#include <Arduino.h>

#define DS18B20_PIN 2  // Replace with the actual pin where your DS18B20 sensors are connected

void writeByte(uint8_t data) {
  for (int i = 0; i < 8; i++) {
    digitalWrite(DS18B20_PIN, LOW);
    delayMicroseconds(2);

    digitalWrite(DS18B20_PIN, data & 1 ? HIGH : LOW);
    delayMicroseconds(60);

    digitalWrite(DS18B20_PIN, HIGH);
    delayMicroseconds(2);

    data >>= 1;
  }
}

uint8_t readByte() {
  uint8_t data = 0;
  for (int i = 0; i < 8; i++) {
    digitalWrite(DS18B20_PIN, LOW);
    delayMicroseconds(2);

    digitalWrite(DS18B20_PIN, HIGH);
    delayMicroseconds(2);

    data |= digitalRead(DS18B20_PIN) << i;

    delayMicroseconds(60);
  }
  return data;
}

void readROM(uint8_t* romID) {
  writeByte(0x33);  // Read ROM command

  for (int i = 0; i < 8; i++) {
    romID[i] = readByte();
  }
}

void selectROM(const uint8_t* romID) {
  writeByte(0x55);  // Match ROM command

  for (int i = 0; i < 8; i++) {
    writeByte(romID[i]);
  }
}

float readTemperature() {
  digitalWrite(DS18B20_PIN, LOW);
  delayMicroseconds(500);

  digitalWrite(DS18B20_PIN, HIGH);
  delayMicroseconds(30);

  pinMode(DS18B20_PIN, INPUT);

  while (digitalRead(DS18B20_PIN) == LOW);

  delayMicroseconds(100);

  if (digitalRead(DS18B20_PIN) == LOW) {
    return -127.0; // Indicates a problem with communication
  }

  delayMicroseconds(100);

  writeByte(0xCC);  // Skip ROM
  writeByte(0x44);  // Convert T

  delay(750);  // Wait for conversion to complete (750ms for 12-bit resolution)

  digitalWrite(DS18B20_PIN, LOW);
  delayMicroseconds(2);

  digitalWrite(DS18B20_PIN, HIGH);
  delayMicroseconds(2);

  pinMode(DS18B20_PIN, INPUT);

  while (digitalRead(DS18B20_PIN) == LOW);

  delayMicroseconds(100);

  if (digitalRead(DS18B20_PIN) == LOW) {
    return -127.0; // Indicates a problem with communication
  }

  writeByte(0xCC);  // Skip ROM
  writeByte(0xBE);  // Read Scratchpad

  int16_t rawTemperature = readByte() | (readByte() << 8);

  // The DS18B20 returns the temperature in 1/16 degrees Celsius
  return static_cast<float>(rawTemperature) * 0.0625;
}

bool checkCRC(const uint8_t* data, int length) {
  uint8_t crc = 0;
  for (int i = 0; i < length; i++) {
    uint8_t inbyte = data[i];
    for (int j = 0; j < 8; j++) {
      uint8_t mix = (crc ^ inbyte) & 0x01;
      crc >>= 1;
      if (mix) {
        crc ^= 0x8C;
      }
      inbyte >>= 1;
    }
  }
  return (crc == 0);
}

void setup() {
  Serial.begin(9600);
}

void loop() {
  uint8_t romID1[8], romID2[8];
  float temperature1, temperature2;

  Serial.println("Reading IDs...");

  // Read the ROM IDs of the sensors
  readROM(romID1);
  readROM(romID2);

  // Check CRC for the ROM IDs
  if (!checkCRC(romID1, 8) || !checkCRC(romID2, 8)) {
    Serial.println("CRC check failed. Skipping reading temperatures.");
    delay(5000);
    return;
  }

  Serial.print("Sensor 1 ID: ");
  for (int i = 0; i < 8; i++) {
    Serial.print(romID1[i], HEX);
    Serial.print(" ");
  }
  Serial.println();

  Serial.print("Sensor 2 ID: ");
  for (int i = 0; i < 8; i++) {
    Serial.print(romID2[i], HEX);
    Serial.print(" ");
  }
  Serial.println();

  // Select and read temperature from Sensor 1
  Serial.println("Reading temperature from Sensor 1...");
  selectROM(romID1);
  temperature1 = readTemperature();

  // Select and read temperature from Sensor 2
  Serial.println("Reading temperature from Sensor 2...");
  selectROM(romID2);
  temperature2 = readTemperature();

  // Display the temperatures
  if (temperature1 != -127.0) {
    Serial.print("Temperature from Sensor 1: ");
    Serial.print(temperature1);
    Serial.println(" °C");
  } else {
    Serial.println("Error reading temperature from Sensor 1");
  }

  if (temperature2 != -127.0) {
    Serial.print("Temperature from Sensor 2: ");
    Serial.print(temperature2);
    Serial.println(" °C");
  } else {
    Serial.println("Error reading temperature from Sensor 2");
  }

  delay(5000);  // Delay before the next reading
}