Cheap/affordable and simple lap timer. Annoyed by your trackday-organizers not publishing laptimes or maybe they don't even provide a rentable laptimer? This is the project you've been looking for.
Includes datalogging to SD-Card so you can analyze what happened using a software that is currently WIP.
- Loads track start/finish-line definitions from SD card and automatically uses the closest by distance
- Shows best and current laptime while going faster than 5 km/h; shows best and cycles past laptimes while going slower/standing still
- Logs laptimes to SD card (laptimes.txt)
- Logs current GPS coordinates and IMU data to SD card (datalogging.txt)
- Instead of just checking that we crossed the start/finish line instead check when exactly we crossed it (-> more accuracy)
- Reduce usage of Arduino "String" class - instead use sprintf/char[] instead (prevent memory fragmentation, reduce memory/cpu usage)
TODO Add these libraries as git submodules
- https://github.com/greiman/SdFat
- https://github.com/mikalhart/TinyGPS
- https://github.com/pololu/l3g-arduino
- https://github.com/pololu/LSM303-arduino
Mostly stuff I had on hand already:
- HD44870 based 1602 LCD Display)
- Ublox Neo-6M/7M/8M or similar GPS-Module
- Teensy 3.0 or better
- micro SD module
- Pololu MinIMU v2
Based on the results of the prototype a increment with the following hardware is planned:
- STM32 Board with integrated SD-Card-reader (8-15€) (only supports 3.3V!)
- Ublox NEO-XM Module (5€)
- ILI9341 LCD Board (7€)
- L3GD20+LSM303D IMU Module (3€)
- No custom PCB needed; only a few wires for interconnects: 1€
- Case (PLA): 5€
Total: about 35€