#include <Adafruit_NeoPixel.h>

const byte pir_pin = 15; 
const byte data_pin = 2;
const byte buzzer_pin = 13;
const byte led_num = 20;

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(led_num, data_pin, NEO_GRB + NEO_KHZ800);

void setup() {
  Serial.begin(115200);
  pinMode(pir_pin, INPUT);
  pinMode(buzzer_pin, OUTPUT);

  pixels.begin();
  pixels.show();
}

void loop() {
  if(digitalRead(pir_pin)) {
    for (int i = 0; i < 10; i++) {
      digitalWrite(buzzer_pin, HIGH);
      delay(10);
      digitalWrite(buzzer_pin, LOW);
      delay(10);
      generatePattern();
    }
  }
  delay(100);
}

void generatePattern() {
  for (int i = 0; i < led_num; i++) {
    pixels.setPixelColor(i, 255, 255, 255);
    pixels.show();
    delay(10);
  }
  for (int i = 0; i < led_num; i++) {
    pixels.setPixelColor(i, 0, 0, 0);
    delay(10);
    pixels.show();
  }
}