diff --git a/src/middleware.py b/src/middleware.py
index c06d0cc..efc64b2 100755
--- a/src/middleware.py
+++ b/src/middleware.py
@@ -136,6 +136,19 @@ def do_set(self, value):
         return do_set
 
 
+class Sleep(DBEntry):
+    prefix = "sleep"
+    fields = {
+        "ready": False,
+        "enabled": True,
+        "sleeping": False,
+        "eye_state": 1,
+        "last_activity": time.time(),
+        "last_interaction": 0.0,
+        "timeout": 300,
+    }
+
+
 class Robot(DBEntry):
     prefix = "robot"
     fields = {
diff --git a/src/sleep_mode.py b/src/sleep_mode.py
new file mode 100644
index 0000000..8a7430a
--- /dev/null
+++ b/src/sleep_mode.py
@@ -0,0 +1,351 @@
+"""
+
+Tool node.
+
+Controls the robot sleep mode state machine and onboard eye transitions.
+
+When there is no user interaction for a configurable amount of time,
+the node transitions the onboard display through open and dark
+states while coordinating with behaviour nodes that may temporarily own
+the display.
+
+"""
+
+import time
+from threading import Event, Thread
+
+from mode_manager import ModeManager
+import middleware as mw
+
+
+EYES_OPENED = 1
+EYES_CLOSED = 2
+
+VIDEO_DURATIONS = {
+    "open_dark.webm": 2.0,
+    "dark_open.webm": 2.0,
+    "dark_squint_dark.webm": 7.0,
+}
+
+
+class SleepMode:
+    """
+    Manages the onboard display sleep transitions based on inactivity.
+
+    Owns the onboard display during idle mode. Yields it to behaviours
+    when they raise their active flag, and resumes when the flag clears.
+
+    Publishes eye state through mw.Sleep().eye_state (EYES_OPENED=1, EYES_CLOSED=2)
+    so behaviours can choose the correct transition animation without depending on
+    sleep_mode internals.
+
+    > ## Attributes
+
+    ``touch : mw.TouchSensors`` : Middleware touch sensor state.
+
+    ``gpio : mw.GPIO`` : Middleware GPIO state.
+
+    ``display : mw.Onboard`` : Middleware onboard display controller.
+
+    ``server : mw.Server`` : Middleware server helper for resource URLs.
+
+    ``mode_manager : ModeManager`` : Mode manager used to determine idle and active states.
+
+    ``video_urls : dict`` : Mapping between filenames and resolved video URLs.
+
+    ``last_activity : float`` : Timestamp of the latest detected interaction.
+
+    ``current_state : str | None`` : Current eye state label.
+
+    ``last_idle_state : bool | None`` : Last detected idle state.
+
+    ``playing_video : bool`` : True while a transition video is active.
+
+    ``wake_event : threading.Event`` : Synchronisation event used to wake the main loop.
+
+    ``next_state : float`` : Timestamp for the next dark-mode peek animation.
+
+    > ## Functions
+    """
+
+    def __init__(self):
+        """
+        Initialise middleware objects, pre-resolve URLs, and start monitor threads.
+        """
+        self.touch = mw.TouchSensors()
+        self.display = mw.Onboard()
+        self.server = mw.Server()
+        self.mode_manager = ModeManager()
+        self.sleep = mw.Sleep()
+        self.node = mw.Node()
+
+        self.video_urls = {
+            f: self.server.url_for_video(f)
+            for f in ["open_dark.webm", "dark_open.webm", "dark_squint_dark.webm"]
+        }
+
+        self.sleep.last_activity = time.time()
+        self.current_state = None
+        self.last_idle_state = None
+        self.playing_video = False
+        self.was_behaviour_active = False
+        self.next_state = time.time() + self.sleep.timeout
+        self.wake_event = Event()
+
+        self.sleep.eye_state = EYES_OPENED
+        Thread(target=self.monitor_touch, daemon=True).start()
+        Thread(target=self.monitor_mode, daemon=True).start()
+
+    def monitor_touch(self):
+        """
+        Background thread: resets the activity timer on a new chest touch
+        and wakes the main loop immediately.
+
+        Only chest touches are handled here. Head touches are exclusively
+        used by behaviour_blush — reacting to them here would cause
+        sleep_mode to call eyes_opening() at the same time blush fires,
+        creating a display race condition.
+        """
+        last_touch = False
+        while True:
+            touched = self.touch.touch_chest
+            if touched and not last_touch:
+                self.sleep.last_activity = time.time()
+                self.wake_event.set()
+            last_touch = touched
+            time.sleep(0.1)
+
+    def monitor_mode(self):
+        """
+        Background thread: resets the activity timer on idle/non-idle
+        transitions caused by other behaviours becoming active or inactive,
+        and when a behaviour explicitly signals interaction via
+        mw.Sleep().last_interaction.
+        """
+        last_interaction = 0.0
+        while True:
+            idle = self.is_idle_mode()
+            if idle != self.last_idle_state:
+                self.last_idle_state = idle
+                self.sleep.last_activity = time.time()
+                self.wake_event.set()
+            try:
+                t = self.sleep.last_interaction
+                if t > last_interaction:
+                    last_interaction = t
+                    self.sleep.last_activity = t
+                    self.wake_event.set()
+            except TypeError:
+                self.node.loginfo("Invalid slee.last_interaction value.")
+                pass
+            time.sleep(0.2)
+
+    def is_idle_mode(self):
+        """
+        Check whether the robot is currently in idle mode.
+
+        Returns
+        -------
+        bool
+            True if no active non-idle behaviour is running.
+        """
+        b = self.mode_manager.behaviours
+        return not (b.conversation or b.photographer or b.akinator or b.wifi_connect)
+
+    def is_behaviour_active(self):
+        """
+        Check whether any behaviour currently owns the display.
+
+        Returns
+        -------
+        bool
+        """
+        try:
+            return mw.get_key("behaviour_blush_active") or mw.get_key(
+                "behaviour_hello_active"
+            )
+        except TypeError:
+            return False
+
+    def set_image(self, url, state, eye_state):
+        """
+        Show a static image and publish the new eye state.
+        Only updates the display and middleware state when
+        the state actually changes.
+
+        Parameters
+        ----------
+        url : str
+            Image URL to display.
+        state : str
+            New state label ("open" or "dark").
+        eye_state : int
+            Semaphore value to publish (EYES_OPENED or EYES_CLOSED).
+        """
+        if self.current_state != state:
+            self.display.image = url
+            self.current_state = state
+            self.sleep.eye_state = eye_state
+
+    def play_video(self, filename, then_image_url=None, restore=True):
+        """
+        Play a transition video and wait for it to finish.
+
+        Uses known clip duration as timing fallback since Onboard does not
+        expose a video_playing flag.
+
+        Parameters
+        ----------
+        filename : str
+            Video filename (e.g. "dark_open.webm").
+        then_image_url : str, optional
+            Static image URL to restore after playback. Defaults to normal.png.
+            Only used when restore=True.
+        restore : bool, optional
+            If True (default), sets a static image after the video ends.
+            Set to False when the video already ends on the correct frame —
+            forcing an image while the video is still playing would interrupt
+            it mid-frame and cause a visual double-play artifact.
+        """
+        self.playing_video = True
+        self.display.video = self.video_urls[filename]
+        if hasattr(self.display, "video_playing"):
+            while self.display.video_playing:
+                time.sleep(0.05)
+        else:
+            time.sleep(VIDEO_DURATIONS.get(filename, 3.0))
+        if restore:
+            self.display.image = (
+                then_image_url
+                if then_image_url is not None
+                else self.server.url_for_image("normal.png")
+            )
+        self.playing_video = False
+
+    def eyes_closing(self):
+        """
+        Transition from open eyes to fully dark screen.
+
+        Plays open_dark.webm for a smooth animation. restore=False because
+        the video already ends on the dark frame — forcing display.image
+        mid-playback would interrupt the video and cause a visual artifact.
+        Publishes EYES_CLOSED to the semaphore.
+        No-op if already in dark state.
+        """
+        if self.sleep.sleeping:
+            return
+        self.play_video("open_dark.webm", restore=False)
+        self.sleep.sleeping = True
+        self.current_state = "dark"
+        self.sleep.eye_state = EYES_CLOSED
+
+    def eyes_opening(self):
+        """
+        Wake from dark to open eyes.
+
+        Plays dark_open.webm then restores the open static image.
+        Publishes EYES_OPENED and resets the activity timer.
+        """
+        self.play_video(
+            "dark_open.webm", then_image_url=self.server.url_for_image("normal.png")
+        )
+        self.sleep.sleeping = False
+        self.current_state = "open"
+        self.sleep.eye_state = EYES_OPENED
+        self.sleep.last_activity = time.time()
+
+    def eyes_look_around(self):
+        """
+        While in the dark state, play a spontaneous peek animation
+        at the configured sleep interval, then return to the dark
+        static image.
+
+        Does nothing if a behaviour owns the display, or if it is too soon.
+        If a behaviour becomes active mid-playback, the dark restore is skipped
+        so it does not clobber the behaviour's animation.
+        """
+        if time.time() < self.next_state:
+            return
+        if self.is_behaviour_active():
+            return
+        self.playing_video = True
+        self.display.video = self.video_urls["dark_squint_dark.webm"]
+        if hasattr(self.display, "video_playing"):
+            while self.display.video_playing:
+                time.sleep(0.05)
+        else:
+            time.sleep(VIDEO_DURATIONS["dark_squint_dark.webm"])
+        if not self.is_behaviour_active():
+            self.display.image = self.server.url_for_image("background_black.png")
+        self.playing_video = False
+        self.next_state = time.time() + self.sleep.timeout
+
+    def run(self):
+        """
+        Main loop.
+
+        Priority order each iteration:
+        1. Yield the display while any behaviour is active.
+        2. Yield while a transition video is playing.
+        3. Idle path:
+            - Touch while dark → eyes_opening.
+            - Inactive >= configured timeout → dark screen; spontaneous peeks.
+            - Otherwise → open eyes (static PNG).
+        4. Non-idle path: restore open eyes and reset timer.
+
+        Uses wake_event to avoid busy-waiting; timeout is 1 second.
+        """
+        while True:
+            behaviour_active = self.is_behaviour_active()
+            if not self.sleep.enabled:
+                if self.sleep.sleeping:
+                    self.eyes_opening()
+
+                self.wake_event.wait(timeout=1.0)
+                self.wake_event.clear()
+                continue
+            if behaviour_active:
+                self.was_behaviour_active = True
+                self.wake_event.wait(timeout=0.1)
+                self.wake_event.clear()
+                continue
+            if self.was_behaviour_active:
+                self.was_behaviour_active = False
+                self.current_state = None
+            if self.playing_video:
+                self.wake_event.wait(timeout=0.1)
+                self.wake_event.clear()
+                continue
+            inactive_time = time.time() - self.sleep.last_activity
+
+            if self.is_idle_mode():
+                touched = self.touch.touch_chest
+                if touched and self.sleep.sleeping:
+                    self.eyes_opening()
+                elif inactive_time >= self.sleep.timeout:
+                    if not self.sleep.sleeping:
+                        self.eyes_closing()
+                        self.next_state = time.time() + self.sleep.timeout
+                    else:
+                        self.eyes_look_around()
+                else:
+                    self.set_image(
+                        self.server.url_for_image("normal.png"), "open", EYES_OPENED
+                    )
+            else:
+                if self.current_state != "open":
+                    if self.sleep.sleeping:
+                        self.eyes_opening()
+                    else:
+                        self.display.image = self.server.url_for_image("normal.png")
+                        self.current_state = "open"
+                        self.sleep.eye_state = EYES_OPENED
+                    self.sleep.last_activity = time.time()
+
+            self.wake_event.wait(timeout=1.0)
+            self.wake_event.clear()
+
+
+if __name__ == "__main__":
+    node = SleepMode()
+    node.run()
diff --git a/src/static/videos/dark_open.mp4 b/src/static/videos/dark_open.mp4
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diff --git a/src/static/videos/dark_squint_dark.mp4 b/src/static/videos/dark_squint_dark.mp4
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diff --git a/src/static/videos/open_dark.mp4 b/src/static/videos/open_dark.mp4
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