int trig=13;
int echo=12;
int buz=2;
int LED=5;
void setup()
{

pinMode(trig,OUTPUT);
pinMode(echo,INPUT);
pinMode(buz,OUTPUT);
pinMode(LED,OUTPUT);
Serial.begin(9600);

}
void loop()
{
digitalWrite(trig,LOW);
delayMicroseconds(10);
digitalWrite(trig,HIGH);
delayMicroseconds(10);
digitalWrite(echo,HIGH);
digitalWrite(trig,LOW);
int duration=pulseIn(echo,HIGH);
int distance=(duration*0.034)/2;
Serial.println(distance);

if(distance<100)
{
digitalWrite(buz,HIGH);
digitalWrite(LED,HIGH);
Serial.println("Alert");
delay(1000);
}
else
{
digitalWrite(buz,LOW);
digitalWrite(LED,LOW);
Serial.println("Safe");
delay(1000);
}
}