05 Firebase Realtime Database + ESP32 | How to save sensor data & read data to control devices?

Introduction

In this tutorial, you will learn how to save and retrieve sensor data using the Firebase Realtime Database with the ESP32 microcontroller. This process allows you to control devices remotely by storing sensor data in the cloud and accessing it as needed. By following these steps, you can enhance your IoT projects with real-time data management.

Step 1: Gather Materials and Set Up the Circuit

Before starting, ensure you have the following materials:

• ESP32 development board
• Sensors (e.g., temperature, humidity)
• Jumper wires
• Breadboard (optional)
• Computer with Arduino IDE installed
• Firebase account

Circuit Connection

1. Connect the sensor to the ESP32 according to its specifications.
2. Use jumper wires to connect:
   • Sensor output to an appropriate GPIO pin on the ESP32
   • Power and ground connections as required by the sensor

Step 2: Understand Firebase

Firebase is a platform developed by Google for creating mobile and web applications. The Realtime Database is a cloud-hosted database that allows you to store and sync data in real-time.

Key Features of Firebase Realtime Database

• Data is stored as JSON.
• Real-time synchronization across all clients.
• Simple REST API for data requests.

Step 3: Create Firebase Realtime Database

1. Go to the Firebase console and create a new project.
2. In the project settings, navigate to the Realtime Database section.
3. Click on "Create Database" and select the appropriate rules for your application (start in test mode for development purposes).
4. Take note of your database URL and authentication details.

Step 4: Set Up Arduino Firebase ESP Client

1. Install the necessary libraries in the Arduino IDE:

   • Firebase ESP32 client library
   • ArduinoJson library

2. Include the libraries in your sketch:

   #include <FirebaseESP32.h>
   #include <ArduinoJson.h>
   

3. Initialize Firebase in your code:

   #define FIREBASE_HOST "your-database.firebaseio.com"
   #define FIREBASE_AUTH "your-database-secret"
   
   FirebaseData firebaseData;
   

Step 5: Save Sensor Data from ESP32 to Firebase

1. Read the sensor data in your loop function:

   float sensorValue = analogRead(sensorPin);
   

2. Push the data to Firebase:

   Firebase.setFloat(firebaseData, "/sensorData", sensorValue);
   

Practical Tips

• Ensure your ESP32 is connected to Wi-Fi before attempting to send data.
• Use error handling to catch any issues with data transmission.

Step 6: Read Data from Firebase RTDB to ESP32

1. To read data, use the following code snippet:

   if (Firebase.getFloat(firebaseData, "/sensorData")) {
       float receivedValue = firebaseData.floatData();
   }
   

2. Use the received data to control devices or display it on an LCD.

Step 7: Troubleshooting and Challenges

• If you encounter issues, check your Firebase rules and ensure the database URL is correct.
• Monitor the ESP32 serial output for error messages to identify problems.

Conclusion

You have now learned how to save and retrieve sensor data using the Firebase Realtime Database with the ESP32. This knowledge can be applied to various IoT projects, enabling real-time data monitoring and control. For further learning, consider exploring Firebase’s advanced features or integrating additional sensors into your project. Happy coding!