Preliminary RingModulator sketch

Author: tomcombriat

examples/06.Synthesis/RingModulator/RingModulator.ino

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+/*  Example playing a sinewave at a set frequency,
+    using Mozzi sonification library.
+
+    Demonstrates the use of Oscil to play a wavetable.
+
+    Circuit: Audio output on digital pin 9 on a Uno or similar, or
+    DAC/A14 on Teensy 3.1, or
+    check the README or http://sensorium.github.io/Mozzi/
+
+    Mozzi documentation/API
+    https://sensorium.github.io/Mozzi/doc/html/index.html
+
+    Mozzi help/discussion/announcements:
+    https://groups.google.com/forum/#!forum/mozzi-users
+
+    Copyright 2012-2024 Tim Barrass and the Mozzi Team
+
+    Mozzi is licensed under the GNU Lesser General Public Licence (LGPL) Version 2.1 or later.
+*/
+
+#define MOZZI_CONTROL_RATE 64  // Hz, powers of 2 are most reliable; 64 Hz is actually the default, but shown here, for clarity
+#include <Mozzi.h>
+#include <Oscil.h>                // oscillator template
+#include <tables/sin2048_int8.h>  // sine table for oscillator
+#include <EventDelay.h>
+#include <Smooth.h>
+#include <mozzi_rand.h>
+
+EventDelay kModulationChangeDelay;
+Smooth<uint8_t> kSmoothModulation(0.9f);
+// use: Oscil <table_size, update_rate> oscilName (wavetable), look in .h file of table #included above
+Oscil<SIN2048_NUM_CELLS, MOZZI_AUDIO_RATE> aSin(SIN2048_DATA);
+//Oscil <SIN2048_NUM_CELLS, MOZZI_CONTROL_RATE> aSin2(SIN2048_DATA); // controls the amount of Ring Modulation
+
+int8_t prev_sample = 0;
+uint8_t ring_mod, smoothed_ring_mod;
+
+void setup() {
+  Serial.begin(115200);
+  kModulationChangeDelay.set(2000);
+  startMozzi();      // :)
+  aSin.setFreq(64);  // set the frequency
+}
+
+
+void updateControl() {
+  //ring_mod_amount = int(aSin2.next() + 128);
+  //Serial.println(ring_mod_amount);
+  //ring_mod_amount = 255;
+  if (kModulationChangeDelay.ready()) {
+    ring_mod = rand(150);
+    kModulationChangeDelay.start();
+  }
+  smoothed_ring_mod = kSmoothModulation(ring_mod);
+}
+
+
+AudioOutput updateAudio() {
+  prev_sample = aSin.phMod(int32_t(prev_sample) * smoothed_ring_mod);
+  return MonoOutput::from8Bit(prev_sample);  // return an int signal centred around 0
+}
+
+
+void loop() {
+  audioHook();  // required here
+}