Arduino RFID Twitter Lock

#if defined(ARDUINO) && ARDUINO > 18   // Arduino 0019 or later
#include <SPI.h>
#endif
#include <Ethernet.h>
#include <EthernetDNS.h>
#include <Twitter.h>

#include <NewSoftSerial.h>

// Ethernet Shield Settings
byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

// Substitute ip address settings here
byte ip[] = {
  192, 168, 10, 250 };
byte gw[] = {
  192, 168, 10,  1  };
byte nm[] = {
  255, 255, 255, 0  };

// Your Token to Tweet (get it from http://arduino-tweet.appspot.com/)
Twitter twitter("Put Your Tweet token here");

// Message to post
char msg[256]={0};

NewSoftSerial rfid(2,3);

char tagString[12];
int index;
int total;
boolean readStart;
boolean readStop;

int pinUsa = 7;
int pinErr = 5;

unsigned long timpStart;
int interval = 1*1000;
//Register your RFID tags here
struct rfid_tag {
  char tag[13];
  char nickName[20];
};

#define NUM_TAGS  15
struct rfid_tag tags[NUM_TAGS] = {
    {"720065985701", "Constantin Craciun"  },
    {"1F0030C011A7", "Viorel Spinu"},
    {"170011D29BCF", "Andrei Dore"},
    {"4010BE77AB22", "Liana Marinescu"},
    {"00109B4DAE77", "Ionut Cotoi"},
};

void setup(){
  delay(1000);
  Serial.begin(9600);
  rfid.begin(9600);
  Ethernet.begin(mac, ip, gw, nm);
  //ONLY NEEDED IF CONTROLING THESE PINS - EG. LEDs
  pinMode(pinUsa, OUTPUT);
  pinMode(pinErr, OUTPUT);
  pinMode(13, OUTPUT);
  rfidReset();
}

void loop(){

  if(Serial.available()){
    char readByte = Serial.read();

    switch (readByte){
    case 'a':
      deschideUsa();
      break;

    case 'b':
      digitalWrite(pinErr,HIGH);
      delay(1500);
      digitalWrite(pinErr,LOW);
      break;

    default:
      break;
    }

  }

  if(rfid.available() > 0){
    int readByte = rfid.read();
    total++;
    switch(readByte){
    case 2:
      readStart = true;
      total = 1;
      index = 0;
      break;

    case 3:
      readStop = true;
      break;

    case 10:
    case 13:
      break;

    default:
      tagString[index++] = readByte;
      break;
    }
  }

  if(total > 16){
    delay(100);
    rfid.flush();
    rfidReset();
  }
  else   if(readStart && readStop && index == 12){
    Serial.print("1=");
    for(int i = 0; i < index; i++){
      Serial.print(tagString[i],BYTE);
    }
    Serial.print(";");
    checkTag(tagString);
    rfidReset();
    //clearTag(tagString); //Clear the char of all value
  }

  //inchid usa daca a stat deschisa destul timp
  if(timpStart+interval<=millis())
    digitalWrite(pinUsa,LOW);

}

void rfidReset(){
  total = 0;
  index = 0;
  readStart = false;
  readStop = false;
  for(int i = 0; i < strlen(tagString); i++){
    tagString[i] = 0;
  }
}
void checkTag(char tag[]){
  ///////////////////////////////////
  //Check the read tag against known tags
  ///////////////////////////////////

  if(strlen(tag) == 0) return; //empty, no need to contunue
  for(int i=0; i<NUM_TAGS; i++) {
    if(copmarTag(tag, tags[i].tag)){
      deschideUsa();
      sprintf(msg, "%s is at http://inventeaza.ro %ld", tags[i].nickName, millis());
      twitter.post(msg);
      delay(1000);
      digitalWrite(pinUsa,LOW);
      software_Reset();
    }
  }

}
boolean copmarTag(char one[], char two[]){

  if(strlen(one) == 0) return false; //empty

  for(int i = 0; i < 12; i++){
    if(one[i] != two[i]) return false;
  }

  return true; //no mismatches
}
void deschideUsa(){
  timpStart = millis();
  digitalWrite(pinUsa,HIGH);
}

void software_Reset() // Restarts program from beginning but does not reset the peripherals and registers
{
  asm volatile ("  jmp 0"); 
}