Carved gourd/pumpkin flicker with an Arduino and NeoPixels.

gourd.ino

// A simple pumpkin/gourd flicker light
// Written by 2021 George White (stonehippo@gmail.com)
// This code is in the public domain
//
// I built this to power a little carved gourd for a company function.
// I ran it on an Adafruit Trinket 3.3V with two NeoPixels dots, but it
// should work on pretty much any Arduino-compatible board. The main
// thing you'd have to change it the PIXEL_PIN.

#define PIXEL_PIN 0
#define MAX       127

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(2, PIXEL_PIN, NEO_GRBW + NEO_KHZ800);

void setup() {
  pixels.begin();
  pixels.setBrightness(120);
}

void loop() {
  setEye(0);
  setEye(1);
  delay(random(80,150));
}

void setEye(int eye) {
   pixels.setPixelColor(eye, eyeColor());
   pixels.show();
}

uint32_t eyeColor() {
  int hue;
  // flip a coin on direction from pure red
  if (random(0,1) == 0) {
    hue = random(0,1000);
  } else {
    hue = random(64335,65335);
  }
  int sat = random(50,255);
  int value = random(25,127);
  return pixels.gamma32(pixels.ColorHSV(hue, sat, value));
}