#define STEP_PIN 3
#define DIR_PIN 2
#define TRIG_PIN 7
#define ECHO_PIN 6

const int stepsPerRevolution = 200;
const int distanceThreshold = 20;  // Adjust as needed (in cm)

void setup() {
  pinMode(STEP_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  Serial.begin(9600);  // For debugging
}

void loop() {
  long duration, distance;
  distance = calculateDistance(); 

  Serial.print("Distance: ");  
  Serial.println(distance);

  if (distance <= distanceThreshold) {
    // Object detected: Rotate clockwise
    digitalWrite(DIR_PIN, HIGH);
    rotateStepper();
  } else {
    // No object detected: Stop motor 
    // (You don't need to explicitly turn it off)
  }

  delay(500); // Adjust the sensor reading interval
}

long calculateDistance() {
  long duration; // Declare the variable here
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  duration = pulseIn(ECHO_PIN, HIGH); 
  return duration * 0.034 / 2; 
}

void rotateStepper() {
  for (int i = 0; i < stepsPerRevolution; i++) {
    digitalWrite(STEP_PIN, HIGH);
    delayMicroseconds(500);
    digitalWrite(STEP_PIN, LOW);
    delayMicroseconds(500);
  }
}