smart-chess

Smart Chess

File Structure

Eventually they will all be in 1 controller

chess_game/
  Game Engine - remembers game state, runs game.
  LED Indication Blocks - based on game state, tell which LEDs should be lit up in each scenario
controls/
  Reads user inputs - process user inputs.
  Main - inits game engine, loop between: read user state, LED light up, game engine run if user moved, move pieces...
stockfish/
  Does stockfish stuff. 

LED Format:

Example: Colour + Pattern

Cursor: Cyan + Cross

Selected Piece: Green + Solid

Previous Start: Yellow + Solid

Previous End: YelloW + Solid

Valid Moves: Orange + Solid

Valid Captures: Red + X Pattern

Pawn Promotion: Purple??

Modules Used:

esp32 3.2.1 by Espressif Systems

Arduino_AVRSTL 1.2.5 and ArduinoSTL 1.3.3 by Mike Matera

Adafruit BusIO 1.17.0, Adafruit GFX Library 1.11.11, Adafruit SSD1306 2.5.13 by Adafruit

FastLED 3.9.3 by Daniel Garcia

Timer 1.2.1 by Stefan Staub

Bug Fixes:

In ArduinoSTL new_handler.cpp, comment out line 22: const std::nothrow_t ...

Bug Fix with FASTLED:

In the ArduinoSTL new file, modify the following to namespace std

namespace std{
	class _UCXXEXPORT bad_alloc : public exception {};

    // Check if std::nothrow_t is already defined
    #ifndef __STD_NOTHROW_T_DEFINED
    #define __STD_NOTHROW_T_DEFINED
    #if defined(__AVR__) || defined(ARDUINO)
        // Avoid redefining nothrow_t if included from the Arduino core
        struct nothrow_t; // Declare without defining
        extern const nothrow_t nothrow;
    #else
        // Define nothrow_t if not already defined
        struct _UCXXEXPORT nothrow_t {};
        extern const nothrow_t nothrow;
    #endif
    #endif

	typedef void (*new_handler)();
	_UCXXEXPORT new_handler set_new_handler(new_handler new_p) _UCXX_USE_NOEXCEPT;
}

This allows the code to compile

Raspberry Pi Setup

Raspberry Pi 5, all GPIO and I2C and any other interfaces are set open.

git cloned stockfish from official stockfish into ~/ directory.

created a python venv at ~/venv and installed the stockfish pip library.

Arduino Mega running out of memory

The inclusion of 2 displays is really costly in terms of memory. So some fixes regarding that:

1. Before we run begin_turn, we actually just delete the display object, which also frees the memory associated with its buffer. And whenever we want the display again, we will call init_display() which will create the display object again.
2. We HOPE to re-write the remove_illegal_moves function to be more memory efficient, currently it copies the entire board object which can be expensive.
3. We reduced some memory usage of 3-fold repetition vector, by not storing ANY pawn states, since in our code, we restart any counter / 3-fold checks every time a pawn makes a move (since that state can never be repeated).
4. Reduced the space required for possible_moves vector. Before it stores a vector<pair<pair<int, int>, pair<int, int>>> which is 16 bytes per move. Now it stores a vector<pair<int, int>> which is 8 bytes per move. Done by replacing any pair(x,y) into y*8 + x. (We can extract x and y by y = move/8, x = move%8).
5. We kinda removed one animation for the OLED display, which is the "stars falling" animation. We can re-add it later, but just throw the control code in the main loop, and not in the OLED code... (since this is only for IDLE animation)

Memory regarding LED: LED seems to only need 1 pixel at a time, so we can use some algorithm to reduce memory usage.

Bug with OLED display:

When adding OLED display code, we changed the selected_x, selected_y,... to be initialized to -1. Instead of previously determined 0. This kinda caused a small error in the display code, where a selected_x of -1 causes it to access wrong memory... and cause the print statement to output wrong value..