Pulse Signal Reducer or pulse to current converter

Discussion in 'General Electronics Chat' started by dfellars, Mar 25, 2009.

  1. dfellars

    Thread Starter Member

    Mar 25, 2009
    16
    0
    Hi Everyone, this is my first post and I am a bit of Noob.

    I am looking to design a Pulse Signal Reducer or a pulse to current converter. The input signal is a 12v Hall Effect off an HEI Car Distributor. The Distributer pulses 3x per revolution so at 700 RPMs we are looking at 2100 pulses per minute. I would like to reduce that by a factor of 100. I thought that I might be able to uses a CMOS Decade Counter (CD4017) but I am not sure that can handle the pulse signal I am sending.

    Project Scope:

    I am attempting to build a flashing LED light system for my vehicle that flashes at a rate consistent with the RPMS (as the RPMs increase, so does the rate of the flash.) My thought was that if I can reduce the pulse to a reasonable rate I could simply wire the LEDs directly to the reducer.

    Would this work or is there a more elegant design?

    Thanks for your help.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    Does it have to be 100 ?
    May it be 128 ?

    Take a look at the 4040 or 4060.
    See datasheet.

    Greetings,
    Bertus
     
  3. dfellars

    Thread Starter Member

    Mar 25, 2009
    16
    0
    Yes, specificity is not a requirement.

    Looked at the specs... the problem is the input voltage... I am relatively sure that the inpult signal is a full 12v (unless I am really showing my ignorance and missing something here.) I will test the line though to verify.
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    When you take the CD4040 (or HEF4040),
    pin 11 (reset) is to ground.
    Pin 10 is clock input.
    Pin 2 divides the signal by 64
    Pin 4 divides the signal by 128
    Pin 13 divides the signal by 256
    Pin 12 divides the signal by 512
    (there are more outputs, see datasheet).

    So you have different speeds at your service.

    Greetings,
    Bertus
     
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    Beyond about 20 flashes per second, an LED looks continually "on". For younger people, it goes to about 30/second.

    Divide redline of car by 180, and you should arrive at the divider so that the LED is solid red (or whatever color you pick) at redline/yellowline.

    For input, you could use an opto-isolator to keep any transient peaks from trashing your circuit.
     
  6. dfellars

    Thread Starter Member

    Mar 25, 2009
    16
    0
    Thanks for the help... I wil start to design the circuit and post-it for review. Thanks!
     
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