Arduino RFID Controller for Squeezebox - Arduino side

#include <Ethernet.h>
 
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
byte ip[] = { 192,168,0,250 };
byte server[] = {192,168,0,105};
 
Client client(server, 80);
 
enum STATE {
  RFID, RFID_VERIFY, CONNECTING, READING
};
 
static STATE state;
 
#define DEBUG 0
#define FAKE 0
 
// reset pin for ethernet module, only works on LadyAda shield
#define RESET_PIN 7
 
// RFID enable pin
#define RFID_ENABLE 2
 
int  val = 0;
char reading[11];
char verify[11];
char current[11];
char target[11];
int bytesread = 0;
 
void setup(){
  // rfid is slow as all get out
  Serial.begin(2400);
 
  pinMode(RESET_PIN, OUTPUT);
  pinMode(RFID_ENABLE, OUTPUT);
 
  // sleep for 30 seconds, this gives the squeezebox time to boot up
  delay(30000);
 
  // reset the ethernet board
  digitalWrite(RESET_PIN, LOW);
  delay(2);
  digitalWrite(RESET_PIN, HIGH);
 
  delay(1000);
 
  Ethernet.begin(mac, ip);
  Client client(server, 80);
 
  if (DEBUG) Serial.println("Finishing setup..");
 
  current[0] = '\0';
  reading[0] = '\0';
  verify[0] = '\0';
  target[0] = '\0';
 
  current[10] = '\0';
  reading[10] = '\0';
  verify[10] = '\0';
  target[10] = '\0';
}
 
void loop(){
  if (state == RFID){
    // spin a bit to see if the we are ahead of the reader
    Serial.flush();
    digitalWrite(RFID_ENABLE, LOW);
    int loops = 0;
    while(loops < 10){
      if (Serial.available()) break;
      loops++;
      delay(100);
    }
 
    val = Serial.read();
 
    if((val == 10)){   // check for header
      bytesread = 0;
      while(bytesread<10){  // read 10 digit code
        val = Serial.read();
        if((val == 10)||(val == 13)){  // if header or stop bytes before the 10 digit reading
          break;                       // stop reading
        }
        // or if it looks invalid
        if ((val < 'A' || val > 'Z') && (val < '0' && val > '9')){
          break;
        }
 
        reading[bytesread] = val;         // add the digit
        bytesread++;                   // ready to read next digit
      }
 
      // didn't read a whole tag, clear it
      if(bytesread != 10){
        reading[0] = '\0';
      }
    } else {
      reading[0] = '\0';
    }
 
    if (DEBUG) Serial.print("reading: ");
    if (DEBUG) Serial.println(reading);
 
    // this is something is different, verify it
    if (strcmp(reading, current) != 0){
      state = RFID_VERIFY;
    }
    bytesread = 0;
 
    if (FAKE){
      reading[0] = '1';
      reading[1] = '\0';
      state = RFID_VERIFY;
    }
 
    digitalWrite(RFID_ENABLE, HIGH);
    delay(250);
  }
 
  else if (state == RFID_VERIFY){
    // spin a bit to see if the we are ahead of the reader
    Serial.flush();
    digitalWrite(RFID_ENABLE, LOW);
    int loops = 0;
    while(loops < 10){
      if (Serial.available()) break;
      loops++;
      delay(100);
    }
 
    val = Serial.read();
 
    if((val == 10)){   // check for header
      bytesread = 0;
      while(bytesread<10){  // read 10 digit code
        val = Serial.read();
        if((val == 10)||(val == 13)){  // if header or stop bytes before the 10 digit reading
          break;                       // stop reading
        }
        // or if it looks invalid
        if ((val < 'A' || val > 'Z') && (val < '0' && val > '9')){
          break;
        }
 
        verify[bytesread] = val;         // add the digit
        bytesread++;                   // ready to read next digit
      }
 
      // didn't read a whole tag, clear it
      if(bytesread != 10){
        verify[0] = '\0';
      }
    } else {
      verify[0] = '\0';
    }
 
    if (DEBUG) Serial.print("verify: ");
    if (DEBUG) Serial.println(verify);
 
    // first and second pass the same
    if (strcmp(reading, verify) == 0){
      if (strcmp(reading, current) != 0){
        strncpy(target, reading, 10);
        state = CONNECTING;
      }
    } else {
      state = RFID;
    }
    bytesread = 0;
 
    if (FAKE){
      target[0] = '1';
      target[1] = '\0';
      state = CONNECTING;
    }
 
    digitalWrite(RFID_ENABLE, HIGH);
 
    delay(250);
  }
  else if (state == CONNECTING){
    if (DEBUG) Serial.println("connecting...");
    Ethernet.begin(mac, ip);
    delay(500);
 
    if (client.connect()) {
      if (DEBUG) Serial.println("connected");
 
      if (strlen(target) == 10){
        client.print("GET /tuner/index.php?key=");
        client.print(target);
      } else {
        client.print("GET /tuner/index.php?stop=1");
      }
      client.println(" HTTP/1.0");
      client.println("Host: 192.168.0.105");
      client.println("User-Agent: AVR ethernet");
      client.println("Accept: text/html");
 
      client.println();
 
      strcpy(current, target);
 
      state=RFID;
 
      client.flush();
      client.stop();
  } else {
      if (DEBUG) Serial.println("connection failed");
      client.flush();
      client.stop();
 
      // reset the board
      if (DEBUG) Serial.println("resetting!");
      // reset the ethernet board
      digitalWrite(RESET_PIN, LOW);
      delay(2);
      digitalWrite(RESET_PIN, HIGH);
   }
   delay(500);
   state = RFID;
  }
 
  // never get into this state, just for debugging
  else if (state==READING){
    if (client.available()) {
      char c = client.read();
      if (DEBUG) Serial.print(c);
      state=READING;
    } else if (!client.connected()){
      if (DEBUG) Serial.println();
      if (DEBUG) Serial.println("disconnecting.");
      client.stop();
      delay(2000);
      state=RFID;
    }
  }
  }