LED brightness control in Raspberry Pi - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the PWM class from the gpiozero library.

Raspberry Pi

from gpiozero import [1]

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

APWMLED

BLED

CButton

DOutputDevice

Attempts:

3 left

💡 Hint

Common Mistakes

Importing 'LED' instead of 'PWMLED' which only supports on/off control.

The PWMLED class allows control of LED brightness using PWM signals.

2fill in blank

medium

Complete the code to create a PWMLED object on GPIO pin 18.

Raspberry Pi

led = PWMLED([1])

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A17

B18

C22

D23

Attempts:

3 left

💡 Hint

Common Mistakes

Using a pin that does not support PWM or is not connected to the LED.

GPIO pin 18 is commonly used for PWM output on Raspberry Pi.

3fill in blank

hard

Fix the error in setting the LED brightness to 50%.

Raspberry Pi

led.value = [1]

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A50

B1

C0.5

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using integer 50 instead of decimal 0.5 causes the LED to stay fully on or off.

The value property expects a float between 0 (off) and 1 (full brightness). 50% brightness is 0.5.

4fill in blank

hard

Fill both blanks to create a dictionary that maps brightness levels to LED values for 0%, 50%, and 100%.

Raspberry Pi

brightness_levels = {0: [1], 50: [2], 100: 1.0}

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A0.0

B0.5

C1

D50

Attempts:

3 left

💡 Hint

Common Mistakes

Using integer percentages instead of decimal values for LED brightness.

Brightness 0% is 0.0, 50% is 0.5, and 100% is 1.0 for the LED value.

5fill in blank

hard

Fill all three blanks to set the LED brightness to 75% using the dictionary and print the value.

Raspberry Pi

level = 75
led.value = brightness_levels.get([1], [2])
print(f"LED brightness set to [3]")

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Alevel

B0.75

D75%

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong key or default value causes the LED to not set correctly.

We use the variable level to get the brightness from the dictionary. If not found, default to 0.75. Then print '75%'.