GPIO cleanup on exit in Raspberry Pi - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of calling GPIO.cleanup() in a Raspberry Pi program?

It resets all the GPIO pins used by the program back to their default state, preventing warnings or errors in future runs and avoiding unintended behavior.

beginner

When should you call GPIO.cleanup() in your Raspberry Pi script?

You should call it at the end of your program or when your program exits, including when interrupted by the user, to ensure pins are properly reset.

intermediate

How can you ensure GPIO.cleanup() runs even if the program is stopped with Ctrl+C?

Use a try-except block to catch KeyboardInterrupt and call GPIO.cleanup() in the except block or use a finally block to always run cleanup.

beginner

What happens if you don't call GPIO.cleanup() before your program exits?

GPIO pins may remain set as inputs or outputs, causing warnings on next run or unexpected hardware behavior, like LEDs staying on or motors running.

beginner

Show a simple Python code snippet that safely cleans up GPIO pins on program exit.

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.OUT)

try:
    GPIO.output(18, GPIO.HIGH)
    time.sleep(2)
except KeyboardInterrupt:
    pass
finally:
    GPIO.cleanup()

Why is it important to call GPIO.cleanup() in a Raspberry Pi program?

A To increase CPU usage

B To speed up the program

C To reset GPIO pins to a safe state

D To install new libraries

Calling GPIO.cleanup() resets the pins to avoid warnings and unintended behavior.

Which Python statement ensures GPIO.cleanup() runs even if the program is interrupted by Ctrl+C?

A Using a while loop

B Using a try-except block catching KeyboardInterrupt

C Using an if statement

D Using a print statement

A try-except block catching KeyboardInterrupt allows cleanup code to run on interruption.

What could happen if you forget to call GPIO.cleanup() before your program exits?

A GPIO pins may stay active causing hardware issues

B The program will run faster next time

C The Raspberry Pi will shut down

D Nothing happens

Pins may remain set, causing warnings or hardware to stay powered.

Where is the best place to put GPIO.cleanup() in your code?

A At the start of the program

B In a comment

C Inside a print statement

D In a finally block

A finally block runs no matter what, ensuring cleanup always happens.

What does GPIO.cleanup() do to the pins?

A Resets them to input mode and frees resources

B Turns them all on

C Changes their voltage to 5V

D Disables the Raspberry Pi

Cleanup resets pins to input mode and releases resources.

Explain why and how you should use GPIO.cleanup() in a Raspberry Pi program.

Think about what happens to pins after your program stops.

Describe a simple Python code structure that ensures GPIO pins are cleaned up even if the user stops the program with Ctrl+C.

Use try, except, and finally keywords.