MPGuino additon? BIG instant speed?

[gtkid2002]

Howdy everyone, I am almost about to get an MPGuino, but I want to see if I can clarify a question about it. Would it be possible with the stock chip, to add a BIG speedo readout?

Here's why:

I drive an '89 Prelude Si. It uses a mechanical speedometer. The 90/91 Preludes do not. Now, the problem with the 88/89's is a gear on the inside of the speedometer wears out. Then your speedo no longer works when YOU want it to, but at it's own discretion. So I almost need the mpguino to double as a speedometer, with the function of the mpg gauge secondary.

Would it be possible to reflash it with a sort of display setting # 10 or something that has a large Instant speed, and a smaller current mpg rating underneath it perhaps?

I don't know about programming, but if it can be done, I'll fork out and get it as soon as I have the extra cash so I can do this. Otherwise, I have to put this on a back burner. I don't mind if I have to overwrite one of the other display settings, I will just learn to get around that one.

I pretty much plan on removing my stock speedo needle, and putting the MPGuino in a fancy case (the LCD anyways), and putting it on top of my speedo.

Why all the extra effort? Because it's a PITA to gauge speed at night with a double yellow to your left. It can be done, but if I'm sleepy or exhausted, I don't want to. That, and oncoming makes doing that a pain.

[SVOboy]

I'm sure you could do it if you wanted to dig in the code a bit.

A gauge cluster can't cost much for that car though, $20?

[McTimson]

It could easily be done, but you need to make sure your odometer is accurate before you do it, or you'll have a tougher time calibrating it.

Lines 263-274, and 532-565 define the different screens, all you have to do is change something like this:
(line 267)

  doDisplayBigInstant,

(line 540)

void doDisplayBigInstant() {bigNum(instantmpg(),"INST","MPG ");}

to this:

void doDisplayBigInstant() {bigNum(instantmph(),"INST","MPH ");}

And line 267 could remain the same.

You could add another screen, but it might increase the sketch size too much, so it might not fit on the ordinary board.

Changing how the stuff is displayed is easy, if you root through the code around those line numbers, you should be able to figure out how it works. You can use something like Notepad++ to show line numbers if you don't have a program to do it already.

[gtkid2002]

Oh sweet. Thanks for the codingness McTimson~

@SVOboy:
A gauge cluster for my car isn't really an option for me. The lone part I need has to be from the same year, which my local scrap yard does not have. The other option is to buy the part online, but that runs 50 bucks, not including shipping. That, and due to the fact that it's a cluster that reads out everything on my car, I don't want to risk screwing that up. I trust myself to work on computers and engine work and such, but the threat of ruining an entire cluster scares the crap out of me.

@McTimson:

I think i'm going to try to get my hands on the code so I can play with it. I tried getting into arudino *cant spell, don't care* a while back, but I've always been limited to the budget. It's tempting to run an arudio for the sole purpose of my speedo, then get an MPGuino so I don't have to worry about screwing one up too much.

Heh, an LED "analog" needle sweep would be pretty wicked for a speedo. Have it move up a set of LEDs per 5Mph. Make another one to move up and down per 5Mpg or something too.

Ugh, just talking about this stuff makes my head explode with ideas.

[Nevyn]

Agreed. I'm willing to poke the code for you too, if you'd like, and send you a modified file.

You did give me another idea, though. Make a "speedometer" out of tiny surface-mount LEDs. Have it light up in a "sweep" motion like an analog gauge for speed, but have the length of the "needle" change to indicate MPG.

[nickdigger]

Originally Posted by gtkid2002

I drive an '89 Prelude Si. It uses a mechanical speedometer. The 90/91 Preludes do not. Now, the problem with the 88/89's is a gear on the inside of the speedometer wears out. Then your speedo no longer works when YOU want it to, but at it's own discretion. So I almost need the mpguino to double as a speedometer, with the function of the mpg gauge secondary.

Hope i'm not missing something here, but if your speedo is mechanical, do you even have a VSS?? And without a VSS, isn't the mpguino basically a paperweight?

[dcb]

Originally Posted by nickdigger

And without a VSS, isn't the mpguino basically a paperweight?

Lol, no it will still keep track of your injectors and track fuel consumption. Typically cars have some sort of distance/speed instrumentation built in and you just have to do the math in your head or on paper till you get good at it.

[gtkid2002]

Yeah, it would be, but the ECU needs it to keep track of the cruise control. No cruise control, no VSS, no MPGuino. The cable that powers the speedo gearbox is for that, and the odometer.

On another note, I wish I could merge threads. I'm gonna hopefully do the needle sweep idea with the MPGuino Mega, and hopefully have another one for gas consumption as well, and both of them with an LED driver if that works as I think it does.

[americasfuture2k]

so has anyone tried this yet to see if those code mods work? im not seeing any objection to it, so im guessing it does. but some clarification would be grand.

[gtkid2002]

That would be cool if someone could test it, but If not, no matter. I'll hopefully have this whole thing up and running before October, but that depends on a lot of things.