TwinStick

Universal Arcade Controller Platform with USB + Bluetooth support and multiple HID profiles.

Architecture

TwinStick is divided into three major components:

TwinStick
 ├── HydraCore   (ESP32 Bluetooth stack / HID profiles)
 ├── NexusUI     (RP2040 inputs + LCD + system interface)
 └── ArcadeLink  (UART protocol between RP2040 and ESP32)

HydraCore (ESP32)

Responsible for wireless connectivity.

Features:

• Bluetooth pairing
• HID profile emulation
• XInput
• DInput
• Nintendo Switch HID
• Communication with RP2040

NexusUI (RP2040)

Responsible for the user interface and input scanning.

Features:

• Button scanning
• Shift register support
• LCD menu system
• Profile selection
• Bluetooth control
• USB HID mode
• Communication with ESP32

ArcadeLink Protocol

UART communication protocol connecting NexusUI and HydraCore.

Responsibilities:

• Button state transmission
• Profile change commands
• Bluetooth management commands
• System status exchange

Connection Modes

USB Mode

Buttons → RP2040 → USB HID → Host

Advantages:

• ~1ms latency
• maximum compatibility

Bluetooth Mode

Buttons → RP2040 → UART → ESP32 → Bluetooth HID → Host

Advantages:

• wireless support
• multi-profile compatibility

HID Profiles

Supported modes:

• XInput (Xbox compatible)
• DInput (generic PC controller)
• Nintendo Switch Pro Controller

Selectable through NexusUI menu.

Repository Layout

firmware/
    hydra-core-esp32/
    nexus-ui-rp2040/

protocol/
    arcade-link/

hardware/
    schematics/
    pcb/

docs/

tools/

License

Open hardware / open firmware project.