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Redson Dev · Idea

IoTIntermediateAges 18+A weekend

Low-Cost Asset Tracker for Fleet Vehicles with GPS & SMS

Published July 13, 2026

This project enables small businesses to monitor their fleet vehicles without expensive subscriptions. You'll build a DIY GPS tracker that sends location updates via SMS, allowing real-time tracking of assets like delivery vans or service trucks. Imagine a local plumber in Phoenix tracking their service vehicles to optimize routes and respond faster to emergencies.

What you'll need

  • 1x ESP32 Development Board (e.g., ESP32-WROOM-32U)
  • 1x NEO-6M GPS Module
  • 1x SIM800L GPRS/GSM Module
  • 1x Micro SIM card (activated with SMS plan)
  • 1x Small project enclosure (weather-resistant if exposed)
  • 1x 3.7V LiPo battery (1000mAh or higher)
  • 1x USB to micro-USB cable
  • Jumper wires
  • Soldering iron and solder

Step-by-step

  1. 01

    Assemble Hardware Components

    Begin by connecting the NEO-6M GPS module to the ESP32. Typically, GPS TX connects to ESP32 RX2 (GPIO16) and GPS RX to ESP32 TX2 (GPIO17). Next, wire the SIM800L module: SIM800L TX to ESP32 RX (GPIO16) and SIM800L RX to ESP32 TX (GPIO17), ensuring power and ground connections are correct. Double-check all connections to prevent damage.

  2. 02

    Prepare SIM Card and Power

    Insert the activated micro SIM card into the SIM800L module. Connect the 3.7V LiPo battery to the SIM800L module's VIN and GND pins, ensuring proper polarity. Power the ESP32 via its micro-USB port from a computer or power bank. Confirm both modules receive power and show initial status lights.

  3. 03

    Set up ESP32 Development Environment

    Install the Arduino IDE if you haven't already. Add ESP32 board support via the 'Boards Manager' (search for 'ESP32'). Install necessary libraries: 'TinyGPSPlus' for GPS data parsing and 'Adafruit FONA' or a similar GSM library for SIM800L communication. These libraries simplify interaction with the modules.

  4. 04

    Flash Firmware and Test GPS/GSM

    Upload a basic sketch to the ESP32 that initializes both the GPS and GSM modules. The sketch should continuously read GPS data and periodically attempt to send an SMS with the current latitude and longitude. Use the Arduino Serial Monitor to debug and verify GPS fixes and successful SMS transmissions. You might need to adjust GSM baud rates (e.g., 9600).

  5. 05

    Refine Location Data Transmission

    Modify the sketch to include more robust error checking for both GPS and GSM. Implement a timer to send location updates every 5-10 minutes (or as desired). Consider adding a simple parsing function to format the SMS message cleanly, making it easy to read on a recipient's phone, perhaps including a link to Google Maps.

  6. 06

    Enclose and Deploy

    Once the system is stable, carefully place all components into your chosen project enclosure. Ensure the GPS and GSM antennas have clear lines of sight if possible. Secure the tracker within a vehicle, ensuring it's powered (e.g., via a USB car adapter or integrated into the vehicle's 12V system with appropriate voltage regulation) and protected from environmental elements.

Tips

  • For extended battery life, explore low-power modes for the ESP32 and SIM800L. Consider sending data less frequently.
  • Mount the GPS antenna with a clear view of the sky for faster and more accurate fixes.
  • Test SMS functionality thoroughly indoors and outdoors to ensure reliable network connection.
#gps-tracking#fleet-management#iot-device#sms-alerts#esp32-project
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