#include <Servo.h>
#include <LiquidCrystal_I2C.h>

const int pirPin = 2;
const int trigPin = 11; 
const int echoPin = 12; 
const int ledPin = 6; 
const int buttonPin = 4; 
const int buzzerPin = 5; 
Servo servo; 
LiquidCrystal_I2C lcd(0x27, 16, 2); 

int systemActive = 0; 
long duration, distance;
int pirState = LOW;
int buttonState = 0;
int lastButtonState = 0;

const int distanceLimit = 30; 

void setup() {
  pinMode(pirPin, INPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(buzzerPin, OUTPUT);
  
  servo.attach(3); 
  lcd.begin(16, 2); 
  lcd.setBacklight(LOW);
  servo.write(90); 
  
  digitalWrite(ledPin, LOW);
  lcd.print("Sistema Desativado");
}

void loop() {
  pirState = digitalRead(pirPin);
  
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration / 2) / 29.1; 
  
  buttonState = digitalRead(buttonPin);
  if (buttonState != lastButtonState) {
    if (buttonState == LOW) {
      systemActive = !systemActive; 
      if (systemActive) {
        digitalWrite(ledPin, HIGH); 
        lcd.clear();
        lcd.print("Sistema Ativado");
        lcd.setBacklight(HIGH); 
      } else {
        digitalWrite(ledPin, LOW); 
        lcd.clear();
        lcd.print("Sistema Desativado");
        lcd.setBacklight(LOW); 
        digitalWrite(buzzerPin, LOW); 
        servo.write(90); 
      }
    }
  }
  lastButtonState = buttonState;

  if (systemActive == 1 && pirState == HIGH) {
    if (distance < distanceLimit) { 
      digitalWrite(buzzerPin, HIGH); 
      servo.write(0); 
      lcd.clear();
      lcd.print("Alerta! Distancia:");
      lcd.setCursor(0, 1);
      lcd.print(distance);
      lcd.print(" cm");
    } else { 
      digitalWrite(buzzerPin, LOW); 
      servo.write(90); 
      lcd.clear();
      lcd.print("Distancia:");
      lcd.setCursor(0, 1);
      lcd.print(distance);
      lcd.print(" cm");
    }
  }
  delay(500); 
}