Reducing power consumption tips in Arduino - 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() {
  // Empty loop
}

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ASLEEP_MODE_POWER_DOWN

BSLEEP_MODE_ADC

CSLEEP_MODE_IDLE

DSLEEP_MODE_STANDBY

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a sleep mode that does not reduce power significantly.

The SLEEP_MODE_POWER_DOWN mode puts the Arduino into the lowest power state, reducing power consumption significantly.

2fill in blank

medium

Complete the code to disable the ADC to save power.

Arduino

void setup() {
  ADCSRA [1] 0;
}

void loop() {
  // Main code
}

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A|=

B=

C^=

D&=

Attempts:

3 left

💡 Hint

Common Mistakes

Using OR or AND operators which do not clear all bits properly.

Using = 0 disables all bits in the ADCSRA register, turning off the ADC to save power.

3fill in blank

hard

Fix the error in the code to turn off the built-in LED to save power.

Arduino

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, [1]);
}

void loop() {
  // Empty loop
}

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AINPUT

BHIGH

CLOW

DOUTPUT

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the pin HIGH which keeps the LED on.

Setting the LED pin to LOW turns off the LED, reducing power consumption.

4fill in blank

hard

Fill both blanks to create a dictionary of sensor readings only if the reading is above 100.

Arduino

int readings[] = {120, 90, 150, 80};

void setup() {
  Serial.begin(9600);
  for (int i = 0; i < 4; i++) {
    if (readings[i] [1] 100) {
      Serial.println(readings[i] [2] 2);
    }
  }
}

void loop() {}

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A>

B*

C<

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using less than operator which filters wrong values.

Using addition instead of multiplication.

The condition readings[i] > 100 filters readings above 100. Multiplying by 2 doubles the value before printing.

5fill in blank

hard

Fill all three blanks to create a map of sensor names to values only if the value is positive.

Arduino

String sensors[] = {"temp", "light", "sound"};
int values[] = {25, -5, 10};

void setup() {
  Serial.begin(9600);
  for (int i = 0; i < 3; i++) {
    if (values[i] [3] 0) {
      Serial.print(sensors[i].[1]());
      Serial.print(": ");
      Serial.println(values[i] [2] 1);
    }
  }
}

void loop() {}

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AtoUpperCase

B*

C>

DtoLowerCase

Attempts:

3 left

💡 Hint

Common Mistakes

Using toUpperCase instead of toLowerCase.

Using addition instead of multiplication.

The condition values[i] > 0 filters positive values. Using toLowerCase() converts sensor names to lowercase. Multiplying by 1 keeps the value unchanged.