#include <Wire.h>               //Using the Arduino as the controller device,the library enables to communicate with I2C devices

int ADXL345 = 0x53;             //address of an ADXL 
int X_out, Y_out, Z_out;        
#define IR1 4                   //ir sensor pin connecetd to pin 4of Arduino Nano
#define IR2 5                   //ir sensor in connecetd to pin 5 of Arduino Nano
#define buzzer 9                 //buzzer pin connecetd to pin 9 of Arduino Nano
#define relay 11                //realy pin connecetd to pin 6 of Arduino Nano
int i=0;                        //integer i is created to store the value of ir sensor 
int p =0;
int q = 1;
float s ;


void setup ()
{   pinMode (IR1,INPUT);          //Set ir as INPUT device
    pinMode (2,OUTPUT);         
    pinMode (3,OUTPUT);
    pinMode (IR2,INPUT);           //Set ir as INPUT device     
    pinMode (6,OUTPUT);
    pinMode (7,OUTPUT);
    pinMode (buzzer,OUTPUT);       //Set BUZZER as OUTPUT device
    pinMode (8,OUTPUT);
    pinMode (10,OUTPUT);
    pinMode(relay,OUTPUT);        //Set relay as OUTPUT device
    Serial.begin(9600);           // Initiate a serial communication with baud rate of 9600
    Wire.begin();

    digitalWrite(relay,HIGH);
  
  Wire.beginTransmission(ADXL345);
  Wire.write(0x2D);                                 //talk to POWER_CTL Register - 0x2D
  
  Wire.write(8);                                   // Bit D3 High for measuring enable (8dec -> 0000 1000 binary)
  Wire.endTransmission();
  delay(10);

}
void loop()
    {
   
    digitalWrite (2,HIGH);
    digitalWrite (7,HIGH);
    digitalWrite (8,HIGH);
    digitalWrite(10,LOW);
    digitalWrite(3,LOW);
    digitalWrite(6,LOW);
    int I1 = digitalRead(IR1);
    int I2 = digitalRead(IR2);

  Wire.beginTransmission(ADXL345);
  Wire.write(0x32);
  Wire.endTransmission(false);
  Wire.requestFrom(ADXL345, 6, true);

  X_out = ( Wire.read() | Wire.read() << 8);
  Y_out = ( Wire.read() | Wire.read() << 8);
  Z_out = ( Wire.read() | Wire.read() << 8);

  Serial.print(X_out);
  Serial.print(" ");
  Serial.print(Y_out);
  Serial.print(" ");
  Serial.println(Z_out);
  delay(100);
   
   
   while(((I1==0)||(i==!0))&&(q==1))   //when  ir sensor values 
   {
    
    int I1=digitalRead(IR1);           //storing ir sensor values in I1
    int I2=digitalRead(IR2);           //storing ir sensor values in I2
    
    
    delay(10);
    i = i+1;                          // incrementing i value 
    p=p+1   ;                         // incrementing i value to calculate time 
    Serial.println(i);                // displaying the i value on serial monitor
    if (I2 == 0)                      //if vehicle pass through 2 ir sensor 
    {
      i = 0;
      q=0;
      Serial.println("Exit");

 Serial.print("Time in Sec: ");
 Serial.print(p*0.01);                //formula to calculatr time 

 s = 0.15/(p*0.01);                   //formula to calculate speed 
    Serial.println("Speed: ");        //displaying the values of speed on serial monitor 
Serial.print(s);

       }
   }

    if(s > 0.100)                      // if speed of the vehicle is more 
    {
        tone(buzzer,1000,100);        // turn on the buzzer
        digitalWrite(relay,LOW);      //turn on the relay 
       
        }
    
    else
      {
        noTone (buzzer);              // turn off the buzzer
        digitalWrite(relay,HIGH);     // turn off the relay 
                
            }            
  
    }