ELMduino VS RoadApplePi

Coding: You'll need to communicate with the OBD2 scanner somehow. Check out the ELMduino library which is designed to talk to the OBD2 scanner via ELM327 Bluetooth adapters. You might need to read through the library documentation and understand how to send/receive data.

A small approach to a project https://github.com/PowerBroker2/ELMduino

I believe its much harder to get data off of the elm327 via serial, there is a very easy example sketch on the ELMDuino library page on github. Here.

Not quite sure why you'd want to modify the reader. There's a boatload of WiFi ELM327 dongles for under $20 on Amazon. You can tap a 5V line to power the ESP32 in the vehicle for something permanent or use a power port for something portable. If you want to easy mode it, use something like the Elmduino library.

I used this library. 99% of the code was already there. All I had to do was find the UDID number for my bluetooth scanner the esp32 would connect automatically. Now using the library I can pull just about any information from the OBDII port.

So parsing out the ODB2, that device is an ELM based device, so this should make your life easier: https://github.com/PowerBroker2/ELMduino

Also, check out the code AND 3d print files here to make one yourself! If you want to make a different Arduino car-hacking project, be sure to check out my car-hacking library ELMduino!

This is a newer arduino library for interacting with cheapo ELM327 based devices https://github.com/PowerBroker2/ELMduino. I chopped up one of my OBD2 elm devices that was having bluetooth probs and hooked it via serial to an old arduino uno I had laying about. I got his software_serial demo to work, shows live RPM data. The hardest part was finding the serial lines in the ELM unit. If you've got an arduino based device with bluetooth then it should be snap.