diff --git a/csaxs_bec/device_configs/simulated_omny/simulated_lamni.yaml b/csaxs_bec/device_configs/simulated_omny/simulated_lamni.yaml
index e2459d2..9932938 100644
--- a/csaxs_bec/device_configs/simulated_omny/simulated_lamni.yaml
+++ b/csaxs_bec/device_configs/simulated_omny/simulated_lamni.yaml
@@ -324,6 +324,15 @@ cam_xeye:
     transpose: false
     force_monochrome: true
     m_n_colormode: 1
+    # Makes the synthetic frame track lsamrot's live simulated angle (an
+    # eccentric blob orbiting image center) instead of a static blob, so the
+    # smear/composite rotation-center calibration aid can be exercised in
+    # sim. host/port/axis match lsamrot's own sim config above.
+    sim_rotation_coupling:
+      galil_host: mpc2680.psi.ch
+      galil_port: 8081
+      axis: C
+    sim_feature_radius_px: 220
   enabled: true
   onFailure: buffer
   readOnly: false
diff --git a/csaxs_bec/devices/sim/sim_cameras.py b/csaxs_bec/devices/sim/sim_cameras.py
index f87c017..ca9fc7a 100644
--- a/csaxs_bec/devices/sim/sim_cameras.py
+++ b/csaxs_bec/devices/sim/sim_cameras.py
@@ -21,6 +21,8 @@ from bec_lib.logger import bec_logger
 
 from csaxs_bec.devices.ids_cameras.ids_camera import IDSCamera
 from csaxs_bec.devices.omny.webcam_viewer import WebcamViewer
+from csaxs_bec.devices.sim.sim_galil import SimGalilState
+from csaxs_bec.devices.sim.sim_socket import SimStateRegistry
 
 logger = bec_logger.logger
 
@@ -40,6 +42,43 @@ def make_test_pattern(height: int, width: int, rgb: bool) -> np.ndarray:
     return frame
 
 
+def make_rotating_test_pattern(
+    height: int,
+    width: int,
+    rgb: bool,
+    angle_deg: float,
+    radius_px: float,
+    sigma: float | None = None,
+    amplitude: float = 180.0,
+) -> np.ndarray:
+    """Create a synthetic camera frame (uint8) with an eccentric gaussian blob
+    orbiting the image center, for testing rotation-dependent features (e.g.
+    the smear/composite rotation-center calibration aid) in simulation.
+
+    angle_deg follows the standard math convention (0 = +x/right, increasing
+    counter-clockwise); since image rows grow downward, the y term is negated
+    to keep that sense on screen. The fixed crosshair marks image center (the
+    FZP/beam reference), distinct from the orbiting feature -- unlike
+    make_test_pattern, this frame is meant to be regenerated fresh per call
+    as the angle changes, not cached.
+    """
+    yy, xx = np.mgrid[0:height, 0:width]
+    cy, cx = height / 2.0, width / 2.0
+    if sigma is None:
+        sigma = min(height, width) / 12.0
+    angle_rad = np.deg2rad(angle_deg)
+    fy = cy - radius_px * np.sin(angle_rad)
+    fx = cx + radius_px * np.cos(angle_rad)
+    blob = amplitude * np.exp(-(((yy - fy) ** 2) + ((xx - fx) ** 2)) / (2.0 * sigma**2))
+    frame = 20.0 + blob
+    frame[int(cy) - 1 : int(cy) + 2, :] = 230.0  # horizontal crosshair line
+    frame[:, int(cx) - 1 : int(cx) + 2] = 230.0  # vertical crosshair line
+    frame = frame.clip(0, 255).astype(np.uint8)
+    if rgb:
+        frame = np.repeat(frame[:, :, np.newaxis], 3, axis=2)
+    return frame
+
+
 def add_frame_noise(frame: np.ndarray, noise_std: float) -> np.ndarray:
     """Return a copy of the frame with gaussian noise, clipped to uint8."""
     if noise_std <= 0:
@@ -90,15 +129,42 @@ class _SimIDSSensor:
 
 
 class _SimIDSBackend:
-    """Drop-in replacement for `base_integration.camera.Camera` serving synthetic frames."""
+    """Drop-in replacement for `base_integration.camera.Camera` serving synthetic frames.
 
-    def __init__(self, width: int, height: int, rgb: bool, noise_std: float = 0.0):
+    By default serves a single static frame (built once, cached forever), same
+    as always. If `rotation_coupling` is given (a dict with `galil_host`,
+    `galil_port`, `axis` -- same shape/idiom as SimRtLamniState's
+    coarse_coupling), a fresh frame is generated on every get_image_data()
+    call with an eccentric feature tracking that axis' live simulated angle,
+    for testing rotation-dependent features (e.g. the smear/composite
+    rotation-center calibration aid) in simulation.
+    """
+
+    def __init__(
+        self,
+        width: int,
+        height: int,
+        rgb: bool,
+        noise_std: float = 0.0,
+        rotation_coupling: dict | None = None,
+        feature_radius_px: float | None = None,
+    ):
         self.cam = _SimIDSSensor(width, height)
         self.force_monochrome = False
         self._connected = False
         self._rgb = rgb
         self._noise_std = float(noise_std)
-        self._frame = make_test_pattern(height, width, rgb=rgb)
+        self._width = width
+        self._height = height
+        self._rotation_coupling = rotation_coupling
+        self._feature_radius_px = (
+            float(feature_radius_px)
+            if feature_radius_px is not None
+            else min(width, height) / 4.0
+        )
+        self._frame = None if rotation_coupling is not None else make_test_pattern(
+            height, width, rgb=rgb
+        )
 
     def on_connect(self):
         self._connected = True
@@ -106,8 +172,26 @@ class _SimIDSBackend:
     def on_disconnect(self):
         self._connected = False
 
+    def _current_angle_deg(self) -> float:
+        coupling = self._rotation_coupling
+        galil = SimStateRegistry.get(
+            SimGalilState, coupling["galil_host"], coupling["galil_port"]
+        )
+        axis_num = ord(str(coupling["axis"]).lower()) - 97
+        ax = galil.axis(axis_num)
+        return ax.position() / ax.stppermm
+
     def get_image_data(self) -> np.ndarray:
-        frame = self._frame
+        if self._rotation_coupling is None:
+            frame = self._frame
+        else:
+            frame = make_rotating_test_pattern(
+                self._height,
+                self._width,
+                rgb=self._rgb,
+                angle_deg=self._current_angle_deg(),
+                radius_px=self._feature_radius_px,
+            )
         if self.force_monochrome and frame.ndim == 3:
             frame = frame[:, :, 0]
         return add_frame_noise(frame, self._noise_std)
@@ -136,6 +220,8 @@ class SimIDSCamera(IDSCamera):
         channels: int | None = None,  # legacy OMNY config keys, accepted for compatibility
         sim_shape=(1024, 1280),
         sim_noise_std=0.0,
+        sim_rotation_coupling: dict | None = None,
+        sim_feature_radius_px: float | None = None,
         **kwargs,
     ):
         if camera_ID is not None and not camera_id:
@@ -154,6 +240,11 @@ class SimIDSCamera(IDSCamera):
             **kwargs,
         )
         self.cam = _SimIDSBackend(
-            int(sim_shape[1]), int(sim_shape[0]), rgb=not force_monochrome, noise_std=sim_noise_std
+            int(sim_shape[1]),
+            int(sim_shape[0]),
+            rgb=not force_monochrome,
+            noise_std=sim_noise_std,
+            rotation_coupling=sim_rotation_coupling,
+            feature_radius_px=sim_feature_radius_px,
         )
         self.cam.force_monochrome = self._force_monochrome
diff --git a/tests/tests_devices/test_sim_cameras.py b/tests/tests_devices/test_sim_cameras.py
new file mode 100644
index 0000000..9e7f9cc
--- /dev/null
+++ b/tests/tests_devices/test_sim_cameras.py
@@ -0,0 +1,111 @@
+"""Unit tests for the simulated IDS camera frame source (_SimIDSBackend /
+make_rotating_test_pattern / SimIDSCamera's optional rotation coupling)."""
+
+import numpy as np
+import pytest
+
+from csaxs_bec.devices.sim.sim_cameras import (
+    SimIDSCamera,
+    _SimIDSBackend,
+    make_rotating_test_pattern,
+    make_test_pattern,
+)
+from csaxs_bec.devices.sim.sim_galil import SimGalilState
+from csaxs_bec.devices.sim.sim_socket import SimStateRegistry
+
+
+@pytest.fixture(autouse=True)
+def reset_sim_state():
+    """Avoid cross-test leakage of shared (host, port)-keyed simulation state."""
+    SimStateRegistry.reset()
+    yield
+    SimStateRegistry.reset()
+
+
+def test_sim_ids_backend_default_matches_static_pattern():
+    """No rotation_coupling (the default) -> byte-identical to today's static frame.
+
+    Regression guard: this is what keeps flomni's cam_xeye and other existing
+    SimIDSCamera users completely unaffected by the new opt-in feature.
+    """
+    backend = _SimIDSBackend(width=64, height=48, rgb=True)
+    expected = make_test_pattern(48, 64, rgb=True)
+    assert np.array_equal(backend.get_image_data(), expected)
+    # calling it again returns the exact same cached frame, not a fresh one
+    assert np.array_equal(backend.get_image_data(), expected)
+
+
+@pytest.mark.parametrize("angle_deg", [30.0, 120.0, 210.0, 300.0])
+def test_make_rotating_test_pattern_blob_position(angle_deg):
+    height, width = 200, 300
+    radius_px = 60.0
+    frame = make_rotating_test_pattern(
+        height, width, rgb=False, angle_deg=angle_deg, radius_px=radius_px
+    )
+
+    cy, cx = height / 2.0, width / 2.0
+    angle_rad = np.deg2rad(angle_deg)
+    expected_y = cy - radius_px * np.sin(angle_rad)
+    expected_x = cx + radius_px * np.cos(angle_rad)
+
+    # mask out the fixed center crosshair so it can't win the argmax
+    masked = frame.astype(np.int32)
+    masked[int(cy) - 2 : int(cy) + 3, :] = 0
+    masked[:, int(cx) - 2 : int(cx) + 3] = 0
+    py, px = np.unravel_index(np.argmax(masked), masked.shape)
+
+    assert abs(py - expected_y) <= 2
+    assert abs(px - expected_x) <= 2
+
+
+def test_sim_ids_backend_rotation_coupling_tracks_live_angle():
+    host, port, axis_letter = "test-galil.example", 9000, "C"
+    galil = SimStateRegistry.get(SimGalilState, host, port)
+    ax = galil.axis(ord(axis_letter.lower()) - 97)
+    ax.stppermm = 1000.0
+    ax.pos_steps = 0.0  # 0 deg
+
+    coupling = {"galil_host": host, "galil_port": port, "axis": axis_letter}
+    backend = _SimIDSBackend(
+        width=200, height=200, rgb=False, rotation_coupling=coupling, feature_radius_px=50.0
+    )
+
+    frame0 = backend.get_image_data()
+    assert np.array_equal(
+        frame0, make_rotating_test_pattern(200, 200, rgb=False, angle_deg=0.0, radius_px=50.0)
+    )
+
+    # move the simulated axis and confirm the frame is regenerated fresh, not cached
+    ax.pos_steps = 90.0 * ax.stppermm
+    frame90 = backend.get_image_data()
+    assert np.array_equal(
+        frame90, make_rotating_test_pattern(200, 200, rgb=False, angle_deg=90.0, radius_px=50.0)
+    )
+    assert not np.array_equal(frame0, frame90)
+
+
+def test_sim_ids_camera_threads_rotation_coupling_through():
+    """SimIDSCamera's sim_rotation_coupling/sim_feature_radius_px reach _SimIDSBackend."""
+    host, port, axis_letter = "test-galil-2.example", 9100, "C"
+    galil = SimStateRegistry.get(SimGalilState, host, port)
+    ax = galil.axis(ord(axis_letter.lower()) - 97)
+    ax.stppermm = 1000.0
+    ax.pos_steps = 0.0
+
+    camera = SimIDSCamera(
+        name="test_sim_cam",
+        camera_id=1,
+        prefix="test:",
+        scan_info=None,
+        m_n_colormode=1,
+        bits_per_pixel=24,
+        live_mode=False,
+        sim_shape=(64, 64),
+        sim_rotation_coupling={"galil_host": host, "galil_port": port, "axis": axis_letter},
+        sim_feature_radius_px=20.0,
+    )
+
+    frame0 = camera.cam.get_image_data()
+    ax.pos_steps = 180.0 * ax.stppermm
+    frame180 = camera.cam.get_image_data()
+    assert not np.array_equal(frame0, frame180)