support no mic

Author: stefanotorneo

src/arduino/app_bricks/audio_classification/__init__.py

@@ -6,7 +6,7 @@
 import wave
 from typing import Callable
 
-from arduino.app_internal.core.audio import AudioDetector
+from arduino.app_internal.core.audio import AudioDetector, NO_MIC as NO_MIC
 from arduino.app_peripherals.microphone import Microphone
 from arduino.app_utils import brick, Logger
 
@@ -28,6 +28,8 @@ def __init__(self, mic: Microphone = None, confidence: float = 0.8):
 
         Args:
             mic (Microphone, optional): Microphone instance used as the audio source. If None, a default Microphone will be initialized.
+                If NO_MIC is passed, no microphone will be initialized, and only file-based classification
+                will be available.
             confidence (float, optional): Minimum confidence threshold (0.0–1.0) required
                 for a detection to be considered valid. Defaults to 0.8 (80%).
 
@@ -91,6 +93,9 @@ def classify_from_file(self, audio_path: str, confidence: int = None) -> dict |
             AudioClassificationException: If the file cannot be found, read, or processed.
             ValueError: If the file uses an unsupported sample width.
         """
+        if confidence is None:
+            confidence = self.confidence
+
         try:
             with wave.open(audio_path, "rb") as wf:
                 # Get WAV file properties

src/arduino/app_bricks/audio_classification/examples/2_glass_breaking_from_file.py

@@ -4,9 +4,9 @@
 
 # EXAMPLE_NAME = "Detect the glass breaking sound from audio file"
 # EXAMPLE_REQUIRES = "Requires an audio file with the glass breaking sound."
-from arduino.app_bricks.audio_classification import AudioClassification
+from arduino.app_bricks.audio_classification import AudioClassification, NO_MIC
 
-classifier = AudioClassification()
+classifier = AudioClassification(mic=NO_MIC)
 
 classification = classifier.classify_from_file("glass_breaking.wav")
 print("Result:", classification)

src/arduino/app_internal/core/audio.py

@@ -13,6 +13,8 @@
 
 logger = Logger(__name__)
 
+NO_MIC = object()  # Sentinel value for no microphone
+
 
 class AudioDetector(EdgeImpulseRunnerFacade):
     """AudioDetector module for detecting sounds and classifying audio using a specified model."""
@@ -42,7 +44,7 @@ def __init__(self, mic: Microphone = None, confidence: float = 0.8, debounce_sec
             raise ValueError("Model parameters are missing or incomplete in the retrieved model information.")
         self.model_info = model_info
 
-        self._mic = mic if mic else Microphone(sample_rate=model_info.frequency, channels=model_info.axis_count)
+        self._mic = None if mic is NO_MIC else (mic or Microphone(sample_rate=model_info.frequency, channels=model_info.axis_count))
         self._mic_lock = threading.Lock()
 
         self._window_size = int(model_info.input_features_count / model_info.axis_count)