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From: Noozer on 28 Oct 2006 17:56
Anyone have a simple digital tachometer schematic handy?

I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine.
Fed by the TACH output of a six cylinder GMC on distributor coil.

If it isn't much more difficult, I'd like to be able to drive a bar graph of
12 to 16 LEDs as well.


From: Luhan on 28 Oct 2006 18:42
Noozer wrote:
> Anyone have a simple digital tachometer schematic handy?
>
> I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine.
> Fed by the TACH output of a six cylinder GMC on distributor coil.
>
> If it isn't much more difficult, I'd like to be able to drive a bar graph of
> 12 to 16 LEDs as well.

Since you want 'digital', you will need a microcontroller (or a
shitload of logic gates). So the hardware design is only about 10% of
the project - the rest is software.

Parle vous PIC?

Luhan

From: Noozer on 28 Oct 2006 18:53

"Luhan" <luhanis(a)yahoo.com> wrote in message
news:1162075356.005278.127430(a)h48g2000cwc.googlegroups.com...
> Noozer wrote:
>> Anyone have a simple digital tachometer schematic handy?
>>
>> I want to put a 4 digit LED tach into my van. Resolution of 50rpm is
>> fine.
>> Fed by the TACH output of a six cylinder GMC on distributor coil.
>>
>> If it isn't much more difficult, I'd like to be able to drive a bar graph
>> of
>> 12 to 16 LEDs as well.
>
> Since you want 'digital', you will need a microcontroller (or a
> shitload of logic gates). So the hardware design is only about 10% of
> the project - the rest is software.
>
> Parle vous PIC?

PIC, no...

But programming is a snap to pick up... Did some Z80, 6809, etc...

I'd love to get into it, but aren't programmers, etc. expensive?


From: Luhan on 28 Oct 2006 18:58

Noozer wrote:
> "Luhan" <luhanis(a)yahoo.com> wrote in message
> news:1162075356.005278.127430(a)h48g2000cwc.googlegroups.com...
> > Noozer wrote:
> >> Anyone have a simple digital tachometer schematic handy?
> >>
> >> I want to put a 4 digit LED tach into my van. Resolution of 50rpm is
> >> fine.
> >> Fed by the TACH output of a six cylinder GMC on distributor coil.
> >>
> >> If it isn't much more difficult, I'd like to be able to drive a bar graph
> >> of
> >> 12 to 16 LEDs as well.
> >
> > Since you want 'digital', you will need a microcontroller (or a
> > shitload of logic gates). So the hardware design is only about 10% of
> > the project - the rest is software.
> >
> > Parle vous PIC?
>
> PIC, no...
>
> But programming is a snap to pick up... Did some Z80, 6809, etc...
>
> I'd love to get into it, but aren't programmers, etc. expensive?

I did all those and more in assembler. Pic programmers start at about
$50, or build your own for a few bucks.

You could always to it with a Z80, rom, ram, and I/O chips; but PICs
start at under $1.

Luhan

From: BobG on 28 Oct 2006 19:40
Noozer wrote:
> Anyone have a simple digital tachometer schematic handy?
> I want to put a 4 digit LED tach into my van. Resolution of 50rpm is fine.
> Fed by the TACH output of a six cylinder GMC on distributor coil.
> If it isn't much more difficult, I'd like to be able to drive a bar graph of
> 12 to 16 LEDs as well.
============================================
try epanorama. This would also be a good project to learn c programming
on a microcontroller. Use a text lcd as the bar graph. Or a graphics
lcd. Look at the Olimex MT128 at olimex.com

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