/*
  Photoresistor (LDR) Analog Demo
  Serial Monitor Version
*/

#define LDR_PIN 2

// LDR Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;

void setup() {
  pinMode(LDR_PIN, INPUT);

  Serial.begin(9600);
}

void loop() {
  int analogValue = analogRead(A0);
  float voltage = analogValue / 1024.0 * 5.0;
  float resistance = 2000.0 * voltage / (1.0 - voltage / 5.0);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1.0 / GAMMA));

  Serial.print("Room: ");
  if (lux > 50) {
    Serial.print("Light!");
  } else {
    Serial.print("Dark");
  }

  Serial.print(" | Lux: ");
  Serial.println(lux);

  delay(100);
}