DHT 11/DHT22 Temp/Humidity Sensors

The DHT22 (also known as AM2302) is a more accurate and versatile temperature and humidity sensor compared to the DHT11, offering a wider temperature and humidity range, better accuracy, and a wider temperature range, but at a higher cost. 

DHT-11 comes in 3-pin and 4 pin versions

#include <DHT11.h>

#define DHT11_PIN 2

void setup(){

  Serial.begin(9600);

}

void loop(){

int chk DHT.read(DHT11_PIN);

Serial.println("temp:");

Serial.print(DHT.temperature);

Serial.print(" humi:");

Serial.println(DHT.humidity);

delay(1000);

}

#include <Wire.h>

#include <LiquidCrystal_I2C.h>// Liquid Crystal by Arduino, Adafruit

#include <DHT22.h> //DHT22 library by dvarrel

// Set the LCD address to 0x27 for a 16 chars and 2 line display

LiquidCrystal_I2C lcd(0x27, 16, 2);

//Connect to 5V, GND, SDA to A4 , SCL to A5

#define pinDATA 2

//Connect DHT22 to +5V, GND, and Data to Pin 2

DHT22 dht22(pinDATA); //define pin data

void setup()

{

 // Initialize the LCD

 lcd.begin();

 lcd.backlight();

 Serial.begin(9600); //1bit=10µs

 Serial.println("\ntest capteur DTH22");

}

void loop()

{

 float t = dht22.getTemperature();

 float h = dht22.getHumidity();

 if (dht22.getLastError() != dht22.OK) {

   Serial.print("last error :");

   Serial.println(dht22.getLastError());

 }

 Serial.print("h=");Serial.print(h,1);Serial.print("\t");

 Serial.print("t=");Serial.println(t,1);

 delay(2000); //Collecting period should be : >1.7 second

 lcd.clear();

 // Display humidity on line 0

 lcd.setCursor(0, 0);          // First row

 lcd.print("Humidity= ");

 lcd.print(h);

 // Display temperature on line 1

 lcd.setCursor(0, 1);          // Second row

 lcd.print("Temperature= ");

 lcd.print(t);

 delay(5000); // Wait 5 seconds

}