Arduino sleep modes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to put the Arduino into sleep mode.

Arduino

#include <avr/sleep.h>

void setup() {
  Serial.begin(9600);
  set_sleep_mode([1]);
  sleep_enable();
  sleep_cpu();
}

void loop() {
  // Nothing here
}

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ASLEEP_MODE_IDLE

BSLEEP_MODE_PWR_DOWN

CSLEEP_MODE_ADC

DSLEEP_MODE_STANDBY

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a lighter sleep mode that doesn't save much power.

The SLEEP_MODE_PWR_DOWN mode puts the Arduino into the deepest sleep, saving the most power.

2fill in blank

medium

Complete the code to disable sleep mode after waking up.

Arduino

void wakeUp() {
  sleep_disable();
  Serial.println("Woke up!");
}

void setup() {
  attachInterrupt(digitalPinToInterrupt(2), wakeUp, [1]);
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);
  sleep_enable();
  sleep_cpu();
}

void loop() {
  // Sleep until interrupt
}

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ALOW

BCHANGE

CRISING

DFALLING

Attempts:

3 left

💡 Hint

Common Mistakes

Using LOW, which triggers continuously while the pin is held low.

The interrupt triggers on a rising edge signal, waking the Arduino from sleep.

3fill in blank

hard

Fix the error in the code to correctly enter sleep mode.

Arduino

#include <avr/sleep.h>

void setup() {
  Serial.begin(9600);
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);
  [1]();
  sleep_cpu();
}

void loop() {
  // Sleep here
}

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Asleep_enable

Bsleep_mode

Csleep_disable

Dsleep_set

Attempts:

3 left

💡 Hint

Common Mistakes

Calling sleep_disable() instead of sleep_enable().

You must call sleep_enable() before sleep_cpu() to activate sleep mode.

4fill in blank

hard

Fill both blanks to create a dictionary of sleep modes and their descriptions.

Arduino

const char* sleepModes[] = {"[1]", "[2]"};

void setup() {
  Serial.begin(9600);
  Serial.println(sleepModes[0]);
  Serial.println(sleepModes[1]);
}

void loop() {}

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ASLEEP_MODE_IDLE

BSLEEP_MODE_PWR_SAVE

CIdle mode

DPower save mode

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing mode names with descriptions incorrectly.

The array holds the mode name and its description. Here, SLEEP_MODE_IDLE and "Idle mode" are paired.

5fill in blank

hard

Fill all three blanks to create a function that sets sleep mode and enters sleep.

Arduino

void enterSleepMode([1] mode) {
  set_sleep_mode([2]);
  [3]();
  sleep_cpu();
}

void setup() {
  Serial.begin(9600);
  enterSleepMode(SLEEP_MODE_PWR_DOWN);
}

void loop() {}

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Auint8_t

Bmode

Csleep_enable

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong parameter type or forgetting to enable sleep.

The function takes an integer mode, sets it as the sleep mode, enables sleep, then enters sleep.