Smart stick for the visually impaired

//Smart stick for the visually impaired
/* 
<--connection With Arduino Uno R3-->

HC-SR04 Ultrasonic Sensor: 
 #VCC--> +5V
 #TRIG--> D13
 #ECHO--> D12
 #GND--> pin to ground
 
 Buzzeer:
 positive(+)--> D10
 negative(-)--> pin to ground
 
 Vibration Motor:
 positive(+)--> D7
 negative(-)--> pin to ground
 
 LED:
 positive(+)--> D2
 negative(-)--> pin to ground
 
 */

long cm,duration;
    

void setup(){
  Serial.begin(9600);
  pinMode(13,OUTPUT); // TrigPin
  pinMode(12,INPUT);  // EchoPin
  pinMode(10,OUTPUT); // Buzzer
  pinMode(2,OUTPUT);  // LED As a indicaor
  pinMode(7,OUTPUT);  // Vibration Motor


}
void loop() {
 
digitalWrite(13,LOW); //Trig Off
delayMicroseconds(20);
digitalWrite(13,HIGH);//Trig ON
delayMicroseconds(20);
digitalWrite(13,LOW);//Trig Off
delayMicroseconds(20);
  
digitalWrite(2,HIGH); 
    
duration = pulseIn(12, HIGH); //To receive the reflected signal.
Serial.println(duration);  
cm = duration*0.034/2;
Serial.println(cm);

    
    
  if ((cm<100))
  {
    tone(10,3000);
    digitalWrite(7,HIGH);
    delay(500);
    noTone(10);
    delay(30);
  }
  else{
    
  digitalWrite(7,LOW);
  }
  delay(50);
  
}