Automotive Modification: Adding a PC to the system literally.

[DeschutesCore]

First, if this is the wrong forum, I appolgize in advance.

I currently have several choices in front of me for components. Laptop, PC, or PDA. What I would like to do is locate the technical manuals for my car and create or locate and purchase a harness to connect the unit to the car's computer. I know it sounds foolish, but I have seen this done repeatedly in car shows, movies, tech demos, etc.

I'd like to monitor the status and sensors from each area of the vehicle. At this point I'm not worried about permanent integration, just a harness I can serial into and download. The question I have is this: Is it feasible, do-it-yourself-able, and what some of you think about this idea.

TIA,
DC

 

[Evadman]

Sure, very possable. But you need to have access to a person who has "hacked" the computer system in your selected vehicle. Then you have the coding required to build a linkup to your computer system. Readouts would only be possable, as most computers in cars do not have a reprogrammable on the fly computer system.

What kind of car are you going for? Or is this just a general question?

 

[DeschutesCore]

I have a 1994 Dodge Intrepid. The computer does appear to have a diagnostics port. All I want to do is read only, no changes. I got the idea when my engine started to lose power. After seeing "The Fast and the Furious", the laptop idea hit me. Once I had that little gem in my head, the possibilities went on and on.

End goal is to integrate a touch screen in the console where the Stereo / AC units are. I could use the touch screen to control FM / CD / MP3, do the GPS thing (Garvin of course), and monitor the car. The system has a trip computer that is pretty easy to decipher and jack into. Only eight wires required for that, and a BASIC Stamp would do fine there. It's the performance / braking / O2 / etc. i'd like to monitor.

The Intrepid polls over 27 sensors and has a list of 200+ possible error codes. I have the codes, I have the Chilton manual, and I have the tools. What I don't have is a huge budget or a replacement car. I was looking for a "Yeah, it's been done, order the software / harness here..."

Thanks for the input.

DC

 

[unclebabar]

> The question I have is this: Is it feasible, do-it-yourself-able, and what some of you think about this idea.

Seems to me that's just a matter of knowing the access port configuration, running wires, maybe building a little logic and programming a console. Just as long as the on-board computer and the whatever is connected to the port can access the sensors simulateously. (you don't want the on-board computer to be deprived of data (as if it were sitting in a shop) while it is running. I have no idea if that would be an issue or not. The computer needs to have enough cycles to do whatever it needs to do (unless you want overclock it, I say facetiously).

>The Intrepid polls over 27 sensors and has a list of 200+ possible error codes. I have the codes, I have the Chilton manual, and I have the tools.

Will you be able to get the actual engine O2 level / tachometer readings / etc from the port or is it more along the lines of you punch in the code for X sensor and it returns Y error code? If it's the latter, then I'd say 'not especially feasible'.

> What I don't have is a huge budget or a replacement car.
> I was looking for a "Yeah, it's been done, order the software / harness here..."

I can't imagine if you find such a kit, that it would be cheap.

 

[Evadman]

OBDII would pass the voltage signals directly to the connector if polled. So for instance you would be bale to see the exact voltage the O2 sensor is putting out, but you would need the correct programming to turn that voltage into useable signal. ( aka, 14:1 instead of 2.5v )

I am not sure if a '94 is obdII or I though. I am leaning towards OBDI. I was unable to find any info on that online. Call a dealer.

I am also not sure of the computer will act as a translator for you. Snap-On makes a diagnostic scanner that will plug into that port and give you all the info you need though a LCD screen, but you are talking in excess of a grand for said unit. Kinda expensive.

<edit>
spelling sucks.

 

[DeschutesCore]

It appears that OBDII was '96 and on. I'm SOL on the PocketLogger path.

Quote:
OBDI (pre '96 cars)

OBDI is not a standard. While most people refer to cars that aren't OBDII as OBDI, there were no specifications set forth as "OBDI". Cars not manufactured to OBDII spec were not required to adhere to any rules as far as the design of ECU communications. Each manufacturer was free to create there own way to 'talk' to the ECU. It is not as simple as having a cable that plugs into the port. You need to know what to 'say' to the ECU and you need to know what the ECU is going to say back. None of this information is public knowledge. Any information that is out there has been reverse engineered, a very time consuming task. Due to this fact, just because we have a "DSM" version that works with an "OBDI" car doesn't mean it's compatible with other OBDI cars. We may or may not develop a logger version for other popular OBDI cars. At this point no immediate plans have been made.

It also appears the later '98+ Intrepids have issues with PocketLogger style devices. Sounds like this just got a lot harder before I even really started.

Thanks again Evadman,
DC

BTW - This is the kind of effect I was looking for, sans cameras and lane trackers.
ORNL's Instrumented Vehicle

 

[dkozloski]

WWW.AutoTap.com has the answer for you if your vehicle is '96 or newer or one of a few '95 models. I have an AutoTap Pro that is compatible with GM, Ford, and Chrysler as well as some foreign models.

 

[blahblah99]

If all your doing is measuring the voltages (and performaing all the calculations/conversion on your laptop) then why not just get a data acquisition pcmcia card along with its hardware and hook up the wires to the data acquistion device? Most of the daq manufactorers provide a C/C++ library with their daq's so you can program your own software and user display. THe only thing would would need to do is figure out which wires to tap into to connect to the daq. Of course, you would also have to make your own bad ass heads up display program

 

[Evadman]

Originally posted by: blahblah99
If all your doing is measuring the voltages (and performaing all the calculations/conversion on your laptop) then why not just get a data acquisition pcmcia card along with its hardware and hook up the wires to the data acquistion device? Most of the daq manufactorers provide a C/C++ library with their daq's so you can program your own software and user display. THe only thing would would need to do is figure out which wires to tap into to connect to the daq. Of course, you would also have to make your own bad ass heads up display program

Why the hell didn't I think of that?!?

Jameco sells a data acquision pci card along with software if I remember correctly.

 

[DeschutesCore]

Looks very promising, and it's on the cheap! 99.00 is much better than the estimated 1k+ for the other solutions. Now to get my head out of the clouds and start planning some more.

Thanks again!

DC