Software Sensor

• For hardware design see: https://github.com/larus-breeze/hw_sensor

Facts

• STM32CubeIDE
• STM32F407VG
• FreeRTOS
• IMU
• GNSS
• Static pressure
• Differential pressure
• CAN interface
• Bluetooth via HM19 (HW-1.0) ESP32 (HW-2.0)
• RS232 NMEA output channels

How to use it

Some usefull git commands to work with this repository and the included submodule command line:

Clone via https:

git clone --recurse-submodules https://github.com/larus-breeze/sw_sensor

Clone via ssh:

git clone --recurse-submodules git@github.com:larus-breeze/sw_sensor.git

Switch to a branch:

git checkout branch_name --recurse-submodules

Pull latest changes:

git pull --recurse-submodules  

STM32 Build Configurations

• Release used for release versions (Max. optimized, no debug info)
• Debug used for development

Flash and prepare the sensor hardware

STM32

• Flash via USB using the STM32CubeProgrammer and a compiled binary sw_sensor.elf file from here: https://github.com/larus-breeze/sw_sensor/releases
  Hold the Boot Button on power-on to start the STM32 in the DFU bootloader mode. Use the STM32CubeProgrammer to flash the binary to the STM32 micro-controller.

ESP32 controller

• Flash the *.ino file in ESP32_Firmware with arduino studio via the esp32 usb connector.
• Optionally: Use the arduino IDE to change the device name and the RF mode (Bluetooth or WLAN).

Prepare an sd-card with configuration files

• put a sensor_config.txt file (template in configuration/) in the sd cards root directory. Adjust the parameters as described in configuration/README.md Initially the heading may be inaccurate as the magnetic calibration algorithm needs some time in the air to find the exact calibration. A 30 minutes flight with some right and left turns should be sufficient to calibrate the compass module.
• Optionally: Create a directory with the name "logger" to enable logging of all measurement data with 100Hz
• Optionally: Create a directory with the name "magnetic" to enable the logging of magnetic calibration events. There should be a few of these events during the calibration process. If you observe frequent additional events you probabely have moving ferromagnetic parts in the vicinity of the magnetometer.

Additional developer options

• Put an empty file with the name: "sensor.readings" in order to switch the serial output format from Larus NMEA syntax to pure sensor raw data values.
• Additionally put an empty file with the name "magnetic.calibration" onto the root-directory of the sd-card in order to start a magnetic ground calibration. This is a development feature and is usually not required nor advised for a standard installation.

Led signal indications

There are LEDs on the PCBs edge which indicate the following

• SD-CARD (blue)
  • Off: No uSD-Card detected
  • On: uSD-Card detected
  • Flashing: Actively logging (writing) to card
• SYSTEM (blue)
  • Off: System not working at all
  • Flashing: Indicates that FreeRTOS and the tasks are running.
• GNSS (blue)
  • Off: No GNSS fix
  • Flashing: GNSS fix
• ERROR (red)
  • Flashing: at least one of the sensors IMU, static pressure, dynamic pressure or GNSS is not working.
  • Sporadic flashing: DGNSS heading fix is briefly missing.
• ESP (blue)
  • Not used currently