Non-blocking code architecture in Arduino - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if 1 second has passed without blocking.

Arduino

unsigned long currentMillis = millis();
if (currentMillis - previousMillis [1] interval) {
  previousMillis = currentMillis;
  // action to perform
}

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

A>=

B<

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' which may miss the exact millisecond.

Using '<' which checks the wrong condition.

The condition currentMillis - previousMillis >= interval checks if the set time interval has passed without stopping the program.

2fill in blank

medium

Complete the code to update the LED state without delay.

Arduino

if (millis() - previousMillis >= [1]) {
  previousMillis = millis();
  ledState = !ledState;
  digitalWrite(ledPin, ledState);
}

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

A500

Bdelay

C1000

Dmillis

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'delay' which blocks the program.

Using 'millis' which is a function, not a number.

The value 1000 means the LED toggles every 1000 milliseconds (1 second) without blocking.

3fill in blank

hard

Fix the error in the non-blocking blink code by completing the blank.

Arduino

unsigned long previousMillis = 0;
const long interval = 1000;
void loop() {
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis [1] interval) {
    previousMillis = currentMillis;
    digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
  }
}

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

A<

B>=

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' which causes the condition to never be true.

Using '==' which may miss the exact timing.

The correct comparison is >= to check if the interval time has passed.

4fill in blank

hard

Fill both blanks to create a non-blocking timer that toggles an LED every 2 seconds.

Arduino

unsigned long previousMillis = 0;
const long [1] = 2000;
void loop() {
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis [2] interval) {
    previousMillis = currentMillis;
    digitalWrite(ledPin, !digitalRead(ledPin));
  }
}

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

Ainterval

Bdelay

C>=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'delay' instead of a variable name.

Using '<' which causes wrong timing.

The variable interval stores the time delay, and the comparison >= checks if the interval has passed.

5fill in blank

hard

Fill all three blanks to create a non-blocking code that toggles an LED every 500ms and reads a button state.

Arduino

unsigned long previousMillis = 0;
const long [1] = 500;
void loop() {
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis [2] interval) {
    previousMillis = currentMillis;
    ledState = !ledState;
    digitalWrite(ledPin, ledState);
  }
  buttonState = digitalRead([3]);
}

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

Ainterval

B>=

CbuttonPin

Ddelay

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'delay' which blocks the code.

Using '<' which causes wrong timing.

Using wrong pin name for button.

interval holds the delay time, >= checks the time passed, and buttonPin is the pin reading the button state.