#include <Wire.h>
#include <LiquidCrystal_I2C.h> 
#include <DHT.h>
#define DHT_PIN 6
#define DHT_TYPE DHT22
DHT dht(DHT_PIN, DHT_TYPE);

#define BTN_PIN 2
#define TRIG_PIN 3
#define ECHO_PIN 4
#define LED_PIN 8
#define BUZZER_PIN 7 


int btn_state;
float temperature;
float humidity;

LiquidCrystal_I2C lcd(0x27, 16, 2);

float measureDistance(){
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  long duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration*0.034/2;
  return distance;
}

void setup() {
  Serial.begin(115200);
  pinMode(BTN_PIN, INPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  dht.begin();
  lcd.init(); //initialize the lcd
  lcd.backlight(); //open the backlight 
}

void loop() {
  temperature = dht.readTemperature();
  humidity = dht.readHumidity();
  btn_state = digitalRead(BTN_PIN);
  if (btn_state == HIGH){
    float distance = measureDistance();
    lcd.clear();


    lcd.setCursor(0,0);
    lcd.print(distance);
    lcd.setCursor(13,0);
    lcd.print("cm.");
    lcd.setCursor(0,1);
    lcd.print(temperature);
    lcd.setCursor(6,1);
    lcd.print("C");
    lcd.setCursor(9,1);
    lcd.print(humidity);
    lcd.setCursor(15,1); 
    lcd.print("%");   
    digitalWrite(LED_PIN, HIGH);
    tone(BUZZER_PIN, 500);
    delay(500);
    noTone(BUZZER_PIN);
    delay(500);
    delay(250);
  }
  else{
    digitalWrite(LED_PIN, LOW);
  }
  
  delay(100);
}