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Re: [turbobike] Tach question

Dave Morrill (david.p.morrill@fairchildsemi.com)
Mon, 01 Nov 1999 13:21:01 -0500

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Ooops,
    Thanks John, def. the - side.

thanks,
    Dave.

John Williamson wrote:

>  There is no (appreciable) signal at the pos coil wire it's tuther way
> round...- You mean the negative / switched one! bear in mind that the
> EMF feedback as the field collapses here gives spikes ov several
> hundred volts that might kill your chip. If you don't belive this just
> let it run at idle and touch the negative coil wire! Just put a 10,000
> ohm  resistor in line and then a zenner diode at your preffered (4.7v)
> voltage across to ground after this, to leave you a squarish wave of
> 4.7volts. This will work your chip much more reliably. For dyno stuff
> and software check out my site HERE if your interested (Software has a
> couple of examples of turbo and nitrous bikes too for those
> interested) Regards JOHN (Burgerman) UK
>
>      ----- Original Message -----
>      From: Dave Morrill
>      To: CRAIG S WALKER
>      Cc: turbobike@natvideo.com
>      Sent: Monday, November 01, 1999 1:45 PM
>      Subject: Re: [turbobike] Tach question
>       Craig,
>          I'm building a dyno right now.  Your best be is to get a
>      frequency to voltage converter
>      chip (search national semiconductors web site for LM2907).
>      These are real easy to use, I
>      considered doing this on mine but went for a more
>      sophisticated data ac board.  You should
>      be able to order free samples.
>      It also depends if you want to clip onto a spark plug wire,
>      or the + of a coil (better solution +12V
>      square wave from this, much easier to wire).
>
>      Let me know what you come up with, what are you planning to
>      use for a data acquisition
>      board?
>
>      good luck,
>          Dave.
>
>
>      CRAIG S WALKER wrote:
>
>     > Anyone know where I can get a tachometer with an analog
>     > out signal? I 'm  looking to automate my old Stuska dyno,
>     > I'm at a loss right now. thanks,Craig
>

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Ooops,
    Thanks John, def. the - side.

thanks,
    Dave.

John Williamson wrote:

 There is no (appreciable) signal at the pos coil wire it's tuther way round...- You mean the negative / switched one! bear in mind that the EMF feedback as the field collapses here gives spikes ov several hundred volts that might kill your chip. If you don't belive this just let it run at idle and touch the negative coil wire! Just put a 10,000 ohm  resistor in line and then a zenner diode at your preffered (4.7v) voltage across to ground after this, to leave you a squarish wave of 4.7volts. This will work your chip much more reliably. For dyno stuff and software check out my site HERE if your interested (Software has a couple of examples of turbo and nitrous bikes too for those interested) Regards JOHN (Burgerman) UK
----- Original Message -----
From: Dave Morrill
To: CRAIG S WALKER
Cc: turbobike@natvideo.com
Sent: Monday, November 01, 1999 1:45 PM
Subject: Re: [turbobike] Tach question
 Craig,
    I'm building a dyno right now.  Your best be is to get a frequency to voltage converter
chip (search national semiconductors web site for LM2907).  These are real easy to use, I
considered doing this on mine but went for a more sophisticated data ac board.  You should
be able to order free samples.
It also depends if you want to clip onto a spark plug wire, or the + of a coil (better solution +12V
square wave from this, much easier to wire).

Let me know what you come up with, what are you planning to use for a data acquisition
board?

good luck,
    Dave.
 

CRAIG S WALKER wrote:

Anyone know where I can get a tachometer with an analog out signal? I 'm  looking to automate my old Stuska dyno,  I'm at a loss right now. thanks,Craig

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