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

#define ACS712_PIN 34     // Current sensor pin
#define BUZZER_PIN 25     // Buzzer pin
#define POT_PIN 32        // Potentiometer pin (changed from 34 to avoid conflict)
#define ADC_VREF_mV 5000.0 // Voltage reference
#define ADC_RESOLUTION 4096.0 // 12-bit ADC
#define SENSITIVITY 125.0  // 125mV/A for ACS712-20A

LiquidCrystal_I2C lcd(0x27, 16, 2); // LCD 16x2

float voltage = 100.0;    // Measured voltage (80-120V)
float current = 0.0;      // Measured current
unsigned long lastUpdate = 0;
const long updateInterval = 200; // ms

void setup() {
  Serial.begin(115200);
  lcd.init();
  lcd.backlight();
  pinMode(ACS712_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  noTone(BUZZER_PIN);

  // Initial display setup
  lcd.setCursor(0, 0);
  lcd.print("V:       I:     ");
  lcd.setCursor(0, 1);
  lcd.print("Status: Normal  ");
}

void loop() {
  if (millis() - lastUpdate >= updateInterval) {
    lastUpdate = millis();
    
    // Read voltage (80-120V range)
    int potValue = analogRead(POT_PIN);
    voltage = (potValue / 4095.0) * 40.0 + 80.0;

    // Read current (-20A to +20A range)
    int adcValue = analogRead(ACS712_PIN);
    float voltage_mV = adcValue * (ADC_VREF_mV / ADC_RESOLUTION);
    current = ((voltage_mV - 2500) / 2500.0) * 40.0;

    // Update LCD display
    updateDisplay();
    
    // Check and handle alarms
    checkAlarms();

    // Serial monitor output
    Serial.print("Voltage: ");
    Serial.print(voltage, 2);
    Serial.print("V | Current: ");
    Serial.print(current, 2);
    Serial.println("A");
  }
}

void updateDisplay() {
  // Update voltage display (line 1, position 2-7)
  lcd.setCursor(2, 0);
  lcd.print(voltage, 2);
  lcd.print("V ");
  
  // Update current display (line 1, position 11-16)
  lcd.setCursor(11, 0);
  lcd.print(current, 2);
  lcd.print("A ");
}

void checkAlarms() {
  // Voltage alarms
  if (voltage < 100.0) {
    tone(BUZZER_PIN, 1000);
    lcd.setCursor(7, 1);
    lcd.print("LOW VOLTAGE! ");
  } 
  else if (voltage > 110.0) {
    tone(BUZZER_PIN, 1500);
    lcd.setCursor(7, 1);
    lcd.print("HIGH VOLTAGE!");
  }
  // Current alarm
  else if (abs(current) > 15.0) {
    tone(BUZZER_PIN, 2000);
    lcd.setCursor(7, 1);
    lcd.print("OVER CURRENT!");
  }
  // Normal state
  else {
    noTone(BUZZER_PIN);
    lcd.setCursor(7, 1);
    lcd.print("Normal      ");
  }
}