C++ Arduino Game Controller

Arduino-based custom videogame controller with a C++ Windows client that reads button states over serial and maps them to game actions or keyboard events for PC games.

Overview

This project implements a physical game controller built around an Arduino board and a C++ client application for Windows:

• The Arduino firmware reads the state of physical buttons on the controller and encodes them into a compact binary format.
• The data is sent to the PC through the serial (USB) connection.
• On Windows, a C++ application opens the serial port, decodes the incoming bytes and translates them into:
  • internal game actions, and/or
  • virtual keyboard input, so that the controller can be used with existing games.

The goal of this project is to explore embedded programming (Arduino) together with systems programming in C++ on Windows, building a complete end-to-end prototype of a custom game controller.

Features

• Custom physical controller layout (buttons wired to an Arduino board)
• Arduino firmware that:
  • Reads digital inputs using INPUT_PULLUP
  • Packs button states into a single byte (bitmask protocol)
  • Sends data at a fixed rate over the serial port
• C++ Windows client that:
  • Opens and manages a serial connection (e.g., COM3)
  • Parses the bitmask into individual button states
  • Logs or maps button presses to actions
  • Emulates keyboard events (optional) to control PC games

Tech Stack

• Hardware
  • Arduino (e.g., Arduino Uno/Nano)
  • Physical buttons (and/or joystick)
• Firmware
  • Arduino C/C++ (compiled with the Arduino toolchain)
• PC Client
  • C++ (Windows)
  • Serial communication using WinAPI-based serial handling
  • (Optional) Keyboard emulation via WinAPI SendInput

Project Structure

• firmware/ – Arduino code for reading buttons and sending serial data
• pc-client/ – C++ Windows application that reads serial input and maps it to actions/keyboard events
• docs/ – Documentation, diagrams and protocol description
• hardware/ – References for controller layout, wiring, and 3D printed case

Getting Started

1. Firmware (Arduino)

1. Open firmware/game_controller.ino in the Arduino IDE.
2. Adjust the buttonPins array to match your wiring.
3. Upload the sketch to your Arduino board.
4. Make sure the serial baud rate matches the PC client (default: 115200).

2. PC Client (C++ on Windows)

The PC client is a small C++ application that:

• Opens a given serial port (e.g., COM3);
• Continuously reads 1-byte packets representing button states;
• Decodes the bitmask into individual button flags;
• Prints the states to the console and optionally triggers keyboard events.

You can build it using CMake:

cd pc-client
mkdir build
cd build
cmake ..
cmake --build .

Then run, for example:

./pc-client.exe COM3

(or pc-client.exe COM3 on Windows).

Protocol

The Arduino sends 1 byte at a time over serial. Each bit in the byte represents a button:

• Bit 0 → UP
• Bit 1 → DOWN
• Bit 2 → LEFT
• Bit 3 → RIGHT
• Bit 4 → A
• Bit 5 → B

Bit = 1 means "pressed", bit = 0 means "released".

See docs/protocol.md for more details.

Status

Initial prototype focused on:

• reading button states on the Arduino,
• sending them via serial,
• visualizing and mapping them in the C++ Windows client.