Car computer for data logging

[Fourthbean]

I just bought a 7" Lilliput LCD from ebay for my car computer that I am going to put together. According to my figures, it will cost 185 for the screen, 42 for a single protocol OBDII scanner (won't have the maneuverability of a scangauge from one car to another), 40 for a power inverter or old laptop with broken screen, and 30 for various things that I will need to install (unforeseen costs).

I am going to replace my current cd player in my Saturn SL with the 7" LCD Touchscreen, this may require disassembling the LCD casing and creating my own molding to make it look like it belongs there (of course anyone with half a brain would know it doesn't belong in a Saturn ).

Current plans:
Old AMD Athlon processor with 256MB of ram sitting around
8.4GB hard drive
Some form of Linux running with one of the scan tools available in Linux
Wireless adapter for grabbing files from network when I am in driveway.
Plan on using on screen keyboard for when that is needed so I won't need a keyboard.
Suspend to RAM or Suspend to Disk for quicker boot up time.

Down the road:
GPS Receiver for navigation system and possibly more accurate mileage readings? Atleast for comparison sake.
Program for playing audio straight from Hard drive or CDROM drive (should be simple, but want the MPG display first).

I will attempt to keep this updated with how it is going.

[2TonJellyBean]

Sounds excellent...

Maybe you can create the Holy Grail? A green button. You press the button and the car accelerates at optimal efficiency as determined by your program and the feedback it receives from the OBD port. A computer algorithm could do that feat far far easier than us.

A computer controlled pulse button and a glide button (that kills the FI and maybe disables HVAC). I need coffee... LOL

[Fourthbean]

I like the green button idea, but I think it would work better with an automatic transmission.

[SVOboy]

What are your goals for the car computer? What will is control/display and all that?

Sounds like a neat project, I demand a detailed write-up!

[Fourthbean]

Oh boy, you are going to make me work for my membership here aren't you Svoboy.

The program I was looking at (scantool.net) has something like 80 different outputs that I can display relating to my onboard computer. I do not know which ones I want but I will find that out later on down the road when I get some more knowledge about what gets logged and what matters to me.

I would like to see instant (last 10 seconds worth?) MPG, MPG for the tank, and MPG for the trip. I would also like to see open loop/closed loop. I want all of this data logged to a file that I can look at later. I have not gotten beyond that yet.

[omgwtfbyobbq]

Spend the $50-100 and get a CF card for storage. The HD probably won't last long in a car...

[Fourthbean]

I agree that the hard drive probably won't last long. I am using the 8 gig just because I have it around, if everything works out good I will consider getting something solid state. Or going with a well cushioned laptop drive mounted perpendicular to the ground (Something about the platters less likely to be scraped from movement of the car).

[trebuchet03]

Originally Posted by Fourthbean

I agree that the hard drive probably won't last long. I am using the 8 gig just because I have it around, if everything works out good I will consider getting something solid state. Or going with a well cushioned laptop drive mounted perpendicular to the ground (Something about the platters less likely to be scraped from movement of the car).

Some cushy suspension should keep it alive (I'd avoid springs unless you add some mass to it) And ya, perpendicular so the heads don't crash into the platters on a bump (instead they just slide down - no damage)

I had aspirations a couple years ago to do a cheap carPC - the plan was to start really small without a screen and just have a music library (to later be upgraded with a screen etc.). I was going to use an inverter for power and a small 12V battery w/ a battery isolator as a startup/shutdown buffer.... It hasn't happened, but I have parts in my closet should I have time for it one day

Good luck with your project

[rvanengen]

You should get some more RAM, and then get some solid state storage for the machine...it will also reduce your power requirements and likely be a bit faster than an old laptop drive for the smaller writes while logging.

You could get a really good little app written and have it display a quick graph showing how far off your best average MPG you are seeing on your current trip instead of just focusing on the actual MPG while driving...maybe a really big display that is easy to read from the corner of your eye, or even have it talk to you.

I had toyed with the idea for my old car of using a carPC and a megasquirt to really maximize MPG by letting it drop injectors when the engine load gets really low, especially for idling...but I am still in the planning stages of just converting it to an EV and then write an app to help with the power and motor management.

Sounds like you have a great adventure ahead with this car!

[cfg83]

Fourthbean -

Wow! You da man! I would use the INFINITE POWER OF VELCRO to fashion an easy mount/dismount for the lcd panel. That way, you could hide it away when you park it in risky places.

I got a custom fit non-OEM radio enclosure from jcwhitey for my 1999 SW2. I can't find a custom fit for a 2000 for some reason, though, .

But, they have them at e-bay too :

SATURN 00-UP RADIO STEREO DASH INSTALL KIT WIRE COMBO
http://cgi.ebay.com/ebaymotors/SATUR...QQcmdZViewItem
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