Arduino IDE and sketch structure - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the setup function in an Arduino sketch.

Arduino

void [1]() {
  // put your setup code here, to run once:
}

Drag options to blanks, or click blank then click option'

Asetup

Bloop

Cmain

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'loop' instead of 'setup' for the setup function.

The setup() function runs once when the Arduino starts. It is used to initialize settings.

2fill in blank

medium

Complete the code to define the loop function in an Arduino sketch.

Arduino

void [1]() {
  // put your main code here, to run repeatedly:
}

Drag options to blanks, or click blank then click option'

Asetup

Brepeat

Cmain

Dloop

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'setup' instead of 'loop' for the repeating function.

The loop() function runs over and over again after setup() finishes. It is where the main code runs repeatedly.

3fill in blank

hard

Fix the error in the Arduino sketch by completing the missing keyword.

Arduino

[1] setup() {
  pinMode(13, OUTPUT);
}

Drag options to blanks, or click blank then click option'

Avoid

Bextern

Cint

Dstatic

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'int' or other return types instead of 'void'.

The setup() function must be declared with the void keyword to indicate it returns nothing.

4fill in blank

hard

Fill both blanks to create a simple Arduino sketch that turns on the built-in LED.

Arduino

void [1]() {
  pinMode(13, [2]);
}

void loop() {
  digitalWrite(13, HIGH);
}

Drag options to blanks, or click blank then click option'

Asetup

BINPUT

COUTPUT

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'INPUT' instead of 'OUTPUT' for pinMode.

The setup() function runs once to set pin 13 as an OUTPUT. Then loop() turns the LED on.

5fill in blank

hard

Fill all three blanks to complete the Arduino sketch that blinks the built-in LED.

Arduino

void [1]() {
  pinMode(13, [2]);
}

void loop() {
  digitalWrite(13, HIGH);
  delay([3]);
  digitalWrite(13, LOW);
  delay(1000);
}

Drag options to blanks, or click blank then click option'

Asetup

BOUTPUT

C1000

DINPUT

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'INPUT' instead of 'OUTPUT' for pinMode.

Forgetting to set the delay time.

The setup() function sets pin 13 as OUTPUT. The loop() turns the LED on, waits 1000 milliseconds, then turns it off.

Practice

1. What is the main purpose of the setup() function in an Arduino sketch?

easy

A. To run code once at the start to initialize settings

B. To run code repeatedly in a loop

C. To declare variables globally

D. To stop the program from running

Solution

1. Step 1: Understand the role of setup()

   The setup() function runs once when the Arduino starts to prepare the board.

2. Step 2: Compare with loop()

   The loop() function runs repeatedly, but setup() runs only once.

3. Final Answer:

   To run code once at the start to initialize settings -> Option A

4. Quick Check:

   setup() runs once = B [OK]

Hint: Remember: setup runs once, loop runs forever [OK]

Common Mistakes:

• Confusing setup() with loop()
• Thinking setup() runs repeatedly
• Believing setup() stops the program

2. Which of the following is the correct basic structure of an Arduino sketch?

easy

A. void setup() { } void loop() { }

B. void start() { } void repeat() { }

C. void main() { }

D. void initialize() { } void run() { }

Solution

1. Step 1: Recall Arduino sketch structure

   The Arduino sketch must have setup() and loop() functions defined with void return type.

2. Step 2: Check options for correct function names

   Only void setup() { } void loop() { } uses setup() and loop() correctly.

3. Final Answer:

   void setup() { } void loop() { } -> Option A

4. Quick Check:

   Correct function names = C [OK]

Hint: Look for setup() and loop() function names [OK]

Common Mistakes:

• Using wrong function names like main()
• Missing either setup() or loop()
• Using incorrect return types

3. What will be the output on the Serial Monitor when running this Arduino sketch?

void setup() {
  Serial.begin(9600);
  Serial.println("Start");
}

void loop() {
  Serial.println("Looping");
  delay(1000);
}

medium

A. No output because Serial.begin() is missing

B. Start and Looping printed once each

C. Only Looping printed repeatedly, no Start

D. Start printed once, then Looping printed every second

Solution

1. Step 1: Analyze setup() output

   Serial.begin(9600) starts serial communication, then "Start" is printed once.

2. Step 2: Analyze loop() output

   Inside loop(), "Looping" is printed every 1000 milliseconds (1 second) repeatedly.

3. Final Answer:

   Start printed once, then Looping printed every second -> Option D

4. Quick Check:

   setup() once, loop() repeats = D [OK]

Hint: setup() prints once, loop() repeats output [OK]

Common Mistakes:

• Thinking setup() runs repeatedly
• Forgetting Serial.begin() is needed
• Assuming no delay means no output

4. Identify the error in this Arduino sketch:

void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH)
  delay(1000);
  digitalWrite(13, LOW);
  delay(1000);
}

medium

A. pinMode should be in loop()

B. Missing semicolon after digitalWrite(13, HIGH)

C. delay() cannot be used in loop()

D. digitalWrite() needs two arguments

Solution

1. Step 1: Check syntax line by line

   In loop(), the line digitalWrite(13, HIGH) is missing a semicolon at the end.

2. Step 2: Verify other parts

   pinMode is correctly in setup(), delay() is allowed in loop(), and digitalWrite() has correct arguments.

3. Final Answer:

   Missing semicolon after digitalWrite(13, HIGH) -> Option B

4. Quick Check:

   Syntax error: missing semicolon = A [OK]

Hint: Look for missing semicolons after statements [OK]

Common Mistakes:

• Putting pinMode in loop() unnecessarily
• Thinking delay() is not allowed in loop()
• Miscounting digitalWrite() arguments

5. You want to blink an LED connected to pin 9 exactly 5 times, then stop. Which modification to the Arduino sketch structure is best?

hard

A. Remove loop() function entirely

B. Put blinking code inside setup() and leave loop() empty

C. Use a counter variable in loop() and stop blinking after 5 times

D. Use delay(5000) in setup() to blink 5 times

Solution

1. Step 1: Understand blinking 5 times

   Since loop() runs forever, use a counter variable inside loop() to count blinks.

2. Step 2: Evaluate options

   Putting blinking code in setup() runs once, so it performs only one blink cycle, not 5. Removing loop() is invalid. Using delay(5000) only delays, does not blink 5 times.

3. Final Answer:

   Use a counter variable in loop() and stop blinking after 5 times -> Option C

4. Quick Check:

   Counter in loop() controls blink count = A [OK]

Hint: Use a counter in loop() to limit repetitions [OK]

Common Mistakes:

• Trying to remove loop() function
• Putting repeated code only in setup()
• Using delay() to count blinks incorrectly