#include <NewPing.h>

#define TRIG_PIN 9
#define ECHO_PIN 10
#define MAX_DISTANCE 500  // Max distance to scan (in cm)

#define LED_PIN 6
#define BUZZER_PIN 7

NewPing sonar(TRIG_PIN, ECHO_PIN, MAX_DISTANCE);

void setup() {
  Serial.begin(9600);        // Start serial communication
  pinMode(LED_PIN, OUTPUT);  // LED pin output
  pinMode(BUZZER_PIN, OUTPUT); // Buzzer pin output
}

void loop() {
  delay(50);  // Small delay between pings
  unsigned int distance = sonar.ping_cm();  // Measure distance in cm

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

  if (distance > 30 || distance == 0) {
    // Too far or no object detected
    digitalWrite(LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
  } 
  else if (distance <= 30 && distance > 15) {
    // Object between 30cm and 15cm
    digitalWrite(LED_PIN, HIGH);
    delay(300);
    digitalWrite(LED_PIN, LOW);
    delay(300);
    digitalWrite(BUZZER_PIN, LOW);  // Buzzer OFF
  } 
  else if (distance <= 15) {
    // Object closer than 15cm
    digitalWrite(LED_PIN, HIGH);
    digitalWrite(BUZZER_PIN, HIGH);
    delay(100);
    digitalWrite(LED_PIN, LOW);
    digitalWrite(BUZZER_PIN, LOW);
    delay(100);
  }
}