#include <LiquidCrystal.h>

#define trigPin 24
#define echoPin 25
#define relay1Pin 8
#define relay2Pin 9
#define redled 7
#define yellowled 6
#define greenled 10
#define buzzerPin 13


LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(relay1Pin, OUTPUT);
  pinMode(relay2Pin, OUTPUT);
  pinMode(redled,OUTPUT);
  pinMode(yellowled,OUTPUT);
  pinMode(greenled, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.print("Distance:");
}

void loop() {
  // Trigger the ultrasonic sensor to send a pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the pulse duration from the echo pin
  long duration = pulseIn(echoPin, HIGH);

  // Calculate distance in centimeters
  int distance = duration / 58;

  lcd.setCursor(11, 0);
  lcd.print("     ");
  lcd.setCursor(11, 0);
  lcd.print(distance);

  // Print the distance to the serial monitor
  Serial.print("Distance: ");
  Serial.println(distance);

  // Control relays based on distance
  if (distance >200 ) {
    digitalWrite(relay1Pin, LOW);  // Activate Relay 1
    digitalWrite(relay2Pin, LOW);
    digitalWrite(yellowled,LOW);
    digitalWrite(redled,LOW);// Deactivate Relay 2
    digitalWrite(greenled, HIGH);
  } else if (distance >= 100) {
    digitalWrite(relay1Pin, HIGH);   // Deactivate Relay 1
    digitalWrite(relay2Pin, HIGH);// Activate Relay 2
    digitalWrite(yellowled, HIGH);
    digitalWrite(redled, LOW);
    digitalWrite(greenled, LOW);
    digitalWrite(buzzerPin, HIGH);
    delay(500);
    digitalWrite(buzzerPin, LOW);
    
  } else if (distance<100) {
    digitalWrite(relay1Pin, HIGH);   // Deactivate Relay 1
    digitalWrite(relay2Pin, LOW);
    digitalWrite(yellowled, LOW);
    digitalWrite(redled, HIGH);
    digitalWrite(greenled, LOW);
    digitalWrite(buzzerPin, HIGH);
    delay(200);
    digitalWrite(buzzerPin, LOW);
  }
    delay(100); // Delay for stability
}