Interacting with Onboard Car Computers?

joshmccormack asks: "I've seen lots of projects where people are making great looking computers that fit into the dashboard of their cars that play MP3s, movies and even some that do some GPS and mapping stuff. I'd love to find projects where computers connect with the on board computers in most cars from the mid 90s on to show temperature and performance of various parts of the car. There are diagnostic tools that mechanics use, and that you can get to get data, but I'm particularly interested in real time, in-dash, open source options."

Comments

Similar to TEC

[b00m3rang]

Electromotive systems makes a system called T.E.C. (Total Engine Control) that performs the functions you're looking for and much, much more. Although with this setup, you don't interface with the car's computer but replace it entirely. It allows you to control fuel curves, ignition advance, turbo boost, and pretty much any function of the engine to your exact specifications.

Maybe it's time to start developing OpenTEC?

Obstacles

[The Clockwork Troll]

One of the nice side effects of emissions legislation in the past 10 years is that all cars since 1996 are required to have an on-board diagnostics port to which standard tools can connect and report on the vehicle's various operating parameters (ignition timing advance, manifold pressure/mass air flow, various temperatures).

On OBD-II equipped vehicles, the port is typically located to the right of the steering wheel in the driver's side footwell. It is trapezoidal.

There are many systems available for reading this information, from scan tools to computer interfaces.

It sounds like what you want is something like the PSI data display unit (DIN-sized). These connect up to OBD-II enabled cars.

The big problem you may run into is that the OBD-II standard requires only that the most basic parameters be reported to scan tools. Manufacturers are notorious for obscuring the most interesting information and it's typically been up to enthusiasts to reverse engineer manufacturers' proprietary additions to the OBD-II protocol.

Delta Dash

[GeorgeH]

I'm planning on building one of these computers over the summer (what? A slashdot poster with grand plans in a nebulous phase of completion? Never have I heard of such a thing!) based on information over at the mp3car.com forums. You should especially check out the OBD-II forum, which is addressing your specific question.

Personally, I'm going to just buy (now a slashdotter is going to buy software? A sign of the apocolypse!) Delta Dash because it is supposedly great with my WRX.

Well sourceforge to the rescue

[pbox]

Have you actually tried

a. Google
b. SourceForge
c. neither

And the correct answer is c.
While a. or b. would be even correcter!

freediag that I have found on sourceforge which I have googled with "open source obdii".
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freediag

[austad]

Your ECU has most of the info you want. Pull it with FreeDiag and output it to the display of your liking.

Make something neat so I can use it too. Your car needs to be OBDII compliant to use it, most (all?) recent cars are.

Here ya go

[YrWrstNtmr]

I'm designing something similar for my truck.

Inexpensive Free software for Win or Mac. Inexpensive cable.
Expensive. Very pro display, and you can get all the extended codes sets.
Opensource(you still need to build/buy the cable)

There are others out there. Google for obdii

All you need do is hook this up to the serial port of whatever car PC you make, and run the s/w. Presto, virtual dashboard, with more readings than you will ever use.

Friend of mine at work has the cheaper one, and it works quite well. You can even record a drive, and play it back later. Output to OO.org or excel compatible csv for further analysis.