DC motor with transistor driver in Arduino - Mini Project: Build & Apply

DC Motor Control with Transistor Driver

📖 Scenario: You have a small DC motor connected to an Arduino through a transistor driver. You want to control the motor speed by sending a PWM signal from the Arduino to the transistor base pin.This project will guide you step-by-step to write the Arduino code to control the motor speed.

🎯 Goal: Build an Arduino program that sets up the motor control pin, defines a speed value, sends the PWM signal to the transistor to control the motor speed, and prints the speed value to the Serial Monitor.

📋 What You'll Learn

Use pin 9 as the motor control pin connected to the transistor base

Define a variable called motorSpeed with the value 128

Use analogWrite to send the PWM signal to the motor control pin

Print the motor speed value to the Serial Monitor using Serial.println

💡 Why This Matters

🌍 Real World

Controlling DC motors with transistors is common in robotics and small electronics projects where you need to adjust motor speed safely.

💼 Career

Understanding how to control motors with microcontrollers and transistor drivers is a key skill for embedded systems and hardware engineers.

1

Set up the motor control pin

Write a line of code to create a variable called motorPin and set it to 9.

Arduino

# Define the motor control pin
# Your code here

Hint

Use int motorPin = 9; to assign pin 9 to the motorPin variable.

2

Define the motor speed variable

Add a line of code to create a variable called motorSpeed and set it to 128.

Arduino

int motorPin = 9;
// Define the motor speed
# Your code here

Hint

Use int motorSpeed = 128; to set the speed to half of the maximum PWM value.

3

Send PWM signal to control motor speed

Write the setup() function to set motorPin as an output. Then write the loop() function to use analogWrite(motorPin, motorSpeed); to send the PWM signal.

Arduino

int motorPin = 9;
int motorSpeed = 128;

void setup() {
  // Set motorPin as output
  // Your code here
}

void loop() {
  // Send PWM signal to motorPin
  // Your code here
}

Hint

Use pinMode(motorPin, OUTPUT); in setup() and analogWrite(motorPin, motorSpeed); in loop().

4

Print motor speed to Serial Monitor

Add a line inside the loop() function to print the value of motorSpeed to the Serial Monitor using Serial.println(motorSpeed);.

Arduino

int motorPin = 9;
int motorSpeed = 128;

void setup() {
  pinMode(motorPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  analogWrite(motorPin, motorSpeed);
  // Print motorSpeed to Serial Monitor
  // Your code here
}

Hint

Use Serial.println(motorSpeed); to print the speed. Add delay(1000); to slow down the output.