int trigpin = 3;
int echopin = 2;
int time;
int distance;
void setup() {
  // put your setup code here, to run once:
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trigpin, LOW);
  digitalWrite(trigpin, HIGH);
  digitalWrite(trigpin, LOW);
  time = pulseIn(echopin, HIGH);
  distance = time * 0.0172;

  if (distance>30)
{
  digitalWrite(11, HIGH);
  delay(1000);
  digitalWrite(11, LOW);
  delay(3000);
}

else
{
  digitalWrite(11, HIGH);
  delay(1000);
  digitalWrite(11, LOW);
  delay(1000);
}
}