// Source: chapter_03.OMeter.ino
// Description: This program controls the blinking LEDs based on temperature readings from a sensor.
// Programmed by: Douglas Ferreira / February 05, 2024

const int tempSensorPin = A0; 
const float baseTemperature = 20.0; 

void setup() {
  Serial.begin(9600); // Start serial communication at 9600 bps
  // Initialize LED pins as outputs and set them to LOW (off)
  for (int ledPin = 2; ledPin < 5; ledPin++) {
    pinMode(ledPin, OUTPUT);
    digitalWrite(ledPin, LOW);
  }
}

void loop() {
  // Read the value from the temperature sensor
  int sensorValue = analogRead(tempSensorPin);
  Serial.print("Sensor Value: ");
  Serial.print(sensorValue);
  
  // Convert the ADC reading to voltage
  float voltage = (sensorValue / 1024.0) * 5.0;
  Serial.print(", Volts: ");
  Serial.print(voltage);
  
  // Convert the voltage to temperature in degrees Celsius
  float temperatureC = (voltage - 0.5) * 100;
  Serial.print(", degrees C: ");
  Serial.println(temperatureC);
  
  // Control LED states based on temperature readings
  if (temperatureC < baseTemperature) {
    // If temperature is below the baseline, turn all LEDs off
    digitalWrite(2, LOW);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
  } else if (temperatureC >= baseTemperature + 2 && temperatureC < baseTemperature + 4) {
    // Turn on the first LED if temperature is in the first range above the baseline
    digitalWrite(2, HIGH);
    digitalWrite(3, LOW);
    digitalWrite(4, LOW);
  } else if (temperatureC >= baseTemperature + 4 && temperatureC < baseTemperature + 6) {
    // Turn on the first two LEDs if temperature is in the second range above the baseline
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, LOW);
  } else if (temperatureC >= baseTemperature + 6) {
    // Turn on all LEDs if temperature is above the second range
    digitalWrite(2, HIGH);
    digitalWrite(3, HIGH);
    digitalWrite(4, HIGH);
  }
  
  delay(1);
}