#include <LiquidCrystal_I2C.h>
const float GAMMA = 0.7;
const float RL10 = 50;
LiquidCrystal_I2C lcd(0x27, 20, 4);

#include <Adafruit_NeoPixel.h>
#define Din_PIN 10
#define NUMPIXELS 16
Adafruit_NeoPixel pixels (NUMPIXELS, Din_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  lcd.init();
  lcd.backlight();
  pixels.begin();
  pixels.clear();
  pixels.show();
}

float lux ;

void check_light () {
  int analogValue = analogRead(A0);
  float voltage = analogValue / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
  lcd.setCursor(5, 0);
  if (lux > 50) lcd.print("Light!");
  else lcd.print("Dark  ");
  lcd.setCursor(0, 1);
  lcd.print(" Lux: ");
  lcd.print(lux);
  lcd.print("     ");
}

void on_leds ()
{
  pixels.clear();
  if (lux > 50)
  {
    for (int i = 0; i < NUMPIXELS; i++) {
      pixels.setPixelColor(i, pixels.Color(255, 255, 0));
    }
  }
  else {
    for (int i = 0; i < NUMPIXELS; i++) {
      pixels.setPixelColor(i, pixels.Color(255, 0, 255));
    }
  }
  pixels.show();
}
void loop() {
  check_light ();
  on_leds () ;
  delay(100);
}