int echopin=2;
int trigpin=3;
int Time;
int Distance;
void setup() {
  // put your setup code here, to run once:
  pinMode(echopin, INPUT);
  pinMode(trigpin, OUTPUT);
  Serial.begin(9600);
  Serial.print("Ultrasonic sensor......");

}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trigpin, LOW);
  digitalWrite(trigpin, HIGH);
  Time=pulseIn(echopin,HIGH);
  Distance=Time * 0.0172;
  Time=Time/1000;
  Serial.print("Time:");
  Serial.print(Time);
  Serial.print("seconds");
  delay(1000);
  Serial.print(",Distance:");
  Serial.print(Distance);
  Serial.print("cm ");
  delay(1000);
  if(Distance <= '100')
  {
    tone(13,200,150);
  }
  else{
    tone(13,1,0);
  }
}