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Arduino LCD RFID, NFC RC522 Stopwatch Schematics Airsoft Paintball DOMINATOR


  • During several hour events in extreme games such as Airsoft / Paintball / Nerf, different modes are played, such as King of The Hill, for which this project is designed (classic DOMINATOR). Each team earns points for the duration of the placement, or for the time it is held. I used Arduino, RFID reader, LCD display, detector and relay / separate ledgers.
  • Two independent times for two teams that work after adding one of the team cards just to start the team time. In practice, each member of the RFID team has a keypad that can be attached to the reader and activate the time.
  • Maximum time range:
  • 99 hours, 59 minutes and 59 seconds
  • The time is added to the moment until he / she is stopped by the second team by attaching his / her card or the organizer / arbitrator who can pause or the special key / card to reset.
  • The detector signals the card attachment to the reader and the LEDs / relays indicate the current status of the stopwatch signals the color of the team to which the time is added.
  • The project is designed for (almost) an unlimited number of keys, so all teams, event organizers, result deletion cards can be called. Also suitable for clubs that play similar events regularly or for service providers in the industry.
  • Keychains are usually color-differentiated for that team. Relays are used when stronger lights / diodes are used to indicate the active team to which the time is added.
  • The time is displayed on the 16x2 or 20x4 character display.
  • Just add the key to the reader, the time will begin to count and the other team will stop. The organizer stops both times and starts adding up after adding one of the player"s keys to a team. Eraser will delete both times immediately after the card is inserted (before the new game).
  • The solution is universal, once the key codes are added to the code and it works permanently. I will also add to the project the circuit diagram, the necessary libraries and the Arduino sketch in .ino format.
  • Hardware for the project:
  • Arduino Uno Arduino Uno
  • RFID reader RC522 (13.56MHz) RFID reader RC522
  • Keychains / card / combination Keychains 13.56MHz
  • Detector (passive buzzer) Buzzer
  • 2-channel relays, diodes Relé

  • Approach

  • Upload Arduinos attached program to retrieve the addresses of each card
  • Addresses write down, color distinguished (preferably via Excel) by teams, organizers, erasers
  • Send the spreadsheet and wait for your finished DOMINATOR program with your card addresses

  • Result

    Program for reading RFID card addresses - (This is not a program for DOMINATOR!)

    #include <SPI.h>
    #include <MFRC522.h>
    #define RST_PIN         9
    #define SS_1_PIN        10
    #define NR_OF_READERS   1
    byte ssPins[] = {SS_1_PIN};
    MFRC522 mfrc522[NR_OF_READERS];
    void setup() {
      while (!Serial);
      for (uint8_t reader = 0; reader < NR_OF_READERS; reader++) {
        mfrc522[reader].PCD_Init(ssPins[reader], RST_PIN);
        Serial.print(F("Reader "));
        Serial.print(F(": "));
    void loop() {
      for (uint8_t reader = 0; reader < NR_OF_READERS; reader++) {
        if (mfrc522[reader].PICC_IsNewCardPresent() && mfrc522[reader].PICC_ReadCardSerial()) {
          Serial.print(F("Reader "));
          Serial.print(F(": Card UID:"));
          dump_byte_array(mfrc522[reader].uid.uidByte, mfrc522[reader].uid.size);
          Serial.print(F("PICC type: "));
          MFRC522::PICC_Type piccType = mfrc522[reader].PICC_GetType(mfrc522[reader].uid.sak);
    void dump_byte_array(byte *buffer, byte bufferSize) {
      for (byte i = 0; i < bufferSize; i++) {
      unsigned long kod = 10000 * buffer[4] + 1000 * buffer[3] + 100 * buffer[2] + 10 * buffer[1] + buffer[0]; //finalny kod karty


  • RFID -
  • I2C --> LCD -
  • Schéma zapojenia:

    Airsoft Dominator RFID