ReverendDexter
ReverendDexter SuperDork
10/31/11 9:21 a.m.

Okay, so I know next to nothing about electronics, but figured this would be a good learning project.

I'd like to make a shift-light for my car. Not a drag-race style one with the single-light, but the formula-car style one with the 4-6 lights that light up progressively.

I figure what I'll need is to get the tach signal, figure out how to decode that to rpm, then figure out how to light up each LED at the rpm I want it to light up at. I'm guessing one of the hobbyist PCU boards will be the way to do this (Ardiuno?).

Anyone done this or something similar that could give me some pointers?

If it's relevant, this would be going in my '90 5.0.

N Sperlo
N Sperlo SuperDork
10/31/11 9:25 a.m.

I'm sure you can make one relevant to RPM. Downside, all it is, is an LED tach.

I'm more interested in removing the shift light in my Focus. Damn thing drives me nuts.

Donebrokeit
Donebrokeit Reader
10/31/11 9:38 a.m.

I know Summit racing sold a kit (I have used one) that would turn on any type of 12V item at almost any RPM. You could get three of them and place different color light in a housing to show what your current RPMs are.

Paul B

ReverendDexter
ReverendDexter SuperDork
10/31/11 9:45 a.m.
N Sperlo wrote: I'm sure you can make one relevant to RPM. Downside, all it is, is an LED tach.

That's actually kinda the point... just want to be able to see with my peripheral vision certain key rpms.... first torque peak, second torque peak, peak hp, shift, no-point-to-rev-this-high-why-haven't-you-shifted-already!

I was also going to tie it in to having a light for brakes and one for WOT, so I could record this all with my camera and have some sort of feedback system for myself.

Keith
Keith SuperDork
10/31/11 9:56 a.m.

I looked into this a while back, and ended up using a commercial Revlight instead. I figured I couldn't match it for the price, and the fact that it auto-dimmed was nice. That product is gone, but the Shift-I is a nice replacement. More expensive.

Googling "DIY LED tachometer" will get you a number of leads. I remember this one looking pretty good: http://www.niksula.hut.fi/~mdobruck/siililand/mini/diy/alien/tacho/tacho.html

They're really nice to have. I put one on the Targa Miata as well as my Locost.

video of the Targa Miata in action - you can see in this one how the tach will actually flash once all the lights are lit, which means it acts as a shift light as well.

DavidinDurango
DavidinDurango Reader
10/31/11 11:01 a.m.

That's actually kinda the point... just want to be able to see with my peripheral vision certain key rpms.... first torque peak, second torque peak, peak hp, shift, no-point-to-rev-this-high-why-haven't-you-shifted-already!

I was also going to tie it in to having a light for brakes and one for WOT, so I could record this all with my camera and have some sort of feedback system for myself.

>>>>>>>>>>>>>>>>>>>>

Great idea. Don't let the haters get you down.

I had a guy check you my "data acquistion" (video camera, lights, and some gauges) and kind of chuckle.

Next track day I was getting low oil pressure at various points - but 5ive minutes w/ the video and I knew where, how low the pressure actually was, AND that it wasn't really a threat to anything. chuckle chukle.

I use a vacuum gauge, adjustable oil pressue lite, brake lite, oil temp/water temp and oil pressure gauge. Fancy? no. Ultra high tech? no. Affordable and works hurrah!

Check FM for the revlight thingie - I think i have 3.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
10/31/11 11:07 a.m.

DIYAutotune asked what sort of "starter kit" they could produce for people just learning to solder before they jump into a megasquirt setup.

I believe a sequential shift light is what most people wanted. Maybe Matt will pop in and tell us something?

N Sperlo
N Sperlo SuperDork
10/31/11 11:08 a.m.

I'm not hating. I like the idea, just thought you were aiming for something else. I'm actually intrigued by the idea and am waiting for a, "This is how ya do it!" I'm a HAM radio guy and therefore want to know EVERYTHING electronic.

Keith
Keith SuperDork
10/31/11 11:42 a.m.

Well, I DID post "this is how ya do it". Or a link to a circuit diagram anyhow. A ham shouldn't need anything else They're built around a LM3914, which is basically designed exactly for this purpose.

A lot of the guys building homebrew tachs tend to make massive arrays. Honestly, about 5-7 works well.

The Revlight (tm) that I use in my cars is no longer available, sadly. But the Shift-I is a lot easier to program. For the price of a Revlight, it wasn't worth building my own. For the price of a Shift-I, it's more likely.

JoeyM
JoeyM SuperDork
10/31/11 11:56 a.m.
92CelicaHalfTrac wrote: DIYAutotune asked what sort of "starter kit" they could produce for people just learning to solder before they jump into a megasquirt setup. I believe a sequential shift light is what most people wanted. Maybe Matt will pop in and tell us something?

Thanks....I was going to mention his post

Giant Purple Snorklewacker
Giant Purple Snorklewacker SuperDork
10/31/11 12:02 p.m.

A HAM guy will make his own serial port programmer, install the avr toolchain on his linux box, learn C, and use an Atmel atmega8 just to make a programmable shift light with LCD RPM readout.

If you just want a progressive shift light before the sun goes out a freq to voltage converter is cheap and easy.

Keith
Keith SuperDork
10/31/11 12:15 p.m.

My exposure to HAMs (and technically, I are one but I'm not active) comes from the pre-computer crowd. They'd totally build one out of a LM3914. But I imagine things have moved on in the past few decades.

MadScientistMatt
MadScientistMatt SuperDork
10/31/11 12:22 p.m.
92CelicaHalfTrac wrote: DIYAutotune asked what sort of "starter kit" they could produce for people just learning to solder before they jump into a megasquirt setup. I believe a sequential shift light is what most people wanted. Maybe Matt will pop in and tell us something?

Yes, we're still planning to do this. We've taken it as far as a preliminary desing. It's just there are a couple other things competing for the R&D time right now. It's a similar idea to Keith's.

N Sperlo
N Sperlo SuperDork
10/31/11 12:23 p.m.
Giant Purple Snorklewacker wrote: A HAM guy will make his own serial port programmer, install the avr toolchain on his linux box, learn C, and use an Atmel atmega8 just to make a programmable shift light with LCD RPM readout. If you just want a progressive shift light before the sun goes out a freq to voltage converter is cheap and easy.

+1

Because I'm also lazy.

turboswede
turboswede SuperDork
10/31/11 2:31 p.m.
Giant Purple Snorklewacker wrote: A HAM guy will make his own serial port programmer, install the avr toolchain on his linux box, learn C, and use an Atmel atmega8 just to make a programmable shift light with LCD RPM readout. If you just want a progressive shift light before the sun goes out a freq to voltage converter is cheap and easy.

You've met my Dad? (he is a HAM and he built a TSD rally clock from scratch and coded it in assembly. He is also is using an Arduino for DRO on his Lathe and Milling machine)

wclark
wclark New Reader
10/31/11 4:06 p.m.
ReverendDexter wrote: I was also going to tie it in to having a light for brakes and one for WOT, so I could record this all with my camera and have some sort of feedback system for myself.

I have something similar in my hillclimb car. Google"thewalterclark1" and "youtube" and watch any of my racing videos.

The shift light is driven by an LM2917 frequency-voltage converter. The input is set up to connect to the coil - with suitable DC offset and clamping to work with a noisy coil signal. The output comes on at a user settable RPM and drives the yellow LED you see as well as a high intensity white LED mounted in my stock second gen Golf instrument cluster - that one replaced a useless low output yellow LED that originally was a "shift reminder" located top-center in the cluster. I can send you a copy of the schematic if you want.

N Sperlo
N Sperlo SuperDork
10/31/11 4:16 p.m.

In reply to wclark:

I started to watch, but nearly had a heart attack when you spun out. I couldn't see it. Where is it???

EDIT: Watched the full run, but still never saw the LED tach. Nice driving, though.

DOUBLE SUPER NINJA EDIT: FOUND IT! Sunday driver video.

wclark
wclark New Reader
10/31/11 5:05 p.m.

In reply to N Sperlo:

My most recent video-post, spinning at Mt Philo, was me braking at exactly the wrong point going into that short-right-over-crest into-long-left shortly after start. Not much to see regarding the 3 LEDs. My older videos show the lights better. The 2011 vid's are from a camera mounted on the roll cage abut 3 feet from the LEDs and the 2010 and older are from a camera mounted about a foot from them - at the dash. In the earlier ones the LEDS are easier to see but I cant see what I am doing which can be helpful when reviewing a run.

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