Shiftlight

[jbs_racing]

Anyone got an idea for a DIY shiftlight?

I've tried searching everywhere but dont seem to find anything good.

[THAWA]

I've never quite understood the concept of the shift light, care to explain it?

[ciper]

Well the good ones can be set for a different RPM depending on the gear, letting you use your dyno numbers and gear ratio to determine the best RPM to shift at for maximum speed. I still dont quite understand why different RPM would be faster in each gear but I take everyones word for it.

[vrg3]

Most shift lights just turn on above a certain engine speed. More sophisticated ones take into account engine load.

If it's the simple kind you're looking for, what you're looking for is an LM2917 IC. It's a frequency-to-voltage converter with a comparator built in. You could basically do the whole thing with just that chip and some passive components.

Relevant Nabisco threads:

http://forums.nasioc.com/forums/showthr ... did=444703
http://forums.nasioc.com/forums/showthr ... did=437633

[jbs_racing]

Would the LM2907 work to?

I cant seem to find the LM2917 here in sweden.

Do You know how to build a circuit that would work with this IC?

What other components would I need?

I just want to have it for fun since I allready know where to shift my car.

So, how should i do to make the led light up at about 6000 --> 6500 rpm?

Thanks by the way

[vrg3]

The LM2907 would work but it doesn't have the built-in zener diode so you'd have to use some kind of regulated voltage source.

I haven't built a circuit around these for our cars myself, but I've used the chip in other applications. Have you played around with electronic circuits before? It shouldn't be hard to come up with the right components after measuring the tach waveform and doing some calculations.

[jbs_racing]

I believe that I am an amature in this area.

I have done lots of things like this before, but never calculated anything that has anything to do with voltage or anything like that...

I would be really glad if you could help me out with this

I dont really know how to calculate it so maybe you could help with a layout over a shiftlight?

Thanks

[jbs_racing]

I found som pictures on the internet.

Would this work?





I found it in this html file, but dont know where on the net I found it.

http://home.swipnet.se/aspv-24/temp/shift2%5b1%5d.htm

[vrg3]

That seems a bit hard to follow... But I guess it's a 2-stage shift light of some type.

Here's what I think you might want:

http://www.graphics.cornell.edu/~v/pics/shiftlight.png

I came up with those numbers just through some quick calculations, but they ought to work okay. You adjust the 10K potentiometer to choose the trigger RPM, and the output sinks up to 50mA when activated.

Pardon the hand-drawn schematics. :)

[jbs_racing]

Thanks

That dont seem to hard to do.

I will test this as soon as I get my car going again.

The second gear in the transmision is no longer existing, its the second time I wreck my gearbox in 3 month.

Sorry for my bad english, im as you can see from Sweden.

[vrg3]

Let us know if it works.

How are you killing so many gearboxes?

And I'm having no problem understand anything you're saying.

[Psycho_Schmit]

So Mattias my man... so u have the drawings to shiftlight now... well i copied them too so i can test it on my car then i send u a message if it works...
well well
C Ya on the road...
// Psycho

(hehehehe vitlök)

[aspect]

get one of these

http://www.gr8wheels.com/catalog/item/209175/21834.htm

much much much better than a standard on/off lamp.
i've got one in my leg, really good for high speed gravel road adventures =D

[vrg3]

You could actually take the output from an LM2917 and feed it into an LM3914 (the same chip that drives most "air/fuel ratio" gauges) to get the same effect with up to 10 LEDs.