How to build this circuit, interfacing with cars ISO 14230 K line

[stevetinkers]

I'm working on accessing the ISO 14230 K Line of my car's OBD2 port with an Arduino. This is part general guidance and also part how to read the official datasheet application diagram....

I ordered some MC33290 chips and other parts from peoples projects posted online accomplishing a similar task. Some projects just use voltage dividers and transistors! I'm keen to try the interface chips first...

Interface Questions

Here are a couple diagrams from projects which use similar interfaces and the official diagram from the datasheet... Circuit-Compare.png

I don't understand what some of the parts are on the official diagram. The "simplified application diagram" is not so simple to me. How do I figure out what these are?

Some projects use other microcontrollers other than Arduino, such as a tiny. How can I make them Arduino compatible?

General Project Guidance

Ultimately I'm trying to read and repeat commands that pop up on the k-line to get some data. I wonder if I can put an Arduino in the middle of communications so I can see everything that comes by and request my RPM or whatever PID I want at will...
K-Line <----> Arduino <------> K-Line

If you're curious, heres the other transistor/voltage divider options... Other-options.png

Open to any input you have!! Thanks.

[johnwasser]

I think the stuff to the right of the chip is all internal to the car so you don't have to implement that. I think you only need 'Battery Voltage through external resistor and diode" connected to VBB, K-line connected to ISO and Ground connected to GND. It would be nice if they specified the "external resistor". I assume most any power diode would work.