DC Motor Speed Control Using Arduino, PWM, and TIP122 Transistor with LCD Display

In this tutorial, we’ll guide you through an innovative engineering project to control the speed of a high RPM DC motor using PWM (Pulse Width Modulation) with an Arduino Uno, a TIP122 transistor, and a 16×2 LCD display. This project is designed for engineering students and hobbyists seeking hands-on experience with Arduino and electronics. By the end of this project, you’ll understand how to regulate motor speed through PWM and display real-time duty cycle information on an LCD screen, making this project an excellent choice for competitions, academic presentations, and skill-building.

Introduction

Controlling motor speed is a fundamental requirement in robotics, automation, and electronics projects. This project demonstrates how to control the speed of a DC motor using PWM, with the Arduino Uno as the controller and a TIP122 transistor as the power driver. By adjusting a potentiometer, users can change the duty cycle applied to the motor, effectively controlling its speed. This setup is useful in applications like conveyor belts, cooling fans, and any scenario where precise motor speed control is needed.

Components Used

To complete this project, you’ll need the following components:

1. Arduino Uno – The microcontroller that processes the input and controls PWM output.
2. TIP122 Transistor – A powerful NPN transistor used to switch the DC motor based on the PWM signal.
3. High RPM DC Motor – The motor whose speed we want to control.
4. 16×2 LCD Display – Displays the duty cycle in real-time.
5. Potentiometer – Used to vary the PWM duty cycle, adjusting motor speed.
6. Breadboard and Jumper Wires – To connect the components.

This list provides a simple and accessible set of components, making this project suitable for engineering students or electronics enthusiasts looking to build an innovative project.

Video Demonstration :-

Project Kit:- Click Here OR Contact at +91-8571964488 / 8684884488 ( Call or Whatsapp )

Code Of the project :-

#include <LiquidCrystal.h>

// LCD pin setup
const int rs = 7, en = 8, d4 = 9, d5 = 10, d6 = 11, d7 = 12;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

// Define pins
const int potPin = A0;    // Potentiometer connected to analog pin A0
const int motorPin = 5;   // PWM pin connected to the base of TIP122 (via a resistor)

// Variables
int potValue = 0;         // To store the potentiometer value
int dutyCycle = 0;        // To store the calculated duty cycle (0-100%)

void setup() {
  // LCD initialization
  lcd.begin(16, 2);
  lcd.setCursor(0, 0);
  lcd.print("DC Motor Control");

  // Set the motor pin as output
  pinMode(motorPin, OUTPUT);
}

void loop() {
  // Read potentiometer value (0-1023)
  potValue = analogRead(potPin);

  // Map the potentiometer value to a duty cycle (0-255 for PWM)
  int pwmValue = map(potValue, 0, 1023, 0, 255);

  // Calculate duty cycle as a percentage
  dutyCycle = map(pwmValue, 0, 255, 0, 100);

  // Output PWM signal to motor
  analogWrite(motorPin, pwmValue);

  // Display duty cycle on the LCD
  lcd.setCursor(0, 1);
  lcd.print("Duty Cycle: ");
  lcd.print(dutyCycle);
  lcd.print("%   "); // Extra spaces to clear old data

  delay(200); // Short delay for stability
}

Here’s an Arduino code for your project that reads an analog value from a potentiometer, maps it to a duty cycle for PWM control, and displays the motor control message and duty cycle percentage on a 16×2 LCD. The code assumes you’re using a TIP122 transistor for the DC motor control, with a potentiometer connected to an analog pin.

Required Connections:

• Potentiometer: Connect one end to 5V, the other to GND, and the middle wiper to A0 on the Arduino.
• LCD: Connect to appropriate pins (adjust the lcd object settings if different).
• TIP122 Transistor: Connect the base to the PWM pin, the emitter to GND, and the motor between the collector and power source.

Explanation:

• Potentiometer Reading: The analogRead(potPin) function reads the potentiometer’s value and maps it to a range of 0–255 for PWM.
• Duty Cycle Calculation: The dutyCycle variable represents the PWM signal percentage applied to the motor.
• LCD Display: The first line shows “DC Motor Control,” and the second displays the current duty cycle as a percentage.
• PWM Output: analogWrite(motorPin, pwmValue); sends the PWM signal to the TIP122 transistor, controlling the motor speed.

The core of this project is PWM, which allows us to control the average power supplied to the motor by rapidly switching the motor’s power on and off. By adjusting the PWM signal’s duty cycle, we effectively control the motor’s speed.

• Potentiometer: Connected to an analog pin on the Arduino, the potentiometer adjusts the duty cycle value (from 0% to 100%) by reading voltage levels.
• Arduino and TIP122 Transistor: The Arduino reads the potentiometer’s value, maps it to a PWM signal, and sends it to the TIP122 transistor, which controls the motor speed accordingly. This transistor is crucial for amplifying the Arduino’s low power to a level suitable for the motor.
• 16×2 LCD Display: Displays “DC Motor Control” on the first line, while the second line dynamically shows the current duty cycle, providing real-time feedback.

This control system is straightforward yet highly effective for speed control, making it a valuable learning tool for students interested in electronics and robotics.

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Applications of DC Motor Speed Control Using Arduino

This project’s applications are extensive and relevant in both academic and real-world scenarios:

1. Educational Demonstrations: Perfect for engineering labs and academic presentations to demonstrate motor control principles.
2. Industrial Automation: Useful in conveyor belts, robotic arms, and similar applications where speed control is essential.
3. DIY Projects and Hobbyist Applications: Ideal for small personal projects such as automated fans, miniature vehicles, or precision equipment.

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Advantages and Disadvantages

Advantages:

• Precision Control: PWM provides high-precision control over motor speed.
• Cost-Effective: Uses affordable and widely available components.
• Real-Time Monitoring: Displays duty cycle feedback, offering a clear view of motor behavior.

Disadvantages:

• Limited Power Range: The TIP122 can only handle certain power levels; higher loads may require a MOSFET or relay.
• Noise Generation: PWM at high frequencies may produce audible noise in the motor.

Understanding these pros and cons helps students assess whether this approach suits specific project requirements.

Keywords: PWM motor control advantages, TIP122 transistor limitations, Arduino motor speed drawbacks, Arduino engineering project benefits

Future Scope of the Project

This project lays the foundation for more advanced applications:

1. PID Speed Control: Implementing a PID algorithm for accurate speed control and stability.
2. Wireless Control: Integrating Bluetooth or WiFi to control motor speed remotely.
3. Multi-Motor Control: Extending the concept to control multiple motors simultaneously in robotics or automated systems.
4. Integration with IoT: Combining IoT features to monitor and control motor performance from any location.

These enhancements make the project highly adaptable to future engineering and industrial needs.

Keywords: advanced motor control, PID speed control Arduino, IoT motor applications, wireless motor control, robotics motor control

Conclusion

This project provides a hands-on introduction to motor speed control using Arduino PWM and a TIP122 transistor. From understanding basic PWM concepts to displaying feedback on an LCD screen, this setup offers an engaging way for students to explore electronics and control systems. With potential applications in industry and education, it’s a versatile and practical project. Engineering students, hobbyists, and anyone interested in automation will find this tutorial valuable for learning and experimentation.

By following this guide, you can create an efficient DC motor speed control system that’s easy to build and customize. So grab your Arduino and start exploring the exciting world of motor control!

Project Kit:- Click Here OR Contact at +91-8571964488 / 8684884488 ( Call or Whatsapp )