How to Use the 28BYJ-48 Stepper Motor with Arduino and the ULN2003 Driver

The 28BYJ-48 is the motor almost every maker meets first. It is cheap, it is geared, and it will hold a position all day without complaining. Here is how to wire it, code it, and fix the one mistake that catches nearly everybody.

What is the 28BYJ-48?

The 28BYJ-48 is a small, geared unipolar stepper motor. It has become the go-to first motion project for makers, students and hobbyists because it is cheap, hard to damage, and precise enough for a surprising range of builds, from robotic arms and camera sliders to automated blinds and clocks.

Unlike a plain DC motor that just spins when you give it power, a stepper moves in small, repeatable steps. You can tell it to turn an exact amount and it will stay there. That is the whole appeal: controlled, accurate movement you can trust.

It is almost always sold with the ULN2003 driver board, the little green board that sits between your Arduino and the motor. An Arduino pin cannot supply enough current to drive a motor coil directly, so the ULN2003 does the heavy lifting while the Arduino just tells it when to switch.

• 2048Steps per turn
• 0.176°Per full step
• 5VSupply
• ~240 mACurrent draw

Specs at a glance

That heavy gear reduction is the 28BYJ-48's superpower. It buys you fine positioning and decent torque for the size, and the trade is top-end speed. This motor is built for accuracy, not racing.

Wiring it up (Arduino Uno)

There is not much to get wrong here. The motor plugs into the board one way only, and the board takes four signal wires plus power.

1. Push the motor's white plug into the connector on the ULN2003 board. It is keyed, so it only fits one way.
2. Run four jumper wires from IN1, IN2, IN3 and IN4 to Arduino pins 8, 9, 10 and 11.
3. Connect the board's + and - terminals to Arduino 5V and GND, then plug in the USB cable.

Want the full picture, including which coil each colour goes to? This one is worth saving.

The code

This sketch uses the Stepper library that ships with the Arduino IDE, so there is nothing to install. It turns one full revolution each way, forever.

#include <Stepper.h>

const int stepsPerRevolution = 2048;  // 28BYJ-48 in full-step mode

// IMPORTANT: pin order is 8, 10, 9, 11 - NOT 8, 9, 10, 11
// The middle two are swapped to match the motor's coil sequence.
Stepper myStepper(stepsPerRevolution, 8, 10, 9, 11);

void setup() {
  myStepper.setSpeed(10);   // RPM (keep it low - this motor is geared)
}

void loop() {
  myStepper.step(stepsPerRevolution);    // one full turn clockwise
  delay(1000);
  myStepper.step(-stepsPerRevolution);   // one full turn anti-clockwise
  delay(1000);
}

If it buzzes but will not turn, swap the middle two pin numbers.

Troubleshooting

Nearly every problem with this motor lands somewhere in this table.

Project ideas

Once it is turning on command, the fun part starts:

• Automated curtains or blinds on a timer
• Pan and tilt mount for a camera or sensor
• A rotating turntable for product photography
• Analog-style clock movements
• Robotic arm joints
• A dividing head for a mini lathe or a 3D-printed jig

Just getting started? Our breadboard basics guide walks through building a first circuit, and if you would rather drive this from a Wi-Fi capable board, see getting started with the ESP32-WROOM-32.