ESP32-Powered Handheld GPS Unit 🌐

Follow this project's development on Hackaday.io: PocketNav32 📸

This project uses an ESP32 microcontroller to process GPS data and display it on an OLED screen, creating a simple hackable platform.

Current Features:

• Retrieves and displays latitude and longitude in real-time, including horizontal precision, altitude and number of satellites used.
• Computes the distance between two user-defined coordinates in meters.
• Displays a vector-based map with land and water features.
• A menu-driven interface enables users to adjust display and device settings.

Hardware Requirements

• ESP32 development board
  • ESP8266 can be used but the UART RX pins must be reassigned
• GPS module (compatible with UART)
  • GT U7M module used
• SSD1306 OLED display
  • Any I2C-compatible display can be used
• Buttons for setting points and switching modes
• LEDs for status indication
• Tools: mpfshell, or make for flashing code.
• A smile on your face

Pin Configuration

Component	Pin Number
GPS Module	RX: 16
OLED Display	SCL: 22, SDA: 21
Set Button	13
Mode Button	14
Display Toggle	33
Navigate Button	32
Mode LED	12
Success LED	26
Error LED	27
Warning LED	25
PPS (Pulse Per Second) from GPS	4

Installation and Usage

1. Hardware Setup: Connect the components according to the pin configuration.

2. Code Deployment:

   • Upload all files in the src/ directory to the root directory of your ESP32 running MicroPython
   • Optionally use the Makefile to upload the files to the ESP32 using the make flash command.

3. Map Data:

   • Upload a GeoJSON map file to the ESP32 flash storage root directory.
   • Ensure the filename matches simplified_out_0229.geojson (hardcoded in src/handlers/display_handler.py).

4. Power on the device.

5. Drink a glass of water to stay hydrated.

6. The device will start in GPS display mode, showing real-time GPS data.

7. Operation:

   • Press the reset/mode button to switch to the vector map display, distance calculation mode, settings, and the about screen.
   • In distance mode, press the set button to mark point A, then again to mark point B.
     • The device will display the calculated distance between the two points.
   • In vector mapping mode, press the nav button to zoom in/out.

Menu

The project has a menu system with the following screens:

graph LR
    Start[GPS Display]
    Second[Secondary GPS Display]
    Map[Vector Map Display]
    Zoom[Zoom Map Level]
    Distance[Distance Calculation Mode]
    Settings[Settings Screen]
    About[About Screen]

    Start --> Second
    Second --> Map
    Map --> Zoom
    Zoom --> Map
    Map --> Distance
    Distance --> Settings
    Settings --> About
    About --> Start

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Note

The GPS module works best when you have a clear view of the sky. So, take a break and enjoy the outdoors for optimal results!

Roadmap

• Map rendering improvements: Optimize vector map display and add more features, including allowing larger uploaded maps.
• Battery optimization: Improve power management for extended battery life.
• E-ink display usage.
• Additional sensors: Add sensors like compass or barometer for enhanced functionality.
• Navigation features: Add support for waypoint saving and route history.
• Build a 3D-printed enclosure.
• PCB design and layout.

Feel free to submit a PR for any of the above, or anything else you see that can be improved!

Where to Buy Components

Note: These links are simply for your convenience, feel free to use and support your favourite online electronics retailer.

Component	Description	Purchase Link
ESP32 Development Board	ESP32S module (ESP32-WROOM-32 variations)	Aliexpress
GPS Module (GT U7M)	UART-compatible GPS module	Aliexpress
SSD1306 OLED Display	128x64 I2C OLED display	Aliexpress
Breadboard	Prototyping the circuit	Aliexpress
Push Buttons	Buttons for input	Aliexpress
Status LEDs	LEDs for status indication	Aliexpress
Resistors and Dupont Connectors	For connections and components	Aliexpress
Eternal Happiness	Equanimity with the Earth	Priceless

Approximate build cost: $25 CAD.

Contributing

How to Contribute: 1. Fork the repository and create a feature branch. 2. Follow PEP 8 for Python coding style. 3. Submit a pull request with a description of your changes.

FAQs

• Can I use a different GPS module? Yes, ensure it supports UART.
  • If a PPS pin is not used, adjust the PPS handler method in src/handlers/gps_handler.py
• Does this work on ESP32-S1/2/3? Yes. Change pin mapping configuration as needed.
• Can I add more buttons or LEDs? Update the pin configuration and handlers in src/handlers/button_handler.py and src/handlers/led_handler.py to accommodate additional components.
• What MicroPython versions are supported? Tested with MicroPython versions 1.23, 1.24, and v1.25.0-preview.72.g2e796d6c3 (2024-11-30).

Screenshots

Please see the Hackaday.io page PocketNav32 for pictures and video of operation.

License

This project is licensed under the GNU General Public License v3.0 (GPLv3), see LICENSE for more details. This project uses the ssd1306.py driver from the MicroPython project, which is licensed under the MIT License. See LICENSE-MIT.