DHT11 with ESP32 DevBoard

Introduction

This tutorial will guide you through interfacing a DHT11 temperature and humidity sensor with an ESP32 DevBoard. You’ll learn how to wire the sensor, install the necessary library, and upload test code to Arduino.

The DHT11 is a low-cost digital sensor for measuring temperature and humidity. When paired with an ESP32 DevBoard, it can feed real-time environmental data into your sensor projects. By the end of this tutorial, you’ll be able to:

• Read temperature (°C and °F) and humidity (%) from a DHT11 sensor
• Display readings via the Serial Monitor

Materials Needed

• ESP32 DevBoard
• DHT11 Sensor Module (with 3 pins: VCC, GND, Data)
• Male-to-Female Jumper Wires (3×)
• Computer with Arduino IDE installed

Wiring

We need to connect the DHT11 to the DevBoard, follow this wiring:

• DHT11 Vcc → 3V3
• DHT11 Ground → GND
• DHT11 Signal → GPIO21

As illustrated in this picture:

Your wiring should look like this:

NOTE: There are two different models of DHT11. Do not follow the wiring in the picture below

Connect ESP32 DevBoard

1. Open the Arduino IDE
2. Select the new port after you connect your computer to the ESP32 DevBoard
3. For your board, select “ESP32 Dev Module”
4. Now you are ready to upload your code!

Installing the DHT Library

But before we write and upload our code, we need to add a library

1. Go to Sketch → Include Library → Manage Libraries…
2. In the Library Manager, search for “DHT sensor library” by Adafruit
3. Click Install all

Code

Now, upload this code to Arduino

#include <DHT.h>
#define DHT_SENSOR_PIN  21 // ESP32 pin GPIO21 connected to DHT11 sensor
#define DHT_SENSOR_TYPE DHT11

DHT dht_sensor(DHT_SENSOR_PIN, DHT_SENSOR_TYPE);

void setup() {
  Serial.begin(9600);
  dht_sensor.begin(); // initialize the DHT sensor
}

void loop() {
  // read humidity
  float humi  = dht_sensor.readHumidity();
  // read temperature in Celsius
  float tempC = dht_sensor.readTemperature();
  // read temperature in Fahrenheit
  float tempF = dht_sensor.readTemperature(true);

  // check whether the reading is successful or not
  if ( isnan(tempC) || isnan(tempF) || isnan(humi)) {
    Serial.println("Failed to read from DHT sensor!");
  } else {
    Serial.print("Humidity: ");
    Serial.print(humi);
    Serial.print("%");

    Serial.print("  |  ");

    Serial.print("Temperature: ");
    Serial.print(tempC);
    Serial.print("°C  ~  ");
    Serial.print(tempF);
    Serial.println("°F");
  }

  // wait a 2 seconds between readings
  delay(2000);
}

Select tools, then click Serial Monitor. This is the format you should expect to see: