#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define NTC_SENSOR_PIN A0         // Analog pin connected to the NTC thermistor
#define FAN_PIN 9                  // Digital pin connected to the fan

#define VOLTAGE_SENSOR_PIN A1   // Analog pin for the voltage sensor
#define RELAY_PIN 2               // Digital pin connected to the relay

#define ACS712_PIN A2             // Analog pin for the ACS712 sensor
#define ACS712_ADDRESS 0x40       // Address of the ACS712 sensor

#define LCD_ADDRESS 0x27         // I2C address of the LCD
#define LCD_COLUMNS 20           // Number of columns in the LCD
#define LCD_ROWS 4               // Number of rows in the LCD

LiquidCrystal_I2C lcd(LCD_ADDRESS, LCD_COLUMNS, LCD_ROWS);

void setup() {
  Serial.begin(960);
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  //lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("      WELCOME");
  lcd.setCursor(0, 1);
  lcd.print("        To EV");
  lcd.setCursor(0, 2);
  lcd.print(   " Battery Management ");
  lcd.setCursor(0, 3);
  lcd.print("      system ");
  delay(2000);
  lcd.clear();
  
  // Set ACS712 pin as input
  pinMode(ACS712_PIN, INPUT);

  // Set voltage sensor pin and relay pin modes
  pinMode(VOLTAGE_SENSOR_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
  
  // Print initial messages on LCD
  lcd.setCursor(0, 0);
  lcd.print("Battery Voltage:");
  lcd.setCursor(0, 2);
  lcd.print("Temp:");
  
  // Set fan pin mode
  pinMode(FAN_PIN, OUTPUT);
}

void loop() {
  // Read the analog value from the NTC thermistor
  int sensorValueNTC = analogRead(NTC_SENSOR_PIN);

  // Convert the analog value to resistance
  float resistance = 10000.0 / ((1023.0 / sensorValueNTC) - 1.0); // Assuming a 10kΩ thermistor

  // Use the Steinhart-Hart equation to calculate temperature
  float steinhart;
  steinhart = log(resistance / 10000.0);  // (R/Ro)
  steinhart /= 3950.0;  // 1/B * ln(R/Ro)
  steinhart += 1.0 / (25.0 + 273.15);     // + (1/To)
  steinhart = 1.0 / steinhart;            // Invert
  steinhart -= 273.15;                    // Convert to Celsius

  // Print the temperature to the LCD display
  lcd.setCursor(0, 2);        // Set cursor to the third line
  lcd.print("Temperature: ");
  lcd.print(steinhart, 2);    // Print temperature value with two decimal places
  lcd.print(" C");            // Print unit

  // Print the temperature to the serial monitor
  Serial.print("Temp: ");
  Serial.print(steinhart);
  
  // Fan control based on temperature
  if (steinhart < 25) {
    analogWrite(FAN_PIN, 0); // Turn off fan
  } else if (steinhart >= 25 && steinhart < 30) {
    analogWrite(FAN_PIN, 128); // Set fan to half speed
  } else {
    analogWrite(FAN_PIN, 255); // Set fan to full speed
  }
  
  // Read the analog value from the voltage sensor
  int sensorValueVoltage = analogRead(VOLTAGE_SENSOR_PIN);

  // Convert the analog value to voltage (assuming 5V reference)
  float voltageBattery = (sensorValueVoltage / 1023.0) * 5.0;

  // Set threshold values for overflow and low battery
  float overflowThreshold = 14.0;    // Set your overflow threshold voltage here
  float lowBatteryThreshold = 10.0;  // Set your low battery threshold voltage here
  float Battery = (12.0, 13.0);  // Set your Normal battery  voltage here
  // Display voltage on LCD
  lcd.setCursor(0, 1);
  lcd.print("Voltage: ");
  lcd.print(voltageBattery , 2); // Print voltage
  lcd.print(" V");
  
  // Check for overflow condition
  if (voltageBattery > overflowThreshold) {
    // Overflow condition detected, turn off relay to stop charging
    digitalWrite(RELAY_PIN, LOW);
    lcd.setCursor(0, 0);
    lcd.print("Over Voltage    ");
  } else if (voltageBattery < lowBatteryThreshold) {
    // Low battery condition detected, turn on relay to start charging
    digitalWrite(RELAY_PIN, HIGH);
    lcd.setCursor(0, 0);
    lcd.print("Low Battery!    ");
  
  } else if (voltageBattery = Battery) {
    // Normal operation, relay remains in its current state
    lcd.setCursor(0, 0);
    lcd.print("Medium Level    ");

  } else {

  }

  //delay(1000); // Delay for stability

  // Read the analog value from the ACS712 sensor
  int sensorValueACS = analogRead(ACS712_PIN);

  // Convert the analog value to voltage
  float voltageCurrent = sensorValueACS * (5.0 / 1023.0);

  // Convert voltage to current using the ACS712 sensitivity (100mV/A)
  float current = voltageCurrent / 0.1; // 100mV per A

  // Display current on LCD
  //lcd.clear();
  lcd.setCursor(0, 3);
  lcd.print("Current: ");
  lcd.print(current, 2);
  lcd.print(" A");

  // Display current on Serial Monitor
  Serial.print("Current: ");
  Serial.print(current);
  Serial.println(" A");

  delay(1000); // Delay for stability
}