OBD MPGuino gauge

[tom43571]

Its been a while since I visited this forum. At the time we were stuck and could not figure out how to get it to communicate. I have the original setup (picture included), is there a code that will make it work now? I tried reading through all of the posts and 2 hours into it I figured I would just ask. Last I read I had to switch to the ELM327 but then I see the original diagram is still in wiki.

[Froggy]

There are two versions of OBDuino now, the original which fits on the ATmega168 chip, and OBDuino32K which fits on the ATmega328 chip.

In May of this year both were recently updated by Mike for better 9141 communications. The OBDuino32k has had a few additional changes to help reinit (but it still uses the same timings and structure that Mike and others set up.)

It's worth trying.

[Demonhawk]

still having no luck reading other PIDs. I'm currently using the 32k version, do you think I should use the one that fits on the 128 chip?

[Froggy]

Sure, why not... It's the same base code, but anything that may help... It certainly won't hurt to try.

[electromike]

Thanks Froggy for all the support you are giving to the project. I have been busy as of late, but quickly glancing through your discussion the only two things I thought of were:

1) What Arduino IDE version is being used to compile the program with? I always used 0015.

2) Check the hardware! Make sure that 510 ohm resistor is in there correct.

Also, Which is more likely, I did some quick googling and found this line that peeked my interest:
"At a software level, ISO14230 is a vastly extended ISO9141-2 protocol that supports much longer data frames and much quicker communications startup with the ECU. "
I think that might be a clue to what is going on.

What we need is an accurate document of the 14230-4 protocol so we can revise the code accordingly. If someone could find that before me, that would be great!

[electromike]

Here is a document that details the parts of proper init and comm values.
http://www.alfa145.co.uk/obd/14230-2s.pdf

Page 6 describes the header Bytes
Page 7 has the timing... looks like 20ms is the max wait time
Page 12 - something i don't understand but may be an issue later on.
Page 16 KB Values

This document talks about communication
http://www.alfa145.co.uk/obd/14230-3s.pdf
Section 4; all the good stuff


Some More documentation
http://www.koch-engineering.com/file...ISO14230-2.pdf


The exact resource I needed:
http://prj.perquin.com/obdii/

[electromike]

Anyone willing to tackle this?

[Demonhawk]

i could try to help, but I don't know much about coding in C, and I don't understand most of the hardware side, but what ever I could do to help I'd be willing to

[electromike]

So to be clear, you can mostly get the init to go through successful, Which init process works best for you. the 9141 or the 14230 fast or slow?

And you do get some PID's to display? Other times the program crashes?

[Demonhawk]

The 9141 init is the one that works. And I can get a few PIDs to display. But we attempted forcing the program to skip the check to see if the PIDs were valid. When we did that and displayed more than a few unsupported PIDs the arduino would crash and reset.