#include <LiquidCrystal_I2C.h>
const int trigPin = 7;
const int echoPin = 8;
const int buzzer = 6;
LiquidCrystal_I2C lcd(0x27, 20, 4);
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);

pinMode(buzzer, OUTPUT);
pinMode(9, OUTPUT);



//pinMode(4, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(trigPin, HIGH);
delayMicroseconds(2);
digitalWrite(trigPin, LOW);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

long duration = pulseIn(echoPin, HIGH);

int distance = duration * 0.0343 / 2;

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

delay(500);

if (distance<100)
{
tone(6, 262, 250); // Plays 262Hz tone for 0.250 seconds
digitalWrite(9, HIGH);
  lcd.init();
  lcd.backlight();
  lcd.setCursor(1, 0);
  lcd.print("STOP!");


}
else
{
    lcd.init();
  lcd.backlight();
  lcd.setCursor(1, 0);
  lcd.print("SAFE!");

}
}


//if (distance>300)
//{
//digitalWrite(6, HIGH);
//digitalWrite(5, LOW);
//digitalWrite(4, LOW);
//}

//else if (distance>200 )
//{
//digitalWrite(6, LOW);
//digitalWrite(5, HIGH);
//digitalWrite(4, LOW);
//}

//else
//{
//digitalWrite(6, LOW);
//digitalWrite(5, LOW);
//digitalWrite(4, HIGH);
//}