ESP8266 & Stepper Motors

Nothing outrageously complicated but when I used the default arduino stepper library to control my 28BYJ-48 stepper motors on my ESP8266 they only turned one direction. With modifications to the library it was possible to get one stepper motor working correctly but the ESP crashed if I tried to control 2 stepper motors, solution sketch below:

What did work:
– Sketch below. (Note: No fancy acceleration/deceleration but I didnt need it)

int pos_rot = 0;  
int pos_elev = 0; 

int rot_counter = 0;
int elev_counter = 0;

int next_rot = -1;
int next_elev = 1;

int step_delay = 10; //Delay between steps in ms

const int motor_pin_1 = 16; // ESP D0
const int motor_pin_2 = 5;  // ESP D1
const int motor_pin_3 = 4;  // ESP D2
const int motor_pin_4 = 0;  // ESP D3
const int motor_pin_5 = 2;  // ESP D4
const int motor_pin_6 = 14; // ESP D5
const int motor_pin_7 = 12; // ESP D6
const int motor_pin_8 = 13; // ESP D7

void setup() {
  pinMode(motor_pin_1, OUTPUT); // Blue
  pinMode(motor_pin_2, OUTPUT); // Pink
  pinMode(motor_pin_3, OUTPUT); // Yellow
  pinMode(motor_pin_4, OUTPUT); // Orange
  pinMode(motor_pin_5, OUTPUT);
  pinMode(motor_pin_6, OUTPUT);
  pinMode(motor_pin_7, OUTPUT);
  pinMode(motor_pin_8, OUTPUT);
  
  // Begin Serial communication at a baud rate of 9600:
  Serial.begin(115200);
  delay(100);Serial.println("Leaving Setup");delay(100);
}

void loop() {
    //test_sweep();
    rot(2038);delay(2000);rot(-2038);   // 2038 steps clockwise followed by the same counterclockwise
    elev(1019);delay(2000);elev(-1019); // 1019 steps clockwise followed by the same counterclockwise
}

void test_sweep(){
      Serial.print("Rotating CCW, pos_rot = ");Serial.println(pos_rot);

    while (pos_rot < 2038) {
    rot(1);
    pos_rot = pos_rot + 1;
 
        if ((pos_rot < 1019) && ((pos_rot % 2) == 0)) {
          elev(2);          
        }
        else if ((pos_rot > 1019) && ((pos_rot % 2) == 0)) {
          elev(-2);
        }
  }
    while (pos_rot > 0) {
    rot(-1);
    pos_rot = pos_rot - 1;
 
        if ((pos_rot > 1019) && ((pos_rot % 2) == 0)) {
          elev(2);
        }
        else if ((pos_rot < 1019) && ((pos_rot % 2) == 0)) {
          elev(-2);
        }
  }
}

void elev(int num_steps) {
    if (num_steps > 0) {
        while (elev_counter < num_steps) {        
          elev_step(next_elev);
          next_elev = next_elev +1;
          if (next_elev > 7) { next_elev = 0;}
          elev_counter = elev_counter +1;
        }
    }
    else {
        num_steps = abs(num_steps);
        while (elev_counter < num_steps) {        
          elev_step(next_elev);
          next_elev = next_elev - 1;
          if (next_elev < 0) { next_elev = 7;}
          elev_counter = elev_counter +1;
        }    
    }
    elev_counter = 0;
}

void rot(int num_steps) {
    if (num_steps > 0) {
    
        while (rot_counter < num_steps) {        
          rot_step(next_rot);
          next_rot = next_rot +1;
          if (next_rot > 7) { next_rot = 0;}
          rot_counter = rot_counter +1;
        }
    }
    else {
        num_steps = abs(num_steps);
        while (rot_counter < num_steps) {        
          rot_step(next_rot);
          next_rot = next_rot - 1;
          if (next_rot < 0) { next_rot = 7;}
          rot_counter = rot_counter +1;
        }    
    }

    rot_counter = 0;  
}

void rot_step(int go_step) {
  switch (go_step) {
      case 0:  // 0001
        digitalWrite(motor_pin_1, 0);  // Blue
        digitalWrite(motor_pin_2, 0);  // Pink
        digitalWrite(motor_pin_3, 0);  // Yellow
        digitalWrite(motor_pin_4, 1);  // Orange
      break;
      case 1:  // 0011
        digitalWrite(motor_pin_1, 0);
        digitalWrite(motor_pin_2, 0);
        digitalWrite(motor_pin_3, 1);
        digitalWrite(motor_pin_4, 1);
      break;
      case 2:  //0010
        digitalWrite(motor_pin_1, 0);
        digitalWrite(motor_pin_2, 0);
        digitalWrite(motor_pin_3, 1);
        digitalWrite(motor_pin_4, 0);
      break;
      case 3:  //0110
        digitalWrite(motor_pin_1, 0);
        digitalWrite(motor_pin_2, 1);
        digitalWrite(motor_pin_3, 1);
        digitalWrite(motor_pin_4, 0);
      break;
      case 4:  // 0100
        digitalWrite(motor_pin_1, 0);
        digitalWrite(motor_pin_2, 1);
        digitalWrite(motor_pin_3, 0);
        digitalWrite(motor_pin_4, 0);
      break;
      case 5:  // 1100
        digitalWrite(motor_pin_1, 1);
        digitalWrite(motor_pin_2, 1);
        digitalWrite(motor_pin_3, 0);
        digitalWrite(motor_pin_4, 0);
      break;
      case 6:  //1000
        digitalWrite(motor_pin_1, 1);
        digitalWrite(motor_pin_2, 0);
        digitalWrite(motor_pin_3, 0);
        digitalWrite(motor_pin_4, 0);
      break;
      case 7:  //1001
        digitalWrite(motor_pin_1, 1);
        digitalWrite(motor_pin_2, 0);
        digitalWrite(motor_pin_3, 0);
        digitalWrite(motor_pin_4, 1);
      break;
    }
    delay(step_delay);
}

void elev_step(int go_step) {
  //Serial.println(go_step);
  switch (go_step) {
      case 0:  // 0001
        digitalWrite(motor_pin_5, LOW);
        digitalWrite(motor_pin_6, LOW);
        digitalWrite(motor_pin_7, LOW);
        digitalWrite(motor_pin_8, HIGH);
      break;
      case 1:  // 0011
        digitalWrite(motor_pin_5, LOW);
        digitalWrite(motor_pin_6, LOW);
        digitalWrite(motor_pin_7, HIGH);
        digitalWrite(motor_pin_8, HIGH);
      break;
      case 2:  //0010
        digitalWrite(motor_pin_5, LOW);
        digitalWrite(motor_pin_6, LOW);
        digitalWrite(motor_pin_7, HIGH);
        digitalWrite(motor_pin_8, LOW);
      break;
      case 3:  //0110
        digitalWrite(motor_pin_5, LOW);
        digitalWrite(motor_pin_6, HIGH);
        digitalWrite(motor_pin_7, HIGH);
        digitalWrite(motor_pin_8, LOW);
      break;
      case 4:  // 0100
        digitalWrite(motor_pin_5, LOW);
        digitalWrite(motor_pin_6, HIGH);
        digitalWrite(motor_pin_7, LOW);
        digitalWrite(motor_pin_8, LOW);
      break;
      case 5:  // 1100
        digitalWrite(motor_pin_5, HIGH);
        digitalWrite(motor_pin_6, HIGH);
        digitalWrite(motor_pin_7, LOW);
        digitalWrite(motor_pin_8, LOW);
      break;
      case 6:  //1000
        digitalWrite(motor_pin_5, HIGH);
        digitalWrite(motor_pin_6, LOW);
        digitalWrite(motor_pin_7, LOW);
        digitalWrite(motor_pin_8, LOW);
      break;
      case 7:  //1001
        digitalWrite(motor_pin_5, HIGH);
        digitalWrite(motor_pin_6, LOW);
        digitalWrite(motor_pin_7, LOW);
        digitalWrite(motor_pin_8, HIGH);
      break;
    }
    delay(step_delay);
}

That’s it!