i am in troble with when using two ulrasonic sensores, but when working with one sensore, code is working fine. please help me to attach two ultarsnic sensores (HC-SR04) to my code and make this worke fine, 

here i am tring to do thing is i want to keep a object with in the range and if the object move LED lights need to be on.

i am using the PIC 16F877A

Working code for one ultrasonic sensor 

```
    void main()

    {

     int a;

      int b;

      TRISB = 0b00010000;           //RB4 as Input PIN (ECHO)

      TRISC = 0;           //C as Output PINs (LED)

      T1CON = 0x10;                 //Initialize Timer Module

      TRISD  = 1;   // 1 input 0 output ,related to LED (display)

      while(1)

      {

        for(b=1; b<3; b++){

           if (b=2){

                            TMR1H = 0;                  //Sets the Initial Value of Timer

                            TMR1L = 0;                  //Sets the Initial Value of Timer

                            PORTB.F1 = 1;               //TRIGGER HIGH

                            Delay_us(10);               //10uS Delay

                            PORTB.F1 = 0;               //TRIGGER LOW

                            while(!PORTD.F0);           //Waiting for Echo

                            T1CON.F0 = 1;               //Timer Starts

                            while(PORTD.F0);            //Waiting for Echo goes LOW

                            T1CON.F0 = 0;               //Timer Stops

                            a = (TMR1L | (TMR1H<<8));   //Reads Timer Value

                            a = a/58.82;                //Converts Time to Distance

                            a = a + 1;                  //Distance Calibration\
                                     //formular s=ut

                      if(a != 4 ){

                              PORTC = 0b01111111;               // turn on LEDs in the PIC

                              Delay_ms(5);

                              PORTC = 0;               // turn on LEDs in the PIC

                          } else  {

                              //out of range

                              PORTC = 0b00000000;

                          }

                }

              }

      }

    }

```

not working code for two ultarsonic sensers

```
    void main()

    {

     int a;

      int b;

      TRISB = 0b00010000;           //RB4 as Input PIN (ECHO)

      TRISC = 0;           //C as Output PINs (LED)

      T1CON = 0x10;                 //Initialize Timer Module

      TRISD  = 1;   // 1 input 0 output ,related to LED (display)

      while(1)

      {

        for(b=1; b<3; b++){

              if(b=1){

                    TMR1H = 0;                  //Sets the Initial Value of Timer

                    TMR1L = 0;                  //Sets the Initial Value of Timer

                    PORTB.F0 = 1;               //TRIGGER HIGH

                    Delay_us(10);               //10uS Delay

                    PORTB.F0 = 0;               //TRIGGER LOW

                    while(!PORTD.F1);           //Waiting for Echo

                    T1CON.F0 = 1;               //Timer Starts

                    while(PORTD.F1);            //Waiting for Echo goes LOW

                    T1CON.F0 = 0;               //Timer Stops

                    a = (TMR1L | (TMR1H<<8));   //Reads Timer Value

                    a = a/58.82;                //Converts Time to Distance

                    a = a + 1;                  //Distance Calibration\
                                   //formular s=ut

                    if(a != 4 ){
            //        PORTB.F3 = 1;
              //      PORTD = 0xFC;              // display number two in LED displa
                //    Delay_ms(5);
                  //  PORTB.F3 = 0;

                            PORTC = 0b00000011;               // turn on LEDs in the PIC

                            Delay_ms(5);

                            PORTC = 0;               // turn on LEDs in the PIC

                        } else  {

                            //out of range

                            PORTC = 0b00000000;

                        }

                }

                else if (b=2){

                      TMR1H = 0;                  //Sets the Initial Value of Timer

                      TMR1L = 0;                  //Sets the Initial Value of Timer

                      PORTB.F1 = 1;               //TRIGGER HIGH

                      Delay_us(10);               //10uS Delay

                      PORTB.F1 = 0;               //TRIGGER LOW

                      while(!PORTD.F0);           //Waiting for Echo

                      T1CON.F0 = 1;               //Timer Starts

                      while(PORTD.F0);            //Waiting for Echo goes LOW

                      T1CON.F0 = 0;               //Timer Stops

                      a = (TMR1L | (TMR1H<<8));   //Reads Timer Value

                      a = a/58.82;                //Converts Time to Distance

                      a = a + 1;                  //Distance Calibration\
                                     //formular s=ut

                      if(a != 4 ){

                              PORTC = 0b01111111;               // turn on LEDs in the PIC

                              Delay_ms(5);

                              PORTC = 0;               // turn on LEDs in the PIC

                          } else  {

                              //out of range

                              PORTC = 0b00000000;

                          }

                }

              }

      }

    }

```