VU Meter with NodeMCU and KY-037

main.cpp

#include <Arduino.h>
#include <Adafruit_NeoPixel.h>

#define NUM_PIXELS 10
#define PIN_PIXELS 14

#define AUDIO_ANALOG  A0
#define AUDIO_DIGITAL 12


Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUM_PIXELS, PIN_PIXELS, NEO_GRB + NEO_KHZ800);


const int yellowTopLED = (1024 * .4) * NUM_PIXELS / 1024; // 40% LEDs
const int greenTopLED  = (1024 * .8) * NUM_PIXELS / 1024; // 80% LEDs


void setup ()
{
  Serial.begin(115200);

  pinMode(PIN_PIXELS, OUTPUT);
  pinMode(AUDIO_ANALOG, INPUT);
  pinMode(AUDIO_DIGITAL, INPUT);

  pixels.setBrightness(64);
}

void loop ()
{
  int i;
  int sensorValue = analogRead(AUDIO_ANALOG);
  int leds = sensorValue / (1024 / NUM_PIXELS);

  //Serial.printf("sensor %4d, leds %2d\n", sensorValue, leds);

  // turn on leds
  for (i = 0; i < leds; i++)
  {
    if (i < yellowTopLED) // yellow
        pixels.setPixelColor(i, pixels.Color(255, 255, 0));
    else if (i < greenTopLED) // green
        pixels.setPixelColor(i, pixels.Color(0, 255, 0));
    else // red
        pixels.setPixelColor(i, pixels.Color(255, 0, 0));

    pixels.show();
  }

  // turn off all leds
  for(i = NUM_PIXELS - 1; i > 0; i--)
  {
    pixels.setPixelColor(i, pixels.Color(0, 0, 0));
    pixels.show();
  }
}