#include <Adafruit_NeoPixel.h>

const byte pirPin = 13;
const byte ledPin = 15;
const byte ledNum = 16;

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(ledNum, ledPin, NEO_GRB + NEO_KHZ800);

void setup() {
  Serial.begin(115200);
  pinMode(pirPin, INPUT);
  pixels.begin();
  pixels.show();
}

void loop() {
  Serial.println(digitalRead(pirPin));
  if (digitalRead(pirPin)) {
    generateRandomPattern();
  };

  delay(50);
}

void generateRandomPattern() {
  byte pattern = random(1, 3);
  if (pattern == 1) {
    for (int i = 0; i < ledNum; i++) {
      byte red = random(0, 256);
      byte green = random(0, 256);
      byte blue = random(0, 256);
      pixels.setPixelColor(i, red, green, blue);
      pixels.show();
    }
  } else if (pattern == 2) {
    for (int c = 0; c <= 255; c++) {
      for (int i = 0; i < ledNum; i++) {
        pixels.setPixelColor(i, 0, c, c);
      }
      pixels.show();
      delay(10);
    }
    for (int c = 255; c >= 0; c--) {
      for (int i = 0; i < ledNum; i++) {
        pixels.setPixelColor(i, 0, c, c);
      }
      pixels.show();
      delay(10);
    }
  }
}