About this project

The goal is to create a GPS tracking device, that is reliable and easy to use for many different situations.
This is a project for my university course "Internet of things".

Design & architecture

The device is based on the ESP32 platform, and utilizes a GSM module to send location data to the user. The device sends the coordinates of the GPS sensor via a GET request to a python HTTP server, which in turn uploads the coordinates to a MongoDB server. There is also a web app that uses HereMAPS api to display the coordinates from mongoDB in a map UI.

ΙοΤ architecture diagram :

What do you need (to build this for yourself)

Note : you can choose different components, this is just what we used to achieve the shown results.
a.Hardware components
- WEMOS-ESP32 ESP-WROOM-32 (it was chosen because it includes a pre-soldered battery slot)
- 18650 Li-Ion Battery (we chose a 2800mAh battery extracted from an old laptop battery pack)
- GSM SIM800L module
- Power switch for SIM800L module (optional)
- GPS Blox 6MV2 module
- A computer that has atleast 2 GB of RAM and 2 cpu cores, that runs Windows, Linux, MacOS or ChromeOS (for Arduino IDE)
- A computer capable of running linux Debian Buster or newer, MongoDB and python3 (again, 2GB ram and 2 cores should suffice)
b.Software components
- Arduino IDE https://www.arduino.cc/en/Guide
- ESP32 software for Arduino IDE (guide below)
- HereMAPS freemium developer account (for API key required in web app) https://developer.here.com/#
- Debian linux (Buster or newer) https://www.debian.org/
- MongoDB and pymongo driver (instructions below)
- Flask and python3 (instructions below)
- My SMS library for ESP32 (SMSmanager.h)
- My GPRS library for ESP32(NetworkManager.h)
- TinyGPS++ library written by Mikal Hart https://github.com/mikalhart/TinyGPSPlus

Hardware setup

Connection schematic :

IMPORTANT : Connect the GSM module (SIM800L) directly to the battery, NOT the 5V output of the microcontroller, because it needs a lot more power than ESP32 can provide.

It is recommended to use a power switch for the GSM module.

The above schematic is specific to my configuration, but in general in every microcontroller you want to connect the RX pin of the module to the TX pin of the microcontroller and vice versa (TX module pin to RX microcontroller pin).

Also make sure all modules share the same ground.

In my case, the microcontroller TX and RX pins for the GSM module are 16 and 17, and for the GPS module are 21 and 22, make sure you change them to match your configuration.

Images of the configuration we used :

Software setup

a.Setting up Arduino IDE
To program our ESP32 microcontroller we need Arduino IDE (you can use esp flashtool but it is much harder to use). To use Arduino IDE with your ESP32, you must download and install Espressif software and drivers.
- Follow this guide : https://randomnerdtutorials.com/installing-the-esp32-board-in-arduino-ide-windows-instructions/
to install the required software.

We used TTGO-LoRa-32 OLED V1 (in Arduino Board manager) which was the closest library to our board, change this to the board you are using.

After you successfuly set up your IDE, you are ready to compile the arduino project GPSTrackerMain, download the folder or clone the repo, then open GPSTrackerMain.ino .
- Change the host URL to the app server (instructions below how to set it up), change "internet.vodafone.gr" to the APN (access point name) of your network provider and change the pins for GSM and GPS modules (in Serial1 and Serial2 variables).
- After you compile, make sure you press and hold the "BOOT" button on your ESP board while uploading and release when upload has finished.

The ESP32 microcontroller we just programmed, will send location data to a web app which uses python and mongodb for backend and Flask for front end.

Note : the instructions below are for linux Debian Buster or newer

b1.Setting up backend

• Make sure python3 is installed on your system. Install it with :
  

sudo apt-get install python3

• Install mongodb from : https://docs.mongodb.com/manual/tutorial/install-mongodb-on-debian/
• Install pip with :

sudo apt-get install python3-pip

• Install pymongo with :

python3 -m pip install pymongo

After installing all of the above, you are ready to run the backend of the web app. navigate to the "backend" folder of the repo, then open a terminal and execute "GPS_server.py"

python3 GPS_server.py

You will see the message "HTTP server has started"
The server runs on port 8000 so you must forward that port in your router.

Portforwarding is necessary because the backend will be accessed from our ESP32 via GPRS.

You must look up how to port forward your own router model, since there are many different router firmwares and settings.
Your server should now be able to receive data from the ESP32.

b2.Setting up frontend
The frontend of the web app is fairly easy to run since it is contained in a python virtual environment.
To run :

• Install venv for python 3 with :

sudo pip3 install virtualenv 

• CD to the folder "frontend"
• Open the venv with :

source venv/bin/activate

• Finally, run the frontend with:

flask run

The frontend should now be available at localhost:5000
To access it, use a web browser and navigate to 127.0.0.1:5000

Make sure you do

systemctl start mongodb

to start the mongodb service, before you launch the frontend and backend

Making the app accessible from the Internet

Port forward the port you want to use for the web app in your router (for example 9000), then launch the app with

flask run -h 0.0.0.0 -p YOUR_PORT

Where YOUR_PORT is the port you forwarded.

You should now be able to access the app from the Internet.

Demonstration

In the ESP32 program, there is a demo function that can be activated by setting the macro "DEMO" to 1 The demo simulates a person walking accross Iera Odos, in Egaleo Greece.

Screenshot of ESP32 program running (Debugged with PC serial monitor) :
Screenshot of backend and frontend running on Debian :
Screenshot of application interface :
View location history:
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