Because my car is too old to have a trip computer fitted coming from the factory, I've decided to build my own.
It uses the data provided by the engine management ECU, which is polled through a cheap Chinese ELM327 clone and a (modified version of) the Arduino OBD-2 library written by Stanley Huang
The modified version is available on my GitHub page. Nothing too special, I just modified it so it can work with the spaces returned by my ELM327 and added some things to the init-string so the library can talk to my car.
I will modify it slightly so the init string is more flexible
The (very crude) ELM327 "emulator" written in C# is also available on my GitHub page
Very few parts are needed, the latest version of this project uses:
- Arduino Mega 2560
- HX8357 3.2" LCD and SD card shield
- HC-06 Bluetooth module (programmed to connect to your ELM327, see this guide and the datasheet)
The Arduino source is available on my GitHub page