// Application to determine the condition of Room lighting

#define LDR_PIN_AO  A0

// Arduino ADC parameters
const float VREF = 5.0;
const float ADC_resolution = 10;

void setup() {
  Serial.begin(115200); // Configures baudrate of serial port as 115200
}

float get_ldr_voltage() {
  int analog_value = analogRead(LDR_PIN_AO); // Reads the analog value from pin
  // Voltage conversion formula
  float voltage = (analog_value / pow(2,ADC_resolution)) * VREF;
  return voltage;
}

void loop() {
  float voltage_val = get_ldr_voltage();
  Serial.print("Voltage : ");
  Serial.println(voltage_val);
  
  // Voltage value for office lighting is 1.37V and for Stairway lighting is 2.5V
  // Hence choosing a value of 2V between this range.
  // Any value greater than 2V can be assumed to be poor lighting.
  if (voltage_val > 2.0) {
    Serial.println("Poor room lighting !");
  } else {
    Serial.println("Good room lighting.");
  }
  delay(100);
}