain built-in constants in Arduino with examples.

Answer:

• HIGH, LOW (digital signals)

• INPUT, OUTPUT (pin mode)

• true, false (boolean constants)

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5. Explain Arithmetic operators in Arduino with example code.

Answer:
Operators: + - * / %.
Example: int z = x + y;.

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6. Differentiate between comparison and logical operators in Arduino.

Answer:

• Comparison (==, !=, >, <) compares two values.

• Logical (&&, ||, !) combine conditions.

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7. Explain bitwise operators with example.

Answer:
Bitwise operators (&, |, ^, <<, >>) perform operations at the binary level.
Example: 5 & 3 = 1.

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8. Explain compound operators with example code.

Answer:
Operators like +=, -=, *=, /= update values.
Example: x += 5; // same as x=x+5;.

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9. Explain the usage of control statements in Arduino with example.

Answer:
Control statements: if, else if, switch-case.
Example:

if(temp > 30) digitalWrite(fan, HIGH);
else digitalWrite(fan, LOW);

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10. Differentiate between while and for loops in Arduino.

Answer:

• for loop runs for a fixed number of times.

• while loop runs until condition becomes false.

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11. Explain the importance of functions in Arduino programming.

Answer:
Functions allow code reusability and modular programming. Example: void blinkLED() { digitalWrite(LED, HIGH); delay(1000); }.

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12. Differentiate between user-defined functions and library functions in Arduino.

Answer:

• User-defined: Written by the programmer.

• Library functions: Predefined (e.g., digitalRead(), pow()).

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13. Explain I/O functions in Arduino with examples.

Answer:

• digitalWrite(pin, HIGH) → Turns ON output.

• digitalRead(pin) → Reads digital input.

• analogRead(pin) → Reads analog value.

• analogWrite(pin, value) → PWM output.

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14. Explain char functions with example.

Answer:
Functions like isAlpha(), isDigit() help check character properties.
Example: if(isDigit(ch)) { ... }.

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15. Explain math functions in Arduino with examples.

Answer:

• abs(x), pow(x,y), sqrt(x), random(min,max).
  These functions perform mathematical calculations in IoT projects.