primero saber el uid de la tarjeta para tal fin es este codigo
/*
* --------------------------------------------------------------------------------------------------------------------
* Example sketch/program showing how to read new NUID from a PICC to serial.
* --------------------------------------------------------------------------------------------------------------------
* This is a MFRC522 library example; for further details and other examples see: https://github.com/miguelbalboa/rfid
*
* Example sketch/program showing how to the read data from a PICC (that is: a RFID Tag or Card) using a MFRC522 based RFID
* Reader on the Arduino SPI interface.
*
* When the Arduino and the MFRC522 module are connected (see the pin layout below), load this sketch into Arduino IDE
* then verify/compile and upload it. To see the output: use Tools, Serial Monitor of the IDE (hit Ctrl+Shft+M). When
* you present a PICC (that is: a RFID Tag or Card) at reading distance of the MFRC522 Reader/PCD, the serial output
* will show the type, and the NUID if a new card has been detected. Note: you may see "Timeout in communication" messages
* when removing the PICC from reading distance too early.
*
* @license Released into the public domain.
*
* Typical pin layout used:
* -----------------------------------------------------------------------------------------
* MFRC522 Arduino Arduino Arduino Arduino Arduino
* Reader/PCD Uno/101 Mega Nano v3 Leonardo/Micro Pro Micro
* Signal Pin Pin Pin Pin Pin Pin
* -----------------------------------------------------------------------------------------
* RST/Reset RST 9 5 D9 RESET/ICSP-5 RST
* SPI SS SDA(SS) 10 53 D10 10 10
* SPI MOSI MOSI 11 / ICSP-4 51 D11 ICSP-4 16
* SPI MISO MISO 12 / ICSP-1 50 D12 ICSP-1 14
* SPI SCK SCK 13 / ICSP-3 52 D13 ICSP-3 15
*
* More pin layouts for other boards can be found here: https://github.com/miguelbalboa/rfid#pin-layout
*/
#include <SPI.h>
#include <MFRC522.h>
#define SS_PIN 10
#define RST_PIN 9
MFRC522 rfid(SS_PIN, RST_PIN); // Instance of the class
MFRC522::MIFARE_Key key;
// Init array that will store new NUID
byte nuidPICC[4];
void setup() {
Serial.begin(9600);
SPI.begin(); // Init SPI bus
rfid.PCD_Init(); // Init MFRC522
for (byte i = 0; i < 6; i++) {
key.keyByte[i] = 0xFF;
}
Serial.println(F("This code scan the MIFARE Classsic NUID."));
Serial.print(F("Using the following key:"));
printHex(key.keyByte, MFRC522::MF_KEY_SIZE);
}
void loop() {
// Reset the loop if no new card present on the sensor/reader. This saves the entire process when idle.
if ( ! rfid.PICC_IsNewCardPresent())
return;
// Verify if the NUID has been readed
if ( ! rfid.PICC_ReadCardSerial())
return;
Serial.print(F("PICC type: "));
MFRC522::PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak);
Serial.println(rfid.PICC_GetTypeName(piccType));
// Check is the PICC of Classic MIFARE type
if (piccType != MFRC522::PICC_TYPE_MIFARE_MINI &&
piccType != MFRC522::PICC_TYPE_MIFARE_1K &&
piccType != MFRC522::PICC_TYPE_MIFARE_4K) {
Serial.println(F("Your tag is not of type MIFARE Classic."));
return;
}
if (rfid.uid.uidByte[0] != nuidPICC[0] ||
rfid.uid.uidByte[1] != nuidPICC[1] ||
rfid.uid.uidByte[2] != nuidPICC[2] ||
rfid.uid.uidByte[3] != nuidPICC[3] ) {
Serial.println(F("A new card has been detected."));
// Store NUID into nuidPICC array
for (byte i = 0; i < 4; i++) {
nuidPICC[i] = rfid.uid.uidByte[i];
}
Serial.println(F("The NUID tag is:"));
Serial.print(F("In hex: "));
printHex(rfid.uid.uidByte, rfid.uid.size);
Serial.println();
Serial.print(F("In dec: "));
printDec(rfid.uid.uidByte, rfid.uid.size);
Serial.println();
}
else Serial.println(F("Card read previously."));
// Halt PICC
rfid.PICC_HaltA();
// Stop encryption on PCD
rfid.PCD_StopCrypto1();
}
/**
* Helper routine to dump a byte array as hex values to Serial.
*/
void printHex(byte *buffer, byte bufferSize) {
for (byte i = 0; i < bufferSize; i++) {
Serial.print(buffer[i] < 0x10 ? " 0" : " ");
Serial.print(buffer[i], HEX);
}
}
/**
* Helper routine to dump a byte array as dec values to Serial.
*/
void printDec(byte *buffer, byte bufferSize) {
for (byte i = 0; i < bufferSize; i++) {
Serial.print(' ');
Serial.print(buffer[i], DEC);
}
}
el codigo de arriba se encuentra con el nombre ReadNUID de GitHub Community la libreria que se debe instalar
ahora hay que compilar y ejecutar el siguiente codigo en arduino
#include <Servo.h>
#include <SPI.h>
#include <MFRC522.h>
#include <Wire.h>
const byte monUID[4] = {51, 66, 241, 11};
bool valid=true;
#define PIN_LED_ROUGE 32
#define PIN_LED_VERTE 12
#define PIN_RST 17
#define PIN_SDA 5
const int servoPin = 14;
Servo myservo = Servo();
MFRC522 rfid(PIN_SDA, PIN_RST);
void setup()
{
SPI.begin();
rfid.PCD_Init();
myservo.write(servoPin, 90); // set the servo position (degrees)
pinMode(PIN_LED_ROUGE, OUTPUT);
pinMode(PIN_LED_VERTE, OUTPUT);
}
void loop()
{
if (rfid.PICC_IsNewCardPresent()) // A tag/card is detected : Badge détecté
{
if (rfid.PICC_ReadCardSerial())
{
for (int i = 0; i < rfid.uid.size; i++)
{
if (rfid.uid.uidByte[i] != monUID[i])
{valid=false;}
else
{valid=true;}
}
if (valid)
{
digitalWrite(PIN_LED_VERTE, HIGH);
myservo.write(servoPin, 0); // set the servo position (degrees)
delay(4000);
digitalWrite(PIN_LED_VERTE, LOW);
myservo.write(servoPin, 90); // set the servo position (degrees)
}
else
{
digitalWrite(PIN_LED_ROUGE, HIGH);
delay(1000);
digitalWrite(PIN_LED_ROUGE, LOW);
}
}
}
}