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Discussion Starter · #1 ·
Hi everyone,

I'm an engineering student home for the summer (and bored), so I thought I'd work on a project.

End Goal:
Create a bluetooth capable piece of hardware that can emulate the OnStar box/rear CD changer via O-Bus and I-Bus. It'll be able to interface with steering wheel controls, the audio system, the SID, and a bluetooth capable phone to create a handsfree phone solution for our Saabs with the deprecated OnStar systems! I'd also try to include A2DP support for wireless music streaming.


What I'm looking for:

1.) Pinout of the connector that's attached to the OnStar box (holds the optical lines and some conventional ones)

2.) O-Bus/I-Bus documentation!!!! This is the tricky one. I basically need to know what messages the OnStar box sends through the Optical bus so I can mimic them using other hardware!

Thanks guys!!!! ;ol;
 

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Discussion Starter · #3 ·
That's an awesome site, I'll definitely dig through it some more.

I found out that the optical bus is based on the MOST system, which is the same that's used by BMW, Audi, etc. The problem is that a MOST to USB adapter or something of the sort would be very expensive to obtain.

At this point I think I'm going to change strategies, it'll be easier to "hack" the OnStar box which can already talk to the car than it will be to interface with and reverse engineer the optical bus.

Here goes!
 

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years ago I looked into making the onstar box do something and gave up. too much money and effort. I would love to have someone find a DIY solution though
 

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If you're looking for circuit diagrams for the electrical system, WIS for saab has all of that. If you have a computer with win xp or an emulator you can download it.

Also, fellow engineering student here as well!:cheesy:
 

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Discussion Starter · #7 · (Edited)
Progress!!!

And we're off! I had some time to pull the on star control unit out of the car and disassemble it, and I found some VERY promising things.

First, as suspected, the actual phone is a separate unit! It's a sony ericsson model CM-42. I think reverse engineering its communications with the rest of the unit is doable, and if I can do that, I can fool the unit to thinking it's connected to OnStar when it's really connected via bluetooth to my phone!!!!!

If that doesn't work, the cover of the unit had a pinout that shows both microphone and "keypad" connections, so I think it'd be very reasonable to get the steering wheel/dash controls and in-car microphone connected to something if plan A doesn't work.

I'll keep at it and report back when I have something!:D:D:D

UPDATE: I found a full "Integrator's Manual" for the phone! No reverse engineering necessary, time to break out the arduinos!!!!
 

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Discussion Starter · #9 ·
Interesting. I think the issue with those ideas is that they all still rely on a separate phone in the car, which is what I'm trying to avoid.

Right now I'm working on getting a raspberry pi to play nice with my iPhone, after that it should just be a simple python script to emulate the phone that was in the on star box and I can test it out!
 
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