Arduino Project

DHT-11 Module

Course Introduction

In this lesson, we will learn how to use the DHT-11 Module with Arduino.

Note

If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.

1.1 Install Arduino IDE(Important)
1.2 Introduction of Arduino IDE

Required Components

In this project, we need the following components:

SN

COMPONENT INTRODUCTION

QUANTITY

PURCHASE LINK

1

Arduino UNO R4 WIFI

1

BUY

2

USB Type-C cable

1

×

3

Breadboard

1

BUY

4

Wires

Several

BUY

5

DHT-11 Module

1

BUY

Wiring

15_DHT11_Module_bb.webp__PID:269d3e16-f41a-4d12-aa69-91d3d6406790

Common Connections:

DHT11 Humiture Sensor Module
DATA: Connect to 2 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.

Writing the Code

Note
You can copy this code into Arduino IDE.
To install the library, use the Arduino Library Manager and search for DHT and install it.
Don’t forget to select the board(Arduino UNO R4 WIFI) and the correct port before clicking the Upload button.


/*
  This code reads the temperature and humidity values from a DHT11 sensor
  connected to pin 2 and prints them to the serial monitor.
  It also calculates and prints the heat index value in both Celsius and Fahrenheit.

  Board: Arduino Uno R3 (or R4)
  Component: Temperature and humidity module(DHT11)
  Library: https://github.com/adafruit/DHT-sensor-library  (DHT sensor library by Adafruit)
*/

#include 

#define DHTPIN 2       // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11  // Define sensor type: DHT11

DHT dht(DHTPIN, DHTTYPE);  // Create a DHT sensor object

void setup() {
  Serial.begin(9600);      // Start serial communication at 9600 baud rate
  Serial.println(F("DHT11 test!"));

  dht.begin();             // Initialize the DHT sensor
}

void loop() {
  delay(500);  // Wait 500 ms before next reading

  // Read humidity value (%)
  float h = dht.readHumidity();

  // Read temperature value in Celsius (°C)
  float t = dht.readTemperature();

  // Read temperature value in Fahrenheit (°F)
  float f = dht.readTemperature(true);

  // Check if any reading failed
  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;                // Exit and try again
  }

  // Calculate heat index (feels-like temperature)
  float hif = dht.computeHeatIndex(f, h);        // In Fahrenheit
  float hic = dht.computeHeatIndex(t, h, false); // In Celsius

  // Output humidity and temperature to Serial Monitor
  Serial.print(F("Humidity: "));
  Serial.print(h);
  Serial.print(F("%  Temperature: "));
  Serial.print(t);
  Serial.println(F("°C"));
}