Thor data logging Re: PC's and EFI

Steven Gorkowski kb4mxo at mwt.net
Sun Mar 22 13:52:49 GMT 1998


Thor

Telemetry data logging is not very expensive xcevers pair~$100 2 watt
amp ~$75  . Transfer rate 40kbs . To do bi directional half duplex (both
can't talk on the air at the sametime)add $75 for a second amp also
needs switch electronics . Find a ham club they may have some experts on
digital rf in the group (don't use a tnc (ham modem)they will suggest it
) it is slow ,expensive, bigger and uses much more power than the parts
I'm using.
As far as eeprom I'm using serial eeprom 8k x 8 starting with 8 chips
for 32k x 8 this  board will be placed in a db25 plastic hood for easy
removal in car.  chips 24c65 $3.00 each.
The data rate I'm using for rpm is 10 samples per second . Start slow
just put a few sensors on the car and see if you have noise problems and
fix that first . I use twisted pair instrumentation wire to keep noise
down. Then add the other sensors.
If you have any questions I'll try to answer any questions.

Steve Gorkowski

Thor Johnson wrote:

> >  Charles Moore, astronomer and developer of the Forth programming
> > language, used to use a five button 'puck' to chord 5-bit
> alphanumeric
> > input to a portable computer while driving to work.  Of course, he
> had
> > to write his own 5-bit character code, memorize it, and learn to
> chord
> > the characters by pressing the proper buttons, but what else is
> there to
> > do while parked in traffic on the Santa Monica freeway?
>
>   Very interesting.  Is this where the Bat keyboard came from?
>
> >  I don't think that I could drive and program at the same time; I
> tend
> > to get tranced out when programming.  Of course, the average
> cellphone
> > user can't talk and drive at the same time either...
>
> I wasn't actually thinking of tuning the thing while driving it (my
> app
> being FSAE and all.  The vehicle dynamics of ours forces you to work
> very
> hard keeping the thing on course).
>
>   Every time I see something like "ProTune" or whatever that logs the
> data
> from
> the ECM, I wonder, "what does this mean" during playback.  I know more
> about
> electrons than gasoline, so much of the "history" is all but useless
> to me;
> I really would like a vizualization thingy that you could use to
> *generate*
> the tables reqd (since I don't have clue how they *really* ought to
> look).
>
> One of the things that I keep running into with my supersimple efi is
> the
> data logging question.  Telemetry would cost too much.  Anybody
> interface
> a serial flash or sram (ie. cheap) to a 68hc11?
>
> How much data is necessary?  If I log every point at every rev, I get
> ~5K/sec,
> (@13K RPM) which after 20 minutes is about 5M.  I know I won't be
> running
> full
> RPM throughout the course (which will make timestamping this
> difficult), but
> keeping that qty of data in the ECM seems a little much....but I don't
> know
> what
> I could throw out.
>
> Parameters I would like to watch (guessing!):
>  Bytes  Name
>  2              RPM (actually, Trev)
>  1x4            Each cylinder's injector width
>  1x4            Each cylinder's oxygen sensor reading
>  1              Intake Air Temp
>  1              Engine Coolant Temp
>  1              Throttle Position
>  1              MAP
>  1              *Gear / Speed
>  1x3            *Accelerometer
>   * indicates that I don't have these yet.  I am going for the "too
> many
> sensors" award!
>
> Any ideas on what I should throw out?  And how often I should log
> this?
> Also, any help on interfaceing a high-capacity memory chip to the
> 68hc11
> would be
> appreciated.
>
> TIA,
> -Thor Johnson






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