File content as of revision 0:7a46e9e77d32:

#include "mbed.h"
#include "MFRC522.h"
#include "SDFileSystem.h"
#include "NOKIA_5110.h"
#include <stdio.h>

// FRDM-K64F (Freescale) Pin for MFRC522 reset
#define MF_RESET PTD0
FILE *fp;

DigitalOut LedGreen(LED2);

//Serial connection to PC for output
Serial pc(USBTX, USBRX); // serial comm on the FRDM board

//MFRC522    RfChip   (SPI_MOSI, SPI_MISO, SPI_SCK, SPI_CS, MF_RESET);
MFRC522    RfChip   (PTD2, PTD3, PTD1, PTE25, PTD0);

SDFileSystem sd(PTE3, PTE1, PTE2, PTE4, "sd"); // MOSI, MISO, SCK, CS
char buffer[1024]; 
uint8_t user[10];
char Nivedita[17]="7A023C0293028502";
char Apoorva[17]="76029E02C302A502";
char temp[17];
int flag1=0;
int flag2=0; //checks if the card scanner is run for the first time

int main() 

{
    pc.printf("Starting Alert System 2.0 by nivmukka... \n");
    
    LcdPins myPins;
    myPins.sce  = PTC12;
    myPins.rst  = PTC4;
    myPins.dc   = PTB3;
    myPins.mosi = PTD6;
    myPins.miso = NC;
    myPins.sclk = PTD5;
    
    NokiaLcd myLcd( myPins );
    
    // Start the LCD
    myLcd.InitLcd();
    myLcd.DrawString("Alert System    by nivmukka");
    wait( 3 );
    myLcd.ShutdownLcd();
    
    // Init. RC522 Chip
    RfChip.PCD_Init();

   fp = fopen("/sd/niv_alert_log.txt", "r");
    if (fp != NULL) 
    {
        fclose(fp);
        remove("/sd/niv_alert_log.txt");
        pc.printf("Removing an existing file with the same name \n");
    }
   
while (true) 
{
    LedGreen = 1;

    // Look for new cards
    if ( ! RfChip.PICC_IsNewCardPresent())
    {
      RfChip.PCD_Init();
      wait_ms(300);
    //  continue;
    }

    // Select one of the cards
    if ( ! RfChip.PICC_ReadCardSerial())
    {
      wait_ms(200);
      continue;
    }

    LedGreen = 0;

    // Print Card UID
    printf("\n\r");
    printf("-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-READY FOR SCAN-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-\n");
    printf("\nCard UID: ");
    for (uint8_t i = 0; i < RfChip.uid.size; i++)
    {
      printf("%X02", RfChip.uid.uidByte[i]);
      user[i]=RfChip.uid.uidByte[i];
    }
    //printf("\n");

    sprintf(temp,"%X02%X02%X02%X02",user[0],user[1],user[2],user[3]);
    //printf("temp is %s",temp);
    
    if(strcmp(temp, Apoorva)==0)
    { 
        printf("\nWelcome! Apoorva\n");
        if (flag2==1)
        {
            printf("Already logged in!\n");
                              
            myLcd.InitLcd();
            myLcd.DrawString("Welcome!        Apoorva");
            wait( 3 );
            myLcd.ShutdownLcd();
                
        }
        else if (flag2==0)
        {   
            printf("\nWriting data to the SD card log...\n");
            printf("Data successfully logged.\n");
            fp = fopen("/sd/niv_alert_log.txt", "a+");
            if (fp == NULL) 
            {
                pc.printf("Unable to write the file \n");
            } 
            else 
            {   
                fprintf(fp, "\nApoorva logged in. \n");
                fclose(fp); 
            }        
            flag2=1;
                
            myLcd.InitLcd();
            myLcd.DrawString("Welcome!        Apoorva");
            wait( 3 );
            myLcd.ShutdownLcd();
        }
    }        
    else if(strcmp(temp,Nivedita)==0)
    { 
        printf("\nWelcome! Nivedita\n");
        if (flag1==1)
        {
            printf("Already logged in!\n");
                          
            myLcd.InitLcd();
            myLcd.DrawString("Welcome!        Nivedita");
            wait( 3 );
            myLcd.ShutdownLcd();
                
        }
        else if (flag1==0)
        {
            printf("\nWriting data to the SD card log...\n");
            printf("Data successfully logged.\n");
            fp = fopen("/sd/niv_alert_log.txt", "a+");
            if (fp == NULL) 
            {
                pc.printf("Unable to write the file \n");
            }
            else 
            {    
                fprintf(fp, "\nNivedita logged in. \n");
                fclose(fp); 
            }                       
            flag1=1;
            //printf("flag1=%i\n",flag1);
        
            myLcd.InitLcd();
            myLcd.DrawString("Welcome!        Nivedita");
            wait( 3 );
            myLcd.ShutdownLcd();
            
        }
        
        //printf("Just after continue\n");    
    }      
    else if (strcmp(temp,Nivedita) || strcmp(temp,Apoorva) != 0)
    {
        printf("\nUnregistered User Detected!!!\n");
        
        myLcd.InitLcd();
        myLcd.DrawString("Unregistered   User! Alert!!");
        wait(3);
        myLcd.ShutdownLcd();
        
        printf("\nWriting data to the sd card log...\n");
        printf("Data successfully logged.\n");
        fp = fopen("/sd/niv_alert_log.txt", "a+");
        if (fp == NULL)
        {
            pc.printf("Unable to write the file \n");
        }
        else
        {
            fprintf(fp, "\nUnknown user found. Alert!! \n");
            fclose(fp);
        }
    }
    else
    {
        continue;
    }      
    printf("\n\r");
    printf("------------------------------------------------");
    printf("\nReading data from the SD card log... \n");
    fp = fopen("/sd/niv_alert_log.txt", "r");
    if (fp != NULL) 
    {
        int size = fread(buffer, sizeof(char), 1024, fp);
        printf("Size of data: %d, Displaying text from log file: %s\n", size, buffer);
        fclose(fp);
    } 
}
}