diff --git a/idriz/assistant.py b/idriz/assistant.py
index 2d68ed5..2257c66 100644
--- a/idriz/assistant.py
+++ b/idriz/assistant.py
@@ -9,7 +9,7 @@ from pathlib import Path
 
 from openai import AsyncOpenAI
 
-from . import coloring, printer, render, textgen, wiki
+from . import audio, coloring, printer, render, textgen, wiki
 from .audio import Mic, Speaker
 from .config import Config
 
@@ -175,20 +175,29 @@ class Assistant:
 
     # ---------- audio petlje ----------
     async def mic_loop(self) -> None:
-        mic_missing = False
+        """Šalje zvuk modelu. Ako je USB mikrofon isključen prekidačem (nestane iz PipeWire-a), ne sluša ništa."""
+        last_check = 0.0
+        present = False
         while True:
+            now = asyncio.get_event_loop().time()
+            if now - last_check > 1.5:
+                present = await audio.source_present(self.cfg.mic_device)
+                last_check = now
+            if not present:
+                if self.mic.running:
+                    await self.mic.stop()
+                    log.info("mikrofon isključen (prekidač), ne slušam")
+                await asyncio.sleep(0.5)
+                continue
+            if not self.mic.running:
+                await self.mic.start()
+                log.info("mikrofon uključen, slušam")
+                await self.speaker.write(audio.tone())
             chunk = await self.mic.read()
             if not chunk:
-                if not mic_missing:
-                    log.error("mikrofon ne daje podatke (isključen?), čekam da se pojavi")
-                    mic_missing = True
                 await self.mic.stop()
-                await asyncio.sleep(2)
-                await self.mic.start()
+                await asyncio.sleep(1)
                 continue
-            if mic_missing:
-                log.info("mikrofon ponovo radi")
-                mic_missing = False
             if self.speaker.is_playing():
                 continue  # half-duplex: ne šalji dok Idriz govori
             await self.conn.send({"type": "input_audio_buffer.append", "audio": base64.b64encode(chunk).decode()})
@@ -261,7 +270,6 @@ class Assistant:
                 self.conn = None
 
     async def run(self) -> None:
-        await self.mic.start()
         await self.speaker.start()
         if not await printer.printer_ok(self.cfg.printer):
             log.warning("printer %s nije spreman", self.cfg.printer)
diff --git a/idriz/audio.py b/idriz/audio.py
index 7361b31..06379d2 100644
--- a/idriz/audio.py
+++ b/idriz/audio.py
@@ -2,6 +2,7 @@
 import array
 import asyncio
 import logging
+import math
 import time
 
 log = logging.getLogger("idriz.audio")
@@ -28,12 +29,33 @@ def apply_gain(pcm: bytes, gain: float) -> bytes:
     return samples.tobytes()
 
 
+def tone(freq: float = 880.0, ms: int = 150, volume: float = 0.3) -> bytes:
+    """Kratak signalni ton (PCM16 mono)."""
+    n = RATE * ms // 1000
+    samples = array.array("h", (int(volume * 32767 * math.sin(2 * math.pi * freq * i / RATE) * min(1.0, (n - i) / (n * 0.3))) for i in range(n)))
+    return samples.tobytes()
+
+
+async def source_present(name: str) -> bool:
+    """Da li PipeWire trenutno ima izvor tog imena (USB mikrofon nestane kad se isključi prekidač)."""
+    if not name:
+        return True
+    proc = await asyncio.create_subprocess_exec("pactl", "list", "sources", "short",
+                                                stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.DEVNULL)
+    out, _ = await proc.communicate()
+    return any(name in line for line in out.decode(errors="replace").splitlines())
+
+
 class Mic:
     def __init__(self, device: str = "", gain: float = 1.0) -> None:
         self.device = device
         self.gain = gain
         self.proc: asyncio.subprocess.Process | None = None
 
+    @property
+    def running(self) -> bool:
+        return self.proc is not None and self.proc.returncode is None
+
     async def start(self) -> None:
         self.proc = await asyncio.create_subprocess_exec(
             *_pacat_args("--record", self.device),
@@ -50,6 +72,7 @@ class Mic:
         if self.proc and self.proc.returncode is None:
             self.proc.kill()
             await self.proc.wait()
+        self.proc = None
 
 
 class Speaker: