diff --git a/arrive_audio_ui.py b/arrive_audio_ui.py
index 7b099a8..3e57e25 100644
--- a/arrive_audio_ui.py
+++ b/arrive_audio_ui.py
@@ -14,6 +14,18 @@ import struct
 import wave
 import tempfile
 import io
+import time
+
+try:
+    import usb.core
+    import usb.util
+    _HAS_USB = True
+except ImportError:
+    _HAS_USB = False
+
+# ── STM32 companion USB IDs — update after running lsusb ─────────────────────
+_STM32_VID = None   # e.g. 0x0483
+_STM32_PID = None   # e.g. 0x5740
 
 # ── Force framebuffer QPA before any Qt import ────────────────────────────────
 if 'DISPLAY' not in os.environ and 'QT_QPA_PLATFORM' not in os.environ:
@@ -295,6 +307,117 @@ def _vol_btn_style() -> str:
     """
 
 
+# ─────────────────────────────────────────────────────────────────────────────
+# LED Controller  (STM32 companion via USB vendor control transfers)
+# ─────────────────────────────────────────────────────────────────────────────
+
+# Arrive brand colours for the LEDs
+_LED_PURPLE = (95,   1, 111)   # P1 #5F016F
+_LED_PINK   = (255,  51, 187)  # P2 #FF33BB
+
+_BMREQ   = 0x41   # Vendor | Interface | Out
+_CMD_BRI = 0x00   # SET_BRIGHTNESS
+_CMD_COL = 0x01   # SET_COLOR / SET_PATTERN
+
+
+class LedController:
+    """
+    Controls 2 RGB LED strings on the STM32 companion chip via USB.
+    Runs a knight-rider thread: pink strobe bounces over a purple base.
+    """
+
+    STRING_MAIN = 0
+    STRING_EXT  = 1
+
+    def __init__(self):
+        self._dev     = None
+        self._running = False
+        self._thread  = None
+        if _HAS_USB and _STM32_VID:
+            try:
+                self._dev = usb.core.find(idVendor=_STM32_VID, idProduct=_STM32_PID)
+                if self._dev:
+                    self._dev.set_configuration()
+            except Exception:
+                self._dev = None
+
+    # ── Public ────────────────────────────────────────────────────────────────
+
+    def start(self):
+        if self._dev is None or self._running:
+            return
+        self._running = True
+        self._thread = threading.Thread(target=self._knight_rider, daemon=True)
+        self._thread.start()
+
+    def stop(self):
+        self._running = False
+        if self._dev:
+            self._set_brightness(self.STRING_MAIN, 0)
+
+    # ── USB helpers ───────────────────────────────────────────────────────────
+
+    def _windex(self, string):
+        return (string << 8) | 0x01
+
+    def _set_color(self, string, r, g, b, brightness=255):
+        try:
+            self._dev.ctrl_transfer(
+                _BMREQ, _CMD_COL, brightness, self._windex(string), [r, g, b]
+            )
+        except Exception:
+            pass
+
+    def _set_brightness(self, string, brightness):
+        try:
+            self._dev.ctrl_transfer(
+                _BMREQ, _CMD_BRI, brightness, self._windex(string), None
+            )
+        except Exception:
+            pass
+
+    def _set_pattern(self, string, steps):
+        """steps: list of (brightness, duration_ms) — max 5."""
+        data = []
+        for bri, dur in steps[:5]:
+            data += [bri & 0xFF, dur & 0xFF, (dur >> 8) & 0xFF]
+        try:
+            self._dev.ctrl_transfer(
+                _BMREQ, _CMD_COL, 0, self._windex(string), data
+            )
+        except Exception:
+            pass
+
+    # ── Knight rider loop ─────────────────────────────────────────────────────
+
+    def _knight_rider(self):
+        STEPS   = 20       # steps per half-cycle
+        STEP_MS = 0.03     # 30 ms per step → ~600 ms fade up, ~600 ms fade down
+
+        while self._running:
+            # Fade purple → pink
+            for i in range(STEPS):
+                if not self._running:
+                    return
+                t = i / STEPS
+                r = int(_LED_PURPLE[0] + (_LED_PINK[0] - _LED_PURPLE[0]) * t)
+                g = int(_LED_PURPLE[1] + (_LED_PINK[1] - _LED_PURPLE[1]) * t)
+                b = int(_LED_PURPLE[2] + (_LED_PINK[2] - _LED_PURPLE[2]) * t)
+                self._set_color(self.STRING_MAIN, r, g, b)
+                time.sleep(STEP_MS)
+
+            # Fade pink → purple
+            for i in range(STEPS):
+                if not self._running:
+                    return
+                t = i / STEPS
+                r = int(_LED_PINK[0] + (_LED_PURPLE[0] - _LED_PINK[0]) * t)
+                g = int(_LED_PINK[1] + (_LED_PURPLE[1] - _LED_PINK[1]) * t)
+                b = int(_LED_PINK[2] + (_LED_PURPLE[2] - _LED_PINK[2]) * t)
+                self._set_color(self.STRING_MAIN, r, g, b)
+                time.sleep(STEP_MS)
+
+
 def _autocrop(img):
     """Crop a QImage (ARGB32) to the bounding box of non-transparent pixels."""
     if not _HAS_NUMPY:
@@ -361,8 +484,10 @@ class MainWindow(QMainWindow):
         super().__init__()
         self.audio = AudioEngine()
         self.audio.signals.status.connect(self._on_audio_status)
+        self.leds = LedController()
         self._build_ui()
         self._set_bg(C_BG)
+        self.leds.start()
 
     # ── UI construction ───────────────────────────────────────────────────────
 
@@ -604,6 +729,7 @@ class MainWindow(QMainWindow):
         self._fb_snapshot = data
 
     def closeEvent(self, event):
+        self.leds.stop()
         self.audio.shutdown()
         super().closeEvent(event)
         # Restore the framebuffer to what it looked like before Qt launched