Heads up display

Fri May 26 15:59:34 GMT 2000

This will probably be no help at all to you but......
I made a video projector once out of a pocket tv (with an active matrix 
display) Take it apart, lay it on an overhead projector, voila.
When it's not on it looks like tinted glass. The other(non active matrix) tv 
won't work for a video projector but you can see through the display when 
they are powered on or off. It's not a great picture but it might be an 
idea.
The displays can be had very cheaply. I got mine at a pawn shop for about 50 
bucks if I remember, it might be easier to adapt the circuitry in one of 
these than to start from scratch, on the other hand you might keep an eye 
out for an XT laptop. You could probably find one for next to nothing$$.

Probably no real help,
Kelly

>From: Dan Gentry <dang at seanet.com>
>Reply-To: gmecm at diy-efi.org
>To: gmecm at diy-efi.org
>Subject: Re: Heads up display
>Date: Fri, 26 May 2000 07:10:29 -0700
>
>Um, whoops.  See below.
>
>Peter Gargano wrote:
>
> > Did you have a message hidden somewhere within the ">" quotes?
>
>Dave Hempstead wrote:
>
> >  Hi Dan,
> >     Well I can tell you what I know about HUD's and PCM's.  In your 95
> >  Z28, your PCM has software in it for a HUD.  It collects lots of data
> >  from its sensors, and sends it to some HUD hardware.
>
>
>Right.  I don't know if it's a question of having HUD-specific software in 
>the ECM or
>not though.
>
>
> >      Now, never having seen the HUD or the hardware driving it, I can't
> >  tell you how to hook it up, but it sounds like you have some ideas
> >  there.
>
>Yup - I've been lucky enough to find two "friendly" auto dealers here in 
>the Seattle
>area that were kind enough to let me leaf through service manuals and get 
>photocopies of
>some
>rather important data.
>
>
> >      Also, I BELIEVE that you may need to set a bit or two inside the 
>PCM
> >  to enable the HUD.  I'm not sure here, because I haven't studied the 
>HUD
> >  code in that much detail (usually I just skip right past it), but I'm
> >  not sure if it is always enabled, or if it is enabled by plugging in 
>the
> >  HUD hardware.
>
>Oooh, I didn't know that.  Interesting.
>
>
> >     Having said all of this, I am now wondering if we are talking about
> >  the same HUD's or not.  It is my understanding that the 94/95 PCM's
> >  drive a HUD for GM's test purposes.  However, maybe the HUD is one and
> >  the same.
>
> >     Maybe you can enlighten us on what HUD's you know about, and what
> > they are available on.
>
>
>Okay - here goes.
>
>I know for sure that 1999 & 2000 Corvettes and (at least) 1994->2000 Grand 
>Prix models
>have the Heads-Up Display as an option.
>
>I'm casually aware, but not sure in any detail that other GM models have 
>HUDs (Olds,
>Buick, etc).
>
>GM's HUDs are made by Delco Electronics (naturally!), and have the trade 
>name of
>"Eye-Cue".
>
>GM Vehicles equipped with HUDs have a special windshield that is a sandwich 
>of different
>materials to make the HUD image clearer.  I'm assuming that the special 
>quality of the
>material (referred to as PVB in Delco's literature) is some kind of 
>polarizing filter.
>
>The HUD units that I've been able to read about in service manuals are 
>single enclosed
>units with display, optics, and adjustment motors enclosed in a neat and 
>tidy  package.
>
>I do not know if there is enough space behind a Camaro dash to install a 
>Vette or GP
>HUD.  Some mods would certainly be required.
>
>The part number of the HUD on 1994-1996 Grand Prix models is 16141842.  
>HUDs from this
>era that are defective are sent to a third party (Instrument Sales and 
>Service here in
>Seattle, and others across the country).  They will not sell a HUD without 
>an defective
>exchange.  (Darn!)
>
>The GP HUD shows Speed, Turn Signals, and other idiot lights.  It gets 
>speed data from
>the PCM at the rate of 4000 pulses per mile.  The PCM gets it's data from 
>the Vehicle
>Speed
>Sensor.   The manual states that the output of the VSS is a sine wave.  I'm 
>assuming
>that once the analog output of the VSS hits the computer it gets converted 
>to something
>a little
>more TTL.  The output from there goes to the instrument cluster.  BTW: Does 
>anyone know
>the specifics of this signal so I don't have to go buy an o-scope to figure 
>it out?!
>
>The 'Vette HUD seems to be a much more advanced unit.  The Vette service 
>manuals don't
>have nearly the same level of wiring detail as early books do - I'm 
>assuming that there
>is a
>computer program that displays detailed diagrams in the repair bay.  The 
>HUD unit itself
>costs $992 (as quoted by the Chevy dealer) - OUCH!  The wiring harness for 
>the HUD
>looked
>like it plugged into the back of the speedo cluster, but I can't tell.
>
>There is a Japanese company (http://www.defi-shop.com) that sells an add-on 
>HUD which
>uses a polarized window film and sits on top of the dash.  I was going to 
>purchase one,
>but the information states (in the docs on the site) that the input speed 
>pulse must be
>2, 4, 6, 8, or 16 pulses per mile.
>
>Knowing that my Camaro (along with Grand Prix and Vettes) puts out 4000 
>pulses per mile,
>I didn't order it.
>
>There - now you know as much as I do about the subject.  Not much, is it?!
>
>Here's how I'm thinking about proceeding:
>
>1: Try to develop a circuit ( Basic Stamp?) that will divide the VSS pulse 
>by 1000 and
>purchase the Japanese HUD.
>2: Try to develop a whole HUD myself (again, Basic Stamp).  Use the VSS and 
>Tach inputs.
>
>3: Continue to pursue the option of finding a "used" HUD from a Junkyard. 
>(No luck so
>far.)
>4: Use an in-car computer (my MP3 player) to talk to the ALDL and get the 
>data from
>there, driving a display.
>
>
>What do you think?
>
>Dan
>
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