How to use-DTH22 Sensor

Humidity and Temperature

The DHT-22 (also named as AM2302) is a digital-output relative humidity and temperature sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air, and spits out a digital signal on the data pin.
In this tutorial you will learn how to use this sensor with Arduino uno. The room temperature & humidity will be printed to serial monitor.

About the  DHT-22 sensor

The DHT22 is a basic, low-cost digital temperature and humidity sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air, and spits out a digital signal on the data pin (no analog input pins needed).
Connections are simple, the first pin on the left to 3-5V power, the second pin to your data input pin and the right most pin to ground.

Technical details: Power: 3-5V Max Current: 2.5mA Humidity: 0-100%, 2-5% accuracy Temperature: -40 to 80°C, ±0.5°C accuracy

What you will need - Hardware

For this tutorial you will need: Arduino uno Breadboard DHT-22

The Circuit

The connections are pretty easy, see the image above with breadboard circuit schematic.

The code ::

Here's the code,

*************************************************************************************

/* How to use the DHT-22 sensor with Arduino uno

   Temperature and humidity sensor

 */

//Libraries

#include "dht.h";

//Constants

dht DHT;

const int dhtPin = 2; //Data pin of DHT-22 to Arduino digital pin 2

//Variables

int chk;

float hum;  //Stores humidity value

float temp; //Stores temperature value

void setup()

{

    Serial.begin(9600);

}

void loop()

{

chk = DHT.read22(dhtPin); //Check data pin and read values

    //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.

}

  

*************************************************************************************

Well done!

You have successfully completed one more Arduino "How to" tutorial and you learned how to use the DHT-22 sensor.
I hope you liked this, let me know in the comments.

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