====== 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).

===== RFID Readers =====

^ Parameter ^ Value ^
| Reader type | NFC/RFID reader module |
| Maximum readers | 6 per module |
| Reader connection | RS-485 (up to ~25 m cable between module and reader) |

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.

==== Supported Card Types ====

  * 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.

===== How It Works =====

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.

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

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.

===== CAN Bus =====

^ Parameter ^ Value ^
| Standard | CAN 2.0A |
| Baud rate | 500 kbps |
| Protocol | ER-Frame (custom) |

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.

===== Front Panel =====

^ Element ^ Description ^
| Display | 3-digit, 7-segment LED |
| Buttons | 3 — PLUS, MINUS, SEL |
| Status LEDs | RUN (green), STOP (yellow), ERROR (red) |

===== Specifications Summary =====

^ Feature ^ Value ^
| Reader modules | Up to 6 |
| Reader interface | RS-485 (up to ~25 m per reader) |
| Supported cards | MIFARE Classic/Plus/Ultralight, NTAG |
| CAN bus | 500 kbps, ER-Frame protocol |
| Supply voltage | 24V DC (via CAN bus cable) |