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Controlling a 28BYJ-48 Stepper Motor with ULN2003 Driver
2026-06-22 | By Rachana Jain
License: Attribution Non-commercial Stepper Arduino
Stepper motors are widely used when accurate positioning and controlled movement are required. In this project, I interfaced the popular 28BYJ-48 5V stepper motor with an Arduino Uno using the ULN2003 driver module and explored different operating modes and speed control.
The 28BYJ-48 is one of the most beginner-friendly stepper motors available and is commonly used in robotics, automation, camera sliders, CNC mechanisms, and educational projects.
Project Objectives
Understand the working principle of a stepper motor.
Learn the difference between full-step and half-step operation.
Interface the 28BYJ-48 stepper motor with Arduino.
Control motor direction and rotational speed.
Calculate the number of steps required for one complete revolution.
Components Used
Arduino Uno
28BYJ-48 Stepper Motor
Understanding Stepper Motor Operation
Unlike a DC motor that rotates continuously, a stepper motor moves in small angular increments called steps. The rotation is achieved by energizing the internal windings in a specific sequence.
Changing the sequence of coil activation determines the direction of rotation:
Clockwise rotation → IN1 → IN2 → IN3 → IN4
Counter-clockwise rotation → Reverse sequence
Because movement occurs in discrete steps, stepper motors provide excellent positioning accuracy.
Operating Modes
1. Full-Step Mode (Single Coil Energized)
Only one winding is activated at a time.
Advantages
Lower power consumption
Reduced heat generation
Disadvantage
Lower torque
2. Full-Step Mode (Two Coils Energized)
Two phases are energized simultaneously.
Advantages
Maximum torque
Disadvantages
Higher current consumption
Increased vibration
3. Half-Step Mode
Alternates between one-phase and two-phase excitation.
Benefits
Smoother motion
Better resolution
Reduced vibration
The 28BYJ-48 commonly operates in half-step mode, providing 4096 steps per revolution.
About the 28BYJ-48 Stepper Motor
The 28BYJ-48 is a 5V unipolar permanent magnet stepper motor with an integrated gearbox that improves torque.
Key Specifications
Operating Voltage: 5V
Coil Type: Unipolar
Number of Phases: 4
Stride Angle: 5.625°
Gear Reduction Ratio: Approximately 64:1
Full-Step Resolution: 2048 steps/revolution
Half-Step Resolution: 4096 steps/revolution
Why Use the ULN2003 Driver?
The stepper motor requires more current than an Arduino pin can supply directly.
The ULN2003 driver board acts as an interface between the Arduino and the motor and contains seven Darlington transistor arrays, capable of driving loads up to 500 mA.
Important pins on the module:
IN1–IN4 → Control inputs from Arduino.
VCC → 5V supply.
GND → Common ground.
Motor connector → Connects directly to the 28BYJ-48.
Note: Ensure that the power jumper on the ULN2003 board is installed.
Step Calculation
The internal rotor requires 32 steps for one revolution.
Since the gearbox has a reduction ratio close to 64:1:
32 × 64 = 2048 steps
Therefore:
Full-step operation → 2048 steps/revolution.
Half-step operation → 4096 steps/revolution.
Hardware Setup
Connect a regulated 5V power supply to the VCC and GND pins of the ULN2003 driver module.
Connect the driver's control inputs IN1, IN2, IN3, and IN4 to Arduino digital pins 7, 6, 5, and 4, respectively.
Plug the 28BYJ-48 stepper motor into the motor connector on the ULN2003 board.
Connect the ground of the external 5V supply to the Arduino GND pin to establish a common reference.
After completing these connections, the Arduino can control the motor's speed and direction by energizing the motor coils in the appropriate sequence through the ULN2003 driver.
Applications
This type of stepper motor is suitable for:
Robotic systems
Camera sliders
Pan-and-tilt mechanisms
Small CNC projects
Automated valves
Educational motion control experiments
Precision positioning systems
Conclusion
This project demonstrates how easily the low-cost 28BYJ-48 stepper motor can be controlled using an Arduino Uno and a ULN2003 driver module. By understanding stepping sequences, gear reduction, and speed calculations, precise rotational control can be achieved for a wide range of automation and robotics applications.
Acknowledgement
This project is based on work originally published on PlayWithCircuit, where a more detailed explanation, diagrams, Arduino examples, and complete code walkthroughs are available.
Original article:
https://playwithcircuit.com/28byj48-stepper-motor-arduino-tutorial/
Play with Circuit focuses on practical electronics, Arduino, embedded systems, and hands-on engineering tutorials for students, hobbyists, and makers.
