RPM Simulator

Discussion in 'The Projects Forum' started by kenzo42, Feb 26, 2014.

  1. kenzo42

    Thread Starter New Member

    Feb 26, 2014
    2
    0
    [​IMG]
    Coutesy of SgtWookie from thread http://forum.allaboutcircuits.com/showthread.php?t=28010&page=2


    Sorry, some noob questions:

    1) Is it possible to vary RPM w/ a pot in place of R3?
    2) Is the wire loop the output?
    3) The cap you mentioned (220uF) can go anywhere between pin 1 (on the 555) and pin 8 (on the 555)?

    I'm trying to simlulate an RPM signal for an aftermarket ECU (Megasquirt) for a Miata - the tacho signal itself is a simple squarewave of (I believe) 0-12v amplitude, with one pulse per ignition event. If I try to read this on a multimeter, I just see a very low (and unsteady) voltage.

    I'd rather not buy the Jimstim and I think it would be fun to make my first circuit. I'd like to test RPM on the ECU but also make a LED tachometer w/ shift light.
     
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,004
    1,525
    R2 is the pot that controls the "RPM".

    By mentioning a car in your thread it will probably be closed soon. Against AAC terms of service, nothing against you. :)
     
  3. kenzo42

    Thread Starter New Member

    Feb 26, 2014
    2
    0
    What is the reasoning behind not allowing any mention of cars?
     
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,004
    1,525
    The forum doesn't want the liability of a problem resulting from advice from it. It's all in the Terms Of Service, TOS. The TOS is at the bottom of every page, here is the link -
    http://www.allaboutcircuits.com/l_tos.html
     
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