implement front led switch on

src/auracast/server/multicast_frontend.py

@@ -1684,7 +1684,21 @@ if is_started or is_stopped:
 # System expander (collapsed)
 ############################
 with st.expander("System control", expanded=False):
-    
+
+    st.subheader("Status LED")
+    led_enabled_current = bool(saved_settings.get("led_enabled", True))
+    led_enabled = st.checkbox(
+        "Blue LED on while transmitting",
+        value=led_enabled_current,
+        help="When enabled, the blue LED on GPIO pin 12 lights up while the stream is active."
+    )
+    if led_enabled != led_enabled_current:
+        try:
+            requests.post(f"{BACKEND_URL}/set_led_enabled", json={"led_enabled": led_enabled}, timeout=2)
+        except Exception as e:
+            st.error(f"Failed to update LED setting: {e}")
+        st.rerun()
+
     st.subheader("System temperatures")
     temp_col1, temp_col2, temp_col3 = st.columns([1, 1, 1])
     with temp_col1:

src/auracast/server/multicast_server.py

@@ -26,6 +26,53 @@ from auracast.utils.sounddevice_utils import (
 )
 
 load_dotenv()
+
+# Blue LED on GPIO pin 12 (BCM) – turns on while transmitting
+LED_PIN = 12
+try:
+    import RPi.GPIO as _GPIO
+    _GPIO.setmode(_GPIO.BCM)
+    _GPIO.setup(LED_PIN, _GPIO.OUT)
+    _GPIO_AVAILABLE = True
+except Exception:
+    _GPIO_AVAILABLE = False
+    _GPIO = None  # type: ignore
+
+_LED_ENABLED: bool = True  # toggled via /set_led_enabled
+_LED_SETTINGS_FILE = os.path.join(os.path.dirname(__file__), 'led_settings.json')
+
+def _load_led_settings() -> None:
+    global _LED_ENABLED
+    try:
+        if os.path.exists(_LED_SETTINGS_FILE):
+            with open(_LED_SETTINGS_FILE, 'r', encoding='utf-8') as f:
+                data = json.load(f)
+            _LED_ENABLED = bool(data.get('led_enabled', True))
+    except Exception:
+        _LED_ENABLED = True
+
+def _save_led_settings() -> None:
+    try:
+        os.makedirs(os.path.dirname(_LED_SETTINGS_FILE), exist_ok=True)
+        with open(_LED_SETTINGS_FILE, 'w', encoding='utf-8') as f:
+            json.dump({'led_enabled': _LED_ENABLED}, f)
+    except Exception:
+        pass
+
+def _led_on():
+    if _GPIO_AVAILABLE and _LED_ENABLED:
+        try:
+            _GPIO.output(LED_PIN, _GPIO.HIGH)
+        except Exception:
+            pass
+
+def _led_off():
+    if _GPIO_AVAILABLE:
+        try:
+            _GPIO.output(LED_PIN, _GPIO.LOW)
+        except Exception:
+            pass
+
 # make sure pipewire sets latency
 # Primary and secondary persisted settings files
 STREAM_SETTINGS_FILE1 = os.path.join(os.path.dirname(__file__), 'stream_settings.json')
@@ -284,6 +331,7 @@ async def _stop_all() -> bool:
             was_running = True
         finally:
             multicaster2 = None
+    _led_off()
     return was_running
 
 async def _status_primary() -> dict:
@@ -468,6 +516,7 @@ async def init_radio(transport: str, conf: auracast_config.AuracastConfigGroup,
         auto_started = False
         if any(isinstance(big.audio_source, str) and (big.audio_source.startswith("device:") or big.audio_source.startswith("alsa:") or big.audio_source.startswith("file:")) for big in conf.bigs):
             await mc.start_streaming()
+            _led_on()
             auto_started = True
 
         demo_count = sum(1 for big in conf.bigs if isinstance(big.audio_source, str) and big.audio_source.startswith('file:'))
@@ -527,6 +576,16 @@ async def initialize2(conf: auracast_config.AuracastConfigGroup):
         multicaster2 = mc
         save_settings(persisted, secondary=True)
 
+@app.post("/set_led_enabled")
+async def set_led_enabled(body: dict):
+    """Enable or disable the blue status LED. Persisted across restarts."""
+    global _LED_ENABLED
+    _LED_ENABLED = bool(body.get("led_enabled", True))
+    _save_led_settings()
+    if not _LED_ENABLED:
+        _led_off()
+    return {"led_enabled": _LED_ENABLED}
+
 @app.post("/stop_audio")
 async def stop_audio():
     """Stops streaming on both multicaster1 and multicaster2 (worker thread)."""
@@ -590,6 +649,7 @@ async def get_status():
     secondary.update(secondary_persisted)
     status["secondary"] = secondary
     status["secondary_is_streaming"] = bool(secondary.get("is_streaming", False))
+    status["led_enabled"] = _LED_ENABLED
 
     return status
 
@@ -921,6 +981,7 @@ async def _autostart_from_settings():
 async def _startup_autostart_event():
     # Spawn the autostart task without blocking startup
     log.info("[STARTUP] Auracast multicast server startup: initializing settings cache, I2C, and PipeWire cache")
+    _led_off()
     
     # Run install_asoundconf.sh script
     script_path = os.path.join(os.path.dirname(__file__), '..', 'misc', 'install_asoundconf.sh')
@@ -934,6 +995,7 @@ async def _startup_autostart_event():
         log.error(f"[STARTUP] Error running install_asoundconf.sh: {str(e)}")
     
     # Hydrate settings cache once to avoid disk I/O during /status
+    _load_led_settings()
     _init_settings_cache_from_disk()
     await _init_i2c_on_startup()
     # Ensure ADC mixer level is set at startup (default 50%)

src/scripts/blink_led.py

@@ -11,7 +11,7 @@ while True:
     print("toggle led ON")
     GPIO.output(GPIO_PIN, GPIO.HIGH)
     time.sleep(1)
-    print("toggle led ON")
+    print("toggle led OFF")
     GPIO.output(GPIO_PIN, GPIO.LOW)
     time.sleep(1)