Arduino UNO R4 LEDs

Author: pschatzmann

examples/examples-audiokit/streams-audiokit-fft-led/streams-audiokit-fft-led.ino

@@ -1,16 +1,28 @@
-#include "AudioTools.h"
+/**
+ * @file streams-audiokit-fft-led.ino
+ * @author Phil Schatzmann
+ * @brief  We peform FFT on the microphone input of the AudioKit and display the
+ * result on a 32*8 LED matrix
+ * @version 0.1
+ * @date 2022-10-14
+ *
+ * @copyright Copyright (c) 2022
+ *
+ */
 #include "AudioLibs/AudioKit.h"
-#include "AudioLibs/AudioRealFFT.h" // or AudioKissFFT
+#include "AudioLibs/AudioRealFFT.h"  // or AudioKissFFT
 #include "AudioLibs/LEDOutput.h"
+#include "AudioTools.h"
 
 #define PIN_LEDS 22
 #define LED_X 32
 #define LED_Y 8
 
 AudioKitStream kit;  // Audio source
-AudioRealFFT fft; // or AudioKissFFT
+AudioRealFFT fft;    // or AudioKissFFT
+FFTDisplay fft_dis(fft);
+LEDOutput led(fft_dis);       // output to LED matrix
 StreamCopy copier(fft, kit);  // copy mic to fft
-LEDOutput led(fft); // output to LED matrix
 
 void setup() {
   Serial.begin(115200);
@@ -23,24 +35,27 @@ void setup() {
 
   // Setup FFT output
   auto tcfg = fft.defaultConfig();
-  tcfg.length = 1024; 
+  tcfg.length = 1024;
   tcfg.copyFrom(cfg);
   fft.begin(tcfg);
 
+  // Setup FFT Display
+  fft_dis.fft_group_bin = 3;
+  fft_dis.fft_start_bin = 0;
+  fft_dis.fft_max_magnitude = 40000;
+  fft_dis.begin();
+
   // Setup LED matrix output
   auto lcfg = led.defaultConfig();
   lcfg.x = LED_X;
   lcfg.y = LED_Y;
-  lcfg.fft_group_bin = 3;
-  lcfg.fft_start_bin = 0;
-  lcfg.fft_max_magnitude = 40000;
   led.begin(lcfg);
 
   // add LEDs
   FastLED.addLeds<WS2812B, PIN_LEDS, GRB>(led.ledData(), led.ledCount());
 }
 
-void loop() { 
+void loop() {
   // update FFT
   copier.copy();
   // update LEDs

src/AudioLibs/FFTDisplay.h

@@ -0,0 +1,83 @@
+#pragma once
+#include "AudioLibs/AudioFFT.h"
+
+namespace audio_tools {
+
+class FFTDisplay;
+FFTDisplay *selfFFTDisplay = nullptr;
+// fft mutex
+static Mutex fft_mux;
+
+/**
+ * Display FFT result: we can define a start bin and group susequent bins for a
+ * combined result.
+ */
+
+class FFTDisplay {
+ public:
+  FFTDisplay(AudioFFTBase &fft) {
+    p_fft = &fft;
+    selfFFTDisplay = this;
+  }
+
+  /// start bin which is displayed
+  int fft_start_bin = 0;
+  /// group result by adding subsequent bins
+  int fft_group_bin = 1;
+  /// Influences the senitivity
+  int fft_max_magnitude = 700;
+
+  void begin() {
+    // assign fft callback
+    AudioFFTConfig &fft_cfg = p_fft->config();
+    fft_cfg.callback = fftCallback;
+
+    // number of bins
+    magnitudes.resize(p_fft->size());
+    for (int j = 0; j < p_fft->size(); j++) {
+      magnitudes[j] = 0;
+    }
+  }
+
+  /// Returns the magnitude for the indicated led x position. We might
+  /// need to combine values from the magnitudes array if this is much bigger.
+  float getMagnitude(int x) {
+    // get magnitude from fft
+    float total = 0;
+    for (int j = 0; j < fft_group_bin; j++) {
+      int idx = fft_start_bin + (x * fft_group_bin) + j;
+      if (idx >= magnitudes.size()) {
+        idx = magnitudes.size() - 1;
+      }
+      total += magnitudes[idx];
+    }
+    return total / fft_group_bin;
+  }
+
+  int getMagnitudeScaled(int x, int max) {
+    return mapFloat(getMagnitude(x), 0, fft_max_magnitude, 0.0f,
+                    static_cast<float>(max));
+  }
+
+  /// callback method which provides updated data from fft
+  static void fftCallback(AudioFFTBase &fft) {
+    selfFFTDisplay->loadMangnitudes();
+  };
+
+ protected:
+  AudioFFTBase *p_fft = nullptr;
+  Vector<float> magnitudes{0};
+
+  void loadMangnitudes() {
+    // just save magnitudes to be displayed
+#ifdef USE_CONCURRENCY
+    LockGuard guard(fft_mux);
+#endif
+    for (int j = 0; j < p_fft->size(); j++) {
+      float value = p_fft->magnitude(j);
+      magnitudes[j] = value;
+    }
+  }
+};
+
+}  // namespace audio_tools