Build a Smart GPS Tracker with Seeed XIAO ESP32-S3
GPS trackers are incredibly useful for monitoring assets, vehicles, pets, or even loved ones. But many DIY implementations rely on expensive cellular modules and data plans — until now. In this project, we’ll walk through building a fully functional GPS tracker that uses Wi-Fi instead of GSM, includes geofencing, and even sends SMS alerts when your device leaves a defined area — all without a SIM card.
This version uses the small but powerful Seeed Studio XIAO ESP32-S3 microcontroller together with a Neo-6M GPS module. By integrating with the free GeoLinker cloud platform, the tracker sends its GPS coordinates over Wi-Fi so you can visualize locations on a map and handle advanced features like geofence crossings.
What You’ll Build
Your GPS tracker will:
- Read GPS coordinates using an external GPS module.
- Connect to Wi-Fi and send location data to the cloud.
- Display movement history on an interactive map.
- Detect geofence breaches and trigger an alert.
- Send SMS notifications when boundaries are crossed.
How It Works
Here’s a simplified overview of the system:
GPS Collection: The Neo-6M module captures satellite signals and outputs latitude/longitude.
Processing: The ESP32-S3 reads GPS data via UART at 9600 baud.
Cloud Upload: Coordinates are sent to GeoLinker over Wi-Fi at set intervals (e.g., every 15 seconds).
Mapping & History: GeoLinker stores each point with a timestamp and plots them on a map.
Geofencing: The tracker uses the Haversine formula to measure distance from a set “home” coordinate.
SMS Alerts: If the device leaves the defined radius, an SMS is automatically triggered.
Offline Buffering: Lost Wi-Fi? Data is temporarily stored and synced once reconnected.
This setup provides a reliable tracker with features typically found in commercial IoT solutions — but at a fraction of the cost and complexity.
Step-by-Step Assembly
Wiring
- GPS VCC → XIAO 5V
- GPS GND → XIAO GND
- GPS TX → XIAO GPIO44 (RX)
- GPS RX → XIAO GPIO43 (TX)
Add an external GPS antenna to the Neo-6M for better signal.
Simple serial wiring enables the GPS module to stream NMEA data to the ESP32 continuously.
GeoLinker Cloud Setup
GeoLinker provides the backend that:
- Stores incoming GPS data
- Renders it visually on a map
- Handles SMS alerts via a cloud API
To set this up:
- Create an account on the GeoLinker platform.
- Generate your unique API key.
- Link a mobile number for SMS alerts.
The free tier offers enough data points and SMS capacity for most hobbyist projects.
Code Highlights
Your Arduino sketch will:
Initialize GPS serial and Wi-Fi.
- Set up GeoLinker with your API key and device ID.
- Upload data in timed intervals.
- Compute geofence distance using the Haversine formula.
- Send SMS when the device moves outside the preset radius.
You can further customize:
- Update intervals (more frequent updates for finer tracking)
- Geofence radius (from meters to kilometers)
- Multiple geofences
- Speed or battery alerts
Real-World Testing
In practical tests, the tracker:
- Connected to a phone hotspot via Wi-Fi
- Continued local GPS buffering when Wi-Fi dropped
- Synced stored points once reconnected
- Sent SMS notifications as expected when the geofence was breached
The result is a consistent and fault-tolerant tracker suitable for many real use cases.
Where You Can Use It
- Fleet & vehicle tracking
- Asset security
- Child or elderly location alerts
- Pet monitoring
Any mobile object that needs safe-zone notifications
Conclusion
This GPS Tracker with Seeed Studio XIAO ESP32-S3 project shows how Wi-Fi-based GPS tracking can replace more expensive cellular alternatives, adding powerful features like geofencing and SMS alerts. Using a compact board like the XIAO ESP32-S3 and free tools like GeoLinker makes it accessible to makers, students, and hobbyists alike.
Ready to prototype? Jump into the code and circuit, and make your own smart tracker today!
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