Arduino 28BYJ-48 Stepper Motor and ULN2003 Driver counter clockwise rotation

Using Arduino Programming Questions
1

What i'm looking to do :
when the potentiometer (which is linked to the step motor via a cogwheel) is inactive for a set amount of time, return to center. This works when rotating the step motor manually to the left, it then rotates to the right to center. But when rotating it to the right, it keeps going right to center

I want to rotate it similarly to when it's rotated to the left, so when it's rotated to the right, center by rotating the opposite way, not the same way

Using my code in particular, I seem to be unable to reverse the step motor's rotation to return to center, here is my code :

#include <Stepper.h>

// Stepper motor configuration
const int stepsPerRevolution = 200;  // Change this to match your stepper motor
Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);  // Pins for stepper motor

// Constants for tiller control
const int potPin = A0;                  // Pin for potentiometer
const int centerValue = 515;            // Center position value for the potentiometer
const int inactivityTimeout = 5000;      // Time in milliseconds to return to center
const float returnSpeed = 0.3;           // Speed of returning to center
const float smoothingFactor = 0.3;       // Smoothing factor for gradual movement

unsigned long lastMovementTime = 0;      // Timestamp for last movement
float outputAngle = 0;                    // Current output angle

void setup() {
    Serial.begin(9600);
    myStepper.setSpeed(60); // Set the speed of the stepper motor
}

void loop() {
    // Read potentiometer value
    int sensorValue = analogRead(potPin); // Read potentiometer value
    Serial.println(sensorValue); // Send value to serial for debugging

    // Calculate deviation from center
    int deviation = sensorValue - centerValue; // Get difference from center
    Serial.print("Deviation: ");
    Serial.println(deviation); // Send deviation for debugging

    // Apply smoothing
    outputAngle += (deviation - outputAngle) * smoothingFactor;

    // Determine steps to move based on deviation
    int steps = outputAngle / 10; // Adjust divisor for more or fewer steps

    // Move the stepper motor
    myStepper.step(steps);
    
    // Update the last movement time
    lastMovementTime = millis();

    // Check for inactivity
    if (millis() - lastMovementTime > inactivityTimeout) {
        // Gradually bring outputAngle back to center
        if (outputAngle != 0) {
            outputAngle += (0 - outputAngle) * returnSpeed; // Adjust towards center
            
            // Determine steps to return to center
            int returnSteps = outputAngle / 10; // Adjust divisor for more or fewer steps
            
            // Move the stepper motor back to center
            myStepper.step(returnSteps);
        }
    }

    delay(10); 
}

wiring :

(ULN 2003 Driver) :

IN1 -> digital pin 8
IN2 -> digital pin 9
IN3 -> digital pin 10 
IN4 -> digital pin 11

I tried replacing
myStepper.step(steps); with
myStepper.step(-steps);
it did not work.

2

Would you show this sketch that also did not work?

3 
#include <Stepper.h>

// Stepper motor configuration
const int stepsPerRevolution = 200;  // Change this to match your stepper motor
Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);  // Pins for stepper motor

// Constants for tiller control
const int potPin = A0;                  // Pin for potentiometer
const int centerValue = 515;            // Center position value for the potentiometer
const int inactivityTimeout = 5000;      // Time in milliseconds to return to center
const float returnSpeed = 0.3;           // Speed of returning to center
const float smoothingFactor = 0.3;       // Smoothing factor for gradual movement

unsigned long lastMovementTime = 0;      // Timestamp for last movement
float outputAngle = 0;                    // Current output angle

void setup() {
    Serial.begin(9600);
    myStepper.setSpeed(60); // Set the speed of the stepper motor
}

void loop() {
    // Read potentiometer value
    int sensorValue = analogRead(potPin); // Read potentiometer value
    Serial.println(sensorValue); // Send value to serial for debugging

    // Calculate deviation from center
    int deviation = sensorValue - centerValue; // Get difference from center
    Serial.print("Deviation: ");
    Serial.println(deviation); // Send deviation for debugging

    // Apply smoothing
    outputAngle += (deviation - outputAngle) * smoothingFactor;

    // Determine steps to move based on deviation
    int steps = outputAngle / 10; // Adjust divisor for more or fewer steps

    // Move the stepper motor
    myStepper.step(-steps);
    
    // Update the last movement time
    lastMovementTime = millis();

    // Check for inactivity
    if (millis() - lastMovementTime > inactivityTimeout) {
        // Gradually bring outputAngle back to center
        if (outputAngle != 0) {
            outputAngle += (0 - outputAngle) * returnSpeed; // Adjust towards center
            
            // Determine steps to return to center
            int returnSteps = outputAngle / 10; // Adjust divisor for more or fewer steps
            
            // Move the stepper motor back to center
            myStepper.step(returnSteps);
        }
    }

    delay(10); 
}
4

According to the data sheet, when the 28BYJ-48 motor is operated in full-step mode, each step corresponds to a rotation of 11.25°. This means there are 32 steps per revolution (360°/11.25° = 32). In addition, the gearbox inside the motor has a 64:1 gear reduction. This results in 2048 (32*64) steps per revolution.

second thing:

this configuration is for bipolar steppers, your 28byj-48 is unipolar.
use:
Stepper myStepper(2048, 8, 10, 9, 11);
not change wiring.

5

Deviation follows the sensor exactly 515 less (centerline) = 515.
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