Interactive Lighting with Rotary Encoder and WS2812B LED Strip

#include <Encoder.h>
#include <Adafruit_NeoPixel.h>

const int NUM_LEDS = 30;           // Number of LEDs in the strip
const int LED_PIN = 5;             // Pin for the LED strip
const int BRIGHTNESS = 255;        // Brightness of the LEDs
const int WHEEL_SIZE = 256;        // Size of the color wheel
const int ENCODER_PIN_1 = 2;       // Rotary encoder pin 1
const int ENCODER_PIN_2 = 3;       // Rotary encoder pin 2
const int ENCODER_BUTTON = 4;      // Rotary encoder button

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, LED_PIN, NEO_RGB + NEO_KHZ800);
Encoder encoder(ENCODER_PIN_1, ENCODER_PIN_2);
int mode = 0;
long lastPush = 0;
int autoPosition = 0;

void initializeToBlack() {
  for (int i = 0; i < NUM_LEDS; i++) {
    strip.setPixelColor(i, 0);
  }
}

void setup() {
  Serial.begin(9600);
  pinMode(ENCODER_BUTTON, INPUT_PULLUP); // Enable internal pull-up resistor
  strip.begin();
  initializeToBlack();
  strip.show();
}

long normalize(long value, long radix) {
  long rval = value % radix;
  return rval < 0 ? radix + rval : rval;
}

void loop() {
  int button = digitalRead(ENCODER_BUTTON);
  if (button == LOW) {
    if ((millis() - lastPush) > 250) {
      lastPush = millis();
      mode = (mode + 1) % 5; // Cycle through 5 modes
    }
  }
  
  long knobValue = encoder.read() / 2;
  long ledPosition = normalize(knobValue, NUM_LEDS);
  long colorValue = normalize(knobValue * 5, WHEEL_SIZE);
  long sleepValue = abs(knobValue) % 500;
  
  switch (mode) {
    case 0: // All LEDs off
      initializeToBlack();
      break;
    case 1: // Single LED moves with the rotary encoder
      initializeToBlack();
      strip.setPixelColor(ledPosition, colorWheel(BRIGHTNESS, colorValue));
      break;
    case 2: // All LEDs show the same color, changing with the rotary encoder
      for (int i = 0; i < NUM_LEDS; i++) {
        strip.setPixelColor(i, colorWheel(BRIGHTNESS, colorValue));
      }
      break;
    case 3: // One auto-moving light, speed controlled by the rotary encoder
      delay(sleepValue);
      initializeToBlack();
      strip.setPixelColor(autoPosition, colorWheel(BRIGHTNESS, autoPosition * (WHEEL_SIZE / NUM_LEDS)));
      autoPosition = (autoPosition + 1) % NUM_LEDS;
      break;
    case 4: // Auto-moving rainbow slug, speed controlled by the rotary encoder
      const int SLUG_SIZE = 15;
      delay(sleepValue);
      initializeToBlack();
      for (int i = 0; i < SLUG_SIZE; i++) {
        strip.setPixelColor((i + autoPosition) % NUM_LEDS, colorWheel(BRIGHTNESS, i * (WHEEL_SIZE / SLUG_SIZE)));
      }
      autoPosition = (autoPosition + 1) % NUM_LEDS;
      break;
  }
  strip.show();
}

// Function to return a color from the color wheel
uint32_t colorWheel(float intensity, byte wheelPos) {
  const int WHEEL_THIRD = (WHEEL_SIZE - 1) / 3;
  
  intensity = constrain(intensity, 0.0, 1.0);
  
  byte colorIndex = (wheelPos % WHEEL_THIRD) * 3;
  int fadeColor = (255 - colorIndex) * intensity;
  int increaseColor = colorIndex * intensity;
  
  switch (wheelPos / WHEEL_THIRD) {
    case 0: return strip.Color(fadeColor, 0, increaseColor);       // Red to Blue
    case 1: return strip.Color(0, increaseColor, fadeColor);       // Blue to Green
    case 2: return strip.Color(increaseColor, fadeColor, 0);       // Green to Red
  }
  return 0; // Fallback color (black)
}