07 Dynamic Sequences

07DynamicSequences/07DynamicSequences.ino

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+// Basic demo for configuring the MCP4728 4-Channel 12-bit I2C DAC
+#include <Adafruit_MCP4728.h>
+#include <Wire.h>
+
+Adafruit_MCP4728 mcp;
+
+
+// 1 3 5 7 hexany log2
+float hexany[] = { 0.12928301694496647, 0.32192809488736235, 0.3923174227787603, 0.5849625007211562, 0.8073549220576041, 0.9068905956085185 };
+float tuning[18];
+int pitch[] = { 4, 3, 2, 1, 2, 3, 4, 3  };
+float dur[] = { 2, 2, 2, 2, 2, 2, 2, 2  };
+float gate = 0.5;
+int bpm = 135;
+int phrase = 8;
+float beat_s = 60.0 / (float)bpm;
+int beat_m = round(1000.0 * beat_s); 
+float voltrange = 4.85;  // measured this, probably not accurate
+float octave = 4096.0 / voltrange; // number of DAC steps in an octave
+float mod_b = 3.141592653589793 / 4.0;
+
+
+int s;
+bool noteon = false;
+long play_t;
+long release_t;
+long last_t;
+long init_t;
+
+
+void setup(void) {
+  Serial.begin(115200);
+  while (!Serial)
+    delay(10); // will pause Zero, Leonardo, etc until serial console opens
+
+  if (!mcp.begin(0x64)) {
+    Serial.println("Failed to find MCP4728 chip");
+    while (1) {
+      delay(10);
+    }
+    Serial.println("MCP4728 initialised");
+  }
+
+  mcp.setChannelValue(MCP4728_CHANNEL_B, 0);
+
+  float n0 = 0;
+  for( int o = 0; o < 3; o++ ) {
+    for( int i = 0; i < 18; i++ ) {
+      tuning[o * 6 + i] = round(n0 + octave * (o + hexany[i]));
+    }
+  }
+
+  s = 0;
+  release_t = 0;
+  play_t = 0;
+  last_t = millis();
+  init_t = last_t;
+}
+
+
+void make_tuning() {
+  float n0 = 0;
+  for( int i = 0; i < 18; i++ ) {
+      tuning[i] = round(n0 + octave * hexany[i]);
+  }
+ 
+}
+
+
+void loop() {
+  long now = millis();
+  if( noteon ) {
+    if( now - last_t > release_t ) {
+      noteOff();
+      last_t = now;
+      play_t = round(beat_m * dur[s] * (1.0 - gate));
+      noteon = false;
+      s += 1;
+      if( s == phrase ) {
+        s = 0;
+        updatePhrase();
+      }
+    }
+  } else {
+    if( now - last_t > play_t ) {
+      noteOn(pitch[s]);
+      last_t = now;
+      release_t = round(beat_m * dur[s] * gate);
+      noteon = true;
+    }
+  }
+  // // sychronise this better
+  // long mod_t = (now - init_t);
+  // float mod = 0.5 + 0.5 * sin(mod_b * (float)mod_t / (float)beat_m);
+  // mcp.setChannelValue(MCP4728_CHANNEL_C, round(4095.0 * mod));
+}
+
+
+void updatePhrase() {
+  int n = random(phrase);
+  pitch[n] = random(6);
+}
+
+void noteOn(int note) {
+  if( note > -1 ) {
+    mcp.setChannelValue(MCP4728_CHANNEL_A, tuning[note]);
+    mcp.setChannelValue(MCP4728_CHANNEL_B, 4095);
+  }
+}
+
+void noteOff() {
+    mcp.setChannelValue(MCP4728_CHANNEL_B, 0);
+}