int trig=13;
int echo=12;
int led=2;

int distance=150;
float t,d;


void setup() {
  pinMode(led, OUTPUT);
  pinMode(echo, INPUT);
  pinMode(trig, OUTPUT);
  Serial.begin(9600);

}

void loop() {
digitalWrite(trig, HIGH);
delay(1000);
digitalWrite(trig, LOW);

t=pulseIn(echo,HIGH);
d= 0.0171*t ;

if(distance<d){
  digitalWrite(led, HIGH);
}
else{
  digitalWrite(led, LOW);
}

Serial.println("distance is:");
Serial.println(d);
delay(2000);
}