ESP32 DHT11 Temperature and Humidity Sensor

Code Examples

Below you can find code examples of DHT11 Temperature and Humidity Sensor with ESP32 in several frameworks:

• Arduino IDE
• ESP-IDF
• ESPHome
• PlatformIO
• MicroPython

ESP32 DHT11 Arduino IDE Code Example

Example in Arduino IDE

Fill in your main Arduino IDE sketch file with the following code to use the DHT11 Temperature and Humidity Sensor:

#include "DHT.h"

#define DHTPIN 4 // Digital pin connected to the DHT sensor
#define DHTTYPE DHT11 // DHT11 sensor type

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  Serial.println("DHT11 Sensor Initialization");
  dht.begin();
}

void loop() {
  delay(2000); // Wait a few seconds between measurements

  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");
}

This Arduino sketch interfaces with the DHT11 sensor to read temperature and humidity data. It utilizes the DHT library to communicate with the sensor. The setup() function initializes serial communication and the sensor. In the loop() function, it waits for 2 seconds between measurements, reads humidity and temperature, checks for successful readings, and then prints the values to the Serial Monitor.

Connect your ESP32 to your computer via a USB cable, Ensure the correct Board and Port are selected under Tools, Click the "Upload" button in the Arduino IDE to compile and upload the code to your ESP32.

ESP32 DHT11 ESP-IDF Code Example

Example in Espressif IoT Framework (ESP-IDF)

If you're using ESP-IDF to work with the DHT11 Temperature and Humidity Sensor, here's how you can set it up and read data from the sensor. Fill in this code in the main ESP-IDF file:

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"

#define DHT11_PIN GPIO_NUM_4

void dht11_task(void *pvParameter) {
    // DHT11 reading logic here
    while (1) {
        // Read temperature and humidity
        // Print values
        vTaskDelay(2000 / portTICK_PERIOD_MS); // Delay for 2 seconds
    }
}

void app_main() {
    xTaskCreate(&dht11_task, "dht11_task", 2048, NULL, 5, NULL);
}

This ESP-IDF code sets up a FreeRTOS task to read data from the DHT11 sensor connected to GPIO 4. The dht11_task function contains the logic to read temperature and humidity from the sensor and print the values. The task runs in an infinite loop with a 2-second delay between readings. The app_main function creates this task with a stack size of 2048 bytes and a priority of 5.

Update the I2C pins (I2C_MASTER_SDA_IO and I2C_MASTER_SCL_IO) to match your ESP32 hardware setup, Use idf.py build to compile the project, Use idf.py flash to upload the code to your ESP32.

ESP32 DHT11 ESPHome Code Example

Example in ESPHome (Home Assistant)

Fill in this configuration in your ESPHome YAML configuration file (example.yml) to integrate the DHT11 Temperature and Humidity Sensor

sensor:
  - platform: dht
    model: DHT11
    pin: GPIO4
    temperature:
      name: "Living Room Temperature"
    humidity:
      name: "Living Room Humidity"
    update_interval: 60s

This ESPHome configuration specifies the dht platform and sets the model to DHT11 for correct handling of the sensor. The pin key defines the GPIO pin (e.g., GPIO4) to which the sensor's data pin is connected. The temperature and humidity keys define the sensor outputs, giving user-friendly names like 'Living Room Temperature' and 'Living Room Humidity.' The update_interval is set to 60 seconds, which means the ESP32 will read and update the sensor data every 60 seconds.

Upload this code to your ESP32 using the ESPHome dashboard or the esphome run command.

ESP32 DHT11 PlatformIO Code Example

Example in PlatformIO Framework

For PlatformIO, make sure to configure the platformio.ini file with the appropriate environment and libraries, and then proceed with the code.

Configure platformio.ini

First, your platformio.ini should look like below. You might need to include some libraries as shown. Make sure to change the board to your ESP32:

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
lib_deps = 
    adafruit/DHT sensor library @ ^1.4.3
    adafruit/Adafruit Unified Sensor @ ^1.1.6
monitor_speed = 115200

ESP32 DHT11 PlatformIO Example Code

Write this code in your PlatformIO project under the src/main.cpp file to use the DHT11 Temperature and Humidity Sensor:

#include <Adafruit_Sensor.h>
#include <DHT.h>
#include <DHT_U.h>

#define DHTPIN 4 // Define the GPIO pin for the data pin
#define DHTTYPE DHT11 // Specify the DHT model

DHT dht(DHTPIN, DHTTYPE);

void setup() {
    Serial.begin(115200);
    Serial.println("DHT11 Sensor Example");

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

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

    // Check if any readings failed
    if (isnan(temperature) || isnan(humidity)) {
        Serial.println("Failed to read from DHT sensor!");
        return;
    }

    // Print results to Serial Monitor
    Serial.print("Temperature: ");
    Serial.print(temperature);
    Serial.println(" °C");

    Serial.print("Humidity: ");
    Serial.print(humidity);
    Serial.println(" %");

    delay(2000); // Wait before next reading
}

The platform = espressif32 specifies that the project is for ESP32 boards, and board = esp32dev sets the specific development board being used. The lib_deps field includes the required libraries for the DHT11 sensor (DHT sensor library and Adafruit Unified Sensor), ensuring compatibility. The code defines the GPIO pin (e.g., GPIO4) for the sensor’s data line and initializes the DHT11 sensor using the DHT library. Temperature and humidity readings are printed to the Serial Monitor every 2 seconds, with error handling to check for invalid readings.

Upload the code to your ESP32 using the PlatformIO "Upload" button in your IDE or the pio run --target upload command.

ESP32 DHT11 MicroPython Code Example

Example in Micro Python Framework

Fill in this script in your MicroPython main.py file (main.py) to integrate the DHT11 Temperature and Humidity Sensor with your ESP32.

from machine import Pin
from time import sleep
import dht

# Initialize the DHT11 sensor on GPIO4
dht_sensor = dht.DHT11(Pin(4))

print("DHT11 Sensor Example")

while True:
    try:
        # Measure temperature and humidity
        dht_sensor.measure()
        temperature = dht_sensor.temperature()  # Temperature in Celsius
        humidity = dht_sensor.humidity()  # Relative Humidity in %

        # Print temperature and humidity to the console
        print("Temperature: {:.1f} °C".format(temperature))
        print("Humidity: {:.1f} %".format(humidity))
    except OSError as e:
        print("Failed to read sensor.")

    # Delay between readings
    sleep(2)

The dht module simplifies interactions with the DHT11 sensor, handling initialization and data retrieval. The sensor is initialized with the GPIO pin (e.g., GPIO4), and a confirmation message is printed to indicate successful setup. Inside an infinite loop, the script continuously reads the temperature (in Celsius) and relative humidity (in percentage) using the measure() method. The readings are formatted and printed to the console. Error handling with try and except ensures the program can recover from sensor read failures. A 2-second delay between readings ensures manageable updates.

Upload this code to your ESP32 using a MicroPython-compatible IDE, such as Thonny, uPyCraft, or tools like ampy.