Published February 4, 2021 © GPL3+

Basic setup for Arduino with Temp. & Humidity sensor

Most essential, yet very simple project using Temperature & Humidity sensor. This could be part of your Home Automation!

BeginnerProtip3,065

Basic setup for Arduino with Temp. & Humidity sensor

Things used in this project

Hardware components

Arduino UNO

Any type of Arduino can be used for this project.

DHT11 Temperature & Humidity Sensor (3 pins)

You can also use DTH22, don't forget to change the DHT type in code.

Breadboard (generic)

Jumper wires (generic)

USB-A to B Cable

Software apps and online services

Arduino IDE

Story

Connections

Connect Vcc Pin of T&H sensor to 5V on Arduino

Connect GND Pin of T&H sensor to GND on Arduino

Connect Data Pin of T&H sensor to D3 on Arduino

Note: The DHT11 Module has only 3 pins. In case you only have the DHT11 sensor and not the module, you'll notice it has 4 pins. They are as follows: Vcc, Data, NC, GND. Leave the connection for NC pin empty and connect a resistor of 5-10k between the Vcc and Data pin of the sensor. Connect the rest as mentioned above in points. Refer to Circuit diagram for more understanding.

Download the DHT sensor library and add this ZIP file in Include Library under Sketch in Arduino IDE.

Working

As the name suggests, the sensor is used to measure Temperature and Humidity. Humidity is the amount of water vapour in the air. Higher the amount of water vapour in air, higher the humidity.

By asking Google and referring to few webpages, I have come to an understanding that- the sensor is classified into Relative humidity sensor and Absolute humidity sensor based on the type of humidity. Measuring parameters further classifies this sensor as Capacitive humidity sensor, Resistive humidity sensor etc.,

Deep understanding of sensor and it's working is not necessary to complete this project. We are trying to keep this project very basic. We really encourage curious minds to explore more and we'd appreciate if you could share your knowledge in the comments below.

Now, let us see the circuit we put together

Connection as per circuit diagram

Output obtained on Serial Monitor

Code

Optimised Code for Arduino with DHT11 sensor

/* 
 * Credits to all sources on Google, acting as reference to this code below. This code is not 
 * TechValer's own creation. TechValer has referred to different projects and websites to 
 * find an easy code for beginners to get started with Temperature & Humidity sensor(DHT11/DHT22) 
 * and Arduino. TechValer does not claim this code to be its own. TechValer is greatly thankful 
 * for original creaters of this code and also all others who acted as reference. 
 */

/* 
 *  About TechValer
 *  
 *  What comes to mind when you think of tech...hmm, we're sure youre thinking of iPhone, 
 *  Alexa, Boston Dynamics robotic dog etc., at least thats what we would have thought of. 
 *  Our point here is, when you look inside this tech...you'll find weird boards with 
 *  components attached to it. This stuff is electronics and we at Techvaler deeply appreciate 
 *  this piece of tech. As the name suggests, we are Tech Enthusiasts who know the Worth and 
 *  Potential of these amazing tech stuff! So, check out our website techvaler.com and Youtube channel: "Techcafe" to find out 
 *  more.
 */

/* 
 *  Note: Any model of Arduino can be used for this project. Just keep in mind the digital pins.
 *  The readings available in the serial monitor are almost accurate.
 *  Refer to the documentation for better understanding of this particular code and project.
 */

/*
 * Thanks to Drona Automations Pvt.Ltd for Sponsoring this project!
 */

#include "DHT.h" //It is necessary for us to include this library when we use DHT11/DHT22 sensor
#define DHTPIN 3 // Defining the data output pin to Arduino
#define DHTTYPE DHT11 // Specify the sensor type(DHT11 or DHT22)

DHT dht(DHTPIN, DHTTYPE); //Declaration for varibles below...

void setup() {
  Serial.begin(9600); //To engage serial monitor
  dht.begin(); //To initialise DHT sensor
}

void loop() {
  delay(1000);
  //Here h= Humidity; tC= Temperature in degree C; tF= Temperature in degree F
  float h= dht.readHumidity();
  float tC= dht.readTemperature();
  float tF= dht.readTemperature(true);

  if (isnan(h) || isnan(tC) || isnan(tF)){
    Serial.println("Failed to read the DHT sensor. Check connections");
    }
  else{
    Serial.print("Humidity: ");
    Serial.print(h);
    Serial.print("%");
    Serial.print("  ||  ");
    Serial.print("Temperature: ");
    Serial.print(tC);
    Serial.print("C  ");
    Serial.print(tF);
    Serial.println("F");  
    }
}