From 1de4366df714df683539ce7779fd98f3b6f6fffa Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Tue, 10 Feb 2026 15:52:06 +0000
Subject: [PATCH 01/15] Flash LED endpoint in simulator for parity

---
 .../things/camera/simulation.py               |  6 +++++-
 .../things/stage/dummy.py                     | 19 ++++++++++++++++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/openflexure_microscope_server/things/camera/simulation.py b/src/openflexure_microscope_server/things/camera/simulation.py
index 1f956661..521fc7cc 100644
--- a/src/openflexure_microscope_server/things/camera/simulation.py
+++ b/src/openflexure_microscope_server/things/camera/simulation.py
@@ -342,7 +342,11 @@ class SimulatedCamera(BaseCamera):
     def generate_frame(self) -> Image.Image:
         """Generate a frame with blobs based on the stage coordinates."""
         pos = self._stage.instantaneous_position
-        return self.generate_image((pos["y"], pos["x"], pos["z"]))
+        frame = self.generate_image((pos["y"], pos["x"], pos["z"]))
+        # Simulate LED turning off by setting all channels to 0
+        if not self._stage.led_on:
+            frame = np.full((self.shape[0], self.shape[1], 3), 0, dtype=np.uint8)
+        return frame
 
     def __enter__(self) -> Self:
         """Start the capture thread when the Thing context manager is opened."""
diff --git a/src/openflexure_microscope_server/things/stage/dummy.py b/src/openflexure_microscope_server/things/stage/dummy.py
index 7130fcb7..82515d17 100644
--- a/src/openflexure_microscope_server/things/stage/dummy.py
+++ b/src/openflexure_microscope_server/things/stage/dummy.py
@@ -4,7 +4,7 @@ from __future__ import annotations
 
 import time
 from types import TracebackType
-from typing import Any, Optional, Self
+from typing import Any, Literal, Optional, Self
 
 import labthings_fastapi as lt
 
@@ -18,6 +18,8 @@ class DummyStage(BaseStage):
     hardware attached.
     """
 
+    led_on: bool = lt.property(default=True)
+
     def __init__(
         self,
         thing_server_interface: lt.ThingServerInterface,
@@ -115,3 +117,18 @@ class DummyStage(BaseStage):
         """
         self._hardware_position = dict.fromkeys(self.axis_names, 0)
         self.instantaneous_position = self._hardware_position
+
+    # led_channel is unused in the simulation, but must exist to match the real API
+    @lt.action
+    def flash_led(
+        self,
+        number_of_flashes: int = 10,
+        dt: float = 0.5,
+        led_channel: Literal["cc"] = "cc",  # noqa: ARG002
+    ) -> None:
+        """Flash the LED to identify the board (simulated)."""
+        for _ in range(number_of_flashes):
+            self.led_on = False
+            time.sleep(dt)
+            self.led_on = True
+            time.sleep(dt)

From 8435f6ae981fd82684e20d6764d5ddf077e0a164 Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Tue, 10 Feb 2026 18:06:21 +0000
Subject: [PATCH 02/15] Move illumination to new IlluminationThing

---
 ofm_config_full.json                          |  1 +
 .../things/illumination.py                    | 54 +++++++++++++++++++
 .../things/stage/sangaboard.py                | 37 +------------
 3 files changed, 56 insertions(+), 36 deletions(-)
 create mode 100644 src/openflexure_microscope_server/things/illumination.py

diff --git a/ofm_config_full.json b/ofm_config_full.json
index 75534b10..885b65a2 100644
--- a/ofm_config_full.json
+++ b/ofm_config_full.json
@@ -10,6 +10,7 @@
         "autofocus": "openflexure_microscope_server.things.autofocus:AutofocusThing",
         "camera_stage_mapping": "openflexure_microscope_server.things.camera_stage_mapping:CameraStageMapper",
         "system": "openflexure_microscope_server.things.system:OpenFlexureSystem",
+        "illumination": "openflexure_microscope_server.things.illumination:SangaIllumination",
         "smart_scan": {
             "class": "openflexure_microscope_server.things.smart_scan:SmartScanThing",
             "kwargs": {
diff --git a/src/openflexure_microscope_server/things/illumination.py b/src/openflexure_microscope_server/things/illumination.py
new file mode 100644
index 00000000..39d752e8
--- /dev/null
+++ b/src/openflexure_microscope_server/things/illumination.py
@@ -0,0 +1,54 @@
+import time
+from typing import Literal
+
+import labthings_fastapi as lt
+
+
+class Illumination(lt.Thing):
+    """Abstract illumination controller."""
+
+    brightness: float = lt.property(
+        default=0.0,
+        description="Illumination brightness (0-1)",
+    )
+
+    @lt.action
+    def set_brightness(self, brightness: float) -> None:
+        self.brightness = brightness
+
+    @lt.action
+    def flash(
+        self,
+        number_of_flashes: int = 10,
+        dt: float = 0.5,
+    ) -> None:
+        """Flash the illumination source."""
+        for _ in range(number_of_flashes):
+            self.set_brightness(1.0)
+            time.sleep(dt)
+            self.set_brightness(0.0)
+            time.sleep(dt)
+
+
+class SangaIllumination(Illumination):
+    """Illumination driven by a Sangaboard."""
+
+    sangaboard = lt.thing_slot(description="Sangaboard providing LED control")
+
+    @lt.action
+    def set_brightness(self, brightness: float) -> None:
+        self.sangaboard.set_led_brightness(brightness)
+        self.brightness = brightness
+
+    @lt.action
+    def flash(
+        self,
+        number_of_flashes: int = 10,
+        dt: float = 0.5,
+        led_channel: Literal["cc"] = "cc",
+    ) -> None:
+        for _ in range(number_of_flashes):
+            self.sangaboard.set_led(True, led_channel)
+            time.sleep(dt)
+            self.sangaboard.set_led(False, led_channel)
+            time.sleep(dt)
diff --git a/src/openflexure_microscope_server/things/stage/sangaboard.py b/src/openflexure_microscope_server/things/stage/sangaboard.py
index db64ccc3..800a0e31 100644
--- a/src/openflexure_microscope_server/things/stage/sangaboard.py
+++ b/src/openflexure_microscope_server/things/stage/sangaboard.py
@@ -3,11 +3,10 @@
 from __future__ import annotations
 
 import threading
-import time
 from contextlib import contextmanager
 from copy import copy
 from types import TracebackType
-from typing import Any, Iterator, Literal, Optional, Self
+from typing import Any, Iterator, Optional, Self
 
 import semver
 
@@ -173,37 +172,3 @@ class SangaboardThing(BaseStage):
         with self.sangaboard() as sb:
             sb.zero_position()
         self.update_position()
-
-    @lt.action
-    def flash_led(
-        self,
-        number_of_flashes: int = 10,
-        dt: float = 0.5,
-        led_channel: Literal["cc"] = "cc",
-    ) -> None:
-        """Flash the LED to identify the board.
-
-        This is intended to be useful in situations where there are multiple
-        Sangaboards in use, and it is necessary to identify which one is
-        being addressed.
-        """
-        led_command = f"led_{led_channel}"
-        with self.sangaboard() as sb:
-            return_value = sb.query(f"{led_command}?")
-            if not return_value.startswith("CC LED:"):
-                raise IOError("The sangaboard does not support LED control")
-
-            # Reading and setting LED brightness suffers from repeated reads and writes
-            # decreasing the value. Rather than use the value the code warns that the value
-            # cannot be used.
-            intended_brightness = float(return_value[7:])
-            on_brightness = 0.32
-            self.logger.warning(
-                "Brightness control is not yet implemented. Desired brightness: "
-                f"{intended_brightness}. Set brightness: {on_brightness}"
-            )
-            for _i in range(number_of_flashes):
-                sb.query(f"{led_command} 0")
-                time.sleep(dt)
-                sb.query(f"{led_command} {on_brightness}")
-                time.sleep(dt)

From 5682b4d28d35aa8cf32819c227e496f7290359ec Mon Sep 17 00:00:00 2001
From: jaknapper <jaknapper@hotmail.com>
Date: Tue, 10 Feb 2026 18:42:59 +0000
Subject: [PATCH 03/15] Illumination Things for sangaboard and simulator

---
 .../things/camera/simulation.py               | 13 +++--
 .../things/illumination.py                    | 49 ++++++++++---------
 .../things/stage/sangaboard.py                | 30 +++++++++++-
 3 files changed, 65 insertions(+), 27 deletions(-)

diff --git a/src/openflexure_microscope_server/things/camera/simulation.py b/src/openflexure_microscope_server/things/camera/simulation.py
index 521fc7cc..c22b32e6 100644
--- a/src/openflexure_microscope_server/things/camera/simulation.py
+++ b/src/openflexure_microscope_server/things/camera/simulation.py
@@ -140,6 +140,7 @@ class SimulatedCamera(BaseCamera):
         self._capture_thread: Optional[Thread] = None
         self._capture_enabled = False
         self.generate_sprites()
+        self.mult = 1
 
     repeating: bool = lt.property(default=False)
 
@@ -339,14 +340,20 @@ class SimulatedCamera(BaseCamera):
         pl_img = Image.fromarray(np_img.astype("uint8"))
         return pl_img.resize((self.shape[1], self.shape[0]), Image.Resampling.BILINEAR)
 
+    @lt.action
+    def set_led(self, led_on: bool = True, led_channel=None):
+        if led_on:
+            self.mult = 1
+        else:
+            self.mult = 0
+
+
     def generate_frame(self) -> Image.Image:
         """Generate a frame with blobs based on the stage coordinates."""
         pos = self._stage.instantaneous_position
         frame = self.generate_image((pos["y"], pos["x"], pos["z"]))
         # Simulate LED turning off by setting all channels to 0
-        if not self._stage.led_on:
-            frame = np.full((self.shape[0], self.shape[1], 3), 0, dtype=np.uint8)
-        return frame
+        return frame * self.mult
 
     def __enter__(self) -> Self:
         """Start the capture thread when the Thing context manager is opened."""
diff --git a/src/openflexure_microscope_server/things/illumination.py b/src/openflexure_microscope_server/things/illumination.py
index 39d752e8..7cfddf50 100644
--- a/src/openflexure_microscope_server/things/illumination.py
+++ b/src/openflexure_microscope_server/things/illumination.py
@@ -3,19 +3,12 @@ from typing import Literal
 
 import labthings_fastapi as lt
 
+from .stage import BaseStage
+from .camera import BaseCam
 
 class Illumination(lt.Thing):
     """Abstract illumination controller."""
 
-    brightness: float = lt.property(
-        default=0.0,
-        description="Illumination brightness (0-1)",
-    )
-
-    @lt.action
-    def set_brightness(self, brightness: float) -> None:
-        self.brightness = brightness
-
     @lt.action
     def flash(
         self,
@@ -23,22 +16,14 @@ class Illumination(lt.Thing):
         dt: float = 0.5,
     ) -> None:
         """Flash the illumination source."""
-        for _ in range(number_of_flashes):
-            self.set_brightness(1.0)
-            time.sleep(dt)
-            self.set_brightness(0.0)
-            time.sleep(dt)
-
+        raise NotImplementedError(
+            'Flashing the LED can only be done from the simulator or sangaboard'
+        )
 
 class SangaIllumination(Illumination):
     """Illumination driven by a Sangaboard."""
 
-    sangaboard = lt.thing_slot(description="Sangaboard providing LED control")
-
-    @lt.action
-    def set_brightness(self, brightness: float) -> None:
-        self.sangaboard.set_led_brightness(brightness)
-        self.brightness = brightness
+    _stage: BaseStage = lt.thing_slot()
 
     @lt.action
     def flash(
@@ -48,7 +33,25 @@ class SangaIllumination(Illumination):
         led_channel: Literal["cc"] = "cc",
     ) -> None:
         for _ in range(number_of_flashes):
-            self.sangaboard.set_led(True, led_channel)
+            self._stage.set_led(False, led_channel)
             time.sleep(dt)
-            self.sangaboard.set_led(False, led_channel)
+            self._stage.set_led(True, led_channel)
+            time.sleep(dt)
+
+class SimulatorIllumination(Illumination):
+    """Illumination control in the simulator."""
+
+    _cam: BaseCam = lt.thing_slot()
+
+    @lt.action
+    def flash(
+        self,
+        number_of_flashes: int = 10,
+        dt: float = 0.5,
+        led_channel: Literal["cc"] = "cc",
+    ) -> None:
+        for _ in range(number_of_flashes):
+            self._cam.set_led(False, led_channel)
+            time.sleep(dt)
+            self._cam.set_led(True, led_channel)
             time.sleep(dt)
diff --git a/src/openflexure_microscope_server/things/stage/sangaboard.py b/src/openflexure_microscope_server/things/stage/sangaboard.py
index 800a0e31..fb313337 100644
--- a/src/openflexure_microscope_server/things/stage/sangaboard.py
+++ b/src/openflexure_microscope_server/things/stage/sangaboard.py
@@ -6,7 +6,7 @@ import threading
 from contextlib import contextmanager
 from copy import copy
 from types import TracebackType
-from typing import Any, Iterator, Optional, Self
+from typing import Any, Iterator, Literal, Optional, Self
 
 import semver
 
@@ -172,3 +172,31 @@ class SangaboardThing(BaseStage):
         with self.sangaboard() as sb:
             sb.zero_position()
         self.update_position()
+
+    @lt.action
+    def set_led(
+        self,
+        led_on: bool = True,
+        led_channel: Literal["cc"] = "cc",
+    ) -> None:
+        """Flash the LED to identify the board.
+
+        This is intended to be useful in situations where there are multiple
+        Sangaboards in use, and it is necessary to identify which one is
+        being addressed.
+        """
+        led_command = f"led_{led_channel}"
+        with self.sangaboard() as sb:
+            return_value = sb.query(f"{led_command}?")
+            if not return_value.startswith("CC LED:"):
+                raise IOError("The sangaboard does not support LED control")
+
+            # Reading and setting LED brightness suffers from repeated reads and writes
+            # decreasing the value. Rather than use the value the code warns that the value
+            # cannot be used.
+            if led_on:
+                on_brightness = 0.32
+                sb.query(f"{led_command} {on_brightness}")
+            else:    
+                sb.query(f"{led_command} 0")
+            

From 4d788a28179e0856170b1ffdc2d2886e935a79a1 Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Tue, 10 Feb 2026 22:13:09 +0000
Subject: [PATCH 04/15] Remove flash from stage baseclass, add to sim config

---
 ofm_config_simulation.json                    |  1 +
 .../things/camera/simulation.py               |  8 ++++---
 .../things/illumination.py                    | 21 ++++++++++++++++---
 .../things/stage/dummy.py                     | 19 +----------------
 .../things/stage/sangaboard.py                |  3 +--
 5 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/ofm_config_simulation.json b/ofm_config_simulation.json
index b061dbd8..21b97694 100644
--- a/ofm_config_simulation.json
+++ b/ofm_config_simulation.json
@@ -4,6 +4,7 @@
         "stage": "openflexure_microscope_server.things.stage.dummy:DummyStage",
         "autofocus": "openflexure_microscope_server.things.autofocus:AutofocusThing",
         "camera_stage_mapping": "openflexure_microscope_server.things.camera_stage_mapping:CameraStageMapper",
+        "illumination": "openflexure_microscope_server.things.illumination.SimulatorIllumination",
         "system": "openflexure_microscope_server.things.system:OpenFlexureSystem",
         "smart_scan": {
             "class": "openflexure_microscope_server.things.smart_scan:SmartScanThing",
diff --git a/src/openflexure_microscope_server/things/camera/simulation.py b/src/openflexure_microscope_server/things/camera/simulation.py
index c22b32e6..730a6539 100644
--- a/src/openflexure_microscope_server/things/camera/simulation.py
+++ b/src/openflexure_microscope_server/things/camera/simulation.py
@@ -341,19 +341,21 @@ class SimulatedCamera(BaseCamera):
         return pl_img.resize((self.shape[1], self.shape[0]), Image.Resampling.BILINEAR)
 
     @lt.action
-    def set_led(self, led_on: bool = True, led_channel=None):
+    def set_led(self, led_on: bool = True, led_channel: str = None) -> None:  # noqa: ARG002
+        """Set the simulated LED to on or off."""
         if led_on:
             self.mult = 1
         else:
             self.mult = 0
 
-
     def generate_frame(self) -> Image.Image:
         """Generate a frame with blobs based on the stage coordinates."""
         pos = self._stage.instantaneous_position
         frame = self.generate_image((pos["y"], pos["x"], pos["z"]))
         # Simulate LED turning off by setting all channels to 0
-        return frame * self.mult
+        if self.mult == 0:
+            return Image.new(frame.mode, frame.size, 0)
+        return frame
 
     def __enter__(self) -> Self:
         """Start the capture thread when the Thing context manager is opened."""
diff --git a/src/openflexure_microscope_server/things/illumination.py b/src/openflexure_microscope_server/things/illumination.py
index 7cfddf50..d1d5e193 100644
--- a/src/openflexure_microscope_server/things/illumination.py
+++ b/src/openflexure_microscope_server/things/illumination.py
@@ -1,10 +1,13 @@
+"""A module to handle the illumination in LabThings."""
+
 import time
 from typing import Literal
 
 import labthings_fastapi as lt
 
+from .camera import BaseCamera
 from .stage import BaseStage
-from .camera import BaseCam
+
 
 class Illumination(lt.Thing):
     """Abstract illumination controller."""
@@ -17,9 +20,10 @@ class Illumination(lt.Thing):
     ) -> None:
         """Flash the illumination source."""
         raise NotImplementedError(
-            'Flashing the LED can only be done from the simulator or sangaboard'
+            "Flashing the LED can only be done from the simulator or sangaboard"
         )
 
+
 class SangaIllumination(Illumination):
     """Illumination driven by a Sangaboard."""
 
@@ -32,16 +36,22 @@ class SangaIllumination(Illumination):
         dt: float = 0.5,
         led_channel: Literal["cc"] = "cc",
     ) -> None:
+        """Flash an LED a given number of times.
+
+        Flashes the LED on channel led_channel number_of_flashes times,
+        for a duration of dt each.
+        """
         for _ in range(number_of_flashes):
             self._stage.set_led(False, led_channel)
             time.sleep(dt)
             self._stage.set_led(True, led_channel)
             time.sleep(dt)
 
+
 class SimulatorIllumination(Illumination):
     """Illumination control in the simulator."""
 
-    _cam: BaseCam = lt.thing_slot()
+    _cam: BaseCamera = lt.thing_slot()
 
     @lt.action
     def flash(
@@ -50,6 +60,11 @@ class SimulatorIllumination(Illumination):
         dt: float = 0.5,
         led_channel: Literal["cc"] = "cc",
     ) -> None:
+        """Flash an LED a given number of times.
+
+        Flashes the LED on channel led_channel number_of_flashes times,
+        for a duration of dt each.
+        """
         for _ in range(number_of_flashes):
             self._cam.set_led(False, led_channel)
             time.sleep(dt)
diff --git a/src/openflexure_microscope_server/things/stage/dummy.py b/src/openflexure_microscope_server/things/stage/dummy.py
index 82515d17..7130fcb7 100644
--- a/src/openflexure_microscope_server/things/stage/dummy.py
+++ b/src/openflexure_microscope_server/things/stage/dummy.py
@@ -4,7 +4,7 @@ from __future__ import annotations
 
 import time
 from types import TracebackType
-from typing import Any, Literal, Optional, Self
+from typing import Any, Optional, Self
 
 import labthings_fastapi as lt
 
@@ -18,8 +18,6 @@ class DummyStage(BaseStage):
     hardware attached.
     """
 
-    led_on: bool = lt.property(default=True)
-
     def __init__(
         self,
         thing_server_interface: lt.ThingServerInterface,
@@ -117,18 +115,3 @@ class DummyStage(BaseStage):
         """
         self._hardware_position = dict.fromkeys(self.axis_names, 0)
         self.instantaneous_position = self._hardware_position
-
-    # led_channel is unused in the simulation, but must exist to match the real API
-    @lt.action
-    def flash_led(
-        self,
-        number_of_flashes: int = 10,
-        dt: float = 0.5,
-        led_channel: Literal["cc"] = "cc",  # noqa: ARG002
-    ) -> None:
-        """Flash the LED to identify the board (simulated)."""
-        for _ in range(number_of_flashes):
-            self.led_on = False
-            time.sleep(dt)
-            self.led_on = True
-            time.sleep(dt)
diff --git a/src/openflexure_microscope_server/things/stage/sangaboard.py b/src/openflexure_microscope_server/things/stage/sangaboard.py
index fb313337..9a9b7fe5 100644
--- a/src/openflexure_microscope_server/things/stage/sangaboard.py
+++ b/src/openflexure_microscope_server/things/stage/sangaboard.py
@@ -197,6 +197,5 @@ class SangaboardThing(BaseStage):
             if led_on:
                 on_brightness = 0.32
                 sb.query(f"{led_command} {on_brightness}")
-            else:    
+            else:
                 sb.query(f"{led_command} 0")
-            

From f05cb396c8ba7f9296c28db2057b51d51ae01018 Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Tue, 10 Feb 2026 22:20:22 +0000
Subject: [PATCH 05/15] Update FlashLED to new endpoint in webapp

---
 .../tabContentComponents/aboutComponents/statusPane.vue       | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue b/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
index 6b4e8c6f..ce603f83 100644
--- a/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
+++ b/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
@@ -14,8 +14,8 @@
         </div>
         <action-button
           v-if="stageType"
-          thing="stage"
-          action="flash_led"
+          thing="illumination"
+          action="flash"
           submit-label="Flash Illumination"
           :can-terminate="false"
           :submit-data="{ dt: 0.25 }"

From 676d34842a73eeca9402b683592bedec26aac317 Mon Sep 17 00:00:00 2001
From: Joe Knapper <joe.knapper@glasgow.ac.uk>
Date: Wed, 11 Feb 2026 10:19:19 +0000
Subject: [PATCH 06/15] Apply suggestions from code review of branch
 flash-led-sim

Co-authored-by: Julian Stirling <julian@julianstirling.co.uk>
---
 .../things/camera/simulation.py                      |  2 +-
 .../things/illumination.py                           |  8 ++++----
 .../things/stage/sangaboard.py                       |  1 -
 .../aboutComponents/statusPane.vue                   | 12 +++++++++++-
 4 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/openflexure_microscope_server/things/camera/simulation.py b/src/openflexure_microscope_server/things/camera/simulation.py
index 730a6539..916a6067 100644
--- a/src/openflexure_microscope_server/things/camera/simulation.py
+++ b/src/openflexure_microscope_server/things/camera/simulation.py
@@ -340,7 +340,7 @@ class SimulatedCamera(BaseCamera):
         pl_img = Image.fromarray(np_img.astype("uint8"))
         return pl_img.resize((self.shape[1], self.shape[0]), Image.Resampling.BILINEAR)
 
-    @lt.action
+    def set_led(self, led_on: bool = True) -> None:
     def set_led(self, led_on: bool = True, led_channel: str = None) -> None:  # noqa: ARG002
         """Set the simulated LED to on or off."""
         if led_on:
diff --git a/src/openflexure_microscope_server/things/illumination.py b/src/openflexure_microscope_server/things/illumination.py
index d1d5e193..d9d0d2c6 100644
--- a/src/openflexure_microscope_server/things/illumination.py
+++ b/src/openflexure_microscope_server/things/illumination.py
@@ -5,8 +5,8 @@ from typing import Literal
 
 import labthings_fastapi as lt
 
-from .camera import BaseCamera
-from .stage import BaseStage
+from .camera import SimulatedCamera
+from .stage import SangaboardThing
 
 
 class Illumination(lt.Thing):
@@ -27,7 +27,7 @@ class Illumination(lt.Thing):
 class SangaIllumination(Illumination):
     """Illumination driven by a Sangaboard."""
 
-    _stage: BaseStage = lt.thing_slot()
+    _stage: SangaboardThing = lt.thing_slot()
 
     @lt.action
     def flash(
@@ -51,7 +51,7 @@ class SangaIllumination(Illumination):
 class SimulatorIllumination(Illumination):
     """Illumination control in the simulator."""
 
-    _cam: BaseCamera = lt.thing_slot()
+    _cam: SimulatedCamera = lt.thing_slot()
 
     @lt.action
     def flash(
diff --git a/src/openflexure_microscope_server/things/stage/sangaboard.py b/src/openflexure_microscope_server/things/stage/sangaboard.py
index 9a9b7fe5..7429aea3 100644
--- a/src/openflexure_microscope_server/things/stage/sangaboard.py
+++ b/src/openflexure_microscope_server/things/stage/sangaboard.py
@@ -173,7 +173,6 @@ class SangaboardThing(BaseStage):
             sb.zero_position()
         self.update_position()
 
-    @lt.action
     def set_led(
         self,
         led_on: bool = True,
diff --git a/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue b/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
index ce603f83..a2cd0b5d 100644
--- a/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
+++ b/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
@@ -13,7 +13,7 @@
           {{ $store.state.origin }}
         </div>
         <action-button
-          v-if="stageType"
+          v-if="illuminationType"
           thing="illumination"
           action="flash"
           submit-label="Flash Illumination"
@@ -46,6 +46,13 @@
           {{ stageType }}
         </div>
       </div>
+      <div v-if="illuminationType">
+        <b>Illumination:</b>
+        <br />
+        <div>
+          {{ illuminationType }}
+        </div>
+      </div>
 
       <hr />
     </div>
@@ -77,6 +84,9 @@ export default {
     stageType() {
       return this.thingAvailable("stage") ? this.thingDescription("stage").title : undefined;
     },
+    illuminationType() {
+      return this.thingAvailable("illumination") ? this.thingDescription("illumination").title : undefined;
+    },
   },
 
   async mounted() {

From 16458db85bc7961a7063749dd44ce4ff4ca7c7f0 Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Wed, 11 Feb 2026 10:26:04 +0000
Subject: [PATCH 07/15] Fix simulated imports

---
 .../things/camera/simulation.py                       |  1 -
 .../things/illumination.py                            | 11 +++++------
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/openflexure_microscope_server/things/camera/simulation.py b/src/openflexure_microscope_server/things/camera/simulation.py
index 916a6067..a8a00862 100644
--- a/src/openflexure_microscope_server/things/camera/simulation.py
+++ b/src/openflexure_microscope_server/things/camera/simulation.py
@@ -341,7 +341,6 @@ class SimulatedCamera(BaseCamera):
         return pl_img.resize((self.shape[1], self.shape[0]), Image.Resampling.BILINEAR)
 
     def set_led(self, led_on: bool = True) -> None:
-    def set_led(self, led_on: bool = True, led_channel: str = None) -> None:  # noqa: ARG002
         """Set the simulated LED to on or off."""
         if led_on:
             self.mult = 1
diff --git a/src/openflexure_microscope_server/things/illumination.py b/src/openflexure_microscope_server/things/illumination.py
index d9d0d2c6..fdbb2431 100644
--- a/src/openflexure_microscope_server/things/illumination.py
+++ b/src/openflexure_microscope_server/things/illumination.py
@@ -5,8 +5,8 @@ from typing import Literal
 
 import labthings_fastapi as lt
 
-from .camera import SimulatedCamera
-from .stage import SangaboardThing
+from .camera.simulation import SimulatedCamera
+from .stage.sangaboard import SangaboardThing
 
 
 class Illumination(lt.Thing):
@@ -58,15 +58,14 @@ class SimulatorIllumination(Illumination):
         self,
         number_of_flashes: int = 10,
         dt: float = 0.5,
-        led_channel: Literal["cc"] = "cc",
     ) -> None:
         """Flash an LED a given number of times.
 
-        Flashes the LED on channel led_channel number_of_flashes times,
+        Flashes the simulated LED number_of_flashes times,
         for a duration of dt each.
         """
         for _ in range(number_of_flashes):
-            self._cam.set_led(False, led_channel)
+            self._cam.set_led(False)
             time.sleep(dt)
-            self._cam.set_led(True, led_channel)
+            self._cam.set_led(True)
             time.sleep(dt)

From d4dc113a602925bd47ea492c71a2effdf413333c Mon Sep 17 00:00:00 2001
From: jaknapper <jaknapper@hotmail.com>
Date: Wed, 11 Feb 2026 12:12:43 +0000
Subject: [PATCH 08/15] Linter fix in statusPane

---
 .../tabContentComponents/aboutComponents/statusPane.vue       | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue b/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
index a2cd0b5d..209df9ef 100644
--- a/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
+++ b/webapp/src/components/tabContentComponents/aboutComponents/statusPane.vue
@@ -85,7 +85,9 @@ export default {
       return this.thingAvailable("stage") ? this.thingDescription("stage").title : undefined;
     },
     illuminationType() {
-      return this.thingAvailable("illumination") ? this.thingDescription("illumination").title : undefined;
+      return this.thingAvailable("illumination")
+        ? this.thingDescription("illumination").title
+        : undefined;
     },
   },
 

From 21f42d4698c341ce7ada7b93296570236fbb523f Mon Sep 17 00:00:00 2001
From: jaknapper <jaknapper@hotmail.com>
Date: Wed, 11 Feb 2026 12:58:46 +0000
Subject: [PATCH 09/15] Remove flash-led from SangaTest

---
 tests/unit_tests/test_stage.py | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/tests/unit_tests/test_stage.py b/tests/unit_tests/test_stage.py
index aeedc0dc..25c19fa1 100644
--- a/tests/unit_tests/test_stage.py
+++ b/tests/unit_tests/test_stage.py
@@ -284,9 +284,6 @@ def test_thing_description_equivalence(dummy_stage, mocker):
     mocker.patch.dict("sys.modules", {"sangaboard": mock_sangaboard})
     from openflexure_microscope_server.things.stage.sangaboard import SangaboardThing
 
-    # Flash LED isn't a standard stage action, most stages do not control illumination.
-    extra_sanga_actions = ["flash_led"]
-
     base_td = create_thing_without_server(BaseStage).thing_description()
     base_actions = set(base_td.actions.keys())
     base_properties = set(base_td.properties.keys())
@@ -298,9 +295,6 @@ def test_thing_description_equivalence(dummy_stage, mocker):
     sanga_td = create_thing_without_server(SangaboardThing).thing_description()
     # Remove known extra actions
     sanga_actions = list(sanga_td.actions.keys())
-    for action in extra_sanga_actions:
-        index = sanga_actions.index(action)
-        sanga_actions.pop(index)
     sanga_actions = set(sanga_actions)
     sanga_properties = set(sanga_td.properties.keys())
 

From 7da3dbbf8fddc47925523c9857e2753223e5a9a4 Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Wed, 11 Feb 2026 16:11:39 +0000
Subject: [PATCH 10/15] Test illumination

---
 tests/unit_tests/test_illumination.py | 58 +++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 tests/unit_tests/test_illumination.py

diff --git a/tests/unit_tests/test_illumination.py b/tests/unit_tests/test_illumination.py
new file mode 100644
index 00000000..f8edbd8a
--- /dev/null
+++ b/tests/unit_tests/test_illumination.py
@@ -0,0 +1,58 @@
+"""Tests for the Illumination thing."""
+
+import pytest
+
+from labthings_fastapi.testing import create_thing_without_server
+
+from openflexure_microscope_server.things.illumination import (
+    SangaIllumination,
+    SimulatorIllumination,
+)
+
+
+@pytest.fixture
+def sanga_mock_stage():
+    """Return a SangaIllumination with a mocked stage."""
+    return create_thing_without_server(SangaIllumination, mock_all_slots=True)
+
+
+@pytest.fixture
+def sim_mock_cam():
+    """Return a SimulatorIllumination with a mocked camera."""
+    return create_thing_without_server(SimulatorIllumination, mock_all_slots=True)
+
+
+def test_sanga_flash_calls_led(sanga_mock_stage):
+    """Test that flashing calls set_led with correct parameters."""
+    number_of_flashes = 3
+    dt = 0.01  # tiny sleep for test speed
+
+    sanga_mock_stage.flash(number_of_flashes=number_of_flashes, dt=dt)
+
+    # Each flash calls set_led False then True
+    assert sanga_mock_stage._stage.set_led.call_count == 2 * number_of_flashes
+
+    # Check that False and True are alternating when sent to _stage.set_led
+    calls = sanga_mock_stage._stage.set_led.call_args_list
+    expected_sequence = [False, True] * number_of_flashes
+    for call, expected in zip(calls, expected_sequence, strict=True):
+        args, kwargs = call
+        assert args[0] == expected
+
+
+def test_sim_flash_calls_led(sim_mock_cam):
+    """Test that simulator flash calls set_led correctly."""
+    number_of_flashes = 2
+    dt = 0.01
+
+    sim_mock_cam.flash(number_of_flashes=number_of_flashes, dt=dt)
+
+    # Each flash calls set_led False then True
+    assert sim_mock_cam._cam.set_led.call_count == 2 * number_of_flashes
+
+    # Check that False and True are alternating when sent to _cam.set_led
+    calls = sim_mock_cam._cam.set_led.call_args_list
+    expected_sequence = [False, True] * number_of_flashes
+    for call, expected in zip(calls, expected_sequence, strict=True):
+        args, kwargs = call
+        assert args[0] == expected

From 3423d4ed0e85418a27d00feab9457f5a5ae472c3 Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Wed, 11 Feb 2026 16:13:32 +0000
Subject: [PATCH 11/15] Test calling base Illumination

---
 tests/unit_tests/test_illumination.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/unit_tests/test_illumination.py b/tests/unit_tests/test_illumination.py
index f8edbd8a..1c675c0a 100644
--- a/tests/unit_tests/test_illumination.py
+++ b/tests/unit_tests/test_illumination.py
@@ -5,11 +5,19 @@ import pytest
 from labthings_fastapi.testing import create_thing_without_server
 
 from openflexure_microscope_server.things.illumination import (
+    Illumination,
     SangaIllumination,
     SimulatorIllumination,
 )
 
 
+def test_base_illumination_flash_not_implemented():
+    """Check that calling flash on the base Illumination raises NotImplementedError."""
+    ill = create_thing_without_server(Illumination)
+    with pytest.raises(NotImplementedError, match="Flashing the LED can only be done"):
+        ill.flash(number_of_flashes=1, dt=0.01)
+
+
 @pytest.fixture
 def sanga_mock_stage():
     """Return a SangaIllumination with a mocked stage."""

From 18477a663d1ba97292a3f87afc05fe75d79a8b53 Mon Sep 17 00:00:00 2001
From: Julian Stirling <julian@julianstirling.co.uk>
Date: Thu, 12 Feb 2026 13:40:20 +0000
Subject: [PATCH 12/15] Define flash in illumination base class

---
 .../things/illumination.py                    | 60 ++++++++-----------
 1 file changed, 24 insertions(+), 36 deletions(-)

diff --git a/src/openflexure_microscope_server/things/illumination.py b/src/openflexure_microscope_server/things/illumination.py
index fdbb2431..2e444138 100644
--- a/src/openflexure_microscope_server/things/illumination.py
+++ b/src/openflexure_microscope_server/things/illumination.py
@@ -10,19 +10,28 @@ from .stage.sangaboard import SangaboardThing
 
 
 class Illumination(lt.Thing):
-    """Abstract illumination controller."""
+    """Base class for an illumination controller."""
 
     @lt.action
-    def flash(
-        self,
-        number_of_flashes: int = 10,
-        dt: float = 0.5,
-    ) -> None:
-        """Flash the illumination source."""
+    def set_led(self, led_on: bool = True) -> None:
+        """Set the LED to on or off."""
         raise NotImplementedError(
-            "Flashing the LED can only be done from the simulator or sangaboard"
+            "Turning the LED on and off should be implemented by child classes."
         )
 
+    @lt.action
+    def flash(self, number_of_flashes: int = 10, dt: float = 0.5) -> None:
+        """Flash the illumination source.
+
+        :param number_of_flashes: Number of times to flash the LED.
+        :param dt: Flash duration in seconds.
+        """
+        for _ in range(number_of_flashes):
+            self.set_led(False)
+            time.sleep(dt)
+            self.set_led(True)
+            time.sleep(dt)
+
 
 class SangaIllumination(Illumination):
     """Illumination driven by a Sangaboard."""
@@ -30,22 +39,13 @@ class SangaIllumination(Illumination):
     _stage: SangaboardThing = lt.thing_slot()
 
     @lt.action
-    def flash(
+    def set_led(
         self,
-        number_of_flashes: int = 10,
-        dt: float = 0.5,
+        led_on: bool = True,
         led_channel: Literal["cc"] = "cc",
     ) -> None:
-        """Flash an LED a given number of times.
-
-        Flashes the LED on channel led_channel number_of_flashes times,
-        for a duration of dt each.
-        """
-        for _ in range(number_of_flashes):
-            self._stage.set_led(False, led_channel)
-            time.sleep(dt)
-            self._stage.set_led(True, led_channel)
-            time.sleep(dt)
+        """Set the LED to on or off."""
+        self._stage.set_led(led_on, led_channel)
 
 
 class SimulatorIllumination(Illumination):
@@ -54,18 +54,6 @@ class SimulatorIllumination(Illumination):
     _cam: SimulatedCamera = lt.thing_slot()
 
     @lt.action
-    def flash(
-        self,
-        number_of_flashes: int = 10,
-        dt: float = 0.5,
-    ) -> None:
-        """Flash an LED a given number of times.
-
-        Flashes the simulated LED number_of_flashes times,
-        for a duration of dt each.
-        """
-        for _ in range(number_of_flashes):
-            self._cam.set_led(False)
-            time.sleep(dt)
-            self._cam.set_led(True)
-            time.sleep(dt)
+    def set_led(self, led_on: bool = True) -> None:
+        """Set the LED to on or off."""
+        self._cam.set_led(led_on)

From fdf33ce4a88d0e51529a973c8541417c6234fdff Mon Sep 17 00:00:00 2001
From: Joe Knapper <joe.knapper@glasgow.ac.uk>
Date: Thu, 12 Feb 2026 13:48:12 +0000
Subject: [PATCH 13/15] Apply suggestions from code review of branch
 flash-led-sim

Co-authored-by: Julian Stirling <julian@julianstirling.co.uk>
---
 .../things/camera/simulation.py                        | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/openflexure_microscope_server/things/camera/simulation.py b/src/openflexure_microscope_server/things/camera/simulation.py
index a8a00862..36dc600a 100644
--- a/src/openflexure_microscope_server/things/camera/simulation.py
+++ b/src/openflexure_microscope_server/things/camera/simulation.py
@@ -140,7 +140,8 @@ class SimulatedCamera(BaseCamera):
         self._capture_thread: Optional[Thread] = None
         self._capture_enabled = False
         self.generate_sprites()
-        self.mult = 1
+        # Whether the LED is on
+        self.led_on = True
 
     repeating: bool = lt.property(default=False)
 
@@ -342,17 +343,14 @@ class SimulatedCamera(BaseCamera):
 
     def set_led(self, led_on: bool = True) -> None:
         """Set the simulated LED to on or off."""
-        if led_on:
-            self.mult = 1
-        else:
-            self.mult = 0
+        self.led_on = led_on
 
     def generate_frame(self) -> Image.Image:
         """Generate a frame with blobs based on the stage coordinates."""
         pos = self._stage.instantaneous_position
         frame = self.generate_image((pos["y"], pos["x"], pos["z"]))
         # Simulate LED turning off by setting all channels to 0
-        if self.mult == 0:
+        if not self.led_on:
             return Image.new(frame.mode, frame.size, 0)
         return frame
 

From bb5cce3d4e3f6b04ab25ad22be4c1d93897ee75a Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Thu, 12 Feb 2026 13:54:12 +0000
Subject: [PATCH 14/15] Only generate frame if LED is on

---
 .../things/camera/simulation.py                           | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/openflexure_microscope_server/things/camera/simulation.py b/src/openflexure_microscope_server/things/camera/simulation.py
index 36dc600a..a374f764 100644
--- a/src/openflexure_microscope_server/things/camera/simulation.py
+++ b/src/openflexure_microscope_server/things/camera/simulation.py
@@ -347,12 +347,12 @@ class SimulatedCamera(BaseCamera):
 
     def generate_frame(self) -> Image.Image:
         """Generate a frame with blobs based on the stage coordinates."""
-        pos = self._stage.instantaneous_position
-        frame = self.generate_image((pos["y"], pos["x"], pos["z"]))
         # Simulate LED turning off by setting all channels to 0
         if not self.led_on:
-            return Image.new(frame.mode, frame.size, 0)
-        return frame
+            return Image.new(mode="RGB", size=(self.shape[1], self.shape[0]), color=0)
+        # Otherwise, generate a frame from current position
+        pos = self._stage.instantaneous_position
+        return self.generate_image((pos["y"], pos["x"], pos["z"]))
 
     def __enter__(self) -> Self:
         """Start the capture thread when the Thing context manager is opened."""

From e0a8eb08c8cbc6e38c6af45537cad5c27a937227 Mon Sep 17 00:00:00 2001
From: Joe Knapper <jaknapper@hotmail.com>
Date: Thu, 12 Feb 2026 15:33:58 +0000
Subject: [PATCH 15/15] Test illumination baseclass

---
 tests/unit_tests/test_illumination.py | 77 ++++++++++++++++++++++++---
 1 file changed, 69 insertions(+), 8 deletions(-)

diff --git a/tests/unit_tests/test_illumination.py b/tests/unit_tests/test_illumination.py
index 1c675c0a..a7e02ee1 100644
--- a/tests/unit_tests/test_illumination.py
+++ b/tests/unit_tests/test_illumination.py
@@ -1,5 +1,7 @@
 """Tests for the Illumination thing."""
 
+from unittest.mock import call, patch
+
 import pytest
 
 from labthings_fastapi.testing import create_thing_without_server
@@ -10,12 +12,71 @@ from openflexure_microscope_server.things.illumination import (
     SimulatorIllumination,
 )
 
+# Test the BaseClass before testing specific implementation
 
-def test_base_illumination_flash_not_implemented():
-    """Check that calling flash on the base Illumination raises NotImplementedError."""
+
+def test_base_illumination_set_led_not_implemented():
+    """Check that calling set_led on the base Illumination raises NotImplementedError."""
     ill = create_thing_without_server(Illumination)
-    with pytest.raises(NotImplementedError, match="Flashing the LED can only be done"):
-        ill.flash(number_of_flashes=1, dt=0.01)
+    with pytest.raises(
+        NotImplementedError,
+        match="Turning the LED on and off should be implemented by child classes.",
+    ):
+        ill.set_led(led_on=True)
+
+
+def test_flash_calls_set_led_and_raises():
+    """Check that calling flash from Baseclass calls flash with right arguments."""
+    ill = create_thing_without_server(Illumination)
+
+    number_of_flashes = 3  # smaller number for test speed
+    dt = 0  # avoid sleeping
+
+    with pytest.raises(NotImplementedError):
+        ill.flash(number_of_flashes=number_of_flashes, dt=dt)
+
+    # Patch set_led to just record calls without raising
+    with patch.object(ill, "set_led") as mock_set_led:
+        # Call flash normally
+        ill.flash(number_of_flashes=number_of_flashes, dt=dt)
+
+        # Each flash calls set_led twice: False, True
+        expected_sequence = [call(False), call(True)] * number_of_flashes
+        assert mock_set_led.call_args_list == expected_sequence
+
+        # Also check total number of calls
+        assert mock_set_led.call_count == number_of_flashes * 2
+
+
+def test_negative_flash_calls():
+    """Check that calling flash with negative number doesn't call set_led."""
+    ill = create_thing_without_server(Illumination)
+
+    number_of_flashes = -33  # smaller number for test speed
+    dt = 0  # avoid sleeping
+
+    # Patch set_led to just record calls without raising
+    with patch.object(ill, "set_led") as mock_set_led:
+        # Call flash normally
+        ill.flash(number_of_flashes=number_of_flashes, dt=dt)
+
+        # Also check total number of calls
+        assert mock_set_led.call_count == 0
+
+
+def test_negative_flash_dt():
+    """Check that calling flash with negative dt raises ValueError."""
+    ill = create_thing_without_server(Illumination)
+
+    number_of_flashes = 3  # smaller number for test speed
+    dt = -5  # set a negative delay
+
+    # Patch set_led to just record calls without raising
+    with (
+        patch.object(ill, "set_led"),
+        pytest.raises(ValueError, match="sleep length must be non-negative"),
+    ):
+        ill.flash(number_of_flashes=number_of_flashes, dt=dt)
 
 
 @pytest.fixture
@@ -43,8 +104,8 @@ def test_sanga_flash_calls_led(sanga_mock_stage):
     # Check that False and True are alternating when sent to _stage.set_led
     calls = sanga_mock_stage._stage.set_led.call_args_list
     expected_sequence = [False, True] * number_of_flashes
-    for call, expected in zip(calls, expected_sequence, strict=True):
-        args, kwargs = call
+    for led_call, expected in zip(calls, expected_sequence, strict=True):
+        args, kwargs = led_call
         assert args[0] == expected
 
 
@@ -61,6 +122,6 @@ def test_sim_flash_calls_led(sim_mock_cam):
     # Check that False and True are alternating when sent to _cam.set_led
     calls = sim_mock_cam._cam.set_led.call_args_list
     expected_sequence = [False, True] * number_of_flashes
-    for call, expected in zip(calls, expected_sequence, strict=True):
-        args, kwargs = call
+    for led_call, expected in zip(calls, expected_sequence, strict=True):
+        args, kwargs = led_call
         assert args[0] == expected