Turbobike Web Site www.Turborick.com

Re: [turbobike] Tach question

John Williamson (john.williamson5@virgin.net)
Mon, 1 Nov 1999 18:14:23 -0000

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There is no (appreciable) signal at the pos coil wire it's tuther way =
round...=20
- You mean the negative / switched one!=20

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!=20

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 -----=20
  From: Dave Morrill=20
  To: CRAIG S WALKER=20
  Cc: turbobike@natvideo.com=20
  Sent: Monday, November 01, 1999 1:45 PM
  Subject: Re: [turbobike] Tach question


  Craig,=20
      I'm building a dyno right now.  Your best be is to get a frequency =
to voltage converter=20
  chip (search national semiconductors web site for LM2907).  These are =
real easy to use, I=20
  considered doing this on mine but went for a more sophisticated data =
ac board.  You should=20
  be able to order free samples.=20
  It also depends if you want to clip onto a spark plug wire, or the + =
of a coil (better solution +12V=20
  square wave from this, much easier to wire).=20
  Let me know what you come up with, what are you planning to use for a =
data acquisition=20
  board?=20

  good luck,=20
      Dave.=20
   =20

  CRAIG S WALKER wrote:=20

    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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There is no (appreciable) signal at the = pos coil=20 wire it's tuther way round...
- You mean the negative / switched one! =
 
bear in mind that the EMF feedback as = the field=20 collapses here gives spikes ov several hundred volts that might kill = your chip.=20 If you don't belive this just let it run at idle and touch the negative = coil=20 wire!
 
Just put a 10,000 ohm  resistor in = line and=20 then a zenner diode at your preffered (4.7v) voltage across to ground = after=20 this, to leave you a squarish wave of 4.7volts. This will work your chip = much=20 more reliably.
 
For dyno stuff and software check = out my site=20 HERE if = your=20 interested (Software has a couple of examples of turbo and nitrous bikes = too for=20 those interested)
 
Regards JOHN (Burgerman) = UK
----- Original Message -----
From:=20 Dave Morrill
To: CRAIG S WALKER
Cc: turbobike@natvideo.com
Sent: Monday, November 01, 1999 = 1:45=20 PM
Subject: Re: [turbobike] Tach=20 question

Craig,
    I'm building a dyno right = now.  Your best be is to get a frequency to voltage converter =
chip=20 (search national semiconductors web site for LM2907).  These are = real=20 easy to use, I
considered doing this on mine but went for a more=20 sophisticated data ac board.  You should
be able to order = free=20 samples.
It also depends if you want to clip onto a spark plug = wire, or=20 the + of a coil (better solution +12V
square wave from this, much = easier=20 to wire).=20

Let me know what you come up with, what are you planning to use for = a data=20 acquisition
board?=20

good luck,
    Dave.
 =20

CRAIG S WALKER wrote:=20

Anyone know where I can get a = tachometer with=20 an analog out signal? I=20 'm  looking to automate my old Stuska dyno,  I'm at a loss = right=20 now. thanks,Craig
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