FastLED - Burning Fuse effect

#include <FastLED.h>

#define LED_PIN 6
#define NUM_LEDS 60
#define LED_TYPE WS2812B
#define COLOR_ORDER GRB

CRGB leds[NUM_LEDS];

// Fuse simulation variables
int fusePosition = 0;          // Current position of the burning fuse
bool fuseActive = true;        // Whether the fuse is still burning
unsigned long lastUpdate = 0;  // Time tracking for animation
int fuseSpeed = 150;           // Milliseconds between each step (adjust for speed)

// Color definitions
CRGB fuseColor = CRGB::Orange;       // Active burning point
CRGB emberColor = CRGB::Red;         // Hot ember behind the fuse
CRGB coolEmberColor = CRGB(64, 16, 0); // Cooling ember
CRGB deadColor = CRGB::Black;        // Burned out section

void setup() {
  Serial.begin(9600);

  // Initialize FastLED
  FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
  FastLED.setBrightness(200);

  // Initialize all LEDs to represent an unlit fuse (dim yellow/brown)
  for(int i = 0; i < NUM_LEDS; i++) {
    leds[i] = CRGB(40, 25, 0); // Unlit fuse color
  }
  FastLED.show();

  Serial.println("Fuse burning simulation started!");
  Serial.println("Send 'r' to restart the fuse");
}

void loop() {
  // Check for serial input to restart
  if(Serial.available() > 0) {
    char input = Serial.read();
    if(input == 'r' || input == 'R') {
      restartFuse();
    }
  }

  // Update fuse animation
  if(fuseActive && millis() - lastUpdate >= fuseSpeed) {
    updateFuse();
    lastUpdate = millis();
  }

  // Add some flickering to the active burning point
  if(fuseActive && fusePosition < NUM_LEDS) {
    addFlicker();
  }

  FastLED.show();
  delay(20); // Small delay for smooth animation
}

void updateFuse() {
  if(fusePosition >= NUM_LEDS) {
    fuseActive = false;
    Serial.println("BOOM! Fuse has burned completely!");
    // Optional: Add explosion effect
    explosionEffect();
    return;
  }

  // Set the current burning position
  leds[fusePosition] = fuseColor;

  // Update the trail behind the fuse
  updateTrail();

  // Move to next position
  fusePosition++;

  Serial.print("Fuse burning at position: ");
  Serial.println(fusePosition);
}

void updateTrail() {
  // Update the burning trail behind the active fuse
  for(int i = 0; i < fusePosition; i++) {
    int distanceFromFuse = fusePosition - i;

    if(distanceFromFuse == 1) {
      // Hot ember right behind the fuse
      leds[i] = emberColor;
    }
    else if(distanceFromFuse <= 3) {
      // Cooling embers
      int brightness = map(distanceFromFuse, 2, 3, 128, 32);
      leds[i] = CRGB(brightness, brightness/4, 0);
    }
    else if(distanceFromFuse <= 6) {
      // Cool embers
      int brightness = map(distanceFromFuse, 4, 6, 32, 8);
      leds[i] = CRGB(brightness, brightness/8, 0);
    }
    else {
      // Completely burned out
      leds[i] = deadColor;
    }
  }
}

void addFlicker() {
  if(fusePosition < NUM_LEDS) {
    // Add random flickering to the burning point
    int flicker = random(-30, 30);
    CRGB flickerColor = fuseColor;

    flickerColor.r = constrain(flickerColor.r + flicker, 0, 255);
    flickerColor.g = constrain(flickerColor.g + flicker/2, 0, 255);
    flickerColor.b = constrain(flickerColor.b + flicker/4, 0, 255);

    leds[fusePosition] = flickerColor;

    // Occasionally spark ahead
    if(random(100) < 5 && fusePosition + 1 < NUM_LEDS) {
      leds[fusePosition + 1] = CRGB(255, 100, 0);
    }
  }
}

void explosionEffect() {
  // Simple explosion effect at the end
  for(int brightness = 0; brightness < 255; brightness += 10) {
    for(int i = 0; i < NUM_LEDS; i++) {
      // Distance-based explosion effect
      int distance = abs(i - (NUM_LEDS - 1));
      int explosionBrightness = max(0, brightness - (distance * 8));

      leds[i] = CRGB(explosionBrightness, explosionBrightness/2, 0);
    }
    FastLED.show();
    delay(30);
  }

  // Fade out
  for(int brightness = 255; brightness >= 0; brightness -= 5) {
    for(int i = 0; i < NUM_LEDS; i++) {
      leds[i].fadeToBlackBy(5);
    }
    FastLED.show();
    delay(20);
  }
}

void restartFuse() {
  Serial.println("Restarting fuse...");

  fusePosition = 0;
  fuseActive = true;
  lastUpdate = 0;

  // Reset all LEDs to unlit fuse
  for(int i = 0; i < NUM_LEDS; i++) {
    leds[i] = CRGB(40, 25, 0); // Unlit fuse color
  }

  FastLED.show();
}

// Alternative function: Reverse burning (from end to start)
void startReverseFuse() {
  fusePosition = NUM_LEDS - 1;
  fuseActive = true;
  fuseSpeed = -fuseSpeed; // Negative speed for reverse direction
}

// Alternative function: Random spark ignition
void randomSpark() {
  int sparkPos = random(NUM_LEDS);
  leds[sparkPos] = CRGB::White;
  FastLED.show();
  delay(100);
  leds[sparkPos] = CRGB(40, 25, 0);
}