LED brightness control in Raspberry Pi - Mini Project: Build & Apply

LED brightness control

📖 Scenario: You have a Raspberry Pi connected to an LED light. You want to control how bright the LED is by changing its brightness level.

🎯 Goal: Build a simple program that sets up the LED pin, defines a brightness level, changes the LED brightness using PWM, and then shows the brightness level.

📋 What You'll Learn

Use the RPi.GPIO library to control the LED

Set up the GPIO pin 18 for PWM output

Define a brightness level between 0 and 100

Use PWM to set the LED brightness

Print the brightness level to the screen

💡 Why This Matters

🌍 Real World

Controlling LED brightness is useful in projects like mood lighting, indicators, or displays.

💼 Career

Understanding GPIO and PWM control is important for hardware programming and embedded systems jobs.

1

Set up GPIO and LED pin

Import the RPi.GPIO library as GPIO. Set the GPIO mode to GPIO.BCM. Set up GPIO pin 18 as an output pin.

Raspberry Pi

# Your code here

Need a hint?

Use GPIO.setmode(GPIO.BCM) to select pin numbering. Use GPIO.setup(18, GPIO.OUT) to prepare pin 18 for output.

2

Create PWM instance and set brightness level

Create a PWM instance called pwm on pin 18 with frequency 1000 Hz. Define a variable called brightness and set it to 75.

Raspberry Pi

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.OUT)
# Your code here

Need a hint?

Use GPIO.PWM(18, 1000) to create PWM on pin 18 at 1000 Hz. Set brightness to 75 to represent 75% brightness.

3

Start PWM and set duty cycle

Start the PWM with a duty cycle of 0. Then change the duty cycle to the value of brightness to set the LED brightness.

Raspberry Pi

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.OUT)
pwm = GPIO.PWM(18, 1000)
brightness = 75
# Your code here

Need a hint?

Use pwm.start(0) to start PWM with 0% brightness, then pwm.ChangeDutyCycle(brightness) to set brightness to 75%.

4

Print the brightness level

Print the message "LED brightness is set to: " followed by the value of brightness.

Raspberry Pi

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.OUT)
pwm = GPIO.PWM(18, 1000)
brightness = 75
pwm.start(0)
pwm.ChangeDutyCycle(brightness)
# Your code here

Need a hint?

Use print(f"LED brightness is set to: {brightness}") to show the brightness level.