I have some problem regarding RFID madule interfacing…..

[Rahul Ray]

Good evening Sir,i am trying to interface RFID module with 8051 microcontroller version-2 development board.My RFID tag number is FE00458C2413 which i got from hyper-terminal.But when i want to show that unique identification number in a 16×2 LCD through serial communication,there is some error occurs and also whenever i want to match the Id got from hyperterminal & lcd for the same tag,there is some mismatch happens.What can i do now?????Plz kindly suggest something how can i solve this problem???

[AJISH ALFRED]

Suggest you to post your code and a snapshot of the working LCD to get better help.

[Rahul Ray]

#include<reg51.h>

#include<string.h>

#include <intrins.h>

#define cmdport P3

#define dataport P2

sbit rs = P3^0;        //register select pin

sbit rw = P3^1;        //read write pin

sbit  e = P3^2;     //enable pin

sbit motor_pin = P0^7;

unsigned int data_out,temp;

unsigned char card_id[12];

code unsigned char RFID_1[]=”FE00458C2413″;

code unsigned char RFID_2[]=”4E007051B8D7″;

void Delay(unsigned int);

void Delay_servo(unsigned int);

void recieve()     //Function to recieve data serialy from RS232 

{

    unsigned char k;

     for(k=0;k<12;k++)

     { 

         while(RI==0); 

          card_id[k]=SBUF;

          RI=0;

    }

}

void delay(unsigned int msec)    //Function to provide time delay in msec.

{

int i,j;

for(i=0;i<msec;i++)

for(j=0;j<1275;j++);

}

//void Delay(unsigned int ms)

//{

 // unsigned long int us = ms*1000;

  //while(us–)

 // {

   // _nop_();

  //}

//}

 

void Delay_servo(unsigned int us)

{

  while(us–)

  {

    _nop_();

  }

}

void lcdcmd(unsigned char item)    //Function to send command to LCD

{

rs= 0;

rw=0;

e=1;

dataport = item;

delay(10);

e=0;

delay(10);

}

void lcddata(unsigned char iitem)    //Function to send data to LCD

{

rs= 1;

rw=0;

e=1;

dataport = iitem;

delay(10);

e=0;

delay(10);

}

void lcd_init()

{

lcdcmd(0x38);

lcdcmd(0x0E);

lcdcmd(0x01);

}

//void lcd_string(char add,char *str)

void lcd_string(char *iitem)

{

int i;

//lcdcmd(add);

for(i=0;iitem!=’’;i++)

{

lcddata(iitem);

    }

}

void motor_forward()

{

  motor_pin = 0;

 do

  { //Turn to 0 degree

    motor_pin = 1;

    Delay_servo(30);

    motor_pin = 0;

    delay(100);

   //Turn to 90 degree

    motor_pin=1;

    Delay_servo(62);

    motor_pin=0;

    delay(100);

    //Turn to 180 degree

    motor_pin=1;

    Delay_servo(110);

    motor_pin=0;

    delay(100);

  }while(1);

}

void main()

{

    //unsigned char rec_data[12];

int l=12,i;

    TMOD=0x20;            //Enable Timer 1

    TH1=0XFD;

    SCON=0x50;

    TR1=1;

lcd_init();

lcdcmd(0x80);

lcd_string(“SWAP_THE_CARD:”);  // Triggering Timer 1

delay(100);

while(1)

    {

  recieve();

       lcdcmd(0xC1);        //Place cursor to second position of second line

         for(l=0;l<12;l++)

         { 

              lcddata(card_id[l]);

 delay(1000);

         }

i=0;

while(1)

{

i=strcmp(RFID_1,card_id);

if(i!=0)

{

lcdcmd(0x01);

lcdcmd(0x0E);

lcdcmd(0x80);

//lcddata(“MOVE MOTOR”);

lcd_string(“MOVE MOTOR”);

         motor_forward();

}

else

{

lcdcmd(0x01);

lcdcmd(0x0E);

lcdcmd(0x80);

delay(100);

//lcddata(“NO_MOVEMENT”);

lcd_string(“NO MOVEMENT”);

delay(1000);

}

 }

  

}

}

     

i here posted my code…………..due to the mismatching between RFID tag numbers,there is always showing the NO MOVEMENT of motor………………

i already mentioned the rfid tag number from hyperterminal in the above.

 

 

 

 

 

 

 

[Ashutosh Bhatt]

you will get RFID tag number as string of bytes from serial port.

so you have to first store all these bytes in a array

then just display all array characters one by one on LCD

for matching RFID tag you have to do same

make one array with same tag

now read RFID tag and store all characters in another array

compare elements of both array one by one.

[Shailesh Kukna]

See code of RFID based attendance system from this webside. It will helpful to you.

[AJISH ALFRED]

Hi Rahul,

Does your RFID display anything else properly or there is issue with the card number only? I’m concerned about the delay function which your are using, it can happen that the compiler can sometimes optimize the loop and produce no delay at all, which can cause issues in the LCD display.

[AJISH ALFRED]

Also try these modifications,

 

Change the declaration of card_id array to,

 

unsigned char card_id[13];

 

and add one more line inside tne function,

 

void recieve()     //Function to recieve data serialy from RS232 

{

    unsigned char k;

     for(k=0;k<12;k++)

     { 

         while(RI==0); 

          card_id[k]=SBUF;

          RI=0;

    }

 

   card_id[13]=’’;

}

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