// *** Thank : https://wokwi.com/projects/298603580442542605

#include <FastLED.h> //*******************************

#define DATA_PIN 3

#define NUM_ROWS 16
#define NUM_COLS 1
#define BRIGHTNESS 255
#define NUM_LEDS NUM_ROWS * NUM_COLS

const int sampleWindow = 120; // Sample window width in mS (50 mS = 20Hz) 50***********
const int maxScale = 16;  //*******hi
const int redZone = 11;   //*******mid
const int yellowZone = 4; //*******low
const int direct = 1;     // 1 or 0   RGB UP/DN

unsigned int sample;

CRGB leds[NUM_LEDS];

void setup() {
  Serial.begin(9600);
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
  FastLED.setBrightness(BRIGHTNESS);
}

void loop() {
  unsigned long startMillis = millis(); // Start of sample window
  unsigned int peakToPeak = 0;          // Peak-to-peak level

  unsigned int signalMax = 0;
  unsigned int signalMin = 1024;

  while (millis() - startMillis < sampleWindow)
  {
    sample = analogRead(0);    // pin A0
    Serial.println(sample);
    if (sample < 1024)  // Toss out spurious readings
    {
      if (sample > signalMax)
      {
        signalMax = sample;  // Save just the max levels
      }
      else if (sample < signalMin)
      {
        signalMin = sample;  // Save just the min levels
      }
    }
  }

  peakToPeak = signalMax - signalMin;

  // Map 1v p-p level to the max scale of the display
  int displayPeak = map(peakToPeak, 0, 1023, 0, maxScale);

  // Draw the new sample
  if (direct == 1){  // RGB = UP
    for (int i = maxScale - 1; i >= 0; i--) // (int i = maxScale - 1; i >= 0; i--) //(int i = 0; i <= maxScale-1; i++) // 
    {
      if (i >= displayPeak) // Blank these pixels *************************>=
      {
        leds[i] = CRGB::Black; //*********leds[ i] = CRGB::Black; 
      }
      else if (i >= redZone) // Draw in red
      {
        leds[i] = CRGB::Red;
      }
      else if ((i >= yellowZone) && (i < redZone)) // Draw in yellow
      {
        leds[i] = CRGB::Yellow;
      }
      else if (i < yellowZone) // Draw in green
      {
        leds[i] = CRGB::Green;
      }
    }
  }
  if (direct == 0){  // RGB = DN
    for (int i = maxScale - 1 ; i >= 0; i--) // (int i = maxScale - 1; i >= 0; i--) //(int i = 0; i <= maxScale-1; i++) // 
    {
      if (i >= displayPeak) // Blank these pixels *************************>=
      {
        leds[NUM_ROWS-1-i] = CRGB::Black; //*********leds[ i] = CRGB::Black; 
      }
      else if (i >= redZone) // Draw in red
      {
        leds[NUM_ROWS-1-i] = CRGB::Red;
      }
      else if ((i >= yellowZone) && (i < redZone)) // Draw in yellow
      {
        leds[NUM_ROWS-1-i] = CRGB::Yellow;
      }
      else if (i < yellowZone) // Draw in green
      {
        leds[NUM_ROWS-1-i] = CRGB::Green;
      }
    }
  }
  FastLED.show(); // Write the changes we just made to the display
}