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-====== Interactive Electronic Chessboard with RGB LEDs ======
-===== Introduction =====
-The Interactive Electronic Chessboard is a project that aims to enhance the chess-playing experience by providing real-time visual feedback through individually addressable RGB LEDs placed under each of the 64 squares. Pieces are detected using a matrix of reed switches and neodymium magnets embedded in the base of each piece.
-When a player picks up a piece, the board highlights all legal moves in **green**, the selected square in **yellow**, and any check situation in **red**. Invalid moves trigger a short **red flash**. The board state is transmitted in real time to a laptop via UART, where a Python script displays the game.
-**Purpose:** To create an interactive and educational chess experience that helps players — especially beginners — understand legal moves intuitively through direct visual feedback on the board.
-**GitHub Repository:** To be announced
-===== General Description =====
-The system is split into two main subsystems:
-  * **Detection subsystem:** An 8×8 matrix of 64 reed switches, one per square. The ESP32 scans the matrix by driving each of the 8 row pins LOW one at a time and reading the 8 column pins. When a piece (with a N52 neodymium magnet in its base) is placed on a square, the corresponding reed switch closes and the column reads LOW — piece detected.
-  * **Lighting subsystem:** A WS2812B 60LED/m strip cut into 8 segments of 8 LEDs each, wired in a snake pattern (even rows left→right, odd rows right→left). All 64 LEDs are driven from a single GPIO4 pin using the WS2812B one-wire protocol, implemented via the ESP32's hardware RMT peripheral.
-  * **UART communication:** On every board state change, the ESP32 sends the updated board state to the laptop at 115200 baud via USB-Serial. A Python script reads the data and displays the game graphically.
-=== Block Diagram ===
-{{:pm:prj2026:jan.vaduva:schema_bloc_strugariu_alexandru.png?600|}}
-===== Hardware Design =====
-=== Bill of Materials ===
-^ No ^ Component ^ Role ^
-| 1 | ESP32-WROOM-32D DevKit 38P | Main microcontroller, 240MHz dual-core |
-| 2 | WS2812B LED strip 60LED/m IP30, 2×1m | 64 individually addressable RGB LEDs |
-| 3 | Reed switch N/O 2×14mm, 100 pcs | Piece presence detection on each square |
-| 4 | Neodymium magnet N52 disc 5×2mm, 50 pcs | Embedded in piece bases |
-| 5 | 5V 3A DC power supply | Powers the LED strip |
-| 6 | 330Ω resistor 1/4W | DATA line protection for WS2812B |
-| 7 | 10kΩ resistors 1/4W, 8 pcs | Pull-up on column lines (GPIO34/35 mandatory external) |
-| 8 | Electrolytic capacitor 1000µF 6.3V | Inrush current protection for LED strip |
-| 9 | Ceramic capacitors 100nF, 3 pcs | Decoupling on ESP32 power supply |
-| 10 | Dupont wires 30cm (M-M, M-F, F-F) | Component interconnections |
-| 11 | Chess set with pieces | Game pieces (magnets embedded in bases) |
-=== Pin Mapping ===
-^ GPIO ^ Function ^ Direction ^
-| GPIO4 | WS2812B DATA (through 330Ω) | OUTPUT |
-| GPIO2 | Row R1 | OUTPUT |
-| GPIO0 | Row R2 | OUTPUT |
-| GPIO18 | Row R3 | OUTPUT |
-| GPIO19 | Row R4 | OUTPUT |
-| GPIO27 | Row R5 | OUTPUT |
-| GPIO14 | Row R6 | OUTPUT |
-| GPIO12 | Row R7 | OUTPUT |
-| GPIO13 | Row R8 | OUTPUT |
-| GPIO32 | Column A | INPUT + internal pull-up |
-| GPIO33 | Column B | INPUT + internal pull-up |
-| GPIO34 | Column C | INPUT + **external** 10kΩ pull-up (input-only pin) |
-| GPIO35 | Column D | INPUT + **external** 10kΩ pull-up (input-only pin) |
-| GPIO15 | Column E | INPUT + internal pull-up |
-| GPIO16 | Column F | INPUT + internal pull-up |
-| GPIO17 | Column G | INPUT + internal pull-up |
-| GPIO5 | Column H | INPUT + internal pull-up |
-=== Electrical Schematic ===
-//Schematic to be added//
-===== Software Design =====
-=== Development Environment ===
-  * **Arduino IDE 2.x** with esp32 by Espressif Systems v3.3.8
-  * **Python 3.x** on laptop for board visualization
-=== Libraries Used ===
-  * **FastLED** — WS2812B strip control, individual RGB LED addressing
-  * **Arduino Serial** (built-in) — UART communication with laptop at 115200 baud
-=== Firmware Description ===
-**Matrix scanning:** The ESP32 drives each of the 8 row pins LOW sequentially (~100Hz scan rate) and reads the 8 column pins. The result is a 64-bit board occupancy map stored as ''uint8_t board_state[8]''.
-**Board state representation:** ''uint8_t board[64]'' — lower 3 bits = piece type (0=empty, 1=pawn, 2=rook, 3=knight, 4=bishop, 5=queen, 6=king), bit 3 = color (0=white, 1=black).
-**Chess logic:** Legal move generation for all piece types. On piece lift, computes all valid destination squares. Detects check and checkmate conditions.
-**LED control:** On every state change, computes the color map for all 64 LEDs and pushes it via FastLED. Colors: green = valid move, yellow = selected piece, red = check/invalid move, off = empty square.
-**UART output:** On every confirmed move, sends board state in simplified FEN notation at 115200 baud.
-=== Main Algorithm ===
-<code cpp>
-void loop() {
-  scan_matrix(board_state);             // read all 64 reed switches
-  if (board_state != prev_state) {
-    compute_delta(prev_state, board_state);
-    if (piece_lifted) {
-      legal_moves = get_legal_moves(from_square);
-      set_leds_green(legal_moves);
-      set_led_yellow(from_square);
-    }
-    if (piece_placed) {
-      if (is_valid_move(from_square, to_square)) {
-        update_board(from_square, to_square);
-        switch_turn();
-        send_uart_fen();
-        if (king_in_check()) set_led_red(king_square);
-      } else {
-        flash_red(to_square);           // invalid move feedback
-      }
-    }
-    FastLED.show();
-    prev_state = board_state;
-  }
-}
-</code>
-===== Results =====
-  * Correct detection of all 64 squares via reed switch matrix
-  * Visual response time under 50ms from piece lift/place
-  * Stable UART communication at 115200 baud with Python script
-  * Total power consumption under 2A at 50% LED brightness
-===== Conclusions =====
-The project successfully demonstrates the integration of multiple ESP32 peripherals — GPIO matrix scanning, RMT hardware for WS2812B, and UART — into a functional hardware product. The RGB LED visual feedback proved intuitive for indicating legal moves, and the reed switch matrix provided reliable piece detection without complex analog circuitry.
-===== Download =====
-To be posted.
-----
-**Author:** Alexandru-Constantin Strugariu \\
-**Group:** 333CD \\
-**Lab Assistant:** Jan Alexandru Văduva \\