🔍 What is the 28BYJ-48 Stepper Motor?

The 28BYJ-48 is a 5V unipolar stepper motor with a built-in reduction gearbox. This makes it ideal for applications requiring precise control at low speed.

🧾 Specifications

🔁 How Does It Work?

• The motor has 4 coils and a common wire (VCC).
• Coils are energized in a sequence to rotate the internal rotor.
• The gearbox slows down output but increases torque and precision.

⚙️ Full Output Shaft Rotation:

• Internal motor steps: 32 steps/rev (11.25° each)
• Gearbox: 63.68395:1 ratio
• Result:
  32 × 63.68395 ≈ 2048 steps/rev
  That’s 0.176° per step – very precise!

🎯 Advantages of 28BYJ-48

✅ Low voltage (5V) – safe for microcontrollers
✅ High torque due to gearbox
✅ Fine step resolution (2048 steps/rev)
✅ Cheap and widely available
✅ Compatible with ULN2003 board

🧲 Wiring Details

5 Wires (typically colored):

🧪 Test & Troubleshooting

• Motor not rotating? Check wiring and ULN2003 power.
• Wrong direction? Reverse coil order (e.g., IN1 ↔ IN4).
• Skipping steps? Add delay or check power supply.
• Weak torque? Use a stronger 5V supply (≥500mA).

🛠 Advanced Tips

• Use AccelStepper library for smoother motion.
• Gearbox introduces backlash – not ideal for fast direction changes.
• Not suitable for high-speed applications.
• Use microcontroller sleep or disable pins to reduce heat when idle.

🔧 Real-Life Applications

• Robot arms and legs (slow, accurate movement)
• Camera sliders
• Smart blinds/curtains
• Automatic locks
• Hobby CNC or XY plotters (light-duty)

HOW TO OPERATE

 

#include <Stepper.h>

const int stepsPerRevolution = 2048; // or the actual steps per revolution
#define IN1 19
#define IN2 18
#define IN3 5
#define IN4 17

Stepper myStepper(stepsPerRevolution, IN1, IN3, IN2, IN4);

void setup() {
  Serial.begin(115200);
  myStepper.setSpeed(15); // Set speed in RPM
}

void loop() {
  Serial.println("Clockwise");
  myStepper.step(stepsPerRevolution);
  delay(1000);

  Serial.println("Counterclockwise");
  myStepper.step(-stepsPerRevolution);
  delay(1000);
}

HOW TO OPERATE

 

#include <Stepper.h>

const int stepsPerRevolution = 2048; // or the actual steps per revolution
#define IN1 19
#define IN2 18
#define IN3 5
#define IN4 17

Stepper myStepper(stepsPerRevolution, IN1, IN3, IN2, IN4);

void setup() {
  Serial.begin(115200);
  myStepper.setSpeed(15); // Set speed in RPM
}

void loop() {
  Serial.println("Clockwise");
  myStepper.step(stepsPerRevolution);
  delay(1000);

  Serial.println("Counterclockwise");
  myStepper.step(-stepsPerRevolution);
  delay(1000);
}