#include <pitches.h>

#define trigPin  9
#define echoPin 8

#define Buzzer1 5//active

#define Led1 6//Vibration
int sound = 250;

//int diso; // chec direction var
//int dise;

int de;    // delay var
int f;    // frequency


void setup() {
   Serial.begin (9600);
   pinMode(trigPin, OUTPUT);
   pinMode(echoPin, INPUT);
   pinMode(Buzzer1, OUTPUT);
   pinMode(Led1, OUTPUT);
}

void  loop() {
Serial.begin(9600);
//for(int i=0;i>=10;i++){
  long duration, distance;
  digitalWrite(trigPin,  LOW);
  delay(2);
  digitalWrite(trigPin, HIGH);
  delay(10);
  digitalWrite(trigPin,  LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;
  digitalWrite(Buzzer1, LOW);
  digitalWrite(Led1,  LOW);
  //if (i=5){
     //diso=distance;
  //}
  //if (i=10){
    // dise=distance;
 //}

  //if((dise-diso)<0){  
     if (distance<40) {
       digitalWrite(Led1, HIGH);
              tonecal(distance);
       digitalWrite(Buzzer1, HIGH);
              tone(Buzzer1, f); // Send 0.5KHz sound signal...
              delay(de);        // ...for 1 sec
              noTone(Buzzer1);     // Stop sound...
              delay(de);        // ...for 1sec
  }
  //}
 // }
 
  }
  void tonecal(int d )
  { 
     if (d>15){
     de=30*d-300;
     f=1050-(21.25*d+150);
     }
     if (d<=15){
     de=20;
     f=1000;
     }
  }