#define DO_SENSOR_PIN 34  // Analog pin connected to DO sensor AOUT
#define RELAY_PIN 14      // Digital pin connected to air pump relay

// Calibration constants (adjust based on your sensor and calibration results)
#define VREF 3.3           // ESP32 ADC reference voltage
#define ADC_RESOLUTION 4095 // 12-bit ADC resolution
#define DO_SCALING_FACTOR 0.1 // Voltage-to-DO conversion factor (in mg/L per V)

// Thresholds for DO levels (adjust based on algae requirements)
#define DO_LOW_THRESHOLD 5.0  // Minimum DO level (mg/L)
#define DO_HIGH_THRESHOLD 8.0 // Maximum DO level (mg/L)

void setup() {
  Serial.begin(115200); // Initialize serial communication
  analogReadResolution(12); // Set ADC resolution to 12-bit

  pinMode(RELAY_PIN, OUTPUT); // Set relay pin as output
  digitalWrite(RELAY_PIN, LOW); // Ensure air pump is OFF initially

  Serial.println("Dissolved Oxygen Sensor with Air Pump Control Initialized");
}

void loop() {
  int adcValue = analogRead(DO_SENSOR_PIN); // Read raw ADC value
  float sensorVoltage = adcValue * (VREF / ADC_RESOLUTION); // Convert to voltage

  // Calculate dissolved oxygen in mg/L
  float dissolvedOxygen = calculateDissolvedOxygen(sensorVoltage);

  // Print sensor readings
  Serial.print("Sensor Voltage: ");
  Serial.print(sensorVoltage);
  Serial.print(" V | Dissolved Oxygen: ");
  Serial.print(dissolvedOxygen);
  Serial.println(" mg/L");

  // Control air pump based on DO levels
  controlAirPump(dissolvedOxygen);

  delay(2000); // Adjust delay as needed
}

// Function to calculate dissolved oxygen from voltage
float calculateDissolvedOxygen(float voltage) {
  return voltage / DO_SCALING_FACTOR; // Adjust scaling factor based on calibration
}

// Function to control the air pump based on DO levels
void controlAirPump(float doLevel) {
  if (doLevel < DO_LOW_THRESHOLD) {
    digitalWrite(RELAY_PIN, HIGH); // Turn ON air pump
    Serial.println("Air Pump ON: Increasing DO Levels...");
  } else if (doLevel > DO_HIGH_THRESHOLD) {
    digitalWrite(RELAY_PIN, LOW); // Turn OFF air pump
    Serial.println("Air Pump OFF: DO Levels Sufficient.");
  }
}