snapshot

libraries/audio-tools/examples/examples-dsp/examples-stk/streams-stk_myinstrument-audiokit/MyFirstInstrument.h

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+#pragma once
+#include "StkAll.h"
+
+/**
+ * @brief Demo how you can compose your own instrument
+ * @author Phil Schatzmann
+ */
+class MyFirstInstrument : public Instrmnt  {
+  public:
+    MyFirstInstrument() {
+      adsr.setAllTimes( 0.005, 0.01, 0.8, 0.010 );
+      echo.setDelay(1024);
+    }
+
+     //! Start a note with the given frequency and amplitude.
+    void noteOn( StkFloat frequency, StkFloat amplitude ) {
+       wave.setFrequency(frequency);
+       adsr.keyOn();
+    }
+
+     //! Stop a note with the given amplitude (speed of decay).
+    void noteOff( StkFloat amplitude ){
+       adsr.keyOff();
+    }
+
+    float tick( unsigned int channel = 0) override {
+       return echo.tick(wave.tick()) * adsr.tick();
+    };
+
+  protected:
+    stk::SineWave wave;
+    stk::ADSR adsr;
+    stk::Echo echo {1024};
+};

libraries/audio-tools/examples/examples-dsp/examples-stk/streams-stk_myinstrument-audiokit/streams-stk_myinstrument-audiokit.ino

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+/**
+ * @file streams-stk-audioout.ino
+ * @brief Plays random notes on self designed instrument: see https://github.com/pschatzmann/Arduino-STK/wiki/Building-your-own-Instrument
+ * @author Phil Schatzmann
+ * @copyright Copyright (c) 2021
+ */
+#include "AudioTools.h"
+#include "AudioTools/AudioLibs/AudioSTK.h" // install https://github.com/pschatzmann/Arduino-STK
+#include "AudioTools/AudioLibs/AudioBoardStream.h" // install https://github.com/pschatzmann/arduino-audio-driver
+#include "MyFirstInstrument.h"
+
+MyFirstInstrument instrument;
+STKStream<Instrmnt> in(instrument);
+AudioBoardStream out(AudioKitEs8388V1);
+StreamCopy copier(out, in);
+MusicalNotes notes;
+
+float note_amplitude = 0.5;
+static float notes_array[] = { // frequencies aleatoric C-scale
+    N_C3, N_D3, N_E3, N_F3, N_G3, N_A3, N_B3,
+    N_C4, N_D4, N_E4, N_F4, N_G4, N_A4, N_B4,
+    N_C5, N_D5, N_E5, N_F5, N_G5, N_A5, N_B5
+};
+
+void play() {
+  static bool active=true;
+  static float freq;
+  static uint64_t timeout;
+
+  if (millis()>timeout){
+    if (active){
+      // play note for 800 ms
+      freq = notes_array[random(sizeof(notes_array)/sizeof(float))];
+      instrument.noteOn(freq, note_amplitude);
+      timeout = millis()+800;
+      active = false;
+    } else {
+      // silence for 100 ms
+      instrument.noteOff(note_amplitude);
+      timeout = millis()+100;
+      active = true;
+    }
+  }
+}
+
+void setup() {
+  Serial.begin(115200);
+  AudioLogger::instance().begin(Serial,AudioLogger::Warning);
+
+  // setup input
+  auto icfg = in.defaultConfig();
+  in.begin(icfg);
+
+  // setup output
+  auto ocfg = out.defaultConfig(TX_MODE);
+  ocfg.copyFrom(icfg);
+  ocfg.sd_active = false;
+  out.begin(ocfg);
+
+}
+
+void loop() {
+  play();
+  copier.copy();
+}