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

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

// Pins
#define RELAY_PIN 14     // Relay module input pin
#define BUZZER_PIN 27    // Buzzer pin
#define SENSOR_PIN 34    // Potentiometer simulating current sensor

// Constants
float voltage = 220.0;     // Assume fixed mains voltage
float energy = 0.0;        // Energy in Wh
unsigned long lastMillis = 0;
float threshold = 50.0;    // Current threshold for alert (adjust as needed)

void setup() {
  Serial.begin(115200);
  
  lcd.init();
  lcd.backlight();
  
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, LOW);   // Relay OFF initially
  
  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(BUZZER_PIN, LOW);  // Buzzer OFF
  
  lcd.setCursor(0,0);
  lcd.print("Smart Monitor");
  delay(2000);
  lcd.clear();
}

void loop() {
  // Read sensor (0–4095 ADC → 0–5 A example scaling)
  int adcVal = analogRead(SENSOR_PIN);
  float current = (adcVal / 4095.0) * 5.0;  // 0–5 A range
  
  // Calculate power
  float power = voltage * current;  // Watts
  
  // Update energy every second
  unsigned long now = millis();
  if (now - lastMillis >= 1000) {
    energy += power / 3600.0;  // Convert W → Wh per second
    lastMillis = now;
  }

  // Display on LCD
  lcd.setCursor(0,0);
  lcd.print("I:");
  lcd.print(current,2);
  lcd.print("A ");
  lcd.print("P:");
  lcd.print(power,0);
  lcd.print("W ");

  lcd.setCursor(0,1);
  lcd.print("E:");
  lcd.print(energy,2);
  lcd.print("Wh ");

  // Control relay + buzzer
  if (current > threshold/100.0) {  // Example: >0.5A if threshold=50
    digitalWrite(RELAY_PIN, HIGH);   // Turn ON relay
    
    // --- BUZZER ALERT ---
    tone(BUZZER_PIN, 1000); // 1kHz sound
    delay(200);             // short beep
    noTone(BUZZER_PIN);     // stop
  } else {
    digitalWrite(RELAY_PIN, LOW);    // Relay OFF
    noTone(BUZZER_PIN);              // Make sure buzzer is OFF
  }

  delay(500);
}