LinuxPC + FreeDiags + Freefall OBDII<->RS232

[Dan.]

I know it won't do CAN, but this is what I was trying to do way back when

http://www.cleanmpg.com/forums/showthread.php?p=92392

I've seen a lot of posts complaining that the SGII is too expensive. In answer to that I've dug through my bookmarks. There was a time in my life where cheap was better than easy. Now I'm not so picky.

So what you need:

1. A i386 laptop or better with serial and LPT port (0 - $10) - Should take 8 - 40 hours depending on your ebay skills. If someone charges you more than $10 for a 12 year old laptop... punch them in the nose.
2. A Linux kernel capable of running on #1 ($0.00) - This will take between 4 - 4000 hours depending on how good you are at assembling Linux Kernels.
3. http://www.planetfall.com/~jeff/obdii/ ($5 - $10) - Should take 16 - 200 hours depending on your digital logic skills. You'll need the proper project boards a hot iron, a laser printer (library) and a good amount of etching acid. Add the proper parts and a soldering iron and you have a (car) OBDII - RS232 (serial) adapter. Make sure not to melt any skin in the process . You don't have to use these plans, just one of the ones supported in the the software in #4
4. http://freediag.sourceforge.net/index.html ($0.00) - Should take 8 - 400 hours depending on if bugs arise. Checkout the source and compile it targeting #2. This is the software that will talk to your car using #1 through the adapter you made in #3. Please take care to do step #3 properly so as not to fry out your serial port or your cars OBDII port.

So between $5 - $20 cash and between 36 - 4640 hours (0.9 - 116 work weeks) of time.

I made it through step #2 two years ago before giving up and buying the ScanGauge. Cost me $0.00 and about 200 hours of effort.

Don't think this stuff works on CAN cars but feel free to update the freediag software or Jeffs OBDII schematic.

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[dcb]

Note that you can do the mpg part with just a laptop/carPC/tablet (with a sound card), running almost any operating system on any fuel injected car: http://opengauge.org/diympggauge/

[larrydag]

Dan, great insight. I was looking to do something similar before I found out about the Opengauge project. One thing comes to mind. Is it practical for instantaneous FE or is it just for data logging?

I think in the long run the Opengauge will be more practical. But this can have it's uses. I've heard of people hooking up car pc's with OBDII ports. That could be interesting too since most of the time they create a display for it.

Here is a link for a cool car pc concept.

https://www.timekiller.org/carpc/index.php

[Dan.]

Originally Posted by larrydag

One thing comes to mind. Is it practical for instantaneous FE or is it just for data logging?

Yep, this should give MPG (or one should be able to re-write it too). I'm not sure the exact math to derive MPG from the OBD primitives, but something like (MPH/RPM)*X should do it. 'X' would be derived in part from your displacement. That's a real super dumbed down way to get MPG but it's better than nothing. I know the commercial gauges key off of speed an manifold pressure (for what it's worth).

EDIT:
[QUOTE=dcb;24089]Note that you can do the mpg part with just a laptop/carPC/tablet (with a sound card), running almost any operating system on any fuel injected car: http://planetchampions.org/diympggauge/Too cool. I know Prius guys used to tap a line with a curcuit so they could "listen" to the High Volt system. They could tell regen, assist and other things to a degree you couldn't see on the dash. Piped it out through the system speakers. All signal processing was done with the Cranium™ Hu OS (ears ).

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[zjrog]

I've seen the Mazda CarPC before. I have often considered doing a CarPC, but haven't always considered complete system integration like that.

I think I'll try that DIY MPG thing, as I have an old P100 laptop sitting doing nothing. I have never been able to get any iteration of Linux to run on it and that is mostly due to the video interface I believe. It has a 2gb drive and 48mb of RAM. And I can solder failry well... This will help greatly with my pre-OBD2 Jeep.

On the other hand, for my 02 Supercrew and my 03 Neon, I will look for the OBD2 to USB adapter. And in the next weeks I will decide which ultra-portable/mobile laptop to get. I like the completely solid state Asus, but need more storage than 8GB. The Everex is compelling for the same pricepoint as the 4GB Asus.

I'd prefer to get something with a bigger screen as I'd like to get away from my desk at home more frequently, yet the smaller screen models fit so well in a car. I also wish to use the laptop for GPS mapping of trails, digital audio storage (yes, to take my entire collection of music with me), and to have a wireless laptop to hit hotspots where I find them (no, I'm not into war-driving).

Anyway, being able to have a realtime display would be very nice...

[NoCO2]

Originally Posted by dcb

Note that you can do the mpg part with just a laptop/carPC/tablet (with a sound card), running almost any operating system on any fuel injected car: http://planetchampions.org/diympggauge/

Ok, this gives me a reasonable excuse to install a carpc now...I didn't have one before, but for real time mpg feedback, I'll gladly work to install one. I wonder how cheaply I could get a very small LCD screen to give me the feedback that I need...and I wonder if this would still be functional with EOC techniques.

I'll also be testing to see if it works with Linux under Wine.

::EDIT::

I take that back, I now found an application for one of these....

http://www.newegg.com/Product/Produc...82E16834220261

I'll see about making it do some other stuff to besides just do mpg for the money it costs though...

Or I could just use a normal computer with one of these...

http://www.mp3playerstore.com/stuff_...l/IN-700VG.htm

O dear...I'm feeling creative...this usually means something expensive is about to be done...crap.

[dcb]

Originally Posted by NoCO2

Ok, this gives me a reasonable excuse to install a carpc now...I didn't have one before, but for real time mpg feedback, I'll gladly work to install one.

Currently nobody is maintaining that, but it is in sourceforge in the OpenGauge project, and written in Java. If you (or anyone) gets an itch to improve it, let me know and I'll hook you up.

[NoCO2]

Thanks, yea, I'm not terribly fluent in java just yet, I can mess with pre-existing code, but nothing more then that yet. I have a bunch of friends, however, who can write java well though, I might talk them into helping me a bit.

What kinds of information, I wonder, could you get by just using the audio port besides the vss and injector inputs...it doesn't seem like using the audio line-in gives you much room for expansion. I might see if there would be a way to adapt it to either use ethernet, usb or serial inputs though...that would be cool. To make a program that can take the obdII output and give you a readout on your screen...though I think something similar already exists if im not mistaken.

[cbergeron]

Timely topic. I was one of the pioneers of the carputer / dashpc movement back in 1999. You can see my Jetta here:
http://dashpc.com

Here's a picture of my first interface (Perl / TK):


I was one of the developers of FreeDiag for a while on Sourceforge, and I'm the host of the Linux based Dashpc code (it's linked to from my site, or search Sourceforge).

I haven't been active on it for a few years, but maybe I can offer some advice about some of the hurdles I had to overcome doing my installation.

Unfortunately, my Aspire doesn't have ODBII, but my new Insight does.

I just wish I didn't have so many projects on my plate at the same time!

I used to have a BMW concept yet my mom had it replaced because she was really having difficulty reading everything from the computer so I had to change it.

Cool concept! Thanks for sharing.