ESP32, Motor/ Robot

Control Stepper Motor 28BYJ-48 Using TTGO T-Display ESP32

by Idris
December 11, 2019

28BYJ-48, ESP32, Stepper Motor

Control stepper motor with ESP32 and Arduino.

Introduction

A stepper motor is an electric motor that rotates in discrete step increments. The movement of each step is precise and repeatable; therefore, the motor’s position can be controlled precisely without any feedback mechanism. Nowadays, it is being used widely in 3D printers, CNC machine or laser engraving (like Snapmaker). In this tutorial, I will share the basic steps to control stepper motor movement using ESP32 board.

You can read following links to know more how stepper motor works:

Video

This video shows how to control stepper motor model 28BYJ-48 using ESP32 board.

Hardware Preparation

This is the list of items used in the video.

TTGO T-Display ESP32 1.14 Display Module

12V 28BYJ-48 Stepper Motor + ULN2003 Driver Board

LiPo Rechargeable Battery 11.1V 500mAh 25C

Breadboard

Jumper Wire

Sample Program

This sample program will allow user to control stepper movement through button 1 and 2 (on TTGO T-Display ESP32 board). You need to install following library on Library Manager:

TFT_eSPI by Bodmer Version 1.4.20

/*

  Tutorial: Control 28BYJ-48 Stepper Motor Using TTGO T-Display ESP32

  Board:

  – TTGO T-Display ESP32

    https://my.cytron.io/p-ttgo-t-display-esp32-1.14-display-module

  Output:

  – 12V 28BYJ-48 Stepper Motor

    https://my.cytron.io/c-motor-and-motor-driver/c-dc-motor/c-stepper-motor/p-12v-28byj-48-stepper-motor-plus-uln2003-driver-board

  Connection  TTGO | Stepper Driver

               GND | GND

                27 | IN1

                26 | IN2

                25 | IN3

                33 | IN4

  Ext libraries:

  – TFT_eSPI by Bodmer Version 1.4.16

*/

#include <SPI.h>

#include <TFT_eSPI.h>

TFT_eSPI tft = TFT_eSPI(); // Resolution 135 x 240

#define FF17 &FreeSans9pt7b

#define FF21 &FreeSansBold9pt7b

#define ROW1 0,16

#define ROW2 0,38

#define ROW3 0,60

#define ROW4 0,82

#define ROW5 0,104

#define ROW6 0,126

#define BUTTON1 35

#define BUTTON2 0

#define STEPPER_IN1 27

#define STEPPER_IN2 26

#define STEPPER_IN3 25

#define STEPPER_IN4 33

#define REVOLUTION_STEP 2048 // 1 revolution

boolean stepperDirection = false;

int stepperStep = 0;

int stepperStepCount = 0;

boolean stepperMove = false;

long prevMillisStepper = 0;

int intervalStepper = 2; // Minimum is 2, increase for lower speed

boolean button1Pressed = false;

boolean button2Pressed = false;

void setup()

{

  pinMode(BUTTON1, INPUT_PULLUP);

  pinMode(BUTTON2, INPUT_PULLUP);

  pinMode(STEPPER_IN1, OUTPUT);

  pinMode(STEPPER_IN2, OUTPUT);

  pinMode(STEPPER_IN3, OUTPUT);

  pinMode(STEPPER_IN4, OUTPUT);

  tft.init();

  tft.setRotation(1);

  tft.fillScreen(TFT_BLACK);

  tft.setFreeFont(FF21);

  tft.setTextColor(TFT_BLUE);

  tft.setCursor(ROW1);

  tft.print("BUTTON1");

  tft.setCursor(ROW5);

  tft.print("BUTTON2");

  tft.setFreeFont(FF17);

  tft.setTextColor(TFT_RED);

  tft.setCursor(ROW2);

  tft.print("Clockwise");

  tft.setCursor(ROW6);

  tft.print("Counter Clockwise");

}

void loop()

{

  if (digitalRead(BUTTON1) == LOW &&

      button1Pressed == false) {

    button1Pressed = true;

    stepperDirection = false;

    stepperMove = true;

    stepperStepCount = 0;

    stepperStep = 1;

  }

  else if (digitalRead(BUTTON1) == HIGH &&

           button1Pressed == true) {

    button1Pressed = false;

  }

  if (digitalRead(BUTTON2) == LOW) {

    stepperDirection = true;

    stepperMove = true;

    stepperStepCount = 0;

    stepperStep = 1;

  }

  else if (digitalRead(BUTTON2) == HIGH &&

           button2Pressed == true) {

    button2Pressed = false;

  }

  if (millis() – prevMillisStepper > intervalStepper) {

    if (stepperMove == true) {

      if (stepperDirection) {

        if (stepperStep++ >= 3) {

          stepperStep = 0;

        }

      }

      else {

        if (stepperStep– == 0) {

          stepperStep = 3;

        }

      }

      if (stepperStepCount++ == REVOLUTION_STEP) {

        stepperMove = false;

        stepperStep = 4;

      }

      switch (stepperStep) {

        case 0:

          digitalWrite(STEPPER_IN1, HIGH);

          digitalWrite(STEPPER_IN2, LOW);

          digitalWrite(STEPPER_IN3, LOW);

          digitalWrite(STEPPER_IN4, LOW);

          break;

        case 1:

          digitalWrite(STEPPER_IN1, LOW);

          digitalWrite(STEPPER_IN2, HIGH);

          digitalWrite(STEPPER_IN3, LOW);

          digitalWrite(STEPPER_IN4, LOW);

          break;

        case 2:

          digitalWrite(STEPPER_IN1, LOW);

          digitalWrite(STEPPER_IN2, LOW);

          digitalWrite(STEPPER_IN3, HIGH);

          digitalWrite(STEPPER_IN4, LOW);

          break;

        case 3:

          digitalWrite(STEPPER_IN1, LOW);

          digitalWrite(STEPPER_IN2, LOW);

          digitalWrite(STEPPER_IN3, LOW);

          digitalWrite(STEPPER_IN4, HIGH);

          break;

        default:

          digitalWrite(STEPPER_IN1, LOW);

          digitalWrite(STEPPER_IN2, LOW);

          digitalWrite(STEPPER_IN3, LOW);

          digitalWrite(STEPPER_IN4, LOW);

          break;

      }

    }

    prevMillisStepper = millis();

  }

}