Published January 4, 2020

RFID Activated LED

RFID tag turns on LED.

IntermediateFull instructions provided6,830

Things used in this project

Hardware components

Arduino UNO

5 mm LED: Green

Male/Female Jumper Wires

RFID Module (Generic)

9V battery (generic)

9V Battery Clip

Software apps and online services

Arduino IDE

Story

I made this because I wanted to try an RFID tag and thought this might be a simple project to start with.

First of all, connect the RFID module using the picture below.

Then, the LED should go to digital pin 6 and GND. This will be activated when the RFID tag is over the module.

Time to code! Download GETUID.ino. This will get the UID or the tag. The only thing I changed in this code was move the printHex function to before setup() and loop(). Upload this code and in the Serial Monitor, the UID should be displayed.

Next, download RFIDLED.ino. I added the led part in this code. Upload this and hover the RFID tag close to the module. The green LED should come on!

#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;

void printHex(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], HEX);
  }
}

// Init array that will store UID
byte uid[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;
  }
}
 
void loop() {
if (rfid.PICC_IsNewCardPresent() && rfid.PICC_ReadCardSerial()){
 for (byte i = 0; i < 4; i++) {
      uid[i] = rfid.uid.uidByte[i];
 }
 printHex(rfid.uid.uidByte, rfid.uid.size);
 Serial.println();
 rfid.PICC_HaltA();
 rfid.PCD_StopCrypto1();
}

#include <SPI.h>
#include <MFRC522.h>
 
#define SS_PIN 10
#define RST_PIN 9

int ledPin = 6;

MFRC522 rfid(SS_PIN, RST_PIN); // Instance of the class
 
MFRC522::MIFARE_Key key;
 
// Init array that will store UID
byte uid[4];

void printHex(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], HEX);
  }
}

void setup() {
  digitalWrite(ledPin, LOW);
  Serial.begin(9600);
  SPI.begin(); // Init SPI bus
  rfid.PCD_Init(); // Init MFRC522
  for (byte i = 0; i < 6; i++) {
    key.keyByte[i] = 0xFF;
  }
}
 
void loop() {
if (rfid.PICC_IsNewCardPresent() && rfid.PICC_ReadCardSerial()){
 for (byte i = 0; i < 4; i++) {
      uid[i] = rfid.uid.uidByte[i];
 }
 printHex(rfid.uid.uidByte, rfid.uid.size);
 digitalWrite(ledPin, HIGH);
 rfid.PICC_HaltA();
 rfid.PCD_StopCrypto1();
}
}

RFID Activated LED

Things used in this project

Hardware components

Software apps and online services

Story

Code

GETUID

RFIDLED

Credits

BigTogepi

Comments

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RFID Activated LED

RFID Activated LED

Things used in this project

Hardware components

Software apps and online services

Story

Code

GETUID

RFIDLED

Credits

BigTogepi

Comments

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