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Mikeys '72 Datsun 240z


mikey

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Not quite. I'll draw something up for you tomorrow when I'm not posting from my phone, but what you probably want is a transistor with a resistor going into the base as a current limiting resistor. 3K3 or 4K7 will probably cut it. Then the emitter (arrow) goes to ground and the collector to the input of the chip with a pull up resistor (4k7 or something) to 8V

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Coolies.

I always thought this was absoloutly mint to start with. Hah.

 

Exciting times man

 

EXCITING TIMES

 

Yeah, it's funny. Some of the stuff they're replacing I would've probably just lived with. But they bend up steel so fast and well that it's best just to fix everything in steel. 

 

Suits me :)

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They seem t know what they are doing.

 

I'm always scared of panel shops as the seem to charge super heaps for super average/child spec work.

 

But it looks like you're onto a winner. bootlid looks super cash.

 

Cool man.

 

Got a colour yet?

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I've fucked that up haven't I. The load needs to be collector?

 

*Edit* 

 

you bet me. OK cool. I think that makes sense but I'll await instructions :)

 

I have nothing to add here. Thought I had some advice for your tach circuit but I'm wrong.

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Yeah apparently you can't delete posts these days so I had to write something. I didn't want to leave my woffle up there and consufuse the situation though.

 

I had a yarn to Ned about this the other day. If I were you I'd bin the circuit you've built and just make the older microcontroller version. Ned can program a micro no worries. Having said that I'm 99% sure that puting in a buffer transistor to up the input signal voltage will work with your current design. Having a tach that works shouldn't be this hard! Haha.

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Having a tach that works shouldn't be this hard! Haha.

 

HAHA Couldn't agree more!

 

I could move to the older circuit. And I was planning on doing that until I thought maybe I could get away with a little mod.

 

The only little thing that bothers me about doing that is it leaves the original circuit in there and just modifies the signal. Which somehow feels dirty, and replacing the whole thing _feels_ better. Which is a fucken stupid reason really. 

 

Anyway, I'll do which ever one Ned thinks is best really. He knows a fucktonne more than me about this stuff.

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Sorry man, been sick for a few days, but from memory, this is what we did right?

- Zener diode to drop the supply voltage a couple volts

- supply instrument cluster with original voltage with a wire link from before the zener diode

- put an extra zener diode in with a lower clamp voltage now that the supply voltage is lower

qXWN2.jpg

That look/sound right to you?

I suggest you just put a transistor in... I like micros more, but the circuit works so might as well stick with it for now?

ryuxk.jpg

the resistor into the base can be anything from 1K to 10K, just whatever you have lying around already. I suggest a 3K3.

The pullup resistor from VDD to the collector and the A input can be anything from 1K to 10K as well, though i suggest 4K7-10K if you have it

You can use the same BC547 transistor as the circuit already uses, or get something like a BC337 or a PN2222A. Both pretty common NPN transistors that will work just fine.

note - you dont NEED the resistor going into the base, and can just replace the 330R with a 3K3 instead top save space etc, but i like it this way so that the transistor is an additional bit of circuitry and the original filter circuitry with the 330R and 220nF cap still operates as it did before.

I'll send a link to this post out to Cam as well and get him to check it over in case i made a big random fuck up, but pretty sure that's all gravy as it is :)

The signal into the chip will be reversed now, so when the trigger goes high, it will bring the input to the chip low and vice versa, but that shouldn't have any effect on the operation of the circuit.

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Sorry man, been sick for a few days, but from memory, this is what we did right?

 

... Lots of smart stuff...

 

Yep, that all sounds correct. Awesome, I'll do that since it should actually be the easiest route given everything is apart and stuff. I don't have the car to test on at the moment, but will do it all and then I'll have an excuse to pop out to the panel beaters and check up on progress!

 

Then the next electronics project will be getting the speedo to work! But that should actually be easier since it's all micros and digital shit + stepper motor.

 

Thanks for ya help.

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Those are some pretty hefty repairs!

 

I thought this was MINT before you started. Hah.

What was the brief to the panel shop just out of curiosity?

Fix everything that looks dodgy. Or did you tell them what to open up and or replace?

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Those are some pretty hefty repairs!

 

I thought this was MINT before you started. Hah.

What was the brief to the panel shop just out of curiosity?

Fix everything that looks dodgy. Or did you tell them what to open up and or replace?

 

Ahhhhh, yeah, so did I actually. But I can't criticise what they're doing at all, everything they've done has been fucken mint and I would've done the same thing (if I had the skillz).

 

Not much of a brief at all actually, just told them what colours, what I wanted shaved and a few other little bits and bobs. 

 

They want to fix everything up so it's all solid before paint and shit doesn't go wrong 12 months later. And I'm pretty happy about that actually. But yeah, it's more work than I thought. 

 

On the positive side, even though I would've called my car "rust free" before, it will be _absolutely_ rust free after this. And they're so quick and good at these repairs that hopefully shit wont be mega expensive. 

 

It's a car I'm keeping forever so.....

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