Tutorial 2 - LED Control

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Introduction

Turning an LED on and off is often treated as the "Hello World" of hardware programming. It is a simple, foundational task that shows how to control a GPIO output and verify that your hardware is wired correctly.

By writing a program that blinks an LED, you learn how to configure a digital output pin and use delays to create a repeating pattern. That same pattern applies later to motors, relays, sensors, and more complex embedded projects.

Components Needed

Component	Quantity
Raspberry Pi 5	1
Breadboard	1
Wires	Several
LED	1
300 - 1K Ohm Resistor	1

Image credit: SunFounder

Fritzing Diagram

Connect the LED to your Raspberry Pi as shown in the following diagram.

Image credit: SunFounder

Code

from gpiozero import LED
from time import sleep

# Initialize an LED connected to GPIO pin 17 using the GPIO Zero library.
led = LED(17)

while True:
    # Turn on the LED and print a message to the console.
    led.on()
    print('LED ON')

    # Wait for 0.5 seconds with the LED on.
    sleep(0.5)

    # Turn off the LED and print a message to the console.
    led.off()
    print('LED OFF')

    # Wait for 0.5 seconds with the LED off.
    sleep(0.5)

Code Explanation

Importing Libraries

from gpiozero import LED
from time import sleep

from gpiozero import LED imports the LED class from the gpiozero library so the Raspberry Pi can control an LED connected to a GPIO pin.

from time import sleep imports the sleep function so the program can pause between turning the LED on and off.

Initializing the LED

led = LED(17)

led = LED(17) creates an LED object connected to GPIO pin 17.

Infinite Loop

while True:

while True keeps the code running until you stop it manually.

Turning the LED On

led.on()
print('LED ON')

led.on() turns on the LED, and print('LED ON') shows the current state in the terminal.

Delay After Turning On

sleep(0.5)

sleep(0.5) keeps the LED on for half a second.

Turning the LED Off

led.off()
print('LED OFF')

led.off() turns the LED off, and print('LED OFF') confirms the state in the terminal.

Delay After Turning Off

sleep(0.5)

The second sleep(0.5) keeps the LED off for half a second before the loop repeats.

Summary

This code creates a simple blinking LED effect by turning the LED on for 0.5 seconds, turning it off for 0.5 seconds, and repeating the cycle indefinitely.