Freematics Forum

Hi,

In the interest of being somewhat brief:
Over a year ago I purchased an OBD-II adapter, and wasn't able to get communication between arduino-adapter-obd working. The project was shelved until this week, when I gave it another go. It appears that in the mean time the website/company surrounding the product has... changed somewhat.

I recall buying a model A of the OBD-II adapter, since I didn't have a need for GPS/Accel data. But, the label on the blue box of the adapter says "OBD-II; UART Adapter; Designed for Arduino; Version 1.2" and it has 6 wires, which leads me to believe it's actually a model B.

The website states that model B uses I2C, while model A uses UART. Are they exclusive? Or can the model B use UART as well? Can you please help me determine which adapter I actually have, as well as firgure out the wire specifications?

Wires:
[red / black] - Power and ground (Other forum posts mention both 3.3 and 5 volts, which one is it?)
[yellow / blue] - I suppose this matches up with the white and yellow wires mentioned on the product page, which means it's either tx/rx or sda/scl.
[green / grey] - I have no idea, unless it's the additional sensor data for the model B, in which case why is the product labeled UART while the website declares it I2C based?

I apologize if I'm simply reading the wrong documentation, in which case please drop me a link and let me attempt to sort things out

Thank you,
-ctag

Since more than a year ago, we have upgraded I2C version (model B). So now it only has 4 wires.

I'm sorry for the delay I wasn't aware that my thread had actually been posted, since the last notice I got was that it was awaiting moderation.

I measured the voltage to be 5V and Ground on the red and black wires.
The green and grey wires are connected directly to a small adafruit (I think) accelerometer or gyro inside the OBD Adapter's housing.

If the I2C version only has 4 wires, then I truely do have the UART model?

I've been looking for where the serial connection is defined in the OBD library so that I can modify it to use Software Serial on different PWM enabled pins, then use the regular serial interface for debugging. So far no luck, but I'll keep at it.

After over a year of holding up my project, and a month of troubleshooting this UART adapter, I can only assume that the adapter is defective or broken; seeing as the system does not work with combinations from a small collection of arduino boards and three test vehicles.

A different approach to look for problems with the hardware is useless, as opening the shell of the adapter displays a birds nest of wiring and soldering akin to that I would expect from a novice high school student. Now I'm sure that even had the product worked fairly consistently, I would not want to rely on it for any period of time. I'm troubled that it was even sold to me in the first place, and given such nonexistent technical support.

From here on out I've axed OBD-II integration for my vehicle, and am discarding the product purchased here.

In the early stage, the part of the product is hand-soldered. But now, it has been totally reworked and is absolutely neat inside.

You've replied to my post without allowing it through moderation.

I'm here with you. Just opened my wiring up too. I am no pro at putting wiring together or working with this stuff but I don't sell it either where this is being sold to the public with no support. Unfortunately my project has been held for a year now and I cannot do anything at all. I debugged all I can and it's pissing me off that I've spent a lot of my hard earned money on this. I'll have to look elsewhere.