#include <LiquidCrystal_I2C.h>
int trigPin = 2;
int echoPin = 3;
int LEDlampRed = 4;
int LEDlampYellow = 5;
int LEDlampGreen = 6 ;
int soundbuzzer = 7;
int distanceincm = 0;
LiquidCrystal_I2C lcd (0x27, 16, 2);
void setup() {
  Serial.begin (9600);
  lcd.init();
  pinMode(trigPin,  OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(LEDlampRed, OUTPUT);
  pinMode(LEDlampYellow,  OUTPUT);
  pinMode(LEDlampGreen, OUTPUT);
  pinMode(soundbuzzer, OUTPUT);
}
void  loop() {
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  int duration = pulseIn(echoPin, HIGH);
  distanceincm = (duration / 58);
  if (distanceincm < 50) {
    digitalWrite(LEDlampRed, HIGH);
    digitalWrite(LEDlampYellow,  HIGH);
    digitalWrite(LEDlampGreen, HIGH);
    tone(soundbuzzer, 1000, 300);
  } else if (distanceincm < 100) {
    digitalWrite(LEDlampRed, LOW);
    digitalWrite(LEDlampYellow,  HIGH);
    digitalWrite(LEDlampGreen, HIGH);
  } else if (distanceincm < 300) {
    digitalWrite(LEDlampRed, LOW);
    digitalWrite(LEDlampYellow,  LOW);
    digitalWrite(LEDlampGreen, HIGH);
  } else {
    digitalWrite(LEDlampRed, LOW);
    digitalWrite(LEDlampYellow,  LOW);
    digitalWrite(LEDlampGreen, LOW);
  }
  Serial.print("Distance: ");
  Serial.print(distanceincm);
  Serial.println(" cm");
  lcd.setCursor (0, 0);
  lcd.print("Distance: ");
  lcd.setCursor (10, 0);
  lcd.print(distanceincm);
  lcd.setCursor (13, 0);
  lcd.print (" cm");
  delay(300);
}