Car computer

On Mar 31, 2:47 am, "Lawrence" <xmarl...@gmail.com> wrote:
> On Mar 31, 9:54 am, Dave <d...@comteck.com> wrote:
>
> > I hope "managing the car main board from the computer" doesn't mean
> > controlling the Engine Control Module.  Any communications with the ECM
> > will probably be via CAN or J1850.  The Ford version of J1850 is
> > completely different from the GM version.  I don't know what the Chrysler
> > version of J1850 is like.  Other manufacturers???
>
> >     ~Dave~
>
> Well, let me say little.
> For example, I remember I guy who had an extra EngineControlModule and
> he would switch from one to the other with
> a simple switch.The cars which most gain from this things are usually
> with turbo and I've heard mainly diesel.
> I would be cool to touch the screen and see all levels of things in
> the car, even just reading.
> Or, instead of the switch, touch the screen and plugin the enhanced
> engine controle module.
> Anyway,I don't really care about this part, it was just to say.
> And possibly, if i don't have a rs232, I could always plug a usb-rs232
> converter.
> Anyway I'm going to have a look around for CAN/J1850 to see what you
> mean, probably standard manufacturer interface ?

If you are talking about OBD-II standards, there are three.

1. GM Standard
2. Ford Standard
3. Everybody else.

I wonder why GM and Ford are losing sales.

"linnix" <me@linnix.info-for.us> wrote in message 
news:1175358492.531326.68480@o5g2000hsb.googlegroups.com...
> On Mar 31, 2:47 am, "Lawrence" <xmarl...@gmail.com> wrote:
>> On Mar 31, 9:54 am, Dave <d...@comteck.com> wrote:
>>
>> > I hope "managing the car main board from the computer" doesn't mean
>> > controlling the Engine Control Module.  Any communications with the ECM
>> > will probably be via CAN or J1850.  The Ford version of J1850 is
>> > completely different from the GM version.  I don't know what the 
>> > Chrysler
>> > version of J1850 is like.  Other manufacturers???
>>
>> >     ~Dave~
>>
>> Well, let me say little.
>> For example, I remember I guy who had an extra EngineControlModule and
>> he would switch from one to the other with
>> a simple switch.The cars which most gain from this things are usually
>> with turbo and I've heard mainly diesel.
>> I would be cool to touch the screen and see all levels of things in
>> the car, even just reading.
>> Or, instead of the switch, touch the screen and plugin the enhanced
>> engine controle module.
>> Anyway,I don't really care about this part, it was just to say.
>> And possibly, if i don't have a rs232, I could always plug a usb-rs232
>> converter.
>> Anyway I'm going to have a look around for CAN/J1850 to see what you
>> mean, probably standard manufacturer interface ?
>
> If you are talking about OBD-II standards, there are three.
>
> 1. GM Standard
> 2. Ford Standard
> 3. Everybody else.
>
> I wonder why GM and Ford are losing sales.
>
For those wanting to interface the OBDII interfaces, there is the ELM327 IC 
that will interface to the 9 most common protocols, including CAN.  You can 
get the ELM327 already in a ready to use module from www.scantool.net.  You 
can download the software free.  The module interfaces a PC or laptop via a 
RS-232 port.

Don

On Sat, 31 Mar 2007 03:47:18 -0700, Lawrence wrote:

> On Mar 31, 9:54 am, Dave <d...@comteck.com> wrote:
>> I hope "managing the car main board from the computer" doesn't mean
>> controlling the Engine Control Module.  Any communications with the ECM
>> will probably be via CAN or J1850.  The Ford version of J1850 is
>> completely different from the GM version.  I don't know what the Chrysler
>> version of J1850 is like.  Other manufacturers???
> 
> For example, I remember I guy who had an extra EngineControlModule and
> he would switch from one to the other with
> a simple switch.The cars which most gain from this things are usually
> with turbo and I've heard mainly diesel.

Have you looked at the wire bundle to/from an ECM?  You are going to have
to duplicate it to the second ECM.  Changing the calibrations and getting
aggressive with settings (e.g., spark advance) can give you increased
performance.  Pushing them too far can lead to expensive engine repair
bills.  The car manufacturers have calibrators who do nothing but tweak
the settings for all sorts of situations.

And, you're going to have to convince both ECMs to work with the same
theft deterrent code.

> I would be cool to touch the screen and see all levels of things in
> the car, even just reading.
> Or, instead of the switch, touch the screen and plugin the enhanced
> engine controle module.

You do not want them both on at the same time.  So, turning one off and
then the other one on while the car is running?  See above about car
repairs. While this might not harm the engine under certain conditions,
sooner or later you're going to be tempted to do it under the wrong
conditions.


    ~Dave~

On Sat, 31 Mar 2007 09:28:12 -0700, linnix wrote:

> On Mar 31, 2:47 am, "Lawrence" <xmarl...@gmail.com> wrote:

>> Anyway I'm going to have a look around for CAN/J1850 to see what you
>> mean, probably standard manufacturer interface ?
> 
> If you are talking about OBD-II standards, there are three.
> 
> 1. GM Standard
> 2. Ford Standard
> 3. Everybody else.

There is only one OBD-II standard, defined at its lowest level by SAE
J1979 and at its highest level by SAE J2178-1 through J2178-4.  J1979
provides for communications to be performed over several different
physical layers, one of which is SAE J1850.  SAE J1850 defines two
different physical (incompatible!) layers.  

J1850 PWM (pulse width modulation), aka Ford, uses two wires at a data
rate of 41.6 Kbps.  J1850 VPW (variable pulse width), aka GM, uses one
wire at a data rate of 10.4 Kbps.  



    ~Dave~

On Sat, 31 Mar 2007 18:11:34 +0000, Donald Harris wrote:

> For those wanting to interface the OBDII interfaces, there is the ELM327 IC 
> that will interface to the 9 most common protocols, including CAN.  

It is important to note that this is OBD-II communications over the
vehicle bus (buses).  There is a lot of proprietary communications that
this tool can not interpret.  Just so no one gets misled.   ;-)


    ~Dave~

On Mar 31, 12:10 pm, Dave <d...@comteck.com> wrote:
> On Sat, 31 Mar 2007 09:28:12 -0700, linnix wrote:
> > On Mar 31, 2:47 am, "Lawrence" <xmarl...@gmail.com> wrote:
> >> Anyway I'm going to have a look around for CAN/J1850 to see what you
> >> mean, probably standard manufacturer interface ?
>
> > If you are talking about OBD-II standards, there are three.
>
> > 1. GM Standard
> > 2. Ford Standard
> > 3. Everybody else.
>
> There is only one OBD-II standard, defined at its lowest level by SAE
> J1979 and at its highest level by SAE J2178-1 through J2178-4.  J1979
> provides for communications to be performed over several different
> physical layers, one of which is SAE J1850.  SAE J1850 defines two
> different physical (incompatible!) layers.

If you call that a standard, then ISO9141-2 (rest of the auto world)
is the same as RS232.  My point is that GM and Ford are still isolated
from the rest of the world.

>
> J1850 PWM (pulse width modulation), aka Ford, uses two wires at a data
> rate of 41.6 Kbps.  J1850 VPW (variable pulse width), aka GM, uses one
> wire at a data rate of 10.4 Kbps.
>
>     ~Dave~

"Lawrence" <xmarlawx@gmail.com> wrote in message 
news:1175265929.112797.130650@b75g2000hsg.googlegroups.com...
> Hello all,
> soon this summer will be my birthday and I would like to make my self
> a *cool* present.
> I'm a computer science student, last year, and I always liked embedded
> computers and modding.
>
> I want to buy an x86 computer, to put it in my car and play around
> with it.
> For sure you know much better than me, so I'm going to ask you what
> you think will better fit a car computer.
>
> I've seen around all pico/nano/mini ITX that range from 600mhz to
> 1400mhz.
> I believe that as long as they can play video (even via hardware) it
> doesn't matter the power, since to browse the internet, play mp3s,
> etc, computing power is not really a big deal.
> The prices are all between 100$ and 400$.
> I'm not even sure dimension matters as if it doesn't fit in the box
> (don't know the name, the one used for documents in front of the
> passenger) I could always put it in luggage van.
>
> The car for now is a new beatle cabrio, but if I have to change car I
> would like to be able to do that without too much hassle.
>
> I also seen the mac mini and apple tv that are both really small and
> probably enough for the type of application I'm forseeing.
> The power managment would probably be the problem.
>
> I'm not sure on the OS i'm going to use, but most probably one of the
> flavour of *nix, even osx.
> The IO will be a screen (not sure but most probably touchscreen, vga
> or svideo), a gps, a gprs/umts/whatever for Internet access and WIFI +
> bluetooth.
> For wifi I would even like to put a bigger antenna than normal.
>
> Do you have any suggestion what-so-ever for the type of project I'm
> considering ?
> Places to buy, components, anything! :D
>
> Thanks in advance, and sorry for cross-posting but I couldn't find a
> group that was only about car computer.

This guy did something similar in his mazda
http://www.chaos.org.uk/~altman/mp3mobile/

You can also buy ODB-II scanners which run on a PC so you could use one 
of those for talking the car-brains without having to worry about 
getting into the interface yourself. 

In comp.arch.embedded Lawrence <xmarlawx@gmail.com> wrote:
B> But most laptop miss rs232 which would be handy for a bounce of
> application, including managing the
> car main board from the computer.

Assuming it's a not-too-old laptop, a USB->RS232 converter should do the
trick.  I don't know how well they're supported under Mac OS, but they seem
to work quite well under Linux.

Theo