#include <Adafruit_Sensor.h>
#include <OneWire.h>      // For DS18B20 sensor
#include <DallasTemperature.h>
#include <Wire.h>

#define TEMP_THRESHOLD_LOW 25    // Lower temperature threshold for heater in °C
#define TEMP_THRESHOLD_HIGH 35   // Upper temperature threshold for heater in °C

#define DS18B20_PIN 4         // DS18B20 sensor pin (liquid temperature)
#define HEATER_PIN 14         // Heater control pin

float liquidTemperature = 0.0; // Liquid temperature from DS18B20

// Setup for DS18B20
OneWire oneWire(DS18B20_PIN);
DallasTemperature sensors(&oneWire);

bool heaterState = false; // Keeps track of the heater state

void setup() {
  Serial.begin(9600);
  
  // Initialize DS18B20 sensor
  sensors.begin();
  
  // Initialize output devices
  pinMode(HEATER_PIN, OUTPUT);

  // Turn off all output devices initially
  digitalWrite(HEATER_PIN, LOW);
}

void loop() {
  // Read liquid temperature from DS18B20
  sensors.requestTemperatures();
  liquidTemperature = sensors.getTempCByIndex(0); // Assuming one DS18B20 sensor

  // Control logic for heater
  controlHeater();
  
  // Print sensor readings and heater state
  Serial.print("Liquid Temperature: ");
  Serial.print(liquidTemperature);
  Serial.print(" °C | Heater State: ");
  Serial.println(heaterState ? "ON" : "OFF");
  
  delay(2000); // Adjust delay as per required sampling rate
}

void controlHeater() {
  if (liquidTemperature < TEMP_THRESHOLD_LOW && !heaterState) {
    digitalWrite(HEATER_PIN, HIGH); // Turn on the heater
    heaterState = true;
  } 
  else if (liquidTemperature > TEMP_THRESHOLD_HIGH && heaterState) {
    digitalWrite(HEATER_PIN, LOW); // Turn off the heater
    heaterState = false;
  }
}