Duty cycle control for motor/LED in Embedded C - Mini Project: Build & Apply

Duty cycle control for motor/LED

📖 Scenario: You are working on a simple embedded system that controls the brightness of an LED or the speed of a motor using PWM (Pulse Width Modulation). The duty cycle determines how long the signal stays ON in one cycle, affecting brightness or speed.In this project, you will write code to set up the duty cycle and then calculate the ON time based on a fixed period.

🎯 Goal: Build a program that defines a duty cycle percentage, calculates the ON time for a PWM signal with a fixed period, and prints the ON time value.

📋 What You'll Learn

Create a variable to hold the PWM period in microseconds

Create a variable to hold the duty cycle percentage

Calculate the ON time based on the duty cycle and period

Print the ON time value

💡 Why This Matters

🌍 Real World

PWM signals are used in many devices to control motor speed, LED brightness, and other electronics by adjusting the duty cycle.

💼 Career

Understanding duty cycle control is important for embedded systems engineers and anyone working with hardware control and microcontrollers.

1

Set the PWM period

Create an integer variable called pwm_period and set it to 20000 to represent the PWM period in microseconds.

Embedded C

// Create an integer variable called pwm_period and set it to 20000
// Your code here

Need a hint?

The PWM period is the total time of one cycle. Use an integer variable named pwm_period and assign it the value 20000.

2

Set the duty cycle percentage

Create an integer variable called duty_cycle and set it to 30 to represent the duty cycle percentage (30%).

Embedded C

int pwm_period = 20000;
// Create an integer variable called duty_cycle and set it to 30
// Your code here

Need a hint?

The duty cycle is the percentage of time the signal is ON. Use an integer variable named duty_cycle and assign it the value 30.

3

Calculate the ON time

Create an integer variable called on_time and calculate its value as (pwm_period * duty_cycle) / 100 to find the ON time in microseconds.

Embedded C

int pwm_period = 20000;
int duty_cycle = 30;
// Calculate the ON time and store it in an integer variable called on_time
// Your code here

Need a hint?

Multiply pwm_period by duty_cycle and divide by 100 to get the ON time.

4

Print the ON time

Use printf to print the text "ON time: " followed by the value of on_time and then " microseconds\n".

Embedded C

int pwm_period = 20000;
int duty_cycle = 30;
int on_time = (pwm_period * duty_cycle) / 100;
// Print the ON time value
// Your code here

Need a hint?

Use printf("ON time: %d microseconds\n", on_time); to display the ON time.