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From: jasen on 28 Oct 2006 23:09
On 2006-10-28, Noozer <dont.spam(a)me.here> wrote:
>

>> 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?

You can buy an AVRISP programmer (for Atmel AVR series chips)
for about 6 bucks on ebay (it looks like a clone of one of the official
Atmel programmers)

Software's free.

thses programmers are neat as you wire them to the device you're building
and program the chip in-situ. it's all controlled from the host PC, you
don't even have to pull the cable after the program has been sent to the chip.

real handy for debugging.

I think the avr assembler is easier to pick up than pic assembler too,

Bye.
Jasen
From: pjdd on 29 Oct 2006 10:40
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.

How about doing it the old-fashioned analog way ? An
LM2907/2917 as F-V converter, and a 4 1/2-digit DVM module
for readout. Another venerable IC, the LM3914 could provide
the bar graph display, two of them for a 20-dot scale.

From: Homer J Simpson on 29 Oct 2006 10:53

"Noozer" <dont.spam(a)me.here> wrote in message
news:GmQ0h.206269$5R2.25840(a)pd7urf3no...

> 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.

http://www.siliconchip.com.au/cms/A_102835/article.html

A Digital Tachometer For Your Car

Compact design features a 4-digit LED display and a bargraph. It can also
provide gearchange indication and drive a rev limiter.




From: Tam/WB2TT on 29 Oct 2006 22:03

"Noozer" <dont.spam(a)me.here> wrote in message
news:GmQ0h.206269$5R2.25840(a)pd7urf3no...
> 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.
>
Build a frequency counter, and pick the right gate time. I think if you make
the gate time 1/300 of a minute, the display will show RPM/100. Make it
1/30th of a minute (2seconds), and it will display RPM/10. There is a common
coil?

Tam


From: default on 30 Oct 2006 08:17
On Sun, 29 Oct 2006 22:03:50 -0500, "Tam/WB2TT"
<t-tammaru(a)c0mca$t.net> wrote:

>
>"Noozer" <dont.spam(a)me.here> wrote in message
>news:GmQ0h.206269$5R2.25840(a)pd7urf3no...
>> 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.
>>
>Build a frequency counter, and pick the right gate time. I think if you make
>the gate time 1/300 of a minute, the display will show RPM/100. Make it
>1/30th of a minute (2seconds), and it will display RPM/10. There is a common
>coil?
>
>Tam
>
That's too obvious.

I'd stuff a down counter with a preloaded number corresponding to some
very high RPM then use the tach signal to gate a series of pulses from
a crystal oscillator into the counter.

Sort of measuring period, but displaying RPM . . .

Requires some latching/gating to display the count while the next
count is being acquired.

Main advantages: capable of very high resolution and fast response,
with low pulses per revolution. The concept works; I had it bread
boarded and up. An analog display was more intuitive and I could
acquire the RPM in a millisecond glance, so used analog instead.
Digital displays make more sense in slow flying aircraft IMHO.

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