ESP32 Using DHT11 Temperature & Humidity Sensor - Lesson 7 – Zaitronics

Table of Contents

In this lesson you will learn how to use the DHT11 sensor with your ESP32. The DHT11 can measure temperature and humidity, and you can display the readings in the Serial Monitor or on an OLED display.

What you will learn

How the DHT11 sensor works
How to wire the DHT11 to the ESP32
How to install the DHT library
How to read temperature and humidity using code
How to display readings on the Serial Monitor

Components needed

Get All the Parts You Need

This tutorial is part of our comprehensive ESP32 learning series. Instead of buying components individually, save time and money with our ESP32 Basic Starter Kit. It includes everything you need for this lesson and 20+ other projects.

What's Included: ESP32 board, OLED display, sensors (DHT11, PIR, LDR), relay module, buzzers, LEDs, buttons, breadboard, resistors, and all cables, plus access to our complete lesson plans.

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Step 1 - Understanding the DHT11

The DHT11 is a digital sensor that can measure temperature and humidity. It has three main pins: VCC, GND, and DATA. The DATA pin sends the sensor readings to the ESP32.

Step 2 - Wiring the DHT11

Place the DHT11 on the breadboard
Connect the VCC pin to 3.3 V on the ESP32
Connect the GND pin to GND on the ESP32
Connect the DATA pin to GPIO 5 on the ESP32

DHT11 ESP32 wiring diagram

Step 3 - Installing the DHT Library

Within the Arduino IDE, click Sketch
Click Include Library
Click Manage Libraries
In the Library Manager search box, search DHT sensor library
Under DHT sensor library by Adafruit click Install

Step 4 - Writing the Code to Read the DHT11

Open the Arduino IDE and enter the following code. This reads the temperature and humidity and prints it to the Serial Monitor. Once entered, upload the code.

#include "DHT.h"
#define DHTPIN 5      // GPIO pin connected to the DHT11
#define DHTTYPE DHT11 // DHT 11 sensor

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  dht.begin();
}

void loop() {
  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();

  if (isnan(humidity) || isnan(temperature)) {
    Serial.println("Failed to read from DHT sensor");
    return;
  }

  Serial.print("Humidity: ");
  Serial.print(humidity);
  Serial.print("%  Temperature: ");
  Serial.print(temperature);
  Serial.println("°C");

  delay(2000);
}

How the Code Works

This program reads temperature and humidity from the DHT11 sensor and prints it to the Serial Monitor.

#include "DHT.h"
Imports the DHT sensor library so the ESP32 can communicate with the sensor.

#define DHTPIN 5
Specifies GPIO 5 for the DHT11 data pin.

#define DHTTYPE DHT11
Specifies the sensor model as DHT11.

DHT dht(DHTPIN, DHTTYPE);
Creates a DHT sensor object that will read temperature and humidity.

void setup()
Runs once when the ESP32 starts.
Serial.begin(115200);
Starts serial communication to view readings.
dht.begin();
Initializes the DHT11 sensor.

void loop()

Runs continuously after setup.

dht.readHumidity() reads relative humidity
dht.readTemperature() reads temperature in °C
Checks if readings are valid using isnan() and prints an error if not
Serial.print() and Serial.println() output the readings to the Serial Monitor
delay(2000) waits 2 seconds before repeating for stable readings

Step 5 - Expected Result

Open the Serial Monitor in Arduino IDE
Set the baud rate to 115200
Humidity and temperature values should update every two seconds
If it shows “Failed to read from DHT sensor,” check wiring

Optional Challenge

Try simulating a weather monitor by adding a few LEDs that are triggered at certain temperature or humidity levels.

ESP32 Lessons

ESP32 Tutorials Hub
Lesson 1: ESP32 Setup using Arduino IDE
Lesson 2: ESP32 Libraries and Using the Serial Monitor
Lesson 3: LED Blink
Lesson 4: Passive Buzzer
Lesson 5: Reading a Photosensitive Resistor (LDR)
Lesson 6: Using a Push Button with ESP32
Lesson 7: Using DHT11 Temperature & Humidity Sensor
Lesson 8: ESP32 Detecting Motion With HC-SR501 PIR Sensor

Lesson Complete

You have successfully read temperature and humidity from the DHT11 using your ESP32. Next lesson: How to use the PIR motion sensor (HC-SR501) to detect movement.

ESP32 Using DHT11 Temperature & Humidity Sensor - Lesson 7