er-rfid

Multi-reader RFID/NFC module for the Wonder Controlz escape room system. Supports up to 6 independent card readers connected via RS-485 for long-distance placement. Communicates with the Main PC over CAN bus.

Status: Prototype (in development).

Each reader connects to the module via RS-485, which allows placing readers up to ~25 m away from the module — inside props, on walls, or in separate rooms.

• MIFARE Classic
• MIFARE Plus
• MIFARE Ultralight
• NTAG series
• Other NFC-compatible tags

UID length: 4, 7, or 10 bytes depending on card type. All UID lengths are fully supported.

The module sits on the CAN bus like any other Wonder Controlz I/O module. From the CAN side, it communicates with the Main PC using the standard ER-Frame protocol. On the other side, it connects to the RFID/NFC readers via RS-485 — a separate, long-range serial interface designed for distances up to ~25 m.

  CAN bus          er-rfid               reader modules
  ─────────┐      ┌──────────────┐
  ◄── from │──IN──│              │◄──RS-485──► Reader 1
   previous│      │              │
  ──► to   │──OUT─│   er-rfid    │◄──RS-485──► Reader 2
   next    │      │              │
  ─────────┘      │              │◄──RS-485──► ...
                  └──────────────┘

The module continuously polls all connected readers and sends two types of events to Node-RED on the Main PC:

• Tag appeared — a card/tag entered the reader's range. The event includes the full UID and which reader detected it.
• Tag disappeared — the card/tag was removed from the reader's range.

The module sends the raw UID, not a match/no-match result. Following the Wonder Controlz Zero Field Logic principle, the module does not store any card database and does not decide whether a tag is “correct”. All tag comparison and game logic happens in Node-RED. This means you can change which cards are accepted, add new ones, or implement complex multi-card puzzles — all from Node-RED, without touching the hardware.

Long UIDs (7 or 10 bytes) are transmitted using a multipart mechanism that splits the data across multiple CAN frames — fully transparent to the game logic in Node-RED.