Running two stepper motors with two rotary encoders

Question

I'm really bad with this coding part of using two rotary encoders to control two stepper motors [using 28BYJ-48 stepper motor with the ULN2003 board]. This code works fine using one rotary encoder for one stepper motor using this off brainy-bits.com:

https://brainy-bits.com/blogs/tutorials/stepper-motor-rotary-encoder-p1

When I slightly modify the code for two encoders and two stepper motors I'm using this: However I'm not getting the results I expected. The two motors just don't respond.

#include "Stepper.h"
#define STEPS 32   // Number of steps for one revolution of Internal shaft
// 2048 steps for one revolution of External shaft

volatile boolean TurnDetected;  // need volatile for Interrupts
volatile boolean rotationdirection;  // CW or CCW rotation

const int PinCLK = 2; // Generating interrupts using CLK signal
const int PinDT = 3;  // Reading DT signal
const int PinSW = 4;  // Reading Push Button switch
const int PinCLK2 = 46;
const int PinDT2 = 47;
const int PinSW2 = 48;

int RotaryPosition = 0;  // To store Stepper Motor Position
int RotaryPosition2 = 0;

int PrevPosition;     // Previous Rotary position Value to check accuracy
int PrevPosition2;
int StepsToTake;      // How much to move Stepper
int StepsToTake2;

// Setup of proper sequencing for Motor Driver Pins
// In1, In2, In3, In4 in the sequence 1-3-2-4
Stepper small_stepper(STEPS, 8, 10, 9, 11);
Stepper small_stepper2(STEPS, 40, 41, 42, 43);


// Interrupt routine runs if CLK goes from HIGH to LOW
void isr () {
  delay(4);  // delay for Debouncing
  if (digitalRead(PinCLK))
    rotationdirection = digitalRead(PinDT);
  else
    rotationdirection = !digitalRead(PinDT);
  TurnDetected = true;
  /////I added this
  delay(4);  // delay for Debouncing
  if (digitalRead(PinCLK2))
    rotationdirection = digitalRead(PinDT2);
  else
    rotationdirection = !digitalRead(PinDT2);
  TurnDetected = true;
}
/////up to here


void setup () {
  pinMode(PinCLK, INPUT);
  pinMode(PinDT, INPUT);
  pinMode(PinSW, INPUT);
  digitalWrite(PinSW, HIGH); // Pull-Up resistor for switch
  attachInterrupt (0, isr, FALLING); // interrupt 0 always connected to pin 2 on Arduino UNO
  pinMode(PinCLK2, INPUT);
  pinMode(PinDT2, INPUT);
  pinMode(PinSW2, INPUT);
  digitalWrite(PinSW2, HIGH); // Pull-Up resistor for switch
  attachInterrupt (0, isr, FALLING); // interrupt 0 always connected to pin 2 on Arduino UNO
}

void loop () {
  small_stepper.setSpeed(600); //Max seems to be 700
  if (!(digitalRead(PinSW))) {   // check if button is pressed
    if (RotaryPosition == 0) {  // check if button was already pressed
    } else {
      small_stepper.step(-(RotaryPosition * 50));
      RotaryPosition = 0; // Reset position to ZERO
    }
  }

  // Runs if rotation was detected
  if (TurnDetected) {
    PrevPosition = RotaryPosition; // Save previous position in variable
    if (rotationdirection) {
      RotaryPosition = RotaryPosition - 1;
    } // decrase Position by 1
    else {
      RotaryPosition = RotaryPosition + 1;
    } // increase Position by 1

    TurnDetected = false;  // do NOT repeat IF loop until new rotation detected

    // Which direction to move Stepper motor
    if ((PrevPosition + 1) == RotaryPosition) { // Move motor CW
      StepsToTake = 50;
      small_stepper.step(StepsToTake);
    }

    if ((RotaryPosition + 1) == PrevPosition) { // Move motor CCW
      StepsToTake = -50;
      small_stepper.step(StepsToTake);
      small_stepper2.setSpeed(600); //Max seems to be 700
      if (!(digitalRead(PinSW2))) {   // check if button is pressed
        if (RotaryPosition2 == 0) {  // check if button was already pressed
        } else {
          small_stepper2.step(-(RotaryPosition * 50));
          RotaryPosition2 = 0; // Reset position to ZERO
        }
      }

      // Runs if rotation was detected
      if (TurnDetected)
      {
        PrevPosition2 = RotaryPosition2; // Save previous position in variable
        if (rotationdirection) {
          RotaryPosition2 = RotaryPosition2 - 1;
        } // decrase Position by 1
        else {
          RotaryPosition2 = RotaryPosition2 + 1;
        } // increase Position by 1

        TurnDetected = false;  // do NOT repeat IF loop until new rotation detected

        // Which direction to move Stepper motor
        if ((PrevPosition2 + 1) == RotaryPosition2) { // Move motor CW
          StepsToTake = 50;
          small_stepper2.step(StepsToTake);
        }

        if ((RotaryPosition2 + 1) == PrevPosition2) { // Move motor CCW
          StepsToTake = -50;
          small_stepper2.step(StepsToTake);
        }
      }
    }
  }
}

Answer 1

simple:

1) write a set of routines that drive your servo motor via interrupts: you will need to specify the on-time for each servo channel.

2) write a set of routines that read the rotary positions.

3) write a set of routines that convert the rotary positions into the on-time parameter.

4) integrate them all.

in your loop, you will simply need to read one rotary position, convert it into the on-time for that channel, and update the on-time parameter. The servo routines will run in the background transparently to your code.