Why LED and button projects build hardware confidence in Raspberry Pi - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to turn on the LED connected to GPIO pin 17.

Raspberry Pi

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.OUT)
GPIO.output(17, [1])

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AGPIO.LOW

BGPIO.IN

CGPIO.HIGH

DGPIO.PWM

Attempts:

3 left

💡 Hint

Common Mistakes

Using GPIO.LOW instead of GPIO.HIGH to turn on the LED.

GPIO.HIGH sets the pin to high voltage, turning the LED on.

2fill in blank

medium

Complete the code to read the button state connected to GPIO pin 18.

Raspberry Pi

GPIO.setup(18, GPIO.IN, pull_up_down=GPIO.PUD_UP)
button_state = GPIO.input([1])

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A18

B22

C17

D27

Attempts:

3 left

💡 Hint

Common Mistakes

Reading from the wrong GPIO pin number.

The button is connected to GPIO pin 18, so we read from pin 18.

3fill in blank

hard

Fix the error in the code to toggle the LED when the button is pressed.

Raspberry Pi

if GPIO.input(18) == [1]:
    GPIO.output(17, GPIO.HIGH)
else:
    GPIO.output(17, GPIO.LOW)

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AGPIO.HIGH

BGPIO.LOW

CTrue

DFalse

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for GPIO.HIGH instead of GPIO.LOW when button pressed.

The button uses a pull-up resistor, so pressed means GPIO.LOW.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps words to their lengths only if length is greater than 3.

Raspberry Pi

lengths = {word: [1] for word in words if len(word) [2] 3}

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Alen(word)

B>

C<

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > in the condition.

We map each word to its length using len(word) and filter words longer than 3 with > 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase keys to values only if value is positive.

Raspberry Pi

result = { [1]: [2] for k, v in data.items() if v [3] 0}

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Ak.upper()

Bv

C>

Dk

Attempts:

3 left

💡 Hint

Common Mistakes

Using k instead of k.upper() for keys.

We convert keys to uppercase with k.upper(), keep values as v, and filter values > 0.