The TrackFox is an autonomous GPS tracker. The main goals of the project were the following:
- Design a portable device with credit card format, which can be easily integrated in various assets (car, bike, hiking backpack, etc...).
- Embed an accelerometer to detect start and stop events autonomously.
- Achieve the minimum power consumption.
- Use battery-less energy harvesting such as solar panel or dynamo source with supercapacitor.
- Send data over long range IoT networks such as Sigfox.
The boards were designed on Circuit Maker V1.3. Below is the list of hardware revisions:
| Hardware revision | Description | Status |
|---|---|---|
| TKFX HW1.0 | Initial version. | ❌ |
| TKFX HW1.1 | Connect S2LP shutdown pin to MCU to fix startup issues. No more connection from RF TCXO to MCU. |
✅ |
As of version sw0.0.9 the embedded software is developed under Eclipse IDE version 2024-09 (4.33.0) and GNU MCU plugin. The script folder contains Eclipse run/debug configuration files and JLink scripts to flash the MCU.
Warning
To compile any version under sw4.0, the git_version.sh script must be patched when sscanf function is called: the SW prefix must be replaced by sw since Git tags have been renamed in this way.
The TrackFox boards are based on the STM32L041K6U6 microcontroller of the STMicroelectronics L0 family. Each hardware revision has a corresponding build configuration in the Eclipse project, which sets up the code for the selected board version.
The project is organized as follow:
startup: MCU startup code (from ARM).linker: MCU linker script (from ARM).drivers:registers: MCU registers address definition.peripherals: internal MCU peripherals drivers.components: external components drivers.utils: utility functions.
middleware:analog: High level analog measurements driver.cli: AT commands implementation.gps: High level GPS driver.power: Board power tree manager.sigfox: Sigfox EP_LIB and ADDON_RFP submodules and low level implementation.
application: Main application.
Sigfox technology is very well suited for this application for 3 main reasons:
- Data quantity is low, position and monitoring data can be packaged on a few bytes and does not require high speed transmission.
- Low power communication enable energy harvesting (solar cell + supercap in this case), so that the device is autonomous.
- The tracker can operate is very isolated places (mountains, etc...) thanks to the long range performance.
The project is based on the Sigfox end-point open source library which is embedded as a Git submodule.