#include <Adafruit_NeoPixel.h>

#define LED_PIN    5       // Data pin
#define LED_COUNT  20      // Number of LEDs

Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);

// Function to get rainbow color
uint32_t wheel(byte pos) {
  if(pos < 85) {
    return strip.Color(pos * 3, 255 - pos * 3, 0);
  } 
  else if(pos < 170) {
    pos -= 85;
    return strip.Color(255 - pos * 3, 0, pos * 3);
  } 
  else {
    pos -= 170;
    return strip.Color(0, pos * 3, 255 - pos * 3);
  }
}

void setup() {
  strip.begin();
  strip.show();  
}

void loop() {
  int pos = random(0, 255);           // pick random rainbow color
  int led = random(0, LED_COUNT);     // pick random LED

  strip.clear();
  strip.setPixelColor(led, wheel(pos));  // set random rainbow LED
  strip.show();

  delay(random(10, 30));              // fast strobe speed (10–30ms)
}