/*
 Voltaat learn (https://www.voltaat.com)
 Link for full tutorial:
 
 LiquidCrystal I2C Library: https://learn.voltaat.com/wp-content/uploads/2023/05/LCD_library.zip

 Tutorial: Build a motion detection system with Arduino

 The function of this code is to print the phrase "motion detected" on the crystal screen if there is movement,
 while if there is no motion, the screen shows the phrase "no motion detected", meaning no motion was detected.

 Connections from the Arduino to the breadboard:
 
 • Arduino 5v pin → breadboard 5v line
 • Arduino GND pin → breadboard GND line


 Connections from the PIR sensor:
 
 • PIR sensor GND pin → breadboard GND line
 • PIR sensor out pin → Arduino pin 3
 • PIR sensor VCC pin → breadboard 5v line


 Connections from the passive buzzer:

 • buzzer VCC pin (+ pin) → Arduino pin 12
 • buzzer GND pin (- pin) → breadboard GND line

 
 Connection from the LCD:

 • VCC pin → breadboard 5v line
 • GND pin→ breadboard GND line
 • SDA pin→ Arduino analog pin A4
 • SCL pin → Arduino analog pin A5
*/


#include "LiquidCrystal_I2C.h"
LiquidCrystal_I2C lcd(0x27, 16, 2);

int buzzerPin = 12;             // choose the pin for the buzzer
int inputPin = 3;               // choose the input pin (for PIR sensor)
int pirState = LOW;             // we start, assuming no motion detected
int val = 0;                    // variable for reading the pin status

void setup() {
 pinMode(buzzerPin, OUTPUT);      // declare buzzer pin as output
 pinMode(inputPin, INPUT);     // declare sensor as input
 digitalWrite(inputPin, LOW);     // declare sensor as input
 lcd.init();        
 lcd.backlight();
 lcd.clear();    // Clear what is displayed on the LCD
}

void loop(){
 
 val = digitalRead(inputPin);  // read input value
 
 if (val == HIGH)  // check if the input is HIGH
 {            
   digitalWrite(buzzerPin, HIGH);  // turn buzzer ON
 
   if (pirState == LOW)
 {

     lcd.setCursor(0,0);
     lcd.print("Motion detected!");
     lcd.setCursor(0,1);
     lcd.print("                          ");
     pirState = HIGH;
   }
 }
 else
 {
   digitalWrite(buzzerPin, LOW); // turn buzzer OFF
 
   if (pirState == HIGH)
 {
   
     lcd.setCursor(0,0);
     lcd.print("   No motion    ");
     lcd.setCursor(3,1);
     lcd.print("detected!");
     pirState = LOW;
   }
 }
}