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