Integrating ESP32 with DHT11 for Firebase Integration

In modern IoT applications, monitoring environmental parameters like temperature and humidity is crucial for smart systems. The ESP32, a powerful microcontroller with built-in Wi-Fi capabilities, paired with the DHT11 sensor, enables efficient data collection. By integrating this setup with Firebase, a real-time database platform, data can be sent to the cloud for storage and visualization in real time.

Components Required:

ESP32 microcontroller
DHT11 temperature and humidity sensor
Jumper wires
Breadboard
USB cable for ESP32
Firebase account with a configured Realtime Database

Step 1: Setting Up Firebase

1. Create a Firebase Project:

Go to the Firebase Console.
Create a new project and add a Realtime Database.

2. Configure Database Rules:

Set the database rules for read and write as true for testing purposes (not recommended for production).

3. Generate Database URL:

Note the Firebase database URL (e.g., https://your-database-name.firebaseio.com).

Step 2: Connecting DHT11 to ESP32

Wiring Diagram:

Connect the DHT11 pins as follows:
VCC: 3.3V of ESP32
GND: GND of ESP32
DATA: GPIO pin (e.g., D4)

Step 3: Preparing the Software

1. Install Arduino IDE:

Download and install the Arduino IDE.

2. Install ESP32 Board Package:

Add the ESP32 board package URL in Arduino IDE preferences:

arduino

Copy code
https://dl.espressif.com/dl/package_esp32_index.json

Install the ESP32 board in the Board Manager.

3. Install Required Libraries:

Install the following libraries using the Arduino Library Manager:
DHT sensor library by Adafruit
Firebase ESP32 by Mobizt

Step 4: Writing the Code

Sample Code:

#include "DHT.h" 
#define DHTPIN 4 
#define DHTTYPE DHT11 
 
#include <Arduino.h> 
#if defined(ESP32) 
  #include <WiFi.h> 
#elif defined(ESP8266) 
  #include <ESP8266WiFi.h> 
#endif 
#include <Firebase_ESP_Client.h> 

DHT dht(DHTPIN, DHTTYPE); 

//Provide the token generation process info. 
#include "addons/TokenHelper.h" 

//Provide the RTDB payload printing info and other helper functions. 
#include "addons/RTDBHelper.h" 

// Insert your network credentials 
#define WIFI_SSID "YourWiFiSSID" 
#define WIFI_PASSWORD " YourWiFiPassword " 

// Insert Firebase project API Key 
#define API_KEY "Web_API_Key" 

// Insert RTDB URLefine the RTDB URL */ 
#define DATABASE_URL "reference URL"  

 //Define Firebase Data object 
FirebaseData fbdo; 
FirebaseAuth auth; 
FirebaseConfig config; 

//unsigned long sendDataPrevMillis = 0; 

//int count = 0; 
bool signupOK = false; 

void setup(){ 

  pinMode(DHTPIN, INPUT); 
  dht.begin(); 
  Serial.begin(115200); 
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD); 
  Serial.print("Connecting to Wi-Fi"); 
  while (WiFi.status() != WL_CONNECTED){ 
    Serial.print("."); 
    delay(300); 
  } 
  Serial.println(); 
  Serial.print("Connected with IP: "); 
  Serial.println(WiFi.localIP()); 
  Serial.println(); 

  /* Assign the api key (required) */ 
  config.api_key = API_KEY; 

   /* Assign the RTDB URL (required) */ 
  config.database_url = DATABASE_URL; 

  /* Sign up */ 
  if (Firebase.signUp(&config, &auth, "", "")){ 
    Serial.println("ok"); 
    signupOK = true; 
  } 

  else{ 
Serial.printf("%sn",config.signer.signupError.message.c_str()); 
  } 

  /* Assign the callback function for the long running token generation task */ 
  config.token_status_callback = tokenStatusCallback; //see addons/TokenHelper.h 

  Firebase.begin(&config, &auth); 

  Firebase.reconnectWiFi(true); 
} 

void loop(){ 
 delay(1000); 
  float h = dht.readHumidity(); 

  float t = dht.readTemperature(); 

  if (Firebase.ready() && signupOK ) { 

       if (Firebase.RTDB.setFloat(&fbdo, "DHT/humidity",h)){ 
       Serial.print("Humidity: "); 
       Serial.println(h);        

    } 

    else { 

      Serial.println("FAILED"); 

      Serial.println("REASON: " + fbdo.errorReason()); 

    } 

    // Write an Float number on the database path test/float 

    if (Firebase.RTDB.setFloat(&fbdo, "DHT/temperature", t)){ 

       Serial.print("Temperature: "); 

       Serial.println(t); 

    } 

    else { 

      Serial.println("FAILED"); 

      Serial.println("REASON: " + fbdo.errorReason()); 

    } 

  } 

  Serial.println("______________________________"); 

}

Step 5: Uploading the Code

Select the appropriate ESP32 board (e.g., “ESP32 Dev Module”) in the Arduino IDE.
Choose the correct COM port.
Upload the code to the ESP32.

Step 6: Testing the Integration

Open the Serial Monitor to check if the ESP32 is connecting to WiFi and Firebase successfully.
Verify data updates in the Firebase Realtime Database under the nodes /Temperature and /Humidity.

Conclusion

By following this guide, you have successfully integrated an ESP32 microcontroller with a DHT11 sensor and Firebase, enabling real-time monitoring of temperature and humidity data via the cloud.