feat(bridge): add SDL sensor reading and gyro bias calibration

- Add initialize_controller_sensors() for SDL accel/gyro enable
- Add handle_sensor_update() with direct axis passthrough (no remapping)
- Add gyro bias calibration (200 samples, zero gyro until locked)
- Add IMU sample FIFO with pop-to-report before UART send
- Add --debug-imu, --no-imu, --gyro-scale CLI flags

src/switch_pico_bridge/controller_uart_bridge.py

@@ -34,6 +34,14 @@ from rich.table import Table
 
 from .switch_pico_uart import (
     UART_BAUD,
+    MS2_PER_G,
+    RAD_TO_DEG,
+    ACCEL_LSB_PER_G,
+    GYRO_LSB_PER_RAD_S,
+    SENSOR_ACCEL,
+    SENSOR_GYRO,
+    IMU_SAMPLES_PER_REPORT,
+    IMUSample,
     PicoUART,
     SwitchButton,
     SwitchDpad,
@@ -49,9 +57,11 @@ RUMBLE_IDLE_TIMEOUT = 0.25  # seconds without packets before forcing rumble off
 RUMBLE_STUCK_TIMEOUT = 0.60  # continuous same-energy rumble will be stopped after this
 RUMBLE_MIN_ACTIVE = 0.40  # below this, rumble is treated as off/noise
 RUMBLE_SCALE = 1.0
-CONTROLLER_DB_URL_DEFAULT = (
+CONTROLLER_DB_URL_DEFAULT = "https://raw.githubusercontent.com/mdqinc/SDL_GameControllerDB/refs/heads/master/gamecontrollerdb.txt"
-    "https://raw.githubusercontent.com/mdqinc/SDL_GameControllerDB/refs/heads/master/gamecontrollerdb.txt"
+SDL_TRUE = getattr(sdl2, "SDL_TRUE", 1)
-)
+SDL_CONTROLLERSENSORUPDATE = getattr(sdl2, "SDL_CONTROLLERSENSORUPDATE", 0x658)
+GYRO_BIAS_SAMPLES = 200
+IMU_BUFFER_SIZE = 32
 
 
 def parse_mapping(value: str) -> Tuple[int, str]:
@@ -62,7 +72,9 @@ def parse_mapping(value: str) -> Tuple[int, str]:
     try:
         idx = int(idx_str, 10)
     except ValueError as exc:
-        raise argparse.ArgumentTypeError(f"Invalid controller index '{idx_str}'") from exc
+        raise argparse.ArgumentTypeError(
+            f"Invalid controller index '{idx_str}'"
+        ) from exc
     if not port:
         raise argparse.ArgumentTypeError("Serial port cannot be empty")
     return idx, port.strip()
@@ -84,9 +96,13 @@ def download_controller_db(console: Console, destination: Path, url: str) -> boo
     try:
         destination.write_bytes(data)
     except Exception as exc:
-        console.print(f"[red]Failed to write controller database to {destination}: {exc}[/red]")
+        console.print(
+            f"[red]Failed to write controller database to {destination}: {exc}[/red]"
+        )
         return False
-    console.print(f"[green]Updated controller database ({len(data)} bytes) at {destination}[/green]")
+    console.print(
+        f"[green]Updated controller database ({len(data)} bytes) at {destination}[/green]"
+    )
     return True
 
 
@@ -98,7 +114,9 @@ def parse_hotkey(value: str) -> str:
     if not value:
         return ""
     if len(value) != 1:
-        raise argparse.ArgumentTypeError("Hotkeys must be a single character (or empty to disable).")
+        raise argparse.ArgumentTypeError(
+            "Hotkeys must be a single character (or empty to disable)."
+        )
     return value
 
 
@@ -151,7 +169,9 @@ def interactive_pairing(
     mappings: List[Tuple[int, str]] = []
     for controller_idx in controller_info:
         if not available:
-            console.print("[bold red]No more UART devices available for pairing.[/bold red]")
+            console.print(
+                "[bold red]No more UART devices available for pairing.[/bold red]"
+            )
             break
 
         table = Table(
@@ -174,7 +194,9 @@ def interactive_pairing(
         idx = int(selection)
         port = available.pop(idx)
         mappings.append((controller_idx, port["device"]))
-        console.print(f"[bold green]Paired controller {controller_idx} with {port['device']}[/bold green]")
+        console.print(
+            f"[bold green]Paired controller {controller_idx} with {port['device']}[/bold green]"
+        )
     return mappings
 
 
@@ -188,7 +210,7 @@ def apply_rumble(controller: sdl2.SDL_GameController, payload: bytes) -> float:
         return 0.0
     # Attenuate to feel closer to a real controller; cap at ~25% strength.
     scale = RUMBLE_SCALE
-    low = int(min(1.0, left_norm * scale) * 0xFFFF)   # SDL: low_frequency_rumble
+    low = int(min(1.0, left_norm * scale) * 0xFFFF)  # SDL: low_frequency_rumble
     high = int(min(1.0, right_norm * scale) * 0xFFFF)  # SDL: high_frequency_rumble
     duration = 10
     sdl2.SDL_GameControllerRumble(controller, low, high, duration)
@@ -204,9 +226,18 @@ class ControllerContext:
     port: Optional[str]
     uart: Optional[PicoUART]
     report: SwitchReport = field(default_factory=SwitchReport)
-    dpad: Dict[str, bool] = field(default_factory=lambda: {"up": False, "down": False, "left": False, "right": False})
+    dpad: Dict[str, bool] = field(
+        default_factory=lambda: {
+            "up": False,
+            "down": False,
+            "left": False,
+            "right": False,
+        }
+    )
     button_state: Dict[int, bool] = field(default_factory=dict)
-    last_trigger_state: Dict[str, bool] = field(default_factory=lambda: {"left": False, "right": False})
+    last_trigger_state: Dict[str, bool] = field(
+        default_factory=lambda: {"left": False, "right": False}
+    )
     last_send: float = 0.0
     last_reopen_attempt: float = 0.0
     last_rumble: float = 0.0
@@ -215,6 +246,16 @@ class ControllerContext:
     rumble_active: bool = False
     axis_offsets: Dict[int, int] = field(default_factory=dict)
     swap_abxy: bool = False
+    sensors_supported: bool = False
+    sensors_enabled: bool = False
+    imu_samples: List[IMUSample] = field(default_factory=list)
+    last_accel: Tuple[float, float, float] = (0.0, 0.0, 0.0)
+    gyro_bias_x: float = 0.0
+    gyro_bias_y: float = 0.0
+    gyro_bias_z: float = 0.0
+    gyro_bias_samples: int = 0
+    gyro_bias_locked: bool = False
+    last_debug_imu_print: float = 0.0
 
 
 def capture_stick_offsets(controller: sdl2.SDL_GameController) -> Dict[int, int]:
@@ -227,7 +268,9 @@ def capture_stick_offsets(controller: sdl2.SDL_GameController) -> Dict[int, int]
 
 def format_axis_offsets(offsets: Dict[int, int]) -> str:
     """Return a human-friendly summary of per-axis offsets (for logging)."""
-    return ", ".join(f"{label}={offsets.get(axis, 0):+d}" for axis, label in STICK_AXIS_LABELS)
+    return ", ".join(
+        f"{label}={offsets.get(axis, 0):+d}" for axis, label in STICK_AXIS_LABELS
+    )
 
 
 def calibrate_axis_value(value: int, axis: int, ctx: ControllerContext) -> int:
@@ -240,10 +283,63 @@ def calibrate_axis_value(value: int, axis: int, ctx: ControllerContext) -> int:
     return max(-32768, min(32767, value - offset))
 
 
+def clamp_int16(value: float) -> int:
+    return int(max(-32768.0, min(32767.0, round(value))))
+
+
+def convert_accel_to_raw(m_s2: float) -> int:
+    return clamp_int16((m_s2 / MS2_PER_G) * ACCEL_LSB_PER_G)
+
+
+def convert_gyro_to_raw(rad_s: float, scale: float = 1.0) -> int:
+    return clamp_int16(rad_s * GYRO_LSB_PER_RAD_S * scale)
+
+
+def initialize_controller_sensors(ctx: ControllerContext, console: Console) -> None:
+    """Enable SDL accelerometer and gyroscope on the controller if available."""
+    if not all(
+        hasattr(sdl2, name)
+        for name in (
+            "SDL_GameControllerHasSensor",
+            "SDL_GameControllerSetSensorEnabled",
+            "SDL_GameControllerGetSensorData",
+        )
+    ):
+        ctx.sensors_supported = False
+        ctx.sensors_enabled = False
+        return
+    if SENSOR_ACCEL is None or SENSOR_GYRO is None:
+        ctx.sensors_supported = False
+        return
+    accel_ok = bool(sdl2.SDL_GameControllerHasSensor(ctx.controller, SENSOR_ACCEL))
+    gyro_ok = bool(sdl2.SDL_GameControllerHasSensor(ctx.controller, SENSOR_GYRO))
+    ctx.sensors_supported = accel_ok and gyro_ok
+    if not ctx.sensors_supported:
+        console.print(
+            f"[yellow]Controller {ctx.controller_index} has no accelerometer/gyro sensors[/yellow]"
+        )
+        return
+    accel_enabled = (
+        sdl2.SDL_GameControllerSetSensorEnabled(ctx.controller, SENSOR_ACCEL, SDL_TRUE)
+        == 0
+    )
+    gyro_enabled = (
+        sdl2.SDL_GameControllerSetSensorEnabled(ctx.controller, SENSOR_GYRO, SDL_TRUE)
+        == 0
+    )
+    ctx.sensors_enabled = accel_enabled and gyro_enabled
+    if not ctx.sensors_enabled:
+        console.print(
+            f"[yellow]Controller {ctx.controller_index} failed to enable sensors[/yellow]"
+        )
+
+
 class HotkeyMonitor:
     """Platform-aware helper that watches for configured hotkeys without blocking the main loop."""
 
-    def __init__(self, console: Console, key_messages: Optional[Dict[str, str]] = None) -> None:
+    def __init__(
+        self, console: Console, key_messages: Optional[Dict[str, str]] = None
+    ) -> None:
         self.console = console
         self._platform = os.name
         self._fd: Optional[int] = None
@@ -272,7 +368,9 @@ class HotkeyMonitor:
             try:
                 import msvcrt  # type: ignore
             except ImportError:
-                self.console.print("[yellow]Hotkeys disabled: msvcrt unavailable.[/yellow]")
+                self.console.print(
+                    "[yellow]Hotkeys disabled: msvcrt unavailable.[/yellow]"
+                )
                 return False
             self._msvcrt = msvcrt
             self._active = True
@@ -286,9 +384,10 @@ class HotkeyMonitor:
         import termios
         import tty
 
-        self._fd = sys.stdin.fileno()
+        fd = sys.stdin.fileno()
-        self._orig_termios = termios.tcgetattr(self._fd)
+        self._fd = fd
-        tty.setcbreak(self._fd)
+        self._orig_termios = termios.tcgetattr(fd)
+        tty.setcbreak(fd)
         self._active = True
         self._started = True
         self._print_instructions()
@@ -297,7 +396,11 @@ class HotkeyMonitor:
     def suspend(self) -> None:
         if not self._active:
             return
-        if self._platform != "nt" and self._fd is not None and self._orig_termios is not None:
+        if (
+            self._platform != "nt"
+            and self._fd is not None
+            and self._orig_termios is not None
+        ):
             import termios
 
             termios.tcsetattr(self._fd, termios.TCSADRAIN, self._orig_termios)
@@ -317,7 +420,11 @@ class HotkeyMonitor:
         self._active = True
 
     def stop(self) -> None:
-        if self._platform != "nt" and self._fd is not None and self._orig_termios is not None:
+        if (
+            self._platform != "nt"
+            and self._fd is not None
+            and self._orig_termios is not None
+        ):
             import termios
 
             termios.tcsetattr(self._fd, termios.TCSADRAIN, self._orig_termios)
@@ -340,13 +447,19 @@ class HotkeyMonitor:
     def _print_instructions(self) -> None:
         if not self._keys:
             return
-        instructions = " | ".join(f"'{key.upper()}' to {message}" for key, message in self._keys.items())
+        instructions = " | ".join(
+            f"'{key.upper()}' to {message}" for key, message in self._keys.items()
+        )
         self.console.print(f"[magenta]Hotkeys active: {instructions}[/magenta]")
 
     def _read_key(self) -> Optional[str]:
         if self._platform == "nt":
-            if self._msvcrt and self._msvcrt.kbhit():
+            if self._msvcrt is None:
-                ch = self._msvcrt.getwch()
+                return None
+            kbhit = getattr(self._msvcrt, "kbhit", None)
+            getwch = getattr(self._msvcrt, "getwch", None)
+            if callable(kbhit) and callable(getwch) and kbhit():
+                ch = str(getwch())
                 if ch == "\x03":
                     raise KeyboardInterrupt
                 return ch
@@ -362,7 +475,11 @@ class HotkeyMonitor:
         return ch
 
 
-def zero_context_sticks(ctx: ControllerContext, console: Optional[Console] = None, reason: str = "Zeroed stick centers") -> None:
+def zero_context_sticks(
+    ctx: ControllerContext,
+    console: Optional[Console] = None,
+    reason: str = "Zeroed stick centers",
+) -> None:
     """Capture and store the current stick positions for a controller."""
     offsets = capture_stick_offsets(ctx.controller)
     ctx.axis_offsets = offsets
@@ -372,7 +489,9 @@ def zero_context_sticks(ctx: ControllerContext, console: Optional[Console] = Non
         )
 
 
-def zero_all_context_sticks(contexts: Dict[int, ControllerContext], console: Console) -> None:
+def zero_all_context_sticks(
+    contexts: Dict[int, ControllerContext], console: Console
+) -> None:
     """Zero every connected controller's sticks."""
     if not contexts:
         console.print("[yellow]No controllers available to zero right now.[/yellow]")
@@ -391,10 +510,14 @@ def controller_display_name(ctx: ControllerContext) -> str:
     return str(name)
 
 
-def toggle_abxy_for_context(ctx: ControllerContext, config: BridgeConfig, console: Console) -> None:
+def toggle_abxy_for_context(
+    ctx: ControllerContext, config: BridgeConfig, console: Console
+) -> None:
     """Toggle the ABXY layout for a single controller."""
     if config.swap_abxy_global:
-        console.print("[yellow]Global --swap-abxy is enabled; disable it to use per-controller toggles.[/yellow]")
+        console.print(
+            "[yellow]Global --swap-abxy is enabled; disable it to use per-controller toggles.[/yellow]"
+        )
         return
     swapped = ctx.swap_abxy
     action = "standard" if swapped else "swapped"
@@ -412,9 +535,13 @@ def prompt_swap_abxy_controller(
 ) -> None:
     """Prompt the user to choose a controller whose ABXY layout should be toggled."""
     if not contexts:
-        console.print("[yellow]No controllers connected to toggle ABXY layout.[/yellow]")
+        console.print(
+            "[yellow]No controllers connected to toggle ABXY layout.[/yellow]"
+        )
         return
-    controllers = sorted(contexts.values(), key=lambda ctx: (ctx.controller_index, ctx.instance_id))
+    controllers = sorted(
+        contexts.values(), key=lambda ctx: (ctx.controller_index, ctx.instance_id)
+    )
     table = Table(title="Toggle ABXY layout for a controller")
     table.add_column("Choice", justify="center")
     table.add_column("SDL Index", justify="center")
@@ -459,7 +586,9 @@ def open_controller(index: int) -> Tuple[sdl2.SDL_GameController, int, str]:
     """Open an SDL GameController by index and return it with instance ID and GUID string."""
     controller = sdl2.SDL_GameControllerOpen(index)
     if not controller:
-        raise RuntimeError(f"Failed to open controller {index}: {sdl2.SDL_GetError().decode()}")
+        raise RuntimeError(
+            f"Failed to open controller {index}: {sdl2.SDL_GetError().decode()}"
+        )
     joystick = sdl2.SDL_GameControllerGetJoystick(controller)
     instance_id = sdl2.SDL_JoystickInstanceID(joystick)
     guid_str = guid_string_from_joystick(joystick)
@@ -501,7 +630,9 @@ def open_uart_or_warn(port: str, baud: int, console: Console) -> Optional[PicoUA
 
 def build_arg_parser() -> argparse.ArgumentParser:
     """Construct the CLI argument parser for the bridge."""
-    parser = argparse.ArgumentParser(description="Bridge SDL2 controllers to switch-pico UART (with rumble)")
+    parser = argparse.ArgumentParser(
+        description="Bridge SDL2 controllers to switch-pico UART (with rumble)"
+    )
     parser.add_argument(
         "--map",
         action="append",
@@ -514,8 +645,16 @@ def build_arg_parser() -> argparse.ArgumentParser:
         nargs="+",
         help="Serial ports to auto-pair with controllers in ascending index order.",
     )
-    parser.add_argument("--interactive", action="store_true", help="Launch an interactive pairing UI using Rich.")
+    parser.add_argument(
-    parser.add_argument("--all-ports", action="store_true", help="Include non-USB serial ports when listing devices.")
+        "--interactive",
+        action="store_true",
+        help="Launch an interactive pairing UI using Rich.",
+    )
+    parser.add_argument(
+        "--all-ports",
+        action="store_true",
+        help="Include non-USB serial ports when listing devices.",
+    )
     parser.add_argument(
         "--frequency",
         type=float,
@@ -622,10 +761,28 @@ def build_arg_parser() -> argparse.ArgumentParser:
         default=[],
         help="Path to an SDL2 controller mapping database (e.g. controllerdb.txt). Repeatable.",
     )
+    parser.add_argument(
+        "--debug-imu",
+        action="store_true",
+        help="Print raw IMU sensor readings and converted values for debugging.",
+    )
+    parser.add_argument(
+        "--no-imu",
+        action="store_true",
+        help="Disable IMU/sensor reading entirely. Useful for controllers without gyro.",
+    )
+    parser.add_argument(
+        "--gyro-scale",
+        type=float,
+        default=1.0,
+        help="Scale factor for gyro sensitivity (default 1.0). Reduce below 1.0 if camera moves too fast.",
+    )
     return parser
 
 
-def poll_controller_buttons(ctx: ControllerContext, button_map: Dict[int, SwitchButton]) -> None:
+def poll_controller_buttons(
+    ctx: ControllerContext, button_map: Dict[int, SwitchButton]
+) -> None:
     """Update button/hat state based on current SDL controller readings."""
     changed = False
     for sdl_button, switch_bit in button_map.items():
@@ -665,6 +822,9 @@ class BridgeConfig:
     swap_abxy_indices: set[int]
     swap_abxy_ids: set[str]
     swap_abxy_global: bool
+    debug_imu: bool = False
+    no_imu: bool = False
+    gyro_scale: float = 1.0
 
 
 @dataclass
@@ -680,7 +840,9 @@ class PairingState:
     include_port_mfr: List[str] = field(default_factory=list)
 
 
-def load_button_maps(console: Console, args: argparse.Namespace) -> Tuple[Dict[int, SwitchButton], Dict[int, SwitchButton], set[int]]:
+def load_button_maps(
+    console: Console, args: argparse.Namespace
+) -> Tuple[Dict[int, SwitchButton], Dict[int, SwitchButton], set[int]]:
     """Load SDL controller mappings and return button map variants."""
     default_mapping = Path(__file__).parent / "controller_db" / "gamecontrollerdb.txt"
     if args.update_controller_db or not default_mapping.exists():
@@ -695,13 +857,19 @@ def load_button_maps(console: Console, args: argparse.Namespace) -> Tuple[Dict[i
     button_map_swapped[sdl2.SDL_CONTROLLER_BUTTON_B] = SwitchButton.A
     button_map_swapped[sdl2.SDL_CONTROLLER_BUTTON_X] = SwitchButton.Y
     button_map_swapped[sdl2.SDL_CONTROLLER_BUTTON_Y] = SwitchButton.X
-    swap_abxy_indices = {idx for idx in args.swap_abxy_index if idx is not None and idx >= 0}
+    swap_abxy_indices = {
+        idx for idx in args.swap_abxy_index if idx is not None and idx >= 0
+    }
     for mapping_path in mappings_to_load:
         try:
             loaded = sdl2.SDL_GameControllerAddMappingsFromFile(mapping_path.encode())
-            console.print(f"[green]Loaded {loaded} SDL mapping(s) from {mapping_path}[/green]")
+            console.print(
+                f"[green]Loaded {loaded} SDL mapping(s) from {mapping_path}[/green]"
+            )
         except Exception as exc:
-            console.print(f"[red]Failed to load SDL mapping {mapping_path}: {exc}[/red]")
+            console.print(
+                f"[red]Failed to load SDL mapping {mapping_path}: {exc}[/red]"
+            )
     return button_map_default, button_map_swapped, swap_abxy_indices
 
 
@@ -710,7 +878,9 @@ def build_bridge_config(console: Console, args: argparse.Namespace) -> BridgeCon
     interval = 1.0 / max(args.frequency, 1.0)
     deadzone_raw = int(max(0.0, min(args.deadzone, 1.0)) * 32767)
     trigger_threshold = int(max(0.0, min(args.trigger_threshold, 1.0)) * 32767)
-    button_map_default, button_map_swapped, swap_abxy_indices = load_button_maps(console, args)
+    button_map_default, button_map_swapped, swap_abxy_indices = load_button_maps(
+        console, args
+    )
     swap_abxy_guids = {g.lower() for g in args.swap_abxy_guid}
     return BridgeConfig(
         interval=interval,
@@ -724,6 +894,9 @@ def build_bridge_config(console: Console, args: argparse.Namespace) -> BridgeCon
         swap_abxy_indices=swap_abxy_indices,
         swap_abxy_ids=set(swap_abxy_guids),  # filled later once stable IDs are known
         swap_abxy_global=bool(args.swap_abxy),
+        debug_imu=bool(args.debug_imu),
+        no_imu=bool(args.no_imu),
+        gyro_scale=float(args.gyro_scale),
     )
 
 
@@ -734,7 +907,14 @@ def initialize_sdl(parser: argparse.ArgumentParser) -> None:
     set_hint("SDL_JOYSTICK_HIDAPI_SWITCH", "1")
     # Use controller button labels so Nintendo layouts (ABXY) map correctly on Linux.
     set_hint("SDL_GAMECONTROLLER_USE_BUTTON_LABELS", "1")
-    if sdl2.SDL_Init(sdl2.SDL_INIT_GAMECONTROLLER | sdl2.SDL_INIT_JOYSTICK | sdl2.SDL_INIT_EVERYTHING) != 0:
+    if (
+        sdl2.SDL_Init(
+            sdl2.SDL_INIT_GAMECONTROLLER
+            | sdl2.SDL_INIT_JOYSTICK
+            | sdl2.SDL_INIT_EVERYTHING
+        )
+        != 0
+    ):
         parser.error(f"SDL init failed: {sdl2.SDL_GetError().decode(errors='ignore')}")
 
 
@@ -752,8 +932,12 @@ def detect_controllers(
         if sdl2.SDL_IsGameController(index):
             name = sdl2.SDL_GameControllerNameForIndex(index)
             name_str = name.decode() if isinstance(name, bytes) else str(name)
-            if include_controller_name and all(substr not in name_str.lower() for substr in include_controller_name):
+            if include_controller_name and all(
-                console.print(f"[yellow]Skipping controller {index} ({name_str}) due to name filter[/yellow]")
+                substr not in name_str.lower() for substr in include_controller_name
+            ):
+                console.print(
+                    f"[yellow]Skipping controller {index} ({name_str}) due to name filter[/yellow]"
+                )
                 continue
             console.print(f"[cyan]Detected controller {index}: {name_str}[/cyan]")
             controller_indices.append(index)
@@ -761,14 +945,22 @@ def detect_controllers(
         else:
             name = sdl2.SDL_JoystickNameForIndex(index)
             name_str = name.decode() if isinstance(name, bytes) else str(name)
-            if include_controller_name and all(substr not in name_str.lower() for substr in include_controller_name):
+            if include_controller_name and all(
-                console.print(f"[yellow]Skipping joystick {index} ({name_str}) due to name filter[/yellow]")
+                substr not in name_str.lower() for substr in include_controller_name
+            ):
+                console.print(
+                    f"[yellow]Skipping joystick {index} ({name_str}) due to name filter[/yellow]"
+                )
                 continue
-            console.print(f"[yellow]Found joystick {index} (not a GameController): {name_str}[/yellow]")
+            console.print(
+                f"[yellow]Found joystick {index} (not a GameController): {name_str}[/yellow]"
+            )
     return controller_indices, controller_names
 
 
-def list_controllers_with_guids(console: Console, parser: argparse.ArgumentParser) -> None:
+def list_controllers_with_guids(
+    console: Console, parser: argparse.ArgumentParser
+) -> None:
     """Print detected controllers with their GUID strings and exit."""
     count = sdl2.SDL_NumJoysticks()
     if count < 0:
@@ -783,10 +975,16 @@ def list_controllers_with_guids(console: Console, parser: argparse.ArgumentParse
     table.add_column("GUID")
     for idx in range(count):
         is_gc = sdl2.SDL_IsGameController(idx)
-        name = sdl2.SDL_GameControllerNameForIndex(idx) if is_gc else sdl2.SDL_JoystickNameForIndex(idx)
+        name = (
+            sdl2.SDL_GameControllerNameForIndex(idx)
+            if is_gc
+            else sdl2.SDL_JoystickNameForIndex(idx)
+        )
         name_str = name.decode() if isinstance(name, bytes) else str(name)
         guid_str = guid_string_for_device_index(idx)
-        table.add_row(str(idx), "GameController" if is_gc else "Joystick", name_str, guid_str)
+        table.add_row(
+            str(idx), "GameController" if is_gc else "Joystick", name_str, guid_str
+        )
     console.print(table)
 
 
@@ -825,7 +1023,9 @@ def prepare_pairing_state(
     elif auto_pairing_enabled:
         if args.ports:
             available_ports.extend(list(args.ports))
-            console.print(f"[green]Prepared {len(available_ports)} specified UART port(s) for auto-pairing.[/green]")
+            console.print(
+                f"[green]Prepared {len(available_ports)} specified UART port(s) for auto-pairing.[/green]"
+            )
         else:
             # Passive mode: grab whatever UARTs exist now, and keep looking later.
             discovered = discover_serial_ports(
@@ -840,7 +1040,9 @@ def prepare_pairing_state(
                 for info in discovered:
                     console.print(f"  {info['device']} ({info['description']})")
             else:
-                console.print("[yellow]No UART devices detected yet; waiting for hotplug...[/yellow]")
+                console.print(
+                    "[yellow]No UART devices detected yet; waiting for hotplug...[/yellow]"
+                )
 
     mapping_by_index = {index: port for index, port in mappings}
     return PairingState(
@@ -855,7 +1057,9 @@ def prepare_pairing_state(
     )
 
 
-def assign_port_for_index(pairing: PairingState, idx: int, console: Console) -> Optional[str]:
+def assign_port_for_index(
+    pairing: PairingState, idx: int, console: Console
+) -> Optional[str]:
     """Return the UART assigned to a controller index, auto-pairing if allowed."""
     if idx in pairing.mapping_by_index:
         return pairing.mapping_by_index[idx]
@@ -877,12 +1081,21 @@ def ports_in_use(pairing: PairingState, contexts: Dict[int, ControllerContext])
     return used
 
 
-def handle_removed_port(path: str, pairing: PairingState, contexts: Dict[int, ControllerContext], console: Console) -> None:
+def handle_removed_port(
+    path: str,
+    pairing: PairingState,
+    contexts: Dict[int, ControllerContext],
+    console: Console,
+) -> None:
     """Clear mappings/contexts for a UART path that disappeared."""
     if path in pairing.available_ports:
         pairing.available_ports.remove(path)
-        console.print(f"[yellow]UART {path} removed; dropping from available pool[/yellow]")
+        console.print(
-    indices_to_clear = [idx for idx, mapped in pairing.mapping_by_index.items() if mapped == path]
+            f"[yellow]UART {path} removed; dropping from available pool[/yellow]"
+        )
+    indices_to_clear = [
+        idx for idx, mapped in pairing.mapping_by_index.items() if mapped == path
+    ]
     for idx in indices_to_clear:
         pairing.mapping_by_index.pop(idx, None)
         pairing.auto_assigned_indices.discard(idx)
@@ -900,10 +1113,14 @@ def handle_removed_port(path: str, pairing: PairingState, contexts: Dict[int, Co
         ctx.rumble_active = False
         ctx.last_rumble_energy = 0.0
         ctx.last_reopen_attempt = time.monotonic()
-        console.print(f"[yellow]UART {path} removed; controller {ctx.controller_index} waiting for reassignment[/yellow]")
+        console.print(
+            f"[yellow]UART {path} removed; controller {ctx.controller_index} waiting for reassignment[/yellow]"
+        )
 
 
-def discover_new_ports(pairing: PairingState, contexts: Dict[int, ControllerContext], console: Console) -> None:
+def discover_new_ports(
+    pairing: PairingState, contexts: Dict[int, ControllerContext], console: Console
+) -> None:
     """Scan for new serial ports and add unused ones to the available pool."""
     if not pairing.auto_discover_ports:
         return
@@ -927,7 +1144,9 @@ def discover_new_ports(pairing: PairingState, contexts: Dict[int, ControllerCont
         if path in in_use or path in pairing.available_ports:
             continue
         pairing.available_ports.append(path)
-        console.print(f"[green]Discovered UART {path} ({info['description']}); available for pairing.[/green]")
+        console.print(
+            f"[green]Discovered UART {path} ({info['description']}); available for pairing.[/green]"
+        )
 
 
 def pair_waiting_contexts(
@@ -975,7 +1194,9 @@ def open_initial_contexts(
         if index >= sdl2.SDL_NumJoysticks() or not sdl2.SDL_IsGameController(index):
             name = sdl2.SDL_JoystickNameForIndex(index)
             name_str = name.decode() if isinstance(name, bytes) else str(name)
-            console.print(f"[yellow]Index {index} is not a GameController ({name_str}). Trying raw open failed.[/yellow]")
+            console.print(
+                f"[yellow]Index {index} is not a GameController ({name_str}). Trying raw open failed.[/yellow]"
+            )
             continue
         port = assign_port_for_index(pairing, index, console)
         if port is None and not pairing.auto_pairing_enabled:
@@ -986,13 +1207,19 @@ def open_initial_contexts(
             console.print(f"[red]Failed to open controller {index}: {exc}[/red]")
             continue
         stable_id = guid
-        should_swap = index in config.swap_abxy_indices or stable_id in config.swap_abxy_ids
+        should_swap = (
+            index in config.swap_abxy_indices or stable_id in config.swap_abxy_ids
+        )
         uart = open_uart_or_warn(port, args.baud, console) if port else None
         if uart:
             uarts.append(uart)
-            console.print(f"[green]Controller {index} (id {stable_id}, inst {instance_id}) paired to {port}[/green]")
+            console.print(
+                f"[green]Controller {index} (id {stable_id}, inst {instance_id}) paired to {port}[/green]"
+            )
         elif port:
-            console.print(f"[yellow]Controller {index} (id {stable_id}, inst {instance_id}) waiting for UART {port}[/yellow]")
+            console.print(
+                f"[yellow]Controller {index} (id {stable_id}, inst {instance_id}) waiting for UART {port}[/yellow]"
+            )
         else:
             console.print(
                 f"[yellow]Controller {index} (id {stable_id}, inst {instance_id}) connected; waiting for an available UART[/yellow]"
@@ -1006,13 +1233,17 @@ def open_initial_contexts(
             uart=uart,
             swap_abxy=should_swap,
         )
+        if not config.no_imu:
+            initialize_controller_sensors(ctx, console)
         if config.zero_sticks:
             zero_context_sticks(ctx, console)
         contexts[instance_id] = ctx
     return contexts, uarts
 
 
-def handle_axis_motion(event: sdl2.SDL_Event, contexts: Dict[int, ControllerContext], config: BridgeConfig) -> None:
+def handle_axis_motion(
+    event: sdl2.SDL_Event, contexts: Dict[int, ControllerContext], config: BridgeConfig
+) -> None:
     """Process axis motion event into stick/trigger state."""
     ctx = contexts.get(event.caxis.which)
     if not ctx:
@@ -1045,6 +1276,79 @@ def handle_axis_motion(event: sdl2.SDL_Event, contexts: Dict[int, ControllerCont
             ctx.last_trigger_state["right"] = pressed
 
 
+def handle_sensor_update(
+    event: sdl2.SDL_Event,
+    contexts: Dict[int, ControllerContext],
+    config: BridgeConfig,
+) -> None:
+    """Process SDL sensor update event into IMU samples."""
+    ctx = contexts.get(event.csensor.which)
+    if ctx is None or not ctx.sensors_enabled or config.no_imu:
+        return
+
+    sensor_type = event.csensor.sensor
+    data = event.csensor.data
+
+    if sensor_type == SENSOR_ACCEL:
+        ctx.last_accel = (float(data[0]), float(data[1]), float(data[2]))
+        return
+
+    if sensor_type != SENSOR_GYRO:
+        return
+
+    gx, gy, gz = float(data[0]), float(data[1]), float(data[2])
+
+    if not ctx.gyro_bias_locked:
+        if ctx.gyro_bias_samples < GYRO_BIAS_SAMPLES:
+            ctx.gyro_bias_x += gx
+            ctx.gyro_bias_y += gy
+            ctx.gyro_bias_z += gz
+            ctx.gyro_bias_samples += 1
+        if ctx.gyro_bias_samples >= GYRO_BIAS_SAMPLES:
+            n = ctx.gyro_bias_samples
+            ctx.gyro_bias_x /= n
+            ctx.gyro_bias_y /= n
+            ctx.gyro_bias_z /= n
+            ctx.gyro_bias_locked = True
+
+    if not ctx.gyro_bias_locked:
+        bx, by, bz = 0.0, 0.0, 0.0
+    else:
+        bx, by, bz = ctx.gyro_bias_x, ctx.gyro_bias_y, ctx.gyro_bias_z
+
+    ux, uy, uz = gx, gy, gz
+    ux -= bx
+    uy -= by
+    uz -= bz
+
+    ax, ay, az = ctx.last_accel
+    sample = IMUSample(
+        accel_x=convert_accel_to_raw(ax),
+        accel_y=convert_accel_to_raw(ay),
+        accel_z=convert_accel_to_raw(az),
+        gyro_x=convert_gyro_to_raw(ux, config.gyro_scale),
+        gyro_y=convert_gyro_to_raw(uy, config.gyro_scale),
+        gyro_z=convert_gyro_to_raw(uz, config.gyro_scale),
+    )
+
+    ctx.imu_samples.append(sample)
+    if len(ctx.imu_samples) > IMU_BUFFER_SIZE:
+        ctx.imu_samples = ctx.imu_samples[-IMU_BUFFER_SIZE:]
+
+    if config.debug_imu:
+        now = time.monotonic()
+        if now - ctx.last_debug_imu_print > 0.2:
+            ctx.last_debug_imu_print = now
+            print(
+                f"[IMU idx={ctx.controller_index}] "
+                f"accel_m_s2=({ax:.3f},{ay:.3f},{az:.3f}) "
+                f"gyro_rad_s=({gx:.3f},{gy:.3f},{gz:.3f}) "
+                f"bias_rad_s=({bx:.4f},{by:.4f},{bz:.4f}) "
+                f"raw=({sample.accel_x},{sample.accel_y},{sample.accel_z};"
+                f"{sample.gyro_x},{sample.gyro_y},{sample.gyro_z})"
+            )
+
+
 def handle_button_event(
     event: sdl2.SDL_Event,
     config: BridgeConfig,
@@ -1093,7 +1397,9 @@ def handle_device_added(
     if idx >= sdl2.SDL_NumJoysticks() or not sdl2.SDL_IsGameController(idx):
         name = sdl2.SDL_JoystickNameForIndex(idx)
         name_str = name.decode() if isinstance(name, bytes) else str(name)
-        console.print(f"[yellow]Index {idx} is not a GameController ({name_str}). Trying raw open failed.[/yellow]")
+        console.print(
+            f"[yellow]Index {idx} is not a GameController ({name_str}). Trying raw open failed.[/yellow]"
+        )
         return
     try:
         controller, instance_id, guid = open_controller(idx)
@@ -1106,9 +1412,13 @@ def handle_device_added(
     uart = open_uart_or_warn(port, args.baud, console) if port else None
     if uart:
         uarts.append(uart)
-        console.print(f"[green]Controller {idx} (id {stable_id}, inst {instance_id}) paired to {port}[/green]")
+        console.print(
+            f"[green]Controller {idx} (id {stable_id}, inst {instance_id}) paired to {port}[/green]"
+        )
     elif port:
-        console.print(f"[yellow]Controller {idx} (id {stable_id}, inst {instance_id}) waiting for UART {port}[/yellow]")
+        console.print(
+            f"[yellow]Controller {idx} (id {stable_id}, inst {instance_id}) waiting for UART {port}[/yellow]"
+        )
     else:
         console.print(
             f"[yellow]Controller {idx} (id {stable_id}, inst {instance_id}) connected; waiting for an available UART[/yellow]"
@@ -1122,6 +1432,8 @@ def handle_device_added(
         uart=uart,
         swap_abxy=should_swap,
     )
+    if not config.no_imu:
+        initialize_controller_sensors(ctx, console)
     if config.zero_sticks:
         zero_context_sticks(ctx, console)
     contexts[instance_id] = ctx
@@ -1138,7 +1450,9 @@ def handle_device_removed(
     ctx = contexts.pop(instance_id, None)
     if not ctx:
         return
-    console.print(f"[yellow]Controller {instance_id} (id {ctx.stable_id}) removed[/yellow]")
+    console.print(
+        f"[yellow]Controller {instance_id} (id {ctx.stable_id}) removed[/yellow]"
+    )
     if ctx.controller_index in pairing.auto_assigned_indices:
         # Return auto-paired UART back to the pool so a future device can use it.
         freed = pairing.mapping_by_index.pop(ctx.controller_index, None)
@@ -1171,12 +1485,23 @@ def service_contexts(
             uart = open_uart_or_warn(ctx.port, args.baud, console)
             if uart:
                 uarts.append(uart)
-                console.print(f"[green]Reconnected UART {ctx.port} for controller {ctx.controller_index}[/green]")
+                console.print(
+                    f"[green]Reconnected UART {ctx.port} for controller {ctx.controller_index}[/green]"
+                )
                 ctx.uart = uart
         if ctx.uart is None:
             continue
         try:
             if now - ctx.last_send >= config.interval:
+                if ctx.sensors_enabled and not config.no_imu:
+                    count = min(len(ctx.imu_samples), IMU_SAMPLES_PER_REPORT)
+                    if count > 0:
+                        ctx.report.imu_samples = ctx.imu_samples[:count]
+                        ctx.imu_samples = ctx.imu_samples[count:]
+                    else:
+                        ctx.report.imu_samples = []
+                else:
+                    ctx.report.imu_samples = []
                 ctx.uart.send_report(ctx.report)
                 ctx.last_send = now
 
@@ -1199,7 +1524,10 @@ def service_contexts(
                 sdl2.SDL_GameControllerRumble(ctx.controller, 0, 0, 0)
                 ctx.rumble_active = False
                 ctx.last_rumble_energy = 0.0
-            elif ctx.rumble_active and (now - ctx.last_rumble_change) > RUMBLE_STUCK_TIMEOUT:
+            elif (
+                ctx.rumble_active
+                and (now - ctx.last_rumble_change) > RUMBLE_STUCK_TIMEOUT
+            ):
                 sdl2.SDL_GameControllerRumble(ctx.controller, 0, 0, 0)
                 ctx.rumble_active = False
                 ctx.last_rumble_energy = 0.0
@@ -1240,10 +1568,17 @@ def run_bridge_loop(
                 break
             if event.type == sdl2.SDL_CONTROLLERAXISMOTION:
                 handle_axis_motion(event, contexts, config)
-            elif event.type in (sdl2.SDL_CONTROLLERBUTTONDOWN, sdl2.SDL_CONTROLLERBUTTONUP):
+            elif event.type in (
+                sdl2.SDL_CONTROLLERBUTTONDOWN,
+                sdl2.SDL_CONTROLLERBUTTONUP,
+            ):
                 handle_button_event(event, config, contexts)
+            elif event.type == SDL_CONTROLLERSENSORUPDATE:
+                handle_sensor_update(event, contexts, config)
             elif event.type == sdl2.SDL_CONTROLLERDEVICEADDED:
-                handle_device_added(event, args, pairing, contexts, uarts, console, config)
+                handle_device_added(
+                    event, args, pairing, contexts, uarts, console, config
+                )
             elif event.type == sdl2.SDL_CONTROLLERDEVICEREMOVED:
                 handle_device_removed(event, pairing, contexts, console)
 
@@ -1289,7 +1624,9 @@ def main() -> None:
             list_controllers_with_guids(console, parser)
             return
         controller_indices, controller_names = detect_controllers(console, args, parser)
-        pairing = prepare_pairing_state(args, console, parser, controller_indices, controller_names)
+        pairing = prepare_pairing_state(
+            args, console, parser, controller_indices, controller_names
+        )
         hotkey_messages: Dict[str, str] = {}
         if config.zero_hotkey:
             hotkey_messages[config.zero_hotkey] = "re-zero controller sticks"
@@ -1299,14 +1636,20 @@ def main() -> None:
                     hotkey_messages[config.swap_hotkey] + "; toggle ABXY layout"
                 )
             else:
-                hotkey_messages[config.swap_hotkey] = "toggle ABXY layout for a controller"
+                hotkey_messages[config.swap_hotkey] = (
+                    "toggle ABXY layout for a controller"
+                )
         if hotkey_messages:
             candidate = HotkeyMonitor(console, hotkey_messages)
             if candidate.start():
                 hotkey_monitor = candidate
-        contexts, uarts = open_initial_contexts(args, pairing, controller_indices, console, config)
+        contexts, uarts = open_initial_contexts(
+            args, pairing, controller_indices, console, config
+        )
         if not contexts:
-            console.print("[yellow]No controllers opened; waiting for hotplug events...[/yellow]")
+            console.print(
+                "[yellow]No controllers opened; waiting for hotplug events...[/yellow]"
+            )
         run_bridge_loop(args, console, config, pairing, contexts, uarts, hotkey_monitor)
     finally:
         if hotkey_monitor: