tanmaychhatbar / car_datalogger

ESP32-based logger, for IMU and GPS data, onto SD card, display for stats

Car Datalogger

The device logs IMU and GPS data onto an SD card (or slower, serial)

On an SD card, IMU data is recorded at 350-400Hz, target for GPS is 5Hz, but depends on whether the module has a fix.

The screen offers critical stats on where data is being written, whether GPS has a fix, etc.

Hardware

• TTGO TS V1.4 1.8in, with built-in MPU9250 IMU and buzzer
• Adafruit Ultimate GPS
• Some wires
• Basic soldering skills
• Optional 3D Printable case
• Optional custom car mount, near the CG
  • could be easily adapted from the mount included on the repo
  • or just use double-sided tape

Software folders

code

• The project is made in PlatformIO. PlatformIO should take care of all the dependencies and download all that is needed on its own.

data analysis tools

• The logs for GPS and IMU are combined into one file. You can use the included python script to separate the data.
• You can use the MATLAB tools to plot the trajectory on a map, or visualize the IMU data as needed.

TOCHECK

• file.flush() - fix potential data loss if power cut, effects on write speed

TODO

• animation

  • screenshot for the animation

• SDFat library - file.sync() to preserve recent changes, like flush for sd library - FIGURE OUT HOW TO CHANGE SPI PINS

  • https://forum.arduino.cc/t/sdfat-when-to-call-sync/272019
  • https://forum.arduino.cc/t/explanation-of-sd-write-and-flush-please/369320/5

• make imu and GPS sensing interrupt based

• rtOS

  • standardise refresh rate

• GPS - https://airu.coe.utah.edu/wp-content/uploads/sites/62/2017/09/adafruit-ultimate-gps.pdf

  • connection stats on screen
  • battery advantages

• IMU

  • max refresh rate

• Design

  • soft edges

• WiFi

  • autobackup

• data processing

  • https://www.youtube.com/watch?v=hJG08iWlres
  • https://x-io.co.uk/open-source-imu-and-ahrs-algorithms/
  • https://www.mathworks.com/help/fusion/ref/insfilterasync.html