Why PWM is needed for analog-like control in Raspberry Pi - See It in Action

Why PWM is Needed for Analog-Like Control

📖 Scenario: You have a Raspberry Pi and want to control the brightness of an LED. The LED can only be fully ON or fully OFF, but you want it to glow with different brightness levels like a dimmer switch.

🎯 Goal: Learn how to use PWM (Pulse Width Modulation) to simulate analog control of LED brightness using digital signals.

📋 What You'll Learn

Create a variable to represent the LED pin number

Create a variable to represent the PWM frequency

Use PWM to set the LED brightness to 50%

Print the duty cycle value to show the brightness level

💡 Why This Matters

🌍 Real World

PWM is used in many electronics to control brightness of lights, speed of motors, and volume of sound without needing expensive analog parts.

💼 Career

Understanding PWM is important for jobs in embedded systems, robotics, and hardware programming where digital control of analog devices is common.

1

Set up the LED pin and PWM frequency

Create a variable called led_pin and set it to 18. Create another variable called pwm_freq and set it to 1000 (this is the PWM frequency in Hertz).

Raspberry Pi

# Create variables for LED pin and PWM frequency
# Your code here

Need a hint?

The LED pin is usually a GPIO number. PWM frequency controls how fast the signal switches ON and OFF.

2

Set the PWM duty cycle for brightness

Create a variable called duty_cycle and set it to 50 to represent 50% brightness.

Raspberry Pi

led_pin = 18
pwm_freq = 1000
# Set the PWM duty cycle to 50%
# Your code here

Need a hint?

The duty cycle is the percentage of time the signal is ON in one cycle.

3

Explain why PWM is used for analog-like control

Write a comment explaining that PWM switches the LED ON and OFF very fast to simulate different brightness levels by changing the duty_cycle.

Raspberry Pi

led_pin = 18
pwm_freq = 1000
duty_cycle = 50
# Explain why PWM is used for analog-like control
# Your code here

Need a hint?

Think about how turning a light ON and OFF quickly can look like dimming.

4

Print the PWM duty cycle

Write a print statement to display the text "LED brightness set to 50%" using the duty_cycle variable.

Raspberry Pi

led_pin = 18
pwm_freq = 1000
duty_cycle = 50
# PWM rapidly switches the LED ON and OFF
# Changing duty_cycle changes how long it stays ON
# This makes the LED appear dimmer or brighter

# Print the LED brightness
# Your code here

Need a hint?

Use an f-string to include the duty_cycle variable inside the print text.