Added tone samples generator (and convesion to midi key)

python/samples.py

@@ -0,0 +1,31 @@
+#! /usr/bin/env python3
+
+from tones import SQUARE_WAVE
+from tones.mixer import Mixer
+import csv
+import math
+
+def frequency_to_midi(frequency):
+    '''
+    There are only 128 midi notes. The don't map nicely
+    to the SELCAL frequencies :'(
+
+    MIDI note #69 is A4 @ 440 Hz. The other notes are given by:
+    f = 440 * 2 ^ (n - 69)/12
+    '''
+    note = 12 * (math.log(frequency/220)/math.log(2)) + 57
+    return round(note)
+
+tones = {}
+with open('tones.csv', newline='') as csvfile:
+    reader = csv.DictReader(csvfile)
+    for row in reader:
+        tones[row['designator']] = float(row['frequency'])
+
+for tone in tones:
+    print(f"{tone} is MIDI #{frequency_to_midi(tones[tone])}")
+
+    mixer = Mixer(44100, 1)
+    mixer.create_track(0, SQUARE_WAVE)
+    mixer.add_tone(0, frequency=tones[tone], duration=1.0)
+    mixer.write_wav(f'samples/{tone}.wav')