28BYJ-48 Stepper Motor 5V DC and ULN2003 Stepper Motor Driver

Specifications

• Motor Type: Unipolar Stepper Motor
• Operating Voltage: 5V DC
• Phases: 4-Phase
• Wiring: 5-Wire setup (Standard JST connector)
• Step Angle: 5.625° / 64 (approx. 0.088° per step)
• Gear Reduction Ratio: 1:64
• Steps per Revolution: 2048 (in half-step mode)
• Friction Torque: 600-1200 gf.cm
• Pull-in Torque: 300 gf.cm
• Driver IC: ULN2003A Darlington Transistor Array
• Driver Board Features: 4x LED indicators (A, B, C, D) for step visualization
• Motor Diameter: 28mm
• Shaft: 5mm flattened shaft (Double-D shape)

Applications

• Home Automation: Automated window blinds, smart curtain openers, and motorized pet feeders.
• Camera Rigs: DIY camera sliders, slow-pan timelapse mounts, and automated focus pullers.
• HVAC Control: Automated air conditioning louvers and vent direction controls.
  Robotics: Lightweight robotic arm joints, sensor sweeping platforms (LIDAR/Ultrasonic).

Unlock New Capabilities

• Past Projects: If you've mastered basic movement using standard DC motors and L298N drivers, you know they are great for speed but terrible for exact positioning.
• The Upgrade: This stepper motor kit unlocks positional awareness. You can tell the motor to turn exactly 90 degrees and stop, allowing for precise dispensing, aiming, or opening mechanisms.
• Effort Level: Beginner to Intermediate. You will need a basic microcontroller (Arduino, ESP32, or Raspberry Pi) and an understanding of looping code.

Virtual Technician & Wiring Guide

• ⚠️ Critical Power Warning: While the control signals are low-current, the motor itself draws significant power. Do NOT power the motor directly from your microcontroller's 5V pin, as this can cause reboots or burn out your board's voltage regulator. Always use an external 5V power supply for the driver board.
• Control Safety: The ULN2003 module is Probots Logic-Safe, meaning you can safely trigger it using both 5V (Arduino Uno) and 3.3V (ESP32/STM32) logic signals without damaging your microcontroller.

Wiring Pinout:

• Motor to Driver: Plug the white 5-pin connector from the motor into the white socket on the ULN2003 board.
• IN1 to IN4 (Driver): Connect to Digital Pins 8, 9, 10, 11 on your Arduino.
• "+" (Driver): Connect to external 5V Power Supply (Positive).
• "-" (Driver): Connect to external Power Supply Ground AND Arduino Ground.

Package Includes:

• 1 x 28BYJ-48 Stepper Motor 5V DC and ULN2003 Stepper Motor Driver 

Frequently Asked Questions (FAQ)

• What is the operating voltage for this motor?
  It requires a strict 5V DC power supply.
• Can I power it directly from my Arduino's 5V pin?
  It is highly discouraged. Always use a dedicated external 5V power supply to avoid damaging your Arduino.
• What is the gear reduction ratio?
  The internal gear train has a ratio of 1:64, providing higher torque at lower speeds.
• How many steps does it take to complete one full revolution?
  It takes 2048 steps in half-step mode, or 4096 depending on your library configuration.
• Why is my motor vibrating but not rotating?
  This is almost always caused by an incorrect wiring sequence. Double-check your IN1, IN2, IN3, and IN4 pin assignments in your code.
• Will this work with a 3.3V microcontroller like the ESP32 or Raspberry Pi Pico?
  Yes, the ULN2003 driver will accept 3.3V logic signals, but the motor power pins (+/-) must still be supplied with 5V.
• What do the 4 LEDs on the driver board do?
  They light up sequentially to show which of the 4 electromotor coils are currently energized.
• Can I use the A4988 driver for this motor?
  No, the 28BYJ-48 is a 5-wire unipolar stepper, while the A4988 is designed for 4-wire bipolar steppers. You must use the included ULN2003.
• How much weight can this motor lift?
  It has a pull-in torque of roughly 300 gf.cm. It is designed for lightweight mechanisms, not heavy lifting.
• How fast can this motor spin?
  Due to the 1:64 gear reduction, the maximum reliable speed is around 15 to 20 RPM.
• Can I reverse the direction of rotation?
  Yes, by reversing the step firing sequence in your microcontroller code.
• Does the motor hold its position when stopped?
  Yes, if you leave the current coil energized, it will hold its position. However, this will cause the motor to heat up over time.
• Why is the motor getting warm during use?
  Stepper motors draw maximum current when holding a position. Getting warm is normal, but if it is too hot to touch, check your voltage.
• How long is the cable attached to the motor?
  The standard cable length is approximately 25cm.
• Can I extend the motor wires?
  Yes, you can use standard jumper wires or solder extensions, but keep them as short as possible to prevent voltage drop.
• Can I run two motors off a single ULN2003 board?
  No, each motor requires its own dedicated ULN2003 driver board.
• What is the best library to use for this in Arduino?
  For beginners, the built-in Stepper library is great. For smooth movements, use the AccelStepper library.
• Can this motor rotate continuously?
  Yes, it can rotate continuously in either direction without any physical stops.
• What is the shaft size?
  The motor features a 5mm diameter flattened (Double-D) shaft, perfect for mounting standard pulleys or gears.
• Can I modify this to be a bipolar stepper motor?
  Yes, advanced users can cut the common power trace inside the motor casing to convert it into a 4-wire bipolar motor, though this voids the warranty.