Receive USB serial data in arduino in combination with RFID reader

Question

I'm working on an Arduino project. The Arduino board saves a timestamp and RFID code to the ROM when an RFID tag is scanned. The RFID data is received by Serial.read() but now I need to get the stored data from my Arduino ROM to my computer.

To do that I have to read the serial data (in this case using C#) and that works fine. But because my Arduino board needs to know when to write data to the serial I first need to send a command to the Arduino board.

Using Arduino IDE's 'Serial Monitor', I tried sending some data but it doesn't get received by the Arduino. When I place an RFID tag in front of the RFID, the Arduino board does receive data. So it seems to me like the serial port input is somehow reserved by the RFID reader? Is that even possible?

Does someone know an solution for my problem? Note that this is my first Arduino project and C is new to me.

Some info:

• Arduino UNO
• RFID Reader: Innovations ID12
• RTC Clock module
• C
• C#
• .NET

The code below is the whole Arduino project.

#include "Wire.h"
#include <EEPROM.h>
#include "EEPROMAnything.h"

#define DS1307_ADDRESS 0x68
byte   zero = 0; //workaround for issue #527
int    buttonState = 0;
byte   value;
int    byteaddress = 0;
int    bytesize = 0;
int    lastTag = 0;
byte   incomingByte;

struct config_t
{
    int seconds;
    int hours;
    int minutes;
} timestamp;

int  RFIDResetPin = 13;

//Register your RFID tags here
char tag1[13] = "03000DEB55B0";
char tag2[13] = "03000DB88137";
char tag3[13] = "03000DC8E026";
char tag4[13] = "03000623FBDD";
char tag5[13] = "03000DB8B701";

void setup()
{
  pinMode(7, INPUT);
  Wire.begin();

  Serial.begin(9600);

  pinMode(RFIDResetPin, OUTPUT);
  digitalWrite(RFIDResetPin, HIGH);

  EEPROM_readAnything(0, timestamp);
  setDateTime(); //MUST CONFIGURE IN FUNCTION

  pinMode(11, OUTPUT);
}

void loop()
{
  buttonState = digitalRead(7);

  char tagString[13];
  int index = 0;
  boolean reading = false;

  if (buttonState == HIGH) {   
    // turn LED on:    
    printDate(); 
    delay(200);
  }

  while(Serial.available()){

    buttonState = digitalRead(7);

    int readByte = Serial.read(); //read next available byte

    if(readByte == 2) reading = true; //begining of tag
    if(readByte == 3) reading = false; //end of tag

    if(reading && readByte != 2 && readByte != 10 && readByte != 13){
      //store the tag
      tagString[index] = readByte;
      index ++;
    }

    incomingByte = Serial.read();
    Serial.println(incomingByte);
  }

  checkTag(tagString); //Check if it is a match
  clearTag(tagString); //Clear the char of all value
  resetReader(); //eset the RFID reader
}

void checkTag(char tag[]){
///////////////////////////////////
//Check the read tag against known tags
///////////////////////////////////

  int currentTag = 0;

  if(strlen(tag) == 0 || strlen(tag) < 12)
     return; //empty, no need to continue

  if(compareTag(tag, tag1) && lastTag != 1){ // if matched tag1, do   this
    Serial.println("Scanned tag 1");
    lastTag = 1;
    currentTag = 1;
    printDate();
    bleepSucces(11);
  }
  else
  if(compareTag(tag, tag2) && lastTag != 2){ //if matched tag2, do this
    Serial.println("Scanned tag 2");
    lastTag = 2;
    currentTag = 2;
    printDate();
    bleepSucces(11);
  }
  else
  if(compareTag(tag, tag3) && lastTag != 3){
    Serial.println("Scanned tag 3");
    lastTag = 3;
    currentTag = 3;
    printDate();
    bleepSucces(11);
  }
  else
  if(compareTag(tag, tag4) && lastTag != 4){
    Serial.println("Scanned tag 4");
    lastTag = 4;
    currentTag = 4;
    printDate();
    bleepSucces(11);
  }
  else
  if(compareTag(tag, tag5) && lastTag != 5){
    Serial.println("Scanned tag 5");
    lastTag = 5;
    currentTag = 5;
    printDate();
    bleepSucces(11);
  }
  else
  {
    if(currentTag == 0 && lastTag == 0){
      Serial.println("Unknown Tag, see below:");
      Serial.println(tag); //read out any unknown tag
      //resetReader();
      lastTag = 0;
      bleepFail(11);
    }
    return;
  }
}

void bleepSucces(int pin)
{
  digitalWrite(pin, HIGH);
  delay(300);
  digitalWrite(pin, LOW);
  delay(20);
  digitalWrite(pin, HIGH);
  delay(150);
  digitalWrite(pin, LOW);
}

void bleepFail(int pin)
{
  digitalWrite(pin, HIGH);
  delay(1200);
  digitalWrite(pin, LOW);
}

void resetReader()
{    //Reset the RFID reader to read again.
  digitalWrite(RFIDResetPin, LOW);
  digitalWrite(RFIDResetPin, HIGH);
  delay(150);
}

void clearTag(char one[])
{
//clear the char array by filling with null - ASCII 0
//Will think same tag has been read otherwise
  for(int i = 0; i < strlen(one); i++)
    one[i] = 0;
}

boolean compareTag(char one[], char two[])
{ //compare two tags to see if same,
  //strcmp not working 100% so we do this

  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 setDateTime()
{
  byte second =      20; //0-59
  byte minute =      37; //0-59
  byte hour =        20; //0-23
  byte weekDay =     2; //1-7
  byte monthDay =    3; //1-31
  byte month =       4; //1-12
  byte year  =       12; //0-99

  Wire.beginTransmission(DS1307_ADDRESS);
  Wire.write(zero); //stop Oscillator

  Wire.write(decToBcd(second));
  Wire.write(decToBcd(minute));
  Wire.write(decToBcd(hour));
  Wire.write(decToBcd(weekDay));
  Wire.write(decToBcd(monthDay));
  Wire.write(decToBcd(month));
  Wire.write(decToBcd(year));

  Wire.write(zero); //start 

  Wire.endTransmission();
}

byte decToBcd(byte val)
{  // Convert normal decimal numbers to binary coded decimal
  return val / 10 * 16  +  val % 10;
}

byte bcdToDec(byte val)
{  // Convert binary coded decimal to normal decimal numbers
  return val / 16 * 10  +  val % 16;
}

void printDate()
{
  // Reset the register pointer
  Wire.beginTransmission(DS1307_ADDRESS);
  Wire.write(zero);
  Wire.endTransmission();

  Wire.requestFrom(DS1307_ADDRESS, 7);

  int second = bcdToDec(Wire.read());
  int minute = bcdToDec(Wire.read());
  int hour = bcdToDec(Wire.read() & 0b111111); //24 hour time
  int weekDay = bcdToDec(Wire.read()); //0-6 -> sunday - Saturday
  int monthDay = bcdToDec(Wire.read());
  int month = bcdToDec(Wire.read());
  int year = bcdToDec(Wire.read());

  //Set variables in our struct
  timestamp.hours = hour;
  timestamp.minutes = minute;
  timestamp.seconds = second;

  //Save the timestamp to EEPROM
  bytesize = EEPROM_writeAnything(byteaddress, timestamp);
  byteaddress = byteaddress + bytesize;

  //if (Serial.available() > 0) {
    writeSerial();
  //}
}

void writeSerial()
{  
  Serial.print("{");
  // read a byte from the current address of the EEPROM
  for (int i=0; i <= byteaddress + 4; i = i + 2){
      value = EEPROM.read(i);
      Serial.print(value, DEC);

      if (i < byteaddress+4)
         Serial.print(((i-1)%3 == 0) ? ", " : " ");
  }
  Serial.println("}");     
}

Answer 1

When you read from the arduino ide,
if you enter a '2' that will actually equal 50 as ('0'==48).

Try changing the if statement to readByte != '2'

Unless you are entering some kind of control character actually equal to 2.

Answer 2

Sibster is correct pin 0 and 1 are used for hardware serial and USB connection to PC. use SPI, I2c or software serial for the RFID (depending on what you've got). Also you'd probably be better off using an SD card.

Answer 3

The arduino UNO only has 1 serial port, pin 0 and 1 are actualy connected to the usb port.

You will need to use softwareserial to create a serial port in the software to talk to your RFID Reader and connect the RFID reader to other pins then 0 and 1