First GPIO program (LED blink) in Raspberry Pi - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is GPIO on a Raspberry Pi?

GPIO stands for General Purpose Input/Output. It is a set of pins on the Raspberry Pi that can be programmed to control electronic components like LEDs or read sensors.

beginner

Why do we need to set the GPIO pin mode before using it?

Setting the GPIO pin mode tells the Raspberry Pi if the pin will be used to send signals (output) or receive signals (input). For blinking an LED, we set it as output.

beginner

What does the following Python code do? <br>

GPIO.output(18, GPIO.HIGH)

This code turns on the device connected to GPIO pin 18 by sending a HIGH signal (3.3V), which can light up an LED.

beginner

Why do we use a delay (like time.sleep) in an LED blink program?

The delay pauses the program so the LED stays on or off long enough for us to see the blinking effect clearly.

beginner

What is the purpose of cleaning up GPIO pins at the end of a program?

Cleaning up resets the GPIO pins to a safe state, preventing unexpected behavior or damage when the program finishes.

Which GPIO pin mode should you set to blink an LED?

A Analog

B Input

C PWM

D Output

To control an LED, the pin must send signals, so it should be set as Output.

What does GPIO.HIGH mean in a Raspberry Pi program?

A Pin is disconnected

B Pin is off

C Pin is on (3.3V)

D Pin is set to input

GPIO.HIGH means the pin outputs a high voltage (3.3V), turning on connected devices like LEDs.

Why do we use time.sleep() in an LED blink program?

A To speed up the blinking

B To pause so the LED stays on/off visibly

C To reset the GPIO pins

D To read input from the LED

time.sleep() pauses the program so the LED's on or off state is visible to our eyes.

What Python library is commonly used to control GPIO pins on Raspberry Pi?

A RPi.GPIO

B numpy

C matplotlib

D pandas

RPi.GPIO is the standard library to control GPIO pins on Raspberry Pi.

What should you do at the end of a GPIO program to avoid issues?

A Call GPIO.cleanup()

B Disconnect the power

C Restart the Raspberry Pi

D Leave pins as they are

Calling GPIO.cleanup() resets pins to safe states and prevents problems in future programs.

Explain step-by-step how to write a simple program to blink an LED using Raspberry Pi GPIO pins.

Think about what you need to do to make the LED turn on and off repeatedly.

Why is it important to use GPIO.cleanup() in your Raspberry Pi GPIO programs?

Consider what happens if pins stay set after your program ends.