Connect-ESP32-to-Firebase-via-GSM

Connect ESP32+GSM (Sim800l) to Google Firebase to send sensor data.

Background

As Firebase only accepts HTTPS requests, it becomes a bit difficult to send sensor data to the Real-time Database with an ESP32 and a GSM Module. I did not find any resource for this when I was doing my project, so I am keeping this here for anyone who needs it in the future.

Hardware used

In this project, I develop an IoT application capable of sending data to the Firbase Real-Time database using GPRS and receiving the sent data using a Python script. We utilize the following components:

LILYGO TTGO-TCALL ESP32+ Sim800L: An excellent IOT module that utilizes ESP32 and SIM800L.The ESP32 has built-in capabilities of WiFI and Bluetooth.

Further Requirements -

Create an account on Firebase for data collection.
Create an account on any website hosting service. We used 000WebHost a free web server, for hosting our PHP script along with the libraries.

Instructions

Libraries used:

TinyGSM: it's a simple library that works well with SIM800L

Steps:

Firstly, Add Project on Firebase and give a suitable name to it and Create Project.
Navigate to Project Overview and click Realtime Database. Then Create Database, select a preferable location for your database (doesn’t matter really) and enable Test mode.
Copy and save the database link (in a format: https://xxxxx-xxxx-xxxx-xxxx.firebaseio.com/)
Proceed onto the Project Settings and under Service Accounts click Database secrets show and copy the API KEY. This is required for authentication in sending and extracting the data.
Create an account on Website hosting platform. After signing up and setting a website, go to the folder public.html in the File manager and upload the files from the PHP server folder. This creates a PHP server that accepts an HTTP POST request and sends the data to Firebase.

NOTE: Do not upload the folder, just the files inside it.
Make the necessary changes in the upload.php file to add the details of the database link (DEFAULT_URL)and the API key (DEFAULT_TOKEN). Also, keep in mind the structure of the database the $DEFAULT PATH defines the variable under which the database will record the value. You can add additional paths by adding /<variable_name>.
Create an Arduino script and copy the provided code. Do not forget to add the necessary details as indicated in the script.
Flash the code and run it, you will see an 8 on your real-time database.
You can additionally run the python script on a local machine to extract the data.

Additional Instructions

This will cover the use of Python script to extract the data from the database for processing. The library in use is a Python interface to the Firebase’s REST API.

Install the required library.

pip install python-firebase

Go to your project >>> click on the icon "</>" with the tag add firebase to your web app
Copy the information of the form :

 var firebaseConfig = {
    apiKey: "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    authDomain: "xxxxx-xxxx.firebaseapp.com",
    databaseURL: "https://xxxxx-xxxxx-xxxxx-xxxxx.firebaseio.com",
    projectId: "xxxx-xxxx",
    storageBucket: "xxxx-xxxx.appspot.com",
    messagingSenderId: "xxxxxxxxxxxxxx",
    appId: "1:xxxxxxxxxxxx:web:xxxxxxxxxxxxxxxxx",
    measurementId: "xxxxxxxxxxxxxxxx"
  };

Then copy this relevent information to the python script as indicated in the script.
Once you extract the data you can convert it to the required data type/ structure to perform your analysis.
Additionally you can review this discussion on stackoverflow to understand the method.

Credits:

Madhav Rawal
Aryaman Patel

anoopjayaram / Connect-ESP32-to-Firebase-via-GSM