#include <Servo.h>

// Hardware Pin Configuration
const int IR_PIN    = 7;
const int SERVO_PIN = 9;

Servo gripperServo;

// Mechanical angle configurations for the clamping jaw
const int JAW_OPENED = 10;   // Fully open position (degrees)
const int JAW_CLOSED = 110;  // Clamped/closed position (degrees)

int lastState = HIGH; // IR outputs HIGH when clear, LOW when blocked

void setup() {
  Serial.begin(9600);
  
  pinMode(IR_PIN, INPUT);
  gripperServo.attach(SERVO_PIN);
  
  // Set initial physical state: Open jaw ready for object
  gripperServo.write(JAW_OPENED);
  Serial.println("--- System Initialized: Gripper Open ---");
}

void loop() {
  // Read proximity sensor state
  int irState = digitalRead(IR_PIN);

  // Check for state changes (Object entering or leaving)
  if (irState != lastState) {
    if (irState == LOW) {
      // Object detected inside the assembly
      Serial.println("Target Detected! Clamping gripper...");
      
      // Smooth actuation loop to prevent mechanical stress
      for (int pos = JAW_OPENED; pos <= JAW_CLOSED; pos += 5) {
        gripperServo.write(pos);
        delay(15); 
      }
    } 
    else {
      // Object removed from the assembly
      Serial.println("Target Released! Opening gripper...");
      
      for (int pos = JAW_CLOSED; pos >= JAW_OPENED; pos -= 5) {
        gripperServo.write(pos);
        delay(15);
      }
    }
    // Update tracking state
    lastState = irState;
  }
  
  delay(50); // Polling stability gap
}