#include <LiquidCrystal.h>
#include <OneWire.h>
#include <DallasTemperature.h>

// LCD Connections (4-bit mode)
LiquidCrystal lcd(7, 8, 9, 10, 11, 12); // RS, EN, D4, D5, D6, D7

// Temperature Sensor
#define ONE_WIRE_BUS 2
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

// Analog Pins
const int voltagePin = A0;
const int currentPin = A1;
const int frequencyPin = 3;

// Calibration Constants (Adjust during calibration)
const float VOLTAGE_CALIBRATION = 100;    // For 220V AC
const float CURRENT_CALIBRATION = 50;    // For 30A SCT-013
const float VREF = 5.0;                    // Arduino reference voltage
const int ADC_RESOLUTION = 1023;           // 10-bit ADC

// Measurement Variables
float voltage = 0;
float current = 0;
float power = 0;
float energy = 0;
float frequency = 0;
float temperature = 0;

// Timing Variables
unsigned long lastUpdate = 0;
volatile unsigned long zeroCrossCount = 0;
volatile unsigned long lastZeroCrossTime = 0;
volatile unsigned long currentZeroCrossTime = 0;
volatile bool newZeroCross = false;

void setup() {
  lcd.begin(20, 4);  // Configure for 20x4 character display
  sensors.begin();
  Serial.begin(9600);
  
  // Set up zero-crossing detection interrupt on pin 3
  pinMode(3, INPUT_PULLUP);  // Enable pull-up resistor for better signal
  attachInterrupt(digitalPinToInterrupt(3), zeroCrossISR, RISING);
  
  // Initial display
  lcd.print("220V Power Monitor");
  delay(2000);
  lcd.clear();
  
  // Initialize timing variables
  lastZeroCrossTime = micros();
}

void loop() {
  // Update frequency whenever a new zero-cross is detected
  if (newZeroCross) {
    noInterrupts();
    unsigned long period = currentZeroCrossTime - lastZeroCrossTime;
    newZeroCross = false;
    interrupts();
    
    if (period > 0) {
      frequency = 1000000.0 / period;  // Convert microseconds to Hz
      lastZeroCrossTime = currentZeroCrossTime;
    }
  }
  
  if (millis() - lastUpdate >= 1000) { // Update every second
    measureACVoltage();
    measureCurrent();
    calculatePower();
    calculateEnergy();
    measureTemperature();
    
    updateDisplay();
    
    // Debug output
    Serial.print("Frequency: ");
    Serial.print(frequency, 1);
    Serial.println(" Hz");
    
    lastUpdate = millis();
  }
}

void measureACVoltage() {
  float sum = 0;
  for (int i = 0; i < 500; i++) {
    float sensorValue = analogRead(voltagePin);
    float voltageInstant = (sensorValue - 512) * (VREF / ADC_RESOLUTION);
    sum += sq(voltageInstant);
    delayMicroseconds(200);
  }
  voltage = sqrt(sum / 500) * VOLTAGE_CALIBRATION;
}

void measureCurrent() {
  float sum = 0;
  for (int i = 0; i < 500; i++) {
    float sensorValue = analogRead(currentPin);
    float currentInstant = (sensorValue - 512) * (VREF / ADC_RESOLUTION);
    sum += sq(currentInstant);
    delayMicroseconds(200);
  }
  current = sqrt(sum / 500) * CURRENT_CALIBRATION;
}

void calculatePower() {
  power = voltage * current; // Assuming unity power factor
}

void calculateEnergy() {
  energy += power / 3600.0; // Watt-seconds to Watt-hours
}

void measureTemperature() {
  sensors.requestTemperatures();
  temperature = sensors.getTempCByIndex(0);
}

void zeroCrossISR() {
  // Record time of zero-cross in microseconds
  currentZeroCrossTime = micros();
  newZeroCross = true;
}

void updateDisplay() {
  lcd.clear();
  
  // Line 1: Voltage and Current
  lcd.setCursor(0, 0);
  lcd.print("V:");
  lcd.print(voltage, 1);
  lcd.print("V I:");
  lcd.print(current, 2);
  lcd.print("A");

  // Line 2: Power and Energy
  lcd.setCursor(0, 1);
  lcd.print("Power:");
  lcd.print(power, 1);
  lcd.print("W");
  lcd.setCursor(0, 2);
  lcd.print("Energy:");
  lcd.print(energy, 2);
  lcd.print("Wh");

  // Line 3: Frequency and Temperature
  lcd.setCursor(0, 3);
  lcd.print("Frequency:");
  if (frequency >= 45 && frequency <= 65) {  // Valid frequency range
    lcd.print(frequency, 1);
  } else {
    lcd.print("---Hz");  // Display dashes if frequency is invalid
  }
  //lcd.print("Hz T:");
  //lcd.print(temperature, 1);
  //lcd.write(223); // Degree symbol
  //lcd.print("C");
}