Temperature and Humidity with DHT11

1#include <LiquidCrystal_I2C.h>
2#include <Wire.h> 
3#include <DHT.h>
4
5#define DHTPIN 3
6#define DHTTYPE DHT11
7
8LiquidCrystal_I2C lcd(0x27, 16, 2);
9DHT dht(DHTPIN, DHTTYPE); 
10
11void setup() {
12  dht.begin();
13  lcd.init();      // Modern libraries prefer init() over begin()
14  lcd.backlight();
15}
16 
17void loop() {
18  int humidity = dht.readHumidity();
19  float temperature = dht.readTemperature();
20
21  // Check if readings failed
22  if (isnan(humidity) || isnan(temperature)) {
23    lcd.setCursor(0, 0);
24    lcd.print("Sensor Error!   ");
25    return;
26  }
27
28  lcd.setCursor(0, 0);
29  lcd.print("Temp: ");
30  lcd.print(temperature);
31  lcd.print((char)223); // Degree symbol (°)
32  lcd.print("C   ");
33
34  lcd.setCursor(0, 1);
35  lcd.print("Humidity: %");      
36  lcd.print(humidity);
37  lcd.print("   "); // Trailing spaces to clear old data
38  
39  delay(2000); // DHT11 is slow, 2 seconds is more stable
40}