first draft of esp32 firmware

Signed-off-by: Thomas Schmid <tom@binary-kitchen.de>

firmware/.gitignore

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+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch

firmware/.vscode/extensions.json

@@ -0,0 +1,10 @@
+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}

firmware/include/README

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+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

firmware/include/app.h

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+#ifndef ZAUBERSTAB_APP_H
+#define ZAUBERSTAB_APP_H
+
+struct App {
+    void (*loop)(void);
+    void (*setup)(void);
+};
+
+struct App 
+#endif

firmware/include/zauberstab.h

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+#pragma once
+
+#include <FastLED.h>
+
+#define LED_PIN 12
+#define NUM_LEDS 144
+#define MIC_PIN 15
+
+extern CRGB leds[NUM_LEDS];
+
+int zauberstab_init();
+int32_t get_sample();

firmware/lib/README

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+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in a an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

firmware/platformio.ini

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+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:esp32doit-devkit-v1]
+platform = espressif32
+board = esp32doit-devkit-v1
+framework = arduino
+lib_deps = fastled/FastLED @ ^3.5.0
+
+monitor_port = COM5
+monitor_speed = 115200
+
+upload_protocol = esptool
+upload_port = COM5
+
+

firmware/sound_ripple/sound_ripple.cpp

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+/* soundmems_ripple
+ *
+ * By: Andrew Tuline
+ *
+ * Date: August, 2015
+ * 
+ * Updated: January, 2020
+ *
+ * Create a ripple from a calculated peak from a sampled microphone
+ * 
+ * Note: If you are using a microphone powered by the 3.3V signal, such as the Sparkfun MEMS microphone, then connect 3.3V to the AREF pin.
+ * 
+ */
+
+
+//#define FASTLED_ALLOW_INTERRUPTS 0                          // Used for ESP8266.
+#include <FastLED.h>                                          // FastLED library.
+#include "zauberstab.h"
+// Fixed definitions cannot change on the fly.
+#define LED_DT LED_PIN                                             // Data pin to connect to the strip.
+#define LED_CK 11                                             // Clock pin for WS2801 or APA102.
+#define COLOR_ORDER GRB                                       // It's GRB for WS2812 and BGR for APA102.
+#define LED_TYPE WS2812                                       // Using APA102, WS2812, WS2801. Don't forget to modify LEDS.addLeds to suit.
+
+uint8_t squelch = 7;                                          // Anything below this is background noise, so we'll make it '0'.
+int sample;                                                   // Current sample.
+float sampleAvg = 0;                                          // Smoothed Average.
+float micLev = 0;                                             // Used to convert returned value to have '0' as minimum.
+uint8_t maxVol = 11;                                          // Reasonable value for constant volume for 'peak detector', as it won't always trigger.
+bool samplePeak = 0;                                          // Boolean flag for peak. Responding routine must reset this flag.
+
+int max_bright = 255;
+
+CRGB leds[NUM_LEDS];
+// Ripple variables
+uint8_t colour;                                               // Ripple colour is randomized.
+int center = 0;                                               // Center of the current ripple.
+int step = -1;                                                // -1 is the initializing step.
+uint8_t myfade = 255;                                         // Starting brightness.
+#define maxsteps 16                                           // Case statement wouldn't allow a variable.
+
+
+
+void setup() {
+  
+  //analogReference(EXTERNAL);                                  // 3.3V reference for analog input.
+ 
+  Serial.begin(115200);
+
+  LEDS.addLeds<LED_TYPE, LED_DT, COLOR_ORDER>(leds, NUM_LEDS);  // Use this for WS2812B
+//  LEDS.addLeds<LED_TYPE, LED_DT, LED_CK, COLOR_ORDER>(leds, NUM_LEDS);  // Use this for WS2801 or APA102
+
+  FastLED.setBrightness(max_bright);
+  //FastLED.setMaxPowerInVoltsAndMilliamps(5, 500);
+
+} // setup()
+
+
+void getSample() {
+  
+  int16_t micIn;                                              // Current sample starts with negative values and large values, which is why it's 16 bit signed.
+  static long peakTime;
+  
+  micIn = analogRead(MIC_PIN);                                // Poor man's analog Read.
+  micLev = ((micLev * 31) + micIn) / 32;                      // Smooth it out over the last 32 samples for automatic centering.
+  micIn -= micLev;                                            // Let's center it to 0 now.
+  micIn = abs(micIn);                                         // And get the absolute value of each sample.
+  sample = (micIn <= squelch) ? 0 : (sample + micIn) / 2;     // Using a ternary operator, the resultant sample is either 0 or it's a bit smoothed out with the last sample.
+  sampleAvg = ((sampleAvg * 31) + sample) / 32;               // Smooth it out over the last 32 samples.
+
+  if (sample > (sampleAvg+maxVol) && millis() > (peakTime + 50)) {    // Poor man's beat detection by seeing if sample > Average + some value.
+    samplePeak = 1;                                                   // Then we got a peak, else we don't. Display routines need to reset the samplepeak value in case they miss the trigger.
+    peakTime=millis();                
+  }                                                           
+
+}  // getSample()
+
+
+
+void ripple() {
+
+  if (samplePeak == 1) {step = -1; samplePeak = 0; }          // If we have a peak, let's reset our ripple.
+
+  fadeToBlackBy(leds, NUM_LEDS, 64);                          // 8 bit, 1 = slow, 255 = fast
+  
+  switch (step) {
+
+    case -1:                                                  // Initialize ripple variables.
+      center = random(NUM_LEDS);
+      colour = random8();                                     // More peaks/s = higher the hue colour.
+      step = 0;
+      break;
+
+    case 0:
+      leds[center] = CHSV(colour, 255, 255);                  // Display the first pixel of the ripple.
+      step ++;
+      break;
+
+    case maxsteps:                                            // At the end of the ripples.
+      // step = -1;
+      break;
+
+    default:                                                  // Middle of the ripples.
+      leds[(center + step + NUM_LEDS) % NUM_LEDS] += CHSV(colour, 255, myfade/step*2);       // Simple wrap.
+      leds[(center - step + NUM_LEDS) % NUM_LEDS] += CHSV(colour, 255, myfade/step*2);
+      step ++;                                                // Next step.
+      break;  
+  } // switch step
+  
+} // ripple()
+
+
+void loop() {
+
+  getSample();
+
+  EVERY_N_MILLISECONDS(20) {
+   ripple();
+  }
+
+   FastLED.show();
+
+} // loop()
+
+

firmware/sound_wave/sound_wave.ino

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+
+/* sound_wave
+ *
+ * By: Andrew Tuline
+ * 
+ * Date: February, 2017
+ *
+ * Basic code to read from the Sparkfun INMP401 microphone, and create waves based on sampled input. This does NOT include sensitivity adjustment.
+ * 
+ * My hardware setup:
+ * 
+ * Arduino Nano & Addressable LED strips
+ *  - Powered by USB power bank 
+ *  - APA102 or WS2812 data connected to pin 12.
+ *  - APA102 clock connected to pin 11.
+ *  - 5V on APA102 or WS2812 connected to 5V on Nano (good for short strips).
+ *  - Gnd to Gnd on Nano.
+ * 
+ * 
+ * Sparkfun MEMS microphone
+ *  - Vcc on microphone is connected to 3.3V on Nano.
+ *  - AREF on Nano connected to 3.3V on Nano.
+ *  - Mic out connected to A5.
+ *  - Gnd to Gnd on Nano.
+ * 
+ * Note: If you are using a microphone powered by the 3.3V signal, such as the Sparkfun MEMS microphone, then connect 3.3V to the AREF pin.
+ * 
+ */
+
+//#define FASTLED_ALLOW_INTERRUPTS 0                          // Used for ESP8266.
+#include <FastLED.h>                                          // FastLED library.
+#include "zauberstab.h"
+
+uint8_t squelch = 7;                                          // Anything below this is background noise, so we'll make it '0'.
+int sample;                                                   // Current sample.
+float sampleAvg = 0;                                          // Smoothed Average.
+float micLev = 0;                                             // Used to convert returned value to have '0' as minimum.
+uint8_t maxVol = 11;                                          // Reasonable value for constant volume for 'peak detector', as it won't always trigger.
+bool samplePeak = 0;                                          // Boolean flag for peak. Responding routine must reset this flag.
+
+int sampleAgc, multAgc;
+uint8_t targetAgc = 60;                                       // This is our setPoint at 20% of max for the adjusted output.
+
+ 
+// Fixed definitions cannot change on the fly.
+#define LED_DT LED_PIN                                             // Data pin to connect to the strip.
+#define LED_CK 11                                             // Clock pin for WS2801 or APA102.
+#define COLOR_ORDER GRB                                       // It's GRB for WS2812 and BGR for APA102.
+#define LED_TYPE WS2812                                       // Using APA102, WS2812, WS2801. Don't forget to modify LEDS.addLeds to suit.
+
+
+struct CRGB leds[NUM_LEDS];                                   // Initialize our LED array.
+
+int max_bright = 255;
+
+CRGBPalette16 currentPalette = OceanColors_p;
+CRGBPalette16 targetPalette = OceanColors_p;
+TBlendType    currentBlending = LINEARBLEND;                  // NOBLEND or LINEARBLEND
+
+
+
+void setup() {
+  //analogReference(EXTERNAL);                                  // 3.3V reference for analog input.
+ 
+  Serial.begin(115200);                                        // Initialize serial port for debugging.
+  delay(1000);                                                // Soft startup to ease the flow of electrons.
+
+  LEDS.addLeds<LED_TYPE, LED_DT, COLOR_ORDER>(leds, NUM_LEDS);      // Use this for WS2812B
+//  LEDS.addLeds<LED_TYPE, LED_DT, LED_CK, COLOR_ORDER>(leds, NUM_LEDS);  // Use this for WS2801 or APA102
+
+  FastLED.setBrightness(max_bright);
+  FastLED.setMaxPowerInVoltsAndMilliamps(5, 500);               // FastLED Power management set at 5V, 500mA.
+
+} // setup()
+
+
+void getSample() {
+  
+  int16_t micIn;                                              // Current sample starts with negative values and large values, which is why it's 16 bit signed.
+  static long peakTime;
+  
+  micIn = analogRead(MIC_PIN)>>2;                                // Poor man's analog Read.
+  micLev = ((micLev * 31) + micIn) / 32;                      // Smooth it out over the last 32 samples for automatic centering.
+  micIn -= micLev;                                            // Let's center it to 0 now.
+  micIn = abs(micIn);                                         // And get the absolute value of each sample.
+  sample = (micIn <= squelch) ? 0 : (sample + micIn) / 2;     // Using a ternary operator, the resultant sample is either 0 or it's a bit smoothed out with the last sample.
+  sampleAvg = ((sampleAvg * 31) + sample) / 32;               // Smooth it out over the last 32 samples.
+
+  if (sample > (sampleAvg+maxVol) && millis() > (peakTime + 50)) {    // Poor man's beat detection by seeing if sample > Average + some value.
+    samplePeak = 1;                                                   // Then we got a peak, else we don't. Display routines need to reset the samplepeak value in case they miss the trigger.
+    peakTime=millis();                
+  }                                                           
+
+}  // getSample()
+
+
+void agcAvg() {                                                   // A simple averaging multiplier to automatically adjust sound sensitivity.
+  
+  multAgc = (sampleAvg < 1) ? targetAgc : targetAgc / sampleAvg;  // Make the multiplier so that sampleAvg * multiplier = setpoint
+  sampleAgc = sample * multAgc;
+  if (sampleAgc > 255) sampleAgc = 255;
+
+//------------ Oscilloscope output ---------------------------
+ Serial.print(targetAgc); Serial.print(" ");
+ Serial.print(multAgc); Serial.print(" ");
+ Serial.print(sampleAgc); Serial.print(" ");
+
+ Serial.print(micLev); Serial.print(" ");
+ Serial.print(sample); Serial.println(" ");
+//  Serial.print(sampleAvg); Serial.print(" ");
+//  Serial.print(samplePeak); Serial.print(" "); samplePeak = 0;
+//  Serial.print(100); Serial.print(" ");
+//  Serial.print(0); Serial.print(" ");
+//  Serial.println(" ");
+
+} // agcAvg()
+
+
+
+void sndwave() {
+  
+  leds[NUM_LEDS/2] = ColorFromPalette(currentPalette, sampleAgc, sampleAgc, currentBlending); // Put the sample into the center
+  
+  for (int i = NUM_LEDS - 1; i > NUM_LEDS/2; i--) {       //move to the left      // Copy to the left, and let the fade do the rest.
+    leds[i] = leds[i - 1];
+  }
+
+  for (int i = 0; i < NUM_LEDS/2; i++) {                  // move to the right    // Copy to the right, and let the fade to the rest.
+    leds[i] = leds[i + 1];
+  }
+  
+} // sndwave()
+
+
+void loop() {
+
+
+  EVERY_N_SECONDS(5) {                                        // Change the palette every 5 seconds.
+    for (int i = 0; i < 16; i++) {
+      targetPalette[i] = CHSV(random8(), 255, 255);
+    }
+  }
+  
+  EVERY_N_MILLISECONDS(100) {                                 // AWESOME palette blending capability once they do change.
+    uint8_t maxChanges = 24; 
+    nblendPaletteTowardPalette(currentPalette, targetPalette, maxChanges);
+  }
+
+
+  EVERY_N_MILLIS_I(thistimer,20) {                            // For fun, let's make the animation have a variable rate.
+    uint8_t timeval = beatsin8(10,20,50);                     // Use a sinewave for the line below. Could also use peak/beat detection.
+    thistimer.setPeriod(timeval);                             // Allows you to change how often this routine runs.
+    fadeToBlackBy(leds, NUM_LEDS, 16);                        // 1 = slow, 255 = fast fade. Depending on the faderate, the LED's further away will fade out.
+    getSample();
+    agcAvg();
+    sndwave();
+  }
+
+  FastLED.show();
+
+} // loop()
+
+

firmware/src/vumeter.cpp

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+#include "zauberstab.h"
+
+unsigned long last_sample_time;
+static int sample_counter = 0;
+unsigned int top_led_pos = 0; 
+float rms_avg = 0;
+float vu_filt = 0.0f;
+float vu_filt_slow = 0.0f;
+
+void setup()
+{
+    zauberstab_init();
+    Serial.begin(115200);
+    FastLED.setBrightness(100);
+}
+
+void loop() {
+    if (micros()-last_sample_time >= 500){
+        last_sample_time = micros();
+        int32_t sample = get_sample();
+        float in = sample*sample;
+        sample_counter++;
+        rms_avg += (in - rms_avg)/(sample_counter + 1);
+    }
+    
+    EVERY_N_MILLIS(10){
+
+        float vu = 20 * log10f(rms_avg);
+        vu_filt = (vu-vu_filt) * 0.8 + vu_filt;
+        vu_filt_slow = (vu_filt-vu_filt_slow) * 0.01 + vu_filt_slow;
+        //Serial.println(vu);
+        int max_led = vu_filt;
+        int top_led = vu_filt_slow;
+
+        max_led = max_led > 0xFF ? 0xFF : max_led;
+
+        if (top_led < max_led){
+            vu_filt_slow = vu_filt;
+            top_led = max_led;
+        }
+
+        fill_solid(leds, NUM_LEDS, CRGB::Black);
+        for(int i = 0; i < max_led; i++) {
+            int idx = map(i, 0, NUM_LEDS, 0, 0xFF);
+            leds[i] = ColorFromPalette(RainbowColors_p, idx);
+        }
+        
+        leds[top_led] = CRGB::White;
+
+        FastLED.show();
+        rms_avg = 0.0f;
+        sample_counter = 0;
+    }
+}

firmware/src/zauberstab.cpp

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+#include "zauberstab.h"
+
+CRGB leds[NUM_LEDS];
+static int16_t mic_offset = 0;
+
+static uint16_t read_mic() {
+    return analogRead(MIC_PIN);
+}
+
+static uint16_t get_mic_offset() {
+    float average = 0.f;
+    uint32_t num_samples = 0;
+
+    for(num_samples = 0; num_samples < 10000; num_samples++) {
+        uint16_t sample = read_mic();
+        average += ((float) sample - average) / (num_samples + 1);
+    }
+    
+    return (uint16_t)average;
+}
+
+int zauberstab_init() {
+    FastLED.addLeds<WS2812, LED_PIN, RGB>(leds, NUM_LEDS);
+    //FastLED.setMaxPowerInVoltsAndMilliamps(5, 300);
+    mic_offset = get_mic_offset();
+    return 0;
+}
+
+int32_t get_sample() {
+    return read_mic() - mic_offset;
+}

firmware/temp/alex_beat_detect.cpp

@@ -0,0 +1,204 @@
+#include "zauberstab.h"
+#include "app.h"
+
+#define SAMPLING_FREQUENCY_BP 40     // number of energy chunks per second
+#define SAMPLING_FREQUENCY_CONTROL 1 // check number of times per second if the current band pass is the best one
+#define Q 20.                        // quality factor of band pass filters
+#define PI 3.1415926535897932384626433832795
+#define n_BP 30 //number of band pass filters
+
+static unsigned long sampling_period_bp = 1000000L / SAMPLING_FREQUENCY_BP;
+static unsigned long sampling_period_control = 1000000L / SAMPLING_FREQUENCY_CONTROL;
+static double energy = 0;
+static unsigned long last_us_bp = 0L;
+static unsigned long last_us_control = 0L;
+
+static float a0[n_BP];
+static float a1[n_BP];
+static float a2[n_BP];
+static float b0[n_BP];
+//static float b1[n_BP];
+static float b2[n_BP];
+
+static float a[n_BP];
+static float w0[n_BP];
+
+static float yy1[n_BP];
+static float yy2[n_BP];
+static float yy3[n_BP];
+static float yy4[n_BP];
+static float yy5[n_BP];
+static float yy6[n_BP];
+
+static float u1[n_BP];
+static float u2[n_BP];
+static float y[n_BP];
+static float y_fil[n_BP];
+
+static float angle;
+static float angle2;
+
+static double energy_fil = 800.;
+
+static float pos_target = NUM_LEDS / 2;
+static float pos_target_filtered = NUM_LEDS / 2;
+
+static float microphone_offset = 675;
+static long initial_time;
+
+static int active = 15;
+static int candidate = 15;
+static int rounds = 0;
+
+static int get_value(int pos, float pos0)
+{
+  if (abs(pos0 - pos) > 20)
+  {
+    return 0;
+  }
+  else
+  {
+    return (40 - abs(pos0 - pos) * 2);
+  }
+}
+
+static void set_filter()
+{
+  for (int i = 0; i < n_BP; i++)
+  {
+    float frequency = 1.75 + i * (2.4 - 1.75) / n_BP;
+    w0[i] = 2. * PI * frequency / SAMPLING_FREQUENCY_BP;
+    a[i] = sin(w0[i] / (2. * Q));
+    b0[i] = a[i];
+    //b1[i] = 0;
+    b2[i] = -a[i];
+    a0[i] = 1. + a[i];
+    a1[i] = -2. * cos(w0[i]);
+    a2[i] = 1. - a[i];
+  }
+}
+
+static void abeat_setup()
+{
+  zauberstab_init();
+  Serial.begin(115200);
+  set_filter();
+  initial_time = micros();
+}
+static void abeat_loop()
+{
+
+  int sample = int(analogRead(MIC_PIN) - microphone_offset);
+  energy += abs(sample) * abs(sample);
+
+  if (micros() - last_us_bp > sampling_period_bp)
+  {
+
+    Serial.println(sample);
+
+    microphone_offset += (analogRead(MIC_PIN) - microphone_offset) * 0.001;
+
+    //Serial.println(microphone_offset);
+
+    last_us_bp += sampling_period_bp;
+    energy_fil += (energy - energy_fil) * 0.01;
+    //Serial.println(energy);
+    for (int i = 0; i < n_BP; i++)
+    {
+      y[i] = (b0[i] / a0[i]) * energy + 0. + (b2[i] / a0[i]) * u2[i] - (a1[i] / a0[i]) * yy1[i] - (a2[i] / a0[i]) * yy2[i];
+      u2[i] = u1[i];
+      u1[i] = energy;
+      yy6[i] = yy5[i];
+      yy5[i] = yy4[i];
+      yy4[i] = yy3[i];
+      yy3[i] = yy2[i];
+      yy2[i] = yy1[i];
+      yy1[i] = y[i];
+      y_fil[i] += (abs(y[i]) - y_fil[i]) * 0.005; //linie der scheitelpunkte
+    }
+
+    float delays = constrain(SAMPLING_FREQUENCY_BP * 0.25 / (1.75 + active * (2.4 - 1.75) / n_BP), 4., 6.);
+
+    float delayed = 0;
+    if (delays > 5)
+    {
+      delayed = yy5[active] * (1 - delays + 5) + yy6[active] * (delays - 5);
+    }
+    else
+    {
+      delayed = yy4[active] * (1 - delays + 4) + yy5[active] * (delays - 4);
+    }
+
+    angle = atan2(delayed, y[active]);
+
+    if (PI < abs(angle - angle2) && abs(angle - angle2) < 3 * PI)
+    {
+      angle2 = angle + 2 * PI;
+    }
+    else
+    {
+      angle2 = angle;
+    }
+
+    pos_target = map(angle2, -PI, 3 * PI, -0.3 * NUM_LEDS, NUM_LEDS * 1.5);
+
+    if (pos_target > pos_target_filtered)
+    {
+      pos_target_filtered += (pos_target - pos_target_filtered) * 0.35;
+    }
+    else
+    {
+      pos_target_filtered = pos_target;
+    }
+
+    //       Serial.print(y_fil[active]);
+    //       Serial.print(",");
+    //       Serial.println(y[active]);
+
+    energy = 0;
+
+    for (int i = 0; i < NUM_LEDS; i++)
+    {
+      int brightness = get_value(i, pos_target_filtered);
+      //leds[i].setRGB(brightness, brightness, brightness);
+
+      //leds[i].setHSV(160, (rounds == 6) ? 0xFF : 0, brightness);
+      leds[i] = CRGB::White;
+    }
+    FastLED.show();
+  }
+
+  if (micros() - last_us_control > sampling_period_control)
+  {
+    last_us_control += sampling_period_control;
+    int argmax = -1;
+    float valuemax = 0;
+    for (int i = 0; i < n_BP; i++)
+    {
+      if (y_fil[i] > valuemax)
+      {
+        valuemax = y_fil[i];
+        argmax = i;
+      }
+    }
+
+    if (argmax > -1)
+    {
+      if (argmax == candidate)
+      {
+        rounds++;
+      }
+      else
+      {
+        rounds = 0;
+        candidate = argmax;
+      }
+      if (rounds > 6)
+      {
+        rounds = 0;
+        active = candidate;
+      }
+    }
+  }
+}
+

firmware/temp/beat_detect.cpp

@@ -0,0 +1,203 @@
+#include "zauberstab.h"
+
+#define SAMPLING_FREQUENCY_BP 40     // number of energy chunks per second
+#define SAMPLING_FREQUENCY_CONTROL 1 // check number of times per second if the current band pass is the best one
+#define Q 20.                        // quality factor of band pass filters
+#define PI 3.1415926535897932384626433832795
+#define n_BP 30 //number of band pass filters
+
+static unsigned long sampling_period_bp = 1000000L / SAMPLING_FREQUENCY_BP;
+static unsigned long sampling_period_control = 1000000L / SAMPLING_FREQUENCY_CONTROL;
+static double energy = 0;
+static unsigned long last_us_bp = 0L;
+static unsigned long last_us_control = 0L;
+
+static float a0[n_BP];
+static float a1[n_BP];
+static float a2[n_BP];
+static float b0[n_BP];
+//static float b1[n_BP];
+static float b2[n_BP];
+
+static float a[n_BP];
+static float w0[n_BP];
+
+static float yy1[n_BP];
+static float yy2[n_BP];
+static float yy3[n_BP];
+static float yy4[n_BP];
+static float yy5[n_BP];
+static float yy6[n_BP];
+
+static float u1[n_BP];
+static float u2[n_BP];
+static float y[n_BP];
+static float y_fil[n_BP];
+
+static float angle;
+static float angle2;
+
+static double energy_fil = 800.;
+
+static float pos_target = NUM_LEDS / 2;
+static float pos_target_filtered = NUM_LEDS / 2;
+
+static float microphone_offset = 675;
+static long initial_time;
+
+static int active = 15;
+static int candidate = 15;
+static int rounds = 0;
+
+static int get_value(int pos, float pos0)
+{
+    if (abs(pos0 - pos) > 20)
+    {
+        return 0;
+    }
+    else
+    {
+        return (40 - abs(pos0 - pos) * 2);
+    }
+}
+
+static void set_filter()
+{
+    for (int i = 0; i < n_BP; i++)
+    {
+        float frequency = 1.75 + i * (2.4 - 1.75) / n_BP;
+        w0[i] = 2. * PI * frequency / SAMPLING_FREQUENCY_BP;
+        a[i] = sin(w0[i] / (2. * Q));
+        b0[i] = a[i];
+        //b1[i] = 0;
+        b2[i] = -a[i];
+        a0[i] = 1. + a[i];
+        a1[i] = -2. * cos(w0[i]);
+        a2[i] = 1. - a[i];
+    }
+}
+
+void setup()
+{
+    zauberstab_init();
+    Serial.begin(115200);
+    set_filter();
+    initial_time = micros();
+}
+void loop()
+{
+
+    int sample = int(analogRead(MIC_PIN) - microphone_offset);
+    energy += abs(sample) * abs(sample);
+
+    if (micros() - last_us_bp > sampling_period_bp)
+    {
+
+        Serial.println(sample);
+
+        microphone_offset += (analogRead(MIC_PIN) - microphone_offset) * 0.001;
+
+        //Serial.println(microphone_offset);
+
+        last_us_bp += sampling_period_bp;
+        energy_fil += (energy - energy_fil) * 0.01;
+        //Serial.println(energy);
+        for (int i = 0; i < n_BP; i++)
+        {
+            y[i] = (b0[i] / a0[i]) * energy + 0. + (b2[i] / a0[i]) * u2[i] - (a1[i] / a0[i]) * yy1[i] - (a2[i] / a0[i]) * yy2[i];
+            u2[i] = u1[i];
+            u1[i] = energy;
+            yy6[i] = yy5[i];
+            yy5[i] = yy4[i];
+            yy4[i] = yy3[i];
+            yy3[i] = yy2[i];
+            yy2[i] = yy1[i];
+            yy1[i] = y[i];
+            y_fil[i] += (abs(y[i]) - y_fil[i]) * 0.005; //linie der scheitelpunkte
+        }
+
+        float delays = constrain(SAMPLING_FREQUENCY_BP * 0.25 / (1.75 + active * (2.4 - 1.75) / n_BP), 4., 6.);
+
+        float delayed = 0;
+        if (delays > 5)
+        {
+            delayed = yy5[active] * (1 - delays + 5) + yy6[active] * (delays - 5);
+        }
+        else
+        {
+            delayed = yy4[active] * (1 - delays + 4) + yy5[active] * (delays - 4);
+        }
+
+        angle = atan2(delayed, y[active]);
+
+        if (PI < abs(angle - angle2) && abs(angle - angle2) < 3 * PI)
+        {
+            angle2 = angle + 2 * PI;
+        }
+        else
+        {
+            angle2 = angle;
+        }
+
+        pos_target = map(angle2, -PI, 3 * PI, -0.3 * NUM_LEDS, NUM_LEDS * 1.5);
+
+        if (pos_target > pos_target_filtered)
+        {
+            pos_target_filtered += (pos_target - pos_target_filtered) * 0.35;
+        }
+        else
+        {
+            pos_target_filtered = pos_target;
+        }
+
+        //       Serial.print(y_fil[active]);
+        //       Serial.print(",");
+        //       Serial.println(y[active]);
+
+        energy = 0;
+
+        for (int i = 0; i < NUM_LEDS; i++)
+        {
+            int brightness = get_value(i, pos_target_filtered);
+            if (brightness >= 1) {
+                brightness = 10;
+            }
+            //leds[i].setRGB(brightness, brightness, brightness);
+            leds[i].setHSV(160, (rounds == 6) ? 0xFF : 0, brightness);
+        }
+        FastLED.show();
+    }
+
+    if (micros() - last_us_control > sampling_period_control)
+    {
+        last_us_control += sampling_period_control;
+        int argmax = -1;
+        float valuemax = 0;
+        for (int i = 0; i < n_BP; i++)
+        {
+            if (y_fil[i] > valuemax)
+            {
+                valuemax = y_fil[i];
+                argmax = i;
+            }
+        }
+
+        if (argmax > -1)
+        {
+            if (argmax == candidate)
+            {
+                rounds++;
+            }
+            else
+            {
+                rounds = 0;
+                candidate = argmax;
+            }
+            if (rounds > 6)
+            {
+                rounds = 0;
+                active = candidate;
+            }
+        }
+    }
+}

firmware/temp/main.cpp

@@ -0,0 +1,9 @@
+#include "zauberstab.h"
+
+void setup() {
+  zauberstab_init();
+}
+
+void loop() {
+
+}

firmware/test/README

@@ -0,0 +1,11 @@
+
+This directory is intended for PlatformIO Test Runner and project tests.
+
+Unit Testing is a software testing method by which individual units of
+source code, sets of one or more MCU program modules together with associated
+control data, usage procedures, and operating procedures, are tested to
+determine whether they are fit for use. Unit testing finds problems early
+in the development cycle.
+
+More information about PlatformIO Unit Testing:
+- https://docs.platformio.org/en/latest/advanced/unit-testing/index.html