Welcome to the North American Subaru Impreza Owners Club Wednesday September 17, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Electrical & Lighting

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 01-22-2004, 07:56 PM   #1
ursine
*** Banned ***
 
Member#: 51771
Join Date: Jan 2004
Location: San Diego
Vehicle:
2000 Impreza GC6 SRP
1980 G2 Celica Rally Taxi

Default Any Electrical Engineers out there?

I need help devising something.....

I want to put in a gear display that will tell me what gear I am in on the dash. I figure I can take the RPM's and the MPH and write a small program that will determine what gear I am in and output the results onto a little screen.

Does anyone have the know-how to be able to build something like this or teach me how to do it? I know it cant be something that complex and could probably be done with stuff from Radio Shack, I just dont know how to do it.

Check out this thread to see more information about it:
http://forums.nasioc.com/forums/show...hreadid=488950

-Branden
* Registered users of the site do not see these ads.
ursine is offline   Reply With Quote
Old 01-22-2004, 10:46 PM   #2
Timex
Scooby Newbie
 
Member#: 49317
Join Date: Nov 2003
Location: Virginia
Vehicle:
2003 WRX Wagon
Yellow

Default

Does the car have digital displays for RPM and MPH?
Timex is offline   Reply With Quote
Old 01-22-2004, 11:26 PM   #3
ursine
*** Banned ***
 
Member#: 51771
Join Date: Jan 2004
Location: San Diego
Vehicle:
2000 Impreza GC6 SRP
1980 G2 Celica Rally Taxi

Default

No it does not, its just the standard old MY00 gauges.

-Branden
ursine is offline   Reply With Quote
Old 01-22-2004, 11:32 PM   #4
Mulder
Trust no one
Moderator
 
Member#: 11170
Join Date: Oct 2001
Chapter/Region: Tri-State
Location: NYC
Vehicle:
02 WRX
15 WRX/05 GTO

Default

They are analog gauges, but electronically pulse-driven.
Mulder is offline   Reply With Quote
Old 01-23-2004, 12:00 AM   #5
c_hunter
Scooby Specialist
 
Member#: 32434
Join Date: Jan 2003
Location: Wmsbg, Virginia
Vehicle:
05 Outback XT 5EAT
Gold/Black

Default

You need to pick off the signals coming from the VSS (speed sensor) wire and RPM wire, then it should be possible to feed the signals into a programmable microprocessor and have it control an LED "digit" display. I'm a Mech Engr and haven't done this kind of thing for years, but any EE should be able to do it!

I'd be interested if someone figures it out. I think this would be cool. I'll have to talk to a buddy at work, maybe he can help.

Craig
c_hunter is offline   Reply With Quote
Old 01-23-2004, 03:41 AM   #6
ursine
*** Banned ***
 
Member#: 51771
Join Date: Jan 2004
Location: San Diego
Vehicle:
2000 Impreza GC6 SRP
1980 G2 Celica Rally Taxi

Default

Any help would be greatly appreciated, I would like to be able to figure this out.

-Branden
ursine is offline   Reply With Quote
Old 01-23-2004, 02:42 PM   #7
elsanto
Scooby Specialist
 
Member#: 34832
Join Date: Apr 2003
Chapter/Region: Tri-State
Location: was once a nut like me.
Vehicle:
1989 M3
White

Default

i'll ask my roomate to look at a schematic if you have one.. but if i remmeber right the cluster didnt have any chips on it.. it was all analog which would probably mean that the ecu is modulating the voltage to adjust the gauges. might be tricky to do w/o fubar'ing the cluster.. if you have the schematic i'll gladly run it past him he designs heart monitors for a living i think he could handle this
elsanto is offline   Reply With Quote
Old 01-23-2004, 03:10 PM   #8
ursine
*** Banned ***
 
Member#: 51771
Join Date: Jan 2004
Location: San Diego
Vehicle:
2000 Impreza GC6 SRP
1980 G2 Celica Rally Taxi

Default

I will see what I can do, check out the other thread (link in first post) for more info.

-Branden
ursine is offline   Reply With Quote
Old 02-01-2004, 09:39 PM   #9
vrg3
Scooby Specialist
 
Member#: 25796
Join Date: Oct 2002
Location: Cleveland, OH (sometimes DC)
Vehicle:
1993 Legacy Turbo
Burgundy

Default

I bet you could do it without microcontrollers.

When I have more free time I can come up with something more concrete, but here's what pops into my head:

If you tap the ECU's "tachometer output" wire, you get a 0-12v square wave whose frequency depends on RPM.

If you tap the ECU's "vehicle speed sensor" wire, you get a 0-5v square wave whose frequency depends on engine speed.

If we're lucky, one of these is always at a higher frequency than the other. I would guess the tachometer signal is higher frequency than the VSS. Let's work with this assumption for the moment.

Set up a counter to count clock pulses from the tach signal (through a frequency divider if necessary). On the rising edge of the VSS signal, reset the counter. On the falling edge of the signal, store the counter's output into a latch. Connect the output of the latch to a decoder.

If done right, each of the decoder's outputs will be active only in a particular gear (modulo clutch slippage or being in neutral, although the latter can be detected via the neutral switch). These can drive a little LED single-digit display with a bunch of diode logic OR gates.

Hm, in words it probably sounds much more complicated than it is. And I'm sure someone well versed in microcontrollers could do it in like 2 seconds with almost any PIC or AVR. Oh well.

It would be useful to know the actual VSS and tach signal frequency specifications.
vrg3 is offline   Reply With Quote
Old 02-01-2004, 09:46 PM   #10
brunetmj
Scooby Specialist
 
Member#: 8023
Join Date: Jul 2001
Location: Way-upstate , NY
Vehicle:
2004 2.5 RS

Default

I have never looked under the boot but had an idea for a low tech approach.. would it be possible just to add some small push switches that hit the shifting shaft while in it's various positions? They could activate some different color bulbs? Well just a thought.
brunetmj is offline   Reply With Quote
Old 02-01-2004, 09:50 PM   #11
vrg3
Scooby Specialist
 
Member#: 25796
Join Date: Oct 2002
Location: Cleveland, OH (sometimes DC)
Vehicle:
1993 Legacy Turbo
Burgundy

Default

Even if there isn't room down there in the stock arrangement, maybe you could probably cut an appropriately-sized H-gate into some sheet aluminum or something with microswitches mounted on it, and mount it level with the center shifter console.
vrg3 is offline   Reply With Quote
Old 02-01-2004, 10:40 PM   #12
Silverwheels
Scooby Newbie
 
Member#: 51076
Join Date: Dec 2003
Chapter/Region: South East
Location: Charlotte, NC
Vehicle:
2004 WRX Sti
Baby-Rattle Blue

Default

I like brunetmj's and vrg3's approach. You can use push buttons, Hall effect or reed switches with magnets, or optical sensors. Just run the switch outputs into an encoder, then to a decoder/driver and 7-segment display. Can't remember the CMOS chip numbers at the moment, I'm despondent over my Panthers -
Silverwheels is offline   Reply With Quote
Old 02-03-2004, 10:02 AM   #13
the spacecowboy
Scooby Newbie
 
Member#: 765
Join Date: Jan 2000
Location: westernport,md,usa
Default

if its a 5 speed, you could make a device that triggers a sensor that will display what gear you were in....I had a idea like that for my motorcycle....each time you shifted up or down, it hit a switch that then would increase the number up or down...

should of read the previous post....

space

Last edited by the spacecowboy; 02-06-2004 at 12:10 PM.
the spacecowboy is offline   Reply With Quote
Old 02-03-2004, 06:01 PM   #14
WhatleyWRX
Scooby Specialist
 
Member#: 6634
Join Date: May 2001
Location: Boise, ID
Vehicle:
2002 WRX Sedan, Dirt
with some Silver patches

Default

I'm going to go with vrg3 on this one. That would be the way to go. Pipe that baby into a microcontroller and let it run the logic. Those things are cool as hell. I got an intelligent intercooler sprayer setup with one of those that is neat as hell.

Whatley.
WhatleyWRX is offline   Reply With Quote
Old 02-03-2004, 09:44 PM   #15
ursine
*** Banned ***
 
Member#: 51771
Join Date: Jan 2004
Location: San Diego
Vehicle:
2000 Impreza GC6 SRP
1980 G2 Celica Rally Taxi

Default

What are they and where can you find them?

-Branden
ursine is offline   Reply With Quote
Old 02-03-2004, 10:09 PM   #16
KoneKiller
Scooby Specialist
 
Member#: 39191
Join Date: Jul 2003
Location: Houston
Vehicle:
2004 WRX STi WRB
Red 1990 Spec Miata

Default

KoneKiller is offline   Reply With Quote
Old 02-04-2004, 05:58 PM   #17
wagman01
Scooby Specialist
 
Member#: 3894
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: Royal Oak, MI
Vehicle:
2002 WRX Wagon
Battlewagon Black

Default

Quote:
Originally posted by Silverwheels
I like brunetmj's and vrg3's approach. You can use push buttons, Hall effect or reed switches with magnets, or optical sensors. Just run the switch outputs into an encoder, then to a decoder/driver and 7-segment display. Can't remember the CMOS chip numbers at the moment, I'm despondent over my Panthers -
I was going to suggest using microswitches or optics as well. Somewhat akin to an arcade joystick.

You could have the 7-seg display wired so it showed a mirror image, then put it on top of the dash to do a HUD type thing.

Or you could put a gyroscope in the shifter knob
wagman01 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Any Industrial Engineers out there? wakeboarder109 Mid Atlantic Impreza Club -- MAIC 9 01-15-2008 08:35 PM
Meth specific question....any chemical engineers out there? banzai Water/Methanol Injection, Nitrous & Intercooler Cooling 4 06-05-2006 08:27 PM
Any Mechanical Engineers out there? 5spdfrk Off-Topic 79 01-11-2006 01:29 PM
Any auto engineers out there? wrxsubaru Off-Topic 7 09-27-2004 08:33 PM
OK Igg, Idjiit, and any mechanical engineers out there.... -=C=- Off-Topic 23 08-01-2003 02:21 PM


All times are GMT -4. The time now is 12:48 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.