⚙️ Advanced
🔩 Motors & Actuators
🟢 Wokwi
Stepper Motor Control
28BYJ-48 + ULN2003
Control a 28BYJ-48 stepper motor with an Arduino UNO and ULN2003 driver — including forward/reverse rotation, variable speed, button controls, and serial commands. Fully simulated in Wokwi, no hardware needed.
How a stepper motor works
Stepper vs DC motor
Arduino interfacing
Speed & direction control
Serial command interface
0Requirements
Components Required (Wokwi)
Arduino UNO
Main microcontroller
28BYJ-48 Motor
5V stepper, 64:1 gear
ULN2003 Driver
IN1–IN4 driver board
5× Push Buttons
Fwd/Rev/Speed/Stop
2× LEDs
Green (Fwd) + Red (Rev)
2× Resistors
220Ω for LEDs
Jumper Wires
For all connections
All components are simulated — use the free Wokwi Arduino Simulator at wokwi.com. No physical hardware required.
✨ Overview
Project Features
Forward / Reverse Rotation
Variable Speed (1–15 RPM)
Step Count Tracking
5 Push Button Controls
Serial Command Interface
90°, 180°, 360° Presets
LED Direction Indicators
Position Reset (Z command)
1Wiring
Pin Connections
⚙️ Stepper Motor (28BYJ-48)
IN1 (A−)→Pin 8
IN2 (A+)→Pin 9
IN3 (B−)→Pin 10
IN4 (B+)→Pin 11
V+→5V
GND→GND
🕹️ Push Buttons (INPUT_PULLUP)
Forward BTN→Pin 2 / GND
Reverse BTN→Pin 3 / GND
Speed+ BTN→Pin 4 / GND
Speed− BTN→Pin 5 / GND
Stop BTN→Pin 6 / GND
💡 LED Indicators (220Ω)
LED Green (Fwd)→Pin 12 → R1 → A
LED Red (Rev)→Pin 13 → R2 → A
Both cathodes→GND
⚠️ Note: The Stepper() constructor uses the pin order IN1, IN3, IN2, IN4 — this is correct for the 28BYJ-48's coil sequence.
2Controls
Button Controls
🟢 Forward
Pin 2 — INPUT_PULLUP
🔴 Reverse
Pin 3 — INPUT_PULLUP
🔵 Speed +
Pin 4 — up to 15 RPM
🔵 Speed −
Pin 5 — down to 1 RPM
🟡 Stop
Pin 6 — halt motor
All buttons use hardware debouncing (50ms) in software. They are wired with INPUT_PULLUP — no external resistors needed.
3Wokwi Config
diagram.json
Paste this into the diagram.json tab in Wokwi to auto-wire all components instantly.
diagram.json
{
"version": 1,
"author": "28BYJ-48 Stepper Motor Control",
"editor": "wokwi",
"parts": [
{
"type": "wokwi-arduino-uno", "id": "uno",
"top": 0, "left": 0, "attrs": {}
},
{
"type": "wokwi-stepper-motor", "id": "stepper1",
"top": -100, "left": 300,
"attrs": { "size": "28BYJ-48" }
},
{
"type": "wokwi-pushbutton", "id": "btn1",
"top": 120, "left": -200,
"attrs": { "color": "green", "label": "Forward" }
},
{
"type": "wokwi-pushbutton", "id": "btn2",
"top": 120, "left": -100,
"attrs": { "color": "red", "label": "Reverse" }
},
{
"type": "wokwi-pushbutton", "id": "btn3",
"top": 180, "left": -200,
"attrs": { "color": "blue", "label": "Speed+" }
},
{
"type": "wokwi-pushbutton", "id": "btn4",
"top": 180, "left": -100,
"attrs": { "color": "blue", "label": "Speed-" }
},
{
"type": "wokwi-pushbutton", "id": "btn5",
"top": 240, "left": -150,
"attrs": { "color": "yellow", "label": "STOP" }
},
{
"type": "wokwi-led", "id": "led1",
"top": -80, "left": 500,
"attrs": { "color": "green", "label": "Forward" }
},
{
"type": "wokwi-led", "id": "led2",
"top": -20, "left": 500,
"attrs": { "color": "red", "label": "Reverse" }
},
{
"type": "wokwi-resistor", "id": "r1",
"top": -60, "left": 480,
"attrs": { "value": "220" }
},
{
"type": "wokwi-resistor", "id": "r2",
"top": 0, "left": 480,
"attrs": { "value": "220" }
}
],
"connections": [
[ "uno:GND.1", "stepper1:GND", "black", [ "v0" ] ],
[ "uno:5V", "stepper1:V+", "red", [ "v0" ] ],
[ "uno:8", "stepper1:A-", "orange", [ "v0" ] ],
[ "uno:9", "stepper1:A+", "yellow", [ "v0" ] ],
[ "uno:10", "stepper1:B-", "green", [ "v0" ] ],
[ "uno:11", "stepper1:B+", "blue", [ "v0" ] ],
[ "btn1:1.l", "uno:2", "green", [ "v0" ] ],
[ "btn1:2.l", "uno:GND.2", "black", [ "v0" ] ],
[ "btn2:1.l", "uno:3", "red", [ "v0" ] ],
[ "btn2:2.l", "uno:GND.2", "black", [ "v0" ] ],
[ "btn3:1.l", "uno:4", "blue", [ "v0" ] ],
[ "btn3:2.l", "uno:GND.2", "black", [ "v0" ] ],
[ "btn4:1.l", "uno:5", "blue", [ "v0" ] ],
[ "btn4:2.l", "uno:GND.2", "black", [ "v0" ] ],
[ "btn5:1.l", "uno:6", "yellow", [ "v0" ] ],
[ "btn5:2.l", "uno:GND.2", "black", [ "v0" ] ],
[ "uno:12", "r1:1", "green", [ "v0" ] ],
[ "r1:2", "led1:A", "green", [ "v0" ] ],
[ "led1:C", "uno:GND.3", "black", [ "v0" ] ],
[ "uno:13", "r2:1", "red", [ "v0" ] ],
[ "r2:2", "led2:A", "red", [ "v0" ] ],
[ "led2:C", "uno:GND.3", "black", [ "v0" ] ]
],
"dependencies": {}
}
4Sketch
Arduino Code
⚙️
28BYJ-48 Stepper Motor
⏸ Stopped — click Run Simulation to start
sketch.ino — Arduino C++
/* 28BYJ-48 Stepper Motor Control with ULN2003 Driver ===================================================== Forward/Reverse, variable speed, 5 buttons, serial commands, step tracking Author: Arduino Project | Wokwi Simulator */ #include <Stepper.h> // Motor: 28BYJ-48 has 64:1 gear ratio → 32 steps × 64 = 2048 #define STEPS_PER_REV 2048 // ULN2003 driver pins (IN1–IN4) #define IN1 8 #define IN2 9 #define IN3 10 #define IN4 11 // Button pins #define BTN_FORWARD 2 #define BTN_REVERSE 3 #define BTN_SPEED_UP 4 #define BTN_SPEED_DOWN 5 #define BTN_STOP 6 // LED indicators #define LED_FORWARD 12 #define LED_REVERSE 13 // Note: Stepper(steps, IN1, IN3, IN2, IN4) — coil order for 28BYJ-48 Stepper myStepper(STEPS_PER_REV, IN1, IN3, IN2, IN4); // State variables int motorSpeed = 10; // RPM (1–15 recommended) int currentPosition = 0; bool motorRunning = false; int direction = 1; // 1 = fwd, -1 = rev unsigned long stepCount = 0; // Debounce state bool lastBtnForward = HIGH; bool lastBtnReverse = HIGH; bool lastBtnSpeedUp = HIGH; bool lastBtnSpeedDown = HIGH; bool lastBtnStop = HIGH; void setup() { Serial.begin(9600); Serial.println("========================================"); Serial.println(" 28BYJ-48 Stepper Motor Controller"); Serial.println("========================================"); pinMode(BTN_FORWARD, INPUT_PULLUP); pinMode(BTN_REVERSE, INPUT_PULLUP); pinMode(BTN_SPEED_UP, INPUT_PULLUP); pinMode(BTN_SPEED_DOWN, INPUT_PULLUP); pinMode(BTN_STOP, INPUT_PULLUP); pinMode(LED_FORWARD, OUTPUT); pinMode(LED_REVERSE, OUTPUT); myStepper.setSpeed(motorSpeed); digitalWrite(LED_FORWARD, LOW); digitalWrite(LED_REVERSE, LOW); printInstructions(); } void loop() { checkButtons(); checkSerialCommands(); if (motorRunning) { myStepper.step(direction); stepCount++; currentPosition += direction; if (stepCount % 100 == 0) displayStatus(); } delay(1); } void checkButtons() { bool b; b = digitalRead(BTN_FORWARD); if (b == LOW && lastBtnForward == HIGH) { delay(50); if (digitalRead(BTN_FORWARD) == LOW) rotateForward(); } lastBtnForward = b; b = digitalRead(BTN_REVERSE); if (b == LOW && lastBtnReverse == HIGH) { delay(50); if (digitalRead(BTN_REVERSE) == LOW) rotateReverse(); } lastBtnReverse = b; b = digitalRead(BTN_SPEED_UP); if (b == LOW && lastBtnSpeedUp == HIGH) { delay(50); if (digitalRead(BTN_SPEED_UP) == LOW) increaseSpeed(); } lastBtnSpeedUp = b; b = digitalRead(BTN_SPEED_DOWN); if (b == LOW && lastBtnSpeedDown == HIGH) { delay(50); if (digitalRead(BTN_SPEED_DOWN) == LOW) decreaseSpeed(); } lastBtnSpeedDown = b; b = digitalRead(BTN_STOP); if (b == LOW && lastBtnStop == HIGH) { delay(50); if (digitalRead(BTN_STOP) == LOW) stopMotor(); } lastBtnStop = b; } void checkSerialCommands() { if (Serial.available() > 0) { char cmd = Serial.read(); switch (cmd) { case 'F': case 'f': rotateForward(); break; case 'R': case 'r': rotateReverse(); break; case 'S': case 's': stopMotor(); break; case '+': increaseSpeed(); break; case '-': decreaseSpeed(); break; case '1': rotate90Degrees(); break; case '2': rotate180Degrees(); break; case '3': rotate360Degrees(); break; case 'I': case 'i': displayStatus(); break; case 'Z': case 'z': resetPosition(); break; case 'H': case 'h': printInstructions(); break; } } } void rotateForward() { motorRunning = true; direction = 1; digitalWrite(LED_FORWARD, HIGH); digitalWrite(LED_REVERSE, LOW); Serial.println(">>> FORWARD ROTATION <<<"); } void rotateReverse() { motorRunning = true; direction = -1; digitalWrite(LED_FORWARD, LOW); digitalWrite(LED_REVERSE, HIGH); Serial.println(">>> REVERSE ROTATION <<<"); } void stopMotor() { motorRunning = false; digitalWrite(LED_FORWARD, LOW); digitalWrite(LED_REVERSE, LOW); Serial.print(">>> STOPPED — Total steps: "); Serial.println(stepCount); } void increaseSpeed() { if (motorSpeed < 15) { motorSpeed++; myStepper.setSpeed(motorSpeed); } Serial.print("Speed: "); Serial.print(motorSpeed); Serial.println(" RPM"); } void decreaseSpeed() { if (motorSpeed > 1) { motorSpeed--; myStepper.setSpeed(motorSpeed); } Serial.print("Speed: "); Serial.print(motorSpeed); Serial.println(" RPM"); } void rotate90Degrees() { int steps = STEPS_PER_REV / 4; Serial.println("Rotating 90°..."); myStepper.step(steps); currentPosition += steps; stepCount += steps; Serial.println("Done!"); } void rotate180Degrees() { int steps = STEPS_PER_REV / 2; Serial.println("Rotating 180°..."); myStepper.step(steps); currentPosition += steps; stepCount += steps; Serial.println("Done!"); } void rotate360Degrees() { Serial.println("Full rotation 360°..."); myStepper.step(STEPS_PER_REV); currentPosition += STEPS_PER_REV; stepCount += STEPS_PER_REV; Serial.println("Done!"); } void resetPosition() { currentPosition = 0; stepCount = 0; Serial.println("Position counter reset to zero"); } void displayStatus() { Serial.println("=== Motor Status ==="); Serial.print("Running: "); Serial.println(motorRunning ? "YES" : "NO"); Serial.print("Direction: "); Serial.println(direction == 1 ? "FORWARD" : "REVERSE"); Serial.print("Speed: "); Serial.print(motorSpeed); Serial.println(" RPM"); Serial.print("Position: "); Serial.print(currentPosition); Serial.println(" steps"); Serial.print("Rotations: "); Serial.println((float)currentPosition / STEPS_PER_REV, 2); Serial.println("==================="); } void printInstructions() { Serial.println("BUTTON: Btn1=Fwd Btn2=Rev Btn3=Spd+ Btn4=Spd- Btn5=Stop"); Serial.println("SERIAL: F=Fwd R=Rev S=Stop +=Spd+ -=Spd- 1=90° 2=180° 3=360° I=Info Z=Reset H=Help"); Serial.println("Ready!"); }
💻 Interface
Serial Command Reference
Open the Serial Monitor at 9600 baud and send single characters to control the motor in real time.
FForward rotation
RReverse rotation
SStop motor
+Increase speed (+1 RPM)
−Decrease speed (−1 RPM)
1Rotate exactly 90°
2Rotate exactly 180°
3Rotate exactly 360°
IDisplay motor status
ZReset position counter
HShow help / instructions
5Simulate
Run the Simulation
Paste diagram.json
Copy the diagram.json into Wokwi's diagram tab to auto-wire everything.
Paste the Code
Copy the sketch into the code editor tab.
Click ▶ Play
Press the green start button to run the simulation.
Use Buttons
Click the virtual push buttons to control direction and speed.
Serial Monitor
Open Serial Monitor, type F, R, 1–3 for precise control.
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