WIP: Improve Audio

examples/advanced_examples/modified_express_audio.py

@@ -14,15 +14,17 @@ class ModifiedExpressAudio:
     def __init__(self):
         self._max_sample_rate = 350_000
         self._highest_supported_frequency = 20_000
-        self._normal_sample_length = 300
+        self._normal_sample_length = 100  # This can be just 2 for square wave
         self._samples_change_frequency = self._max_sample_rate / self._normal_sample_length
         self._sample_lengths = (
             self._normal_sample_length,
-            self._max_sample_rate / self._highest_supported_frequency)
+            int(self._max_sample_rate / self._highest_supported_frequency))
         self._speaker_enable = digitalio.DigitalInOut(board.SPEAKER_ENABLE)
         self._speaker_enable.switch_to_output(value=False)
         self._speaker_enable.value = True
-        self._raw_samples = tuple(self._generate_samples())
+        # List of samples lists for each of sine and square waveforms
+        self._raw_samples = self._generate_samples()
+        self._waveform_type_index = 0
         self._audio_out = audioio.AudioOut(board.SPEAKER)
 
     @staticmethod
@@ -34,19 +36,25 @@ def _sine_waveform(length, amplitude=1):
             yield int(amplitude * max_amplitude * (math.sin(angle) + 1))
             angle += angle_change_per_sample
 
+    @staticmethod
+    def _square_waveform(length, amplitude=1):
+        max_amplitude = 2 ** 16 - 1
+        top = int(amplitude * max_amplitude)
+        return (top if i < length / 2 else 0 for i in range(length))
+
     def _generate_samples(self):
-        return [audiocore.RawSample(array.array("H", ModifiedExpressAudio._sine_waveform(length)))
-                for length in self._sample_lengths]
+        'For each of sine and square waveforms, generate one sample each for low and high ranges'
+        return [[audiocore.RawSample(array.array("H", fn(length)))
+            for length in self._sample_lengths]
+            for fn in (ModifiedExpressAudio._sine_waveform, ModifiedExpressAudio._square_waveform)]
 
     def start_tone(self, frequency):
         if frequency <= self._highest_supported_frequency:
-            # Start playing a tone of the specified frequency (hz).
             samples_index = 0 if frequency < self._samples_change_frequency else 1
             length = self._sample_lengths[samples_index]
-            sample_to_play = self._raw_samples[samples_index]
+            sample_to_play = self._raw_samples[self._waveform_type_index][samples_index]
             sample_to_play.sample_rate = int(length * frequency)
-            if not self._audio_out.playing:
-                self._audio_out.play(sample_to_play, loop=True)
+            self._audio_out.play(sample_to_play, loop=True)
 
     def stop_tone(self):
         if self._audio_out is not None and self._audio_out.playing:
@@ -59,24 +67,31 @@ def clear_audio(self):
             self._audio_out = None
 
 
-cpx = ModifiedExpressAudio()
+def play_tone():
+    cpx.start_tone(220)
+    time.sleep(5)
 
-STARTING_NOTE_FREQ = 32.71  # C1
-STARTING_OCTAVE = 1
-NOTE_SPACING_SECONDS = 0.2
-KEYS = 'C Db D Eb E F Gb G Ab A Bb B'.split(' ')  # Using b to represent ♭
 
+def play_scale():
+    STARTING_NOTE_FREQ = 32.70319566257483  # C1
+    STARTING_OCTAVE = 1
+    NOTE_SPACING_SECONDS = 0.2
+    KEYS = 'C Db D Eb E F Gb G Ab A Bb B'.split(' ')  # Using b to represent ♭
 
-for reset in (False, ):
-    next_note_play_time = time.monotonic()
-    for octave_index in range(9):
-        for semitone_index in range(12):
-            semitones_above_start = octave_index * 12 + semitone_index
-            freq = STARTING_NOTE_FREQ * 2 ** (semitones_above_start / 12)
-            print(KEYS[semitone_index % 12] + str(octave_index + STARTING_OCTAVE), '\t', freq)
-            cpx.start_tone(freq)
-            next_note_play_time += NOTE_SPACING_SECONDS
-            time.sleep(next_note_play_time - time.monotonic())
-            cpx.stop_tone()
-    time.sleep(0.5)
+    for i in range(1, 2):
+        cpx._waveform_type_index = i
+        next_note_play_time = time.monotonic()
+        for octave_index in range(7):
+            for semitone_index in range(12):
+                semitones_above_start = octave_index * 12 + semitone_index
+                freq = STARTING_NOTE_FREQ * 2 ** (semitones_above_start / 12)
+                print(KEYS[semitone_index % 12] + str(octave_index + STARTING_OCTAVE), '\t', freq)
+                cpx.start_tone(freq)
+                next_note_play_time += NOTE_SPACING_SECONDS
+                time.sleep(next_note_play_time - time.monotonic())
+                # Not calling stop_tone()
+
+
+cpx = ModifiedExpressAudio()
+play_scale()
 cpx.clear_audio()