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
non-oem_radio.jpg

CarloSW2

[omgwtfbyobbq]

Originally Posted by cfg83

the INFINITE POWER OF VELCRO
CarloSW2

QFT!

[Fourthbean]

Keep the ideas coming, the only thing I see against solid state would be space. I would like to have some space to put audio and video(for showing off). Maybe I will do a small CF card for the Operating System and use a hard drive for any data I want.

I like the Velcro idea, I will have to see what the mount that comes with the lcd looks like, if it has any type of telescoping I may be able to incorporate it and be able to slide the screen off when need be.

As for ram, I can get more if need be. But I plan on running a very minimalistic Linux so it shouldn't be too taxing. I will attempt to get suspend to ram or suspend to disk working for quicker boot up times.

I like the idea of the graph with best vs current, would work nicely for daily commutes where everything is the same and I can see how much better I am doing. That may be a bit further down the road though since I have no idea how to create graphs and I would need to figure that out first .

[omgwtfbyobbq]

That sounds about right. Have the filesystem and log files on the CF card with your bigger audio/video files on the disk since if those get corrupted you can just repartition (assuming it's still usable) and yank 'em from your home system again. Boot times won't be an issue if you keep it minimalistic. I have a 450mhz PIII that boots as fast as a Sempron 3000+ because it doesn't have much in the way of startup services.

In terms of bins, you'd likely be fine going with a minimal install from Arch or Gentoo or *nix and openbox or xdm or whatever with the output from the OBD going to a script that can calculate whatever you want and toss it in log files for easy reading and display via conky. Graphs and figures regarding whatever you want to display.

[skewbe]

Tell you what, you get that installed and cant get a decent mpg log, just let me know and I'll hook you up, or at least talk you through it. I've got a 97sw2.

Dont forget the $10 webcam pointing backwards so you can shave off your mirrors trick (now that you can display it on something)

[cfg83]

skewbe -

Originally Posted by skewbe

Tell you what, you get that installed and cant get a decent mpg log, just let me know and I'll hook you up, or at least talk you through it. I've got a 97sw2.

Dont forget the $10 webcam pointing backwards so you can shave off your mirrors trick (now that you can display it on something)

Ooooooh, that sounds cool!

CarloSW2

[rvanengen]

Originally Posted by Fourthbean

Keep the ideas coming, the only thing I see against solid state would be space. I would like to have some space to put audio and video(for showing off). Maybe I will do a small CF card for the Operating System and use a hard drive for any data I want.

If your laptop supports booting from USB, then you can get an 8gb thumb drive for less than $90.

Takes less space, no shock problems, removable, and takes less power and generates no heat. Then you can just mount the cable into the glove box or anywhere else accessible and can remove it to take it into the house, eliminating the need for wireless for the time-being. Get two, and you can swap OS's depending on your needs. :-) Sorry...just being a nerd with your money. But, seriously, for the $, I would stay away from the HDD if your laptop donor will boot from USB.

[Fourthbean]

Yep, I see how the usb drive could be handy. But I already have a wireless adapter lying around doing nothing, hence the reason to use it. That would be a nice feature to have though, a usb port next to the lcd panel that anyone could plug into and I could play the files off of it .

You guys are really creative, I wish I had a brain that worked like that .

After looking I think I may stick with a desktop system for now. A laptop for 30 bucks is going to be slow and I am afraid of it being sluggish when browsing with the touchscreen. I may change to a more expensive (200) laptop later on, should be able to pick up a nice centrino with a broken screen for that much later on.

[Fourthbean]

I recieved both the lcd screen and OBDii adapter in the mail yesterday. I have been trying to install various programs on my brothers laptop that is running linux. The two that seem to work (haven't put the thing in my car yet) are diagtools (command line based which will from what I see give me the raw data of each channel), and then a java based app called jdash. Jdash is still in development, so it doesn't look too pretty.

I haven't even tried to look at any source code, as that is something I have never really done. May try in a few minutes here and see if I can make heads or tails of anything.

I am planning on using LinuxICE for my distribution of Linux. It has the NGhost front end already installed and is stripped down making for a snappy boot up time.

[cfg83]

Fourthbean -

I'm waiting for some $$ to come in. When it does, I think I will get an elmscan too. I don't know if I will have a fancy setup like you, but I think I will at least use it for calibrating and testing of gizmos.

PS - Since you will have an extra ECU/PCM, so to speak, you will have the ability to *program* your mods. Based on sensor inputs, you will be in a position to turn on and off your gizmos!

CarloSW2

[Fourthbean]

Just had a uereka moment. I have an old UPS with a dead battery (Who doesn't?) and thought "what if I could use it as an inverter". As it does run off of 12 volts. I just did a quick google search and it seems there are some people that have done this succesfully.

I was going to buy a friends laptop with a bad screen, but it doesn't have any serial ports which would cost me another 15-20 bucks for usb adapters (both my elmscan and gps will be serial). And then having to mess with adapters and linux may end up a pain. Adds too many equations for my liking. The desktop I had originally planned on has two serial ports.

Maybe I can have my pc installed this week afterall, I was thinking it was going to be a while since I would have to order an inverter .

[Fourthbean]

Alright, tested the ups theory and read around a bit more. My ups will not allow me to turn it on without ac power applied, so I would have to get another that would allow such a thing and then I would have to be hitting an extra button each time I turn the computer on. What's funny too is that the 250VA UPS couldn't handle the computer, it would shut down when going to battery power. If I took the video card out and unplugged the hard drive it would work ok. lol

I think I will just go buy an inverter. If I don't use it in the end it will be a nice tool to have around for road trips or something.

cfg83, explain to me what you mean by being able to turn on and off gizmo's. Can I actually control the ECU/PCM through the OBDII port?

I am doing all of this but realizing that I am diving headfirst into stuff I know almost nothing about :0.

[cfg83]

Fourthbean -

Originally Posted by Fourthbean

Alright, tested the ups theory and read around a bit more. My ups will not allow me to turn it on without ac power applied, so I would have to get another that would allow such a thing and then I would have to be hitting an extra button each time I turn the computer on. What's funny too is that the 250VA UPS couldn't handle the computer, it would shut down when going to battery power. If I took the video card out and unplugged the hard drive it would work ok. lol

I think I will just go buy an inverter. If I don't use it in the end it will be a nice tool to have around for road trips or something.

cfg83, explain to me what you mean by being able to turn on and off gizmo's. Can I actually control the ECU/PCM through the OBDII port?

This would be a far down the line thing, but let's assume you have the program running and your PC comes with 2 serial ports. The first serial port is taking that data from the OBDII port. Over time you discover that under data input condition A, B, and C, it would be cool to turn on Gizmo X that you have designed and/or bought. Now you can use the second serial port to turn on the gizmo. To turn on the gizmo, you could just turn a pin on the serial port to "on". A relay could be attached to the pin, which is used to turn on the gizmo. Alternatively, you could have a complex serial port protocol that does fancier things in relation to a fancier Gizmo Y. Also, you don't need a second serial port. A parallel port, USB port, or some kind of peripheral connector could do the trick with the right software (that you write or modify for your own porpoise ).

porpoise_01.JPG

I am doing all of this but realizing that I am diving headfirst into stuff I know almost nothing about :0.

Don't worry, the main win will be getting the OBDII connection working so that you can soak up all that data (like gravy to bread!!). I just ordered the same elmscan as you, so I will be doing similar stuff. I won't be as ambitious though. My goal is to have temporary data logging setups with a laptop where I can log ALL the data that the elmscan is able to see. Then I can have fancy graphs saying "here is what happens" instead of what the ScanGauge is willing to tell me in real time.

PS - Thanks Red for pointing out the elmscan!

CarloSW2

[Fourthbean]

Ahh, now I see what you are saying. Yes, that would certainly be neat. This coming from the person who complained about cars being all "computer controlled". I think understanding what those computers are doing makes me more appreciative of their existence.

Now to get that port to give me data! I had it working at some point on my brothers linux laptop. So I know it is possible.

Thanks for the support, this will be more fun with you helping out.

[cfg83]

Fourthbean -

Originally Posted by Fourthbean

Keep the ideas coming, the only thing I see against solid state would be space. I would like to have some space to put audio and video(for showing off). Maybe I will do a small CF card for the Operating System and use a hard drive for any data I want. ...

I just found these :

CF Hard Drive Adapter
http://www.addonics.com/products/fla...ad44midecf.asp

This family of unique CF-IDE Hard Drive Adapters is designed to enable one or two Compact Flash (CFI/II) media to be used as direct replacement for the 2.5" IDE hard drive. As a result, any equipment, such as Notebook computer, that uses a 2.5" IDE hard drive can be easily converted to use the low power and shock resistant CF media. Once installed, the CF appears as an ordinary hard drive to any OS and can be configured as a boot device. The Dual CF-IDE Hard Drive Adapter contains a second CF slot for the slave position of the IDE channel, allowing increased storage capacity with the same low power consumption and solid state benefits of the CF card.

Addonics IDE CompactFlash Card Reader/Writer
http://www.thenerds.net/ADDONICS.Add...0798-2&affid=3

Startech CompactFlash Card Reader to IDE Adapter
http://www.thenerds.net/STARTECHCOM....0911-2&affid=3

The first one is my favorite. For 22 bucks I can use flash memory to setup a master and/or slave hard drive setup. I actually have a circa 1995 486 notebook PC that is still working, so I could have DOS installed on (CF flash based) hard drive(s). Therefore, NO issue with hard drive failure.

CarloSW2

[Fourthbean]

I actually bought one of those and installed it in a laptop I previously had (was stolen). Worked nicely and quiet , which was my main purpose. Linux didn't have any trouble installing on it, and I didn't notice any speed difference. The card was a "slow" 50x version so going with something faster would boost that. Of course for our application speed isn't a big deal for storage.

Looks like the guy I bought it from is not selling them anymore. I managed one for 10 dollars shipped from Hong Kong off of ebay from user mobilesupply. That was the one cf version though, not for two different disks.