#define PIN_RELAIS 3
#define PIN_LDR_DO 2
#define PIN_LDR_AO A0

// These constants should match the photoresistor's "gamma" and "rl10" attributes
const float GAMMA = 0.7;
const float RL10 = 50;
float analogLux;

void setup() {
  pinMode(PIN_RELAIS, OUTPUT);
  pinMode(PIN_LDR_DO, INPUT);
  pinMode(PIN_LDR_AO, INPUT);
  Serial.begin(115200);
}

void loop() {
  analogLux = leesLuxWaardeVanSensor ();
  stuurRelaisAanOpBasisVanLux();
}

void stuurRelaisAanOpBasisVanLux() {
  Serial.println(analogLux);
  if (analogLux > 100) {
    digitalWrite(PIN_RELAIS, HIGH);
  } else {
    digitalWrite(PIN_RELAIS, LOW);
  }
}


float leesLuxWaardeVanSensor () {
  // Convert the analog value into lux value:
  int analogValue = analogRead(PIN_LDR_AO);
  float voltage = analogValue / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
  return lux;
}