Temperature Humidity Sensor DHT 11

Getting Started with DHT Sensors and Arduino

The DHT sensor family (DHT11, DHT22, etc.) are popular choices for measuring temperature and humidity in Arduino projects. These sensors are low-cost, easy to use, and provide reliable readings for a variety of applications. This tutorial will guide you through connecting a DHT sensor to your Arduino and reading the temperature and humidity data.

About DHT11 Temperature and Humidity Sensor

• Operating Voltage: 3 to 5V
• Temperature Range: 0°C to 50°C
• Temperature Accuracy: ±2°C
• Humidity Range: 20% to 80%
• Humidity Accuracy: 5%
• Reading Rate: 1Hz (once every second)

About DHT22 Temperature and Humidity Sensor

• Operating Voltage: 3 to 5V
• Temperature Range: -40°C to 80°C
• Temperature Accuracy: ±0.5°C
• Humidity Range: 0% to 100%
• Humidity Accuracy: ±2% to 5%
• Reading Rate: 0.5 Hz (once every 2 seconds)

• Identify the pins on your DHT sensor. Typically, there will be four pins: VCC (power), GND (ground), DATA (data signal), and NC (no connect).
• Connect the VCC pin of the DHT sensor to the 5V pin on your Arduino.
• Connect the GND pin of the DHT sensor to the GND pin on your Arduino.
• Connect the DATA pin of the DHT sensor to a digital pin on your Arduino. For this tutorial, we’ll use pin 2.

//Libraries
#include <dht.h>
dht DHT;
//Constants
#define DHT11_PIN 2     // or DHT 22  and pin number

//Variables
float hum;  //Stores humidity value
float temp; //Stores temperature value

void setup()
{
    Serial.begin(9600);
}

void loop()
{
    int chk = DHT.read11(DHT11_PIN);
    //Read data and store it to variables hum and temp
    hum = DHT.humidity;
    temp= DHT.temperature;
    //Print temp and humidity values to serial monitor
    Serial.print("Humidity: ");
    Serial.print(hum);
    Serial.print(" %, Temp: ");
    Serial.print(temp);
    Serial.println(" Celsius");
    delay(2000); //Delay 2 sec.
}

View sensor readings:

• Open the Arduino IDE serial monitor (Tools > Serial Monitor).
• You should see the temperature and humidity readings displayed every 2 seconds.