Making VU meter type display with Neopixel ring.

pixel_meter

#include <Adafruit_NeoPixel.h>

// Which pin on the Arduino is connected to the NeoPixels?
// On a Trinket or Gemma we suggest changing this to 1:
#define LED_PIN   13

// How many NeoPixels are attached to the Arduino?
#define LED_COUNT 24

#define HUE_STEP 512;


// Declare our NeoPixel strip object:
Adafruit_NeoPixel strip = Adafruit_NeoPixel(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);
// Argument 1 = Number of pixels in NeoPixel strip
// Argument 2 = Arduino pin number (most are valid)
// Argument 3 = Pixel type flags, add together as needed:
//   NEO_KHZ800  800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
//   NEO_KHZ400  400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
//   NEO_GRB     Pixels are wired for GRB bitstream (most NeoPixel products)
//   NEO_RGB     Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
//   NEO_RGBW    Pixels are wired for RGBW bitstream (NeoPixel RGBW products)
int level = 0;
uint32_t safe = strip.Color(0, 255, 0);
uint32_t warn = strip.Color(255, 255, 0);
uint32_t danger = strip.Color(255, 0, 0);
uint32_t color = safe;
int analogPin = A0;
int maxInput = 1024;


void setup() {
  strip.begin();
  strip.clear(); // Initialize all pixels to 'off'
  strip.setBrightness(10);
//  randomSeed(analogRead(A0));

}

void loop() {

  strip.clear();

  level += change();

  if (level >= LED_COUNT) {
    level = LED_COUNT;
  }
  else if (level <= 0) {
    level = 1;
  }

  level = analogRead(analogPin) / (maxInput / LED_COUNT);

  color = safe;
  if (level > 19) {
    color = danger;
  }
  else if (level > 14) {
    color = warn;
  }

  strip.fill(color, 0, level);

  strip.show();
  delay(50);
}

int change() {
  return random(5) - 2;
}