Data commit

Task/Musical-scale/Julia/musical-scale.julia

@@ -0,0 +1,25 @@
+using PortAudio
+
+function paudio()
+    devs = PortAudio.devices()
+    devnum = findfirst(x -> x.maxoutchans > 0, devs)
+    (devnum == nothing) && error("No output device for audio found")
+    return PortAudioStream(devs[devnum].name, 0, 2)
+end
+
+function play(ostream, pitch, durationseconds)
+    sinewave(t) = 0.6sin(t) + 0.2sin(2t) + .05sin(8t)
+    timesamples = 0:(1 / 44100):(durationseconds * 0.98)
+    v = Float64[sinewave(2π * pitch * t) for t in timesamples]
+    write(ostream, v)
+    sleep(durationseconds * 0.9)
+end
+
+# C major scale starting with middle C
+# pitches from //pages.mtu.edu/~suits/notefreqs.html
+const scale = [261.6, 293.7, 329.6, 349.2, 392, 440, 493.9, 523.3]
+const ostream = paudio()
+for pitch in scale
+    play(ostream, pitch, 0.5)
+    sleep(0.4)
+end