LowPower library usage in Arduino - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of the LowPower library in Arduino?

The LowPower library helps reduce power consumption by putting the Arduino into sleep modes during idle times, saving battery life.

beginner

How do you put an Arduino into sleep mode using the LowPower library?

You call a function like LowPower.powerDown(SLEEP_8S, ADC_OFF, BOD_OFF); to put the Arduino into a low power sleep for 8 seconds, turning off ADC and Brown-out Detector to save power.

beginner

What does the parameter SLEEP_8S mean in the LowPower library?

It means the Arduino will sleep for 8 seconds before waking up automatically.

intermediate

Why would you turn off the ADC and BOD in sleep mode?

Turning off the ADC (Analog to Digital Converter) and BOD (Brown-out Detector) reduces power consumption further because these components use power even when the Arduino is sleeping.

intermediate

Can the Arduino wake up from sleep mode using an external interrupt with the LowPower library?

Yes, the Arduino can wake up from sleep mode when an external interrupt occurs, allowing it to respond to events while still saving power.

Which function puts the Arduino into a low power sleep mode for a set time?

A delay()

B analogRead()

C digitalWrite()

D LowPower.powerDown()

LowPower.powerDown() is used to put the Arduino into sleep mode for a specified duration.

What does turning off ADC during sleep do?

A Saves power by disabling analog to digital conversion

B Prevents the Arduino from waking up

C Makes the Arduino run faster

D Increases power consumption

Disabling ADC saves power because the analog to digital converter won't use energy while sleeping.

How can the Arduino wake up from sleep mode when using the LowPower library?

A By an external interrupt or timer

B By pressing the reset button only

C Only after the sleep timer ends

D It cannot wake up automatically

The Arduino can wake up from sleep mode by an external interrupt or when the sleep timer expires.

What does BOD_OFF do in the LowPower library sleep function?

A Disables the battery

B Turns off the Brown-out Detector to save power

C Turns off the board

D Enables the Brown-out Detector

BOD_OFF disables the Brown-out Detector during sleep to reduce power consumption.

Which of these is NOT a sleep duration option in the LowPower library?

A SLEEP_4S

B SLEEP_1S

C SLEEP_16S

D SLEEP_8S

SLEEP_16S is not a standard sleep duration option; common options include 1s, 2s, 4s, 8s.

Explain how to use the LowPower library to put an Arduino into sleep mode and wake it up with an external event.

Think about how to save power and still respond to buttons or sensors.

Describe why turning off ADC and BOD during sleep helps save power on an Arduino.

Consider what parts of the Arduino keep working even when sleeping.