Particle Photon + RC522 RFID implant reader

rfid-node.ino

#include "MFRC522/MFRC522.h"

/*
  Function           Core Pin      MRFC522 Pin
  Reset             D2            RST
  SPI SS            D1            SDA
  SPI MOSI          A5            MOSI
  SPI MISO          A4            MISO
  SPI SCK           A3            SCK
*/

#define SS_PIN D1
#define RST_PIN D2

MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.

void setup() {
  Serial.begin(9600); // Initialize serial communications with the PC

  mfrc522.setSPIConfig();
  mfrc522.PCD_Init(); // Init MFRC522 card

  RGB.control(true); // take control of onboard RGB led
}

void blink() {
  RGB.color(0, 0, 255);
  delay(150);
  RGB.color(0, 0, 0);
  delay(100);
  RGB.color(0, 0, 255);
  delay(150);
  RGB.color(0, 0, 0);
}

void loop() {
  // Look for new cards
  if ( mfrc522.PICC_IsNewCardPresent()) {
    // Serial.println("New card present...");
    if ( mfrc522.PICC_ReadCardSerial()) {
      // Dump debug info about the card. PICC_HaltA() is automatically called.
      //mfrc522.PICC_DumpToSerial(&(mfrc522.uid));

      String UID = "";

      for (byte i = 0; i < mfrc522.uid.size; i++) {
        UID += String(mfrc522.uid.uidByte[i] < 0x10 ? "0" : "");
        UID += String(mfrc522.uid.uidByte[i], HEX);
      }

      mfrc522.PICC_HaltA();
      Serial.print("UID: ");
      Serial.println(UID);
      Particle.publish("rfid-read", UID, 5, PRIVATE); // publish UID to rest of system

      blink(); // visual feedback of read using onboard led
    }
  }
}

Stripped down, thank you for posting this