Timer interrupts with TimerOne library in Arduino - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize TimerOne with a 1-second interval.

Arduino

#include <TimerOne.h>

void setup() {
  TimerOne.[1](1000000); // 1 second interval
}

void loop() {
  // main code
}

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

Astart

Binitialize

CsetPeriod

Dbegin

Attempts:

3 left

💡 Hint

Common Mistakes

Using start() instead of setPeriod().

Using initialize() which is not a TimerOne function.

The setPeriod function sets the timer interval in microseconds.

2fill in blank

medium

Complete the code to attach an interrupt service routine named blinkLED.

Arduino

void setup() {
  TimerOne.setPeriod(500000); // 0.5 second
  TimerOne.[1](blinkLED);
}

void blinkLED() {
  // toggle LED
}

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

AattachInterrupt

BonTimer

CsetInterrupt

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using start() which only starts the timer.

Using setInterrupt() which is not a TimerOne method.

The attachInterrupt function links the timer to the ISR function.

3fill in blank

hard

Fix the error in the code to start the timer after setting the period and ISR.

Arduino

void setup() {
  TimerOne.setPeriod(2000000); // 2 seconds
  TimerOne.attachInterrupt(blinkLED);
  TimerOne.[1]();
}

void blinkLED() {
  // toggle LED
}

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Astart

Bbegin

Cenable

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Using begin() which is not a TimerOne method.

Using enable() or run() which do not exist.

The start() function starts the timer counting.

4fill in blank

hard

Fill both blanks to create a dictionary of word lengths for words longer than 3 characters.

Arduino

String words[] = {"apple", "bat", "carrot", "dog"};
int lengths[4] = {0};

for (int i = 0; i < 4; i++) {
  if (words[i].length() [1] 3) {
    lengths[i] = words[i].[2]();
  }
}

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A>

Blength

Csize

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > in the if condition.

Using size() which is not a String method in Arduino.

We check if the word length is greater than 3 using > and get the length with length().

5fill in blank

hard

Fill all three blanks to create a map of uppercase words to their lengths if length is greater than 4.

Arduino

String words[] = {"tree", "house", "car", "elephant"};
int lengths[4] = {0};

for (int i = 0; i < 4; i++) {
  if (words[i].[1]() [2] 4) {
    words[i].[3]();
    lengths[i] = words[i].length();
  }
}

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Alength

B>

CtoUpperCase

Dsize

Attempts:

3 left

💡 Hint

Common Mistakes

Using size() which is not valid for Arduino String.

Using < instead of > in the condition.

We get the word length with length(), compare with >, and convert to uppercase with toUpperCase().