OBD-II and Arduino Question

All,

New to the forum. I am trying to develop a design that interfaces with a vehicle’s OBD-II port, but one where I can still use my existing Scangauge (OBD-II vehicle monitor). For my initial project, I would like to use the Arduino as a pass-through, like this:

ScanGauge/OBD2 Reader <-> OBD2-to-RS232 Converter <-> ARDUINO <-> RS232-to-OBD2 Converter
<-> Vehicle OBD2 interface.

I am familiar with Obduino and some of the OBD2/Arduino projects out there, but I haven’t seen anything like this and I don’t understand if something like the ELM237 will work in this configuration. Is this doable? Any tips or comments on this idea for a n00b?

The Arduino does not take RS232 level/type signals, so, no, that won’t work.

PaulS:
The Arduino does not take RS232 level/type signals, so, no, that won’t work.

Isn’t the RS232 to Arduino interface already covered by something like the ELM237? See https://www.clusterfsck.io/blog/arduino-elm327-library/

The Arduino does not take RS232 levels but TTL. You will need some type of converter from TTL to RS232, e.g based on IC MAX232, or OBD to UART directly (TTL levels). I think, you can interest to this: https://www.sparkfun.com/products/9555

The ELM237 I mentioned is similar. So my question is, assuming we are using an ELM237/MAX232/Sparkfun, etc. Will something like this work with Arduino as a pass-through?

ScanGauge/OBD2 Reader <-> ELM237/MAX232/SPARKFUN <-> ARDUINO <-> ELM237/MAX232/SPARKFUN
<-> Vehicle OBD2 interface.