Seeed studio GNSS

Open Source RaceBox Mini Emulator

Disclaimer: This project is independent and open-source. It is not affiliated with, endorsed by, or officially connected to RaceBox. The name “RaceBox Mini” is used only to describe compatibility.

Overview

This project provides firmware for an ESP32-based device that acts as a high-performance GPS/IMU Bluetooth Low Energy (BLE) broadcaster. It integrates a U-blox GNSS module for precise position, velocity, and timing data at 25Hz, along with an MPU6050 accelerometer and gyroscope for motion sensing.

The device is designed to be housed in a custom 3D-printed enclosure, with design files included in this repository.

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[!TIP] Other Hardware Options
Check Out The Mods Folder For Other Hardware Options. For new builds, check out the PCB version.

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Features

• High-Resolution GPS Data: Achieves 25Hz update rate using a U-blox GNSS module.
• Multi-Constellation Support: Leverages GPS, Galileo, GLONASS, and BeiDou for enhanced accuracy and reliability.
• Integrated IMU: Captures 3-axis accelerometer (±8g) and 3-axis gyroscope (±500 deg/s) data from the MPU6050.
• Real-time BLE Streaming: Transmits a custom 88-byte data packet containing comprehensive GNSS and IMU information over BLE.
• Automatic Configuration: Robust GPS initialization.
• Custom RaceBox Protocol: Data is encapsulated in a UBX-like custom protocol for efficient transmission.
• 3D Printable Enclosure: Includes design files for a compact and protective case.

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Bill of Materials (BOM)

To build this project, you'll need the following components:

• ESP32 Development Board: (https://a.co/d/fTThpTl)

• U-blox GNSS Module:

  • MG-902 - https://a.co/d/b6DcUS6
  • SAM-M10Q - https://a.co/d/54zrba3
  • MG-903 - https://a.co/d/fxp2tLk
  • HGLRC M100-5883 - https://a.co/d/47V0TqJ
  • AERO SELFIE M10G-5883L- https://a.co/d/cmYLjBP (Theoretically works but I dont have it)

  Any M10 based U-blox modules should work, the output rate may vary but you should be able to get 25hz with just GPS enabled. But YMMV.

• MPU6050 Accelerometer/Gyroscope Module: (https://a.co/d/dCMwffg or similar)

• 24AWG Hook-up Wire/Jumper Wires or just use the wiring that comes with GNSS module, its perfect for this application.

• M3x6 Screws (2)

• Soldering Iron & Solder

• USB-C or Micro-USB Cable (Depending on your ESP32 board, But USB-C all the things)

• 3D Printer & ABS Filament

The electronics should cost under 40$.

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Assembly Instructions

Wire the Components, load the firmware and test them outdoors.

ESP32 <--> U-blox GNSS Module:

• ESP32 GPIO 16 (RX2) <--> GNSS TX
• ESP32 GPIO 17 (TX2) <--> GNSS RX
• ESP32 5V or 3.3V <--> GNSS VCC (check voltage requirements)
• ESP32 GND <--> GNSS GND

ESP32 <--> MPU6050:

• ESP32 GPIO 21 (SDA) <--> MPU6050 SDA
• ESP32 GPIO 22 (SCL) <--> MPU6050 SCL
• ESP32 5V or 3.3V <--> MPU6050 VCC (check voltage requirements)
• ESP32 GND <--> MPU6050 GND

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Prepare the 3D Printed Case

• You shouldn't need any post processing of the printed parts but make sure the buttons slide smoothly in the holes in the lid

Enclose the Electronics

• Mount the MPU6050 module using M3 screws
• Place the ESP32 in the slot
• Route cables neatly
• Close the case carefully, it should click together. Make sure none of the wires are pinched or in the way of the buttons

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Firmware Setup and Upload

1. Install Arduino IDE

Download from the official Arduino website.

2. Install ESP32 Board Support

• Open Arduino IDE Preferences
• In “Additional Board Manager URLs” add:
  • https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json

3. Install Libraries:

• Go to Sketch > Include Library > Manage Libraries... and install the following:
  • Adafruit MPU6050
  • Adafruit Unified Sensor
  • SparkFun u-blox GNSS Arduino Library (ensure it's version 2)

4. Open the Sketch:

• Open the esp32_racebox_mini_emulator.ino in the Arduino IDE.
  • Configure Board Settings:
  • Go to Tools > Board and select your specific ESP32 board (e.g., "ESP32 Dev Module").
  • Ensure the correct Upload Speed and Port are selected.

5. Configure Firmware

• Update the GNSS constellations to use(lines 26-31).

  • For the SAM-M10Q module, I recommend using GPS and one local one, Galilieo should work great in most places. Selecting too many constellations can cause the update frequency to drop from 25Hz.
  • For the MG-902 module, you can select up to 4 constellations but it doesnt really make it more accurate than the SAM-M10Q module, but it doesnt appear to drop its frequency either, so might as well.

  https://app.qzss.go.jp/GNSSView/gnssview.html This could help you pick which constellations to pick.

• OPTIONAL – You may update the 10-digit number in the deviceName on line 33 to personalize your device.

  • ID Limit: If you intend to use this with the RaceBox App, The number must be less than 4000000000. The RaceBox app will not connect to devices with an ID of 4000000000 or higher.

  • Prefix Requirement: Make sure to keep the "RaceBox Mini " prefix unchanged—only change the numbers.

    ✅ Correct: String deviceName = "RaceBox Mini 3999999999";

    ❌ Incorrect (Prefix changed): String deviceName = "MY GPS 6942069420";

    ❌ Incorrect (Number too high): String deviceName = "RaceBox Mini 4000000000";

6. Upload the Firmware

• Click the Upload button (the right arrow icon) in the Arduino IDE to compile and upload the code to your ESP32.

  • If upload fails, try this sequence while the output shows "Connecting....":

    1. Hold the BOOT button
    2. Press and release the EN button
    3. Then release the BOOT button

• Open the Serial Monitor to verify startup. Initialization is complete when you see:

  BLE Packet Rate: 0.00 Hz | GNSS Update Rate: 25.00 Hz

  printed every 5 seconds.

3D Printed Enclosure

The repository includes *.3mf files for the custom 3D-printed enclosure designed specifically for the components in the BOM.

• 1x Base file.(either the GoPro mount version or the basic one to use with velcro)
• 1x Lid depending on the the type of GPS module you have.
• 2x Buttons (If you print a lid that supports buttons)
• 1x axdl_mount

Theres a Accelerometer blank included if you have a different accelerometer to create your own mount.

Recommended Print Settings:

• Material: ABS (for durability and heat resistance, especially if used in a car)
• Layer Height: 0.2mm
• Infill: 15-20% (for sufficient strength)
• Nozzle Temperature: (Refer to your filament manufacturer's recommendations)
• Bed Temperature: (Refer to your filament manufacturer's recommendations)

Usage

Once the firmware is uploaded and the device is powered on:

1. The ESP32 will start advertising a BLE service named "RaceBox Mini 0123456789"(the devicename you customized before uploading the firmware).
2. Use a compatible BLE client application to connect to the device.
   • Tested compatible apps, theoretically anything that supports a racebox mini should work.
     • Solostorm (Android)
     • RaceChrono (Android)
     • RaceChrono Pro (Android/iOS)
     • NMEAconnect (iOS)
     • AutoX DL(iOS)
     • Racebox App (Android/iOS)

Contribution

Feel free to open issues or submit pull requests if you have suggestions, improvements, or bug fixes.