Arduino - Stepper Motor and Limit Switch

In this Arduino tutorial, We are going to learn how to use Arduino, limit switch, L298N driver and stepper motor. In detail, we are going to learn:

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×Limit Switch
1×Stepper Motor Nema 17
1×L298N Motor Driver Module
1×12V Power Adapter
1×DC Power Jack
n×Jumper Wires
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About Stepper Motor and Limit Switch

If you do not know about stepper motor and limit switch (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

This tutorial provides the Arduino codes for two cases: One stepper motor + one limit switch, One stepper motor + two limit switches.

  • Wiring diagram between the stepper motor and a limit switch
  • Arduino stepper motor and limit switch wiring diagram

    Image is developed using Fritzing. Click to enlarge image

  • Wiring diagram between the stepper motor and two limit switches
  • Arduino stepper motor and two limit switches wiring diagram

    Image is developed using Fritzing. Click to enlarge image

※ NOTE THAT:

Depending on the stepper motor, the wiring connection between the stepper motor and L298N may be different. Please take a close look at this Arduino - Stepper Motor tutorial to see how to connect the stepper motor to the L298N motor driver.

Arduino Code - Stop Stepper Motor by a Limit Switch

There are several ways to make a stepper motor stop:

  • Call stepper.stop() function: This way does NOT stop the stepper motor immediately but gradually
  • Do NOT call stepper.run() function: This way stops the stepper motor immediately

The below code make a stepper motor spin infinitely and stop immediately when a limit switch is touched

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-stepper-motor-and-limit-switch */ #include <ezButton.h> #include <AccelStepper.h> #define MAX_POSITION 0x7FFFFFFF // maximum of position we can set (long type) ezButton limitSwitch(A0); // create ezButton object that attach to pin A0; AccelStepper stepper(AccelStepper::FULL4WIRE, 7, 6, 5, 4); bool isStopped = false; void setup() { Serial.begin(9600); limitSwitch.setDebounceTime(50); // set debounce time to 50 milliseconds stepper.setMaxSpeed(500.0); // set the maximum speed stepper.setAcceleration(50.0); // set acceleration stepper.setSpeed(100); // set initial speed stepper.setCurrentPosition(0); // set position stepper.moveTo(MAX_POSITION); } void loop() { limitSwitch.loop(); // MUST call the loop() function first if (limitSwitch.isPressed()) { Serial.println(F("The limit switch: TOUCHED")); isStopped = true; } if (isStopped == false) { // without this part, the move will stop after reaching maximum position if (stepper.distanceToGo() == 0) { // if motor moved to the maximum position stepper.setCurrentPosition(0); // reset position to 0 stepper.moveTo(MAX_POSITION); // move the motor to maximum position again } stepper.run(); // MUST be called in loop() function } else { // without calling stepper.run() function, motor stops immediately // NOTE: stepper.stop() function does NOT stops motor immediately Serial.println(F("The stepper motor is STOPPED")); } }

Quick Steps

  • Connect Arduino to PC via USB cable
  • Open Arduino IDE, select the right board and port
  • On Arduino IDE, Go to Tools Manage Libraries
  • Arduino add library
  • Search “ezButton”, then find the button library by ArduinoGetStarted.com
  • Click Install button to install ezButton library.
  • Arduino button library
  • Search “AccelStepper”, then find the AccelStepper library by Mike McCauley
  • Click Install button to install AccelStepper library.
  • Arduino AccelStepper library
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
  • If the wiring is correct, you will see the motor rotates clockwise direction.
  • Touch the limit switch
  • You will see the motor is stopped immediately
  • The result on Serial Monitor looks like below
  • COM6
    Send
    The limit switch: TOUCHED The stepper motor is STOPPED The stepper motor is STOPPED The stepper motor is STOPPED The stepper motor is STOPPED
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  

Code Explanation

Read the line-by-line explanation in comment lines of code!

Arduino Code - Change Direction of Stepper Motor by a Limit Switch

The below code make a stepper motor spin infinitely and change its direction when a limit switch is touched

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-stepper-motor-and-limit-switch */ #include <ezButton.h> #include <AccelStepper.h> #define DIRECTION_CCW -1 #define DIRECTION_CW 1 #define MAX_POSITION 0x7FFFFFFF // maximum of position we can set (long type) ezButton limitSwitch(A0); // create ezButton object that attach to pin A0; AccelStepper stepper(AccelStepper::FULL4WIRE, 7, 6, 5, 4); int direction = DIRECTION_CW; long targetPos = 0; void setup() { Serial.begin(9600); limitSwitch.setDebounceTime(50); // set debounce time to 50 milliseconds stepper.setMaxSpeed(500.0); // set the maximum speed stepper.setAcceleration(50.0); // set acceleration stepper.setSpeed(100); // set initial speed stepper.setCurrentPosition(0); // set position targetPos = direction * MAX_POSITION; stepper.moveTo(targetPos); } void loop() { limitSwitch.loop(); // MUST call the loop() function first if (limitSwitch.isPressed()) { Serial.println(F("The limit switch: TOUCHED")); direction *= -1; // change direction Serial.print(F("The direction -> ")); if (direction == DIRECTION_CW) Serial.println(F("CLOCKWISE")); else Serial.println(F("ANTI-CLOCKWISE")); targetPos = direction * MAX_POSITION; stepper.setCurrentPosition(0); // set position stepper.moveTo(targetPos); } // without this part, the move will stop after reaching maximum position if (stepper.distanceToGo() == 0) { // if motor moved to the maximum position stepper.setCurrentPosition(0); // reset position to 0 stepper.moveTo(targetPos); // move the motor to maximum position again } stepper.run(); // MUST be called in loop() function }

Quick Steps

  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
  • If the wiring is correct, you will see the motor spins in the clockwise direction.
  • Touch the limit switch
  • You will see the stepper motor's direction is changed to the anti-clockwise
  • Touch the limit switch again
  • You will see the stepper motor's direction is changed to clockwise
  • The result on Serial Monitor looks like below
  • COM6
    Send
    The limit switch: TOUCHED The direction -> ANTI-CLOCKWISE The limit switch: TOUCHED The direction -> CLOCKWISE
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  

Arduino Code - Change Direction of Stepper Motor by two Limit Switches

The below code make a stepper motor spin infinitely and change its direction when one of two limit switches is touched

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-stepper-motor-and-limit-switch */ #include <ezButton.h> #include <AccelStepper.h> #define DIRECTION_CCW -1 #define DIRECTION_CW 1 #define STATE_CHANGE_DIR 1 #define STATE_MOVE 2 #define STATE_MOVING 3 #define MAX_POSITION 0x7FFFFFFF // maximum of position we can set (long type) ezButton limitSwitch_1(A0); // create ezButton object that attach to pin A0; ezButton limitSwitch_2(A1); // create ezButton object that attach to pin A1; AccelStepper stepper(AccelStepper::FULL4WIRE, 7, 6, 5, 4); int stepperState = STATE_MOVE; int direction = DIRECTION_CW; long targetPos = 0; void setup() { Serial.begin(9600); limitSwitch_1.setDebounceTime(50); // set debounce time to 50 milliseconds limitSwitch_2.setDebounceTime(50); // set debounce time to 50 milliseconds stepper.setMaxSpeed(500.0); // set the maximum speed stepper.setAcceleration(50.0); // set acceleration stepper.setSpeed(100); // set initial speed stepper.setCurrentPosition(0); // set position } void loop() { limitSwitch_1.loop(); // MUST call the loop() function first limitSwitch_2.loop(); // MUST call the loop() function first if (limitSwitch_1.isPressed()) { stepperState = STATE_CHANGE_DIR; Serial.println(F("The limit switch 1: TOUCHED")); } if (limitSwitch_2.isPressed()) { stepperState = STATE_CHANGE_DIR; Serial.println(F("The limit switch 2: TOUCHED")); } switch (stepperState) { case STATE_CHANGE_DIR: direction *= -1; // change direction Serial.print(F("The direction -> ")); if (direction == DIRECTION_CW) Serial.println(F("CLOCKWISE")); else Serial.println(F("ANTI-CLOCKWISE")); stepperState = STATE_MOVE; // after changing direction, go to the next state to move the motor break; case STATE_MOVE: targetPos = direction * MAX_POSITION; stepper.setCurrentPosition(0); // set position stepper.moveTo(targetPos); stepperState = STATE_MOVING; // after moving, go to the next state to keep the motor moving infinity break; case STATE_MOVING: // without this state, the move will stop after reaching maximum position if (stepper.distanceToGo() == 0) { // if motor moved to the maximum position stepper.setCurrentPosition(0); // reset position to 0 stepper.moveTo(targetPos); // move the motor to maximum position again } break; } stepper.run(); // MUST be called in loop() function }

Quick Steps

  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
  • If the wiring is correct, you will see the motor spins in the clockwise direction.
  • Touch the limit switch 1
  • You will see the stepper motor's direction is changed to anti-clockwise
  • Touch the limit switch 2
  • You will see the stepper motor's direction is changed to clockwise
  • The result on Serial Monitor looks like below
  • COM6
    Send
    The limit switch 1: TOUCHED The direction -> ANTI-CLOCKWISE The limit switch 2: TOUCHED The direction -> CLOCKWISE
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  

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