I have a 98' lude and I am an electrical/computer engineering major (yeah it sux!) at Univ of Florida. Here's my idea... remember the nissans (i think) that had the little heads-up digital display that reflected off the front glass so you could see how fast you were going without taking your eyes off the road. Well I always thought this was pimp and I don't know why that feature never made it into more cars.

Anyhoo, All i need is some sort of voltage signal that indicates how fast the car is going. Does anyone know of any wires that feed into the speedometer (or cruise control) that give out a voltage that i can tap into. For example: In order for the speedometer to move the needle i think it must have some sort of voltage/current going to it... if i can get that voltage i can send it through a A/D converter and get a digital readout (through some conversion table) and display that on some leds.

I just need to know what wires to tap into w/o having to take the dash apart and hack the **** out of all the wires there!

 

that would be cool good luck

 

Here is a pic of a heads up display in a corvette:

Also, here is a premade HUD unit I found:
http://www.machv.com/headupdisboo.html

Pretty cool... but i think i can make mine for cheaper and if i make it then i can customize it how i want it. Any ideas on where to get the LED's I need?

 

I have a defi hud, its worth money. I bought it for 160 shipped but i forgot where. Just do a search on defi hud on google or somthing shouldnt be to hard to find

 

you just need to find the speed wire going to the dash. the speedo's nothing more than a coil, and of course the voltage is what changes it's position. It's just the same as the tach, you can detech the signal via measure it for AC at the injector or behind the dash (believe it's still a blue wire back there also). Which is the speedo... don't know. it's back there somewhere. Grab a DMM, rip your dash out, and measure while adjusting your speed (granted you don't have to go fast and is best done in a nice big parking lot).

 

RJR162: Cool... i guess that will be a DC voltage? I think it won't be too hard then to send it to a DAC so i can get a digital value for this.

I was reading and i came upon a few cool sites. Is there a way I can just make something that will connect to the cars computer and get the speed/rpm info from there? If i did that then i could display cool system info also. Check this guy's site out: http://hud.cz28.com/

HEIYU: How easy was that Defi HUD to install, where does it plug into to get it's information? Does the lights around the digits show your RPMs?

I am still kinda confused on a few terms (since I am new to this)... What does ECU, ECM, ALDL mean? Will any of these help me interface with the cars computer to get system info?

I have an HC12 microcontroller (I am in Microelectronics class now) and that's what I plan to use to run this entire system with!


Modified by davem at 5:32 PM 4/21/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by davem &raquo;</TD></TR><TR><TD CLASS="quote">RJR162: Cool... i guess that will be a DC voltage? I think it won't be too hard then to send it to a DAC so i can get a digital value for this.[/i]</TD></TR></TABLE>

You're going the long way around... just feed the voltage into a suitably scaled digital voltmeter module and you're done. Of course if you *want* to use a micro, fine, but it's probably unnecessary. BTW, PIC chips are perfect for this sort of stuff, the HC12 is a little overkill.

 

KB58: That's true, but i'll have to use something to scale the voltage to show the appropriate MPH, and using the micro would be nice cause i could have a nice display then... plus i want to be able to maybe hook up to the computer ECU to get more vehicle information (whatever good system info i can grab from the ECU) and display that on another LCD panel.

Does anyone know how to wire it to the Honda ECU to get system information, such as speed, rpms, other diagnostic info, etc?

 

I understand regarding the other info you might want, but back to the simple DVM for a moment. Scaling is not an issue. Just use a resistor divider on either the input or the reference, depending if the reading needs to read higher or lower.

 

http://www.intellitronix.com

just take one of their digital speedos apart

 

KB58: True, I gues that would work just fine as long as i got the scaling factor correct. I guess I really just have to take the dash apart and find those wires and start testing!

JDM LUDE: Cool site, thanks. Pretty $pricey$ though... but their gauges gave me a good idea for the layout of mine. The parts (the led's themselves) would only be about $10-$20 to make a display that looked like theirs and the only other cost of my project would be resistors, wires and (if i deem it nessessary) the microcontroller - which i may not even need if i do it KB58's way. So $600 or less than $100... no contest

I'll keep posting what i find on this message board so anyone else can try and put it in their cars, cause it should be really cool when i'm done.

If anyone has any other good ideas, post 'em up... also still wondering about that direct connect to ECU question and also if anyone knows where i can get VFD's or superbright LED's for cheap.

 

Go Seminoles!

 

Com'mon man, you've gotta be kidding me... Go Gators baby!!!! I have to give it to Tally though, got a lot of friends there and it's almost as good a party scene as it is here!

 

yea really easy to install just tap into speed signal, tach,ground and 12v power. It shows rpm too but i never use it, its alittle slow to react to my auctual engine speed. Its really nice having your speed displayed on your windshield. i recommend it if you have the money.