This code lets the Arduino read the Parallax brand RFID reader. Once connected and programmed, prints the tag number in the serial monitor window. Note that the serial monitor window runs at an astonishing 2400 baud, so make sure you have your seat belt buckled!
Four easy hardware connections:
// RFID reader for Arduino
// Wiring version by BARRAGAN <https://people.interaction-ivrea.it/h.barragan>
// Modified for Arduino by djmatic
int val = 0;
char code[10];
int bytesread = 0;
void setup() {
Serial.begin(2400); // RFID reader SOUT pin connected to Serial RX pin at 2400bps
pinMode(2,OUTPUT); // Set digital pin 2 as OUTPUT to connect it to the RFID /ENABLE pin
digitalWrite(2, LOW); // Activate the RFID reader
}
void loop() {
if(Serial.available() > 0) { // if data available from reader
if((val = Serial.read()) == 10) { // check for header
bytesread = 0;
while(bytesread<10) { // read 10 digit code
if( Serial.available() > 0) {
val = Serial.read();
if((val == 10)||(val == 13)) { // if header or stop bytes before the 10 digit reading
break; // stop reading
}
code[bytesread] = val; // add the digit
bytesread++; // ready to read next digit
}
}
if(bytesread == 10) { // if 10 digit read is complete
Serial.print("TAG code is: "); // possibly a good TAG
Serial.println(code); // print the TAG code
}
bytesread = 0;
digitalWrite(2, HIGH); // deactivate the RFID reader for a moment so it will not flood
delay(1500); // wait for a bit
digitalWrite(2, LOW); // Activate the RFID reader
}
}
}
// extra stuff
// digitalWrite(2, HIGH); // deactivate RFID reader
another case using SoftwareSerial rxPin=8
// Modified by Worapoht K.
#include <SoftwareSerial.h>
int val = 0;
char code[10];
int bytesread = 0;
#define rxPin 8
#define txPin 9
// RFID reader SOUT pin connected to Serial RX pin at 2400bps to pin8
void setup()
{
Serial.begin(2400); // Hardware serial for Monitor 2400bps
pinMode(2,OUTPUT); // Set digital pin 2 as OUTPUT to connect it to the RFID /ENABLE pin
digitalWrite(2, LOW); // Activate the RFID reader
}
void loop()
{
SoftwareSerial RFID = SoftwareSerial(rxPin,txPin);
RFID.begin(2400);
if((val = RFID.read()) == 10)
{ // check for header
bytesread = 0;
while(bytesread<10)
{ // read 10 digit code
val = RFID.read();
if((val == 10)||(val == 13))
{ // if header or stop bytes before the 10 digit reading
break; // stop reading
}
code[bytesread] = val; // add the digit
bytesread++; // ready to read next digit
}
if(bytesread == 10)
{ // if 10 digit read is complete
Serial.print("TAG code is: "); // possibly a good TAG
Serial.println(code); // print the TAG code
}
bytesread = 0;
delay(500); // wait for a second
}
}
The Parallax 28140 RFID Reader and operation with Arduino C++... I have tried to use the Parallax RFID Reader with both Basic Stamp, PIC Basic Pro, and Arduino C++ code. I have several 125kHz Tags with known, 10-digit codes; three "credit card" style tags, one "round World Tag" tag, and two "key fob" style tags. These tags have actual printed 10-digit decimal numbers on them, but when used with the Basic Stamp, PIC Basic Pro, or Arduino C++ code, produce hexadecimal garbage results as indicated in the list below: DECIMAL HEXIDECIMAL 0009238622 6F008CF85E 0009213929 6F008C97E9 0363842563 0415AFCC03 0004350367 010042619F 0004089722 01003E677A 0050598842 0F030413BA I have a cheap Chinese USB connected RFID Reader which correctly reads the 10-digit decimal codes from these tags. Looking at the bottom of the Chinese unit, I found a code 8H10D-1. Researching this code led me to the information on the 8H10D output format described below. The Unique ID(UID) from the tag is converted using the 8H10D conversion rule from Hexidecimal to Decimal. For Example: Original Tag UID (HEX): 10 00 62 D9 B2 The 8H10D rule says take the last eight hexadecimal digits, 00 62 D9 B2, and convert it to a maximum 10 decimal digits. Hexadecimal 0062D9B2 = Decimal 6478258 So its 8H10D format is: 0006478258 With this in mind, I modified the Arduino RFID software to meet the 8HD10 format as shown below:
// RFID reader for Arduino
// Wiring version by BARRAGAN <https://people.interaction-ivrea.it/h.barragan>
// Modified for Arduino by djmatic
//Modified 1-12-2015 to produce the correct tag number by M. Robertson
int val = 0;
char code[10];
int bytesread = 0;
int i = 0;
int myNum[10];
unsigned long int multArray[] = {1,1,268435456,16777216,1048576,
65536,4096,256,16,1};
unsigned long int trueTag = 0;
void setup() {
Serial.begin(2400); // RFID reader SOUT pin connected to Serial RX pin at 2400bps
pinMode(2,OUTPUT); // Set digital pin 2 as OUTPUT to connect it to the RFID /ENABLE pin
digitalWrite(2, LOW); // Activate the RFID reader
}
void loop() {
if(Serial.available() > 0) { // if data available from reader
if((val = Serial.read()) == 10) { // check for header
bytesread = 0;
while(bytesread<10) { // read 10 digit code
if( Serial.available() > 0) {
val = Serial.read();
if((val == 10)||(val == 13)) { // if header or stop bytes before the 10 digit reading
break; // stop reading
}
code[bytesread] = val; // add the digit
bytesread++; // ready to read next digit
}
}
if(bytesread == 10) { // if 10 digit read is complete
code[0] = 48; //Zero out the first two elements of the code array
code[1] = 48;
//Cycle through the code array and create int elements in myNum
for(i=0;i<10;i++)
{
if(code[i] == '0') //I am not a programmer, but this is the only way I could
myNum[i] = 0;
else if(code[i] == '1') //find to convert elements of a char array to ints...
myNum[i] = 1;
else if(code[i] == '2')
myNum[i] = 2;
else if(code[i] == '3')
myNum[i] = 3;
else if(code[i] == '4')
myNum[i] = 4;
else if(code[i] == '5')
myNum[i] = 5;
else if(code[i] == '6')
myNum[i] = 6;
else if(code[i] == '7')
myNum[i] = 7;
else if(code[i] == '8')
myNum[i] = 8;
else if(code[i] == '9')
myNum[i] = 9;
else if(code[i] == 'A')
myNum[i] = 10;
else if(code[i] == 'B')
myNum[i] = 11;
else if(code[i] == 'C')
myNum[i] = 12;
else if(code[i] == 'D')
myNum[i] = 13;
else if(code[i] == 'E')
myNum[i] = 14;
else if(code[i] == 'F')
myNum[i] = 15;
else
myNum[i] = 9999; //Oops! an error
}
//With trueTag initialized to 0, create the true tag number by summing trueTag with each element of the
//integer myNum array multiplied by the corresponding element of the multArray.
for(i=0;i<10;i++)
{
trueTag = trueTag + (myNum[i]*multArray[i]);
}
Serial.print("TAG = "); //print real TAG number
Serial.println(trueTag);
}
bytesread = 0;
trueTag = 0; //Zero out trueTag for next iteration of the loop
digitalWrite(2, HIGH); // deactivate the RFID reader for a moment so it will not flood
delay(1500); // wait for a bit
digitalWrite(2, LOW); // Activate the RFID reader
}
}
}
// extra stuff
// digitalWrite(2, HIGH); // dea
A more compact version of the above, based on Worapoht's SoftwareSerial rxPin=8 version. This uses the
// RFID reader for Arduino
// Wiring version by BARRAGAN <https://people.interaction-ivrea.it/h.barragan>
// Modified for Arduino by djmatic, further modified by Worapoht K.
//Modified to produce the correct tag number by M. Robertson, refactored by J. Chapman
#include <SoftwareSerial.h>
int val = 0;
char code[11];
int bytesread = 0;
long decval = 0;
#define rxPin 8
#define txPin 9
// RFID reader SOUT pin connected to Serial RX pin at 2400bps to pin8
void setup()
{
Serial.begin(2400); // Hardware serial for Monitor 2400bps
pinMode(2,OUTPUT); // Set digital pin 2 as OUTPUT to connect it to the RFID /ENABLE pin
digitalWrite(2, LOW); // Activate the RFID reader
}
void loop()
{
SoftwareSerial RFID = SoftwareSerial(rxPin,txPin);
RFID.begin(2400);
if((val = RFID.read()) == 10)
{ // check for header
bytesread = 0;
while(bytesread<10)
{ // read 10 digit code
val = RFID.read();
if((val == 10)||(val == 13))
{ // if header or stop bytes before the 10 digit reading
break; // stop reading
}
code[bytesread] = val; // add the digit
bytesread++; // ready to read next digit
}
code[10] = 0; // NULL terminate
if(bytesread == 10)
{ // if 10 digit read is complete
Serial.print("TAG code is: "); // possibly a good TAG
Serial.println(code); // print the TAG code
// Values printed on some tags are decimal with the first
// byte omitted.
decval = strtol(&code[2], 0, 16);
Serial.print("Decimal code is: ");
Serial.println(decval, DEC);
}
bytesread = 0;
delay(500); // wait for a second
}
}
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