R.p.m simulator

Discussion in 'General Electronics Chat' started by hondatech, Sep 25, 2009.

  1. hondatech

    Thread Starter New Member

    Sep 24, 2009
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    hello people :) can someone help me with my project?. im trying to put together a rpm simulator. i have the coponents from a box that a friend had. its a 9v battery,pot,l.e.d, and a small switch. does any know how to wire this together and let me know if im missing something. Please!!:confused:
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Do you have the schematic?
    Do you have a list of the components?

    Greetings,
    Bertus
     
  3. Tobias

    Active Member

    May 19, 2008
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  4. kkazem

    Active Member

    Jul 23, 2009
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    Hi Hondatech,
    In order to help you, I need the specifications of the RPM sensor on the type of car that you are trying to simulate. Or a schematic if you're sure it's accurate.
    Please remember, we're engineers, not mind readers. and I'm sure that a simulator for one make/model of car would be different than for another make/model of car.

    Regards,
    Kamran Kazem
    kkazem
     
  5. swcash

    New Member

    Sep 26, 2009
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    Question is very vague. What exactly are you wanting to simulate the revolutions of? Electric Motor? Diesel Engine? Four cylinder gasoline engine? Steam turbine? Each of these samples would require a separate and unique application.
    Squido W Cash
     
  6. hondatech

    Thread Starter New Member

    Sep 24, 2009
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    sorry guys for not responding soon. the rpms im trying to simulate ar for gas powerd vehicles, from4cyl to v10 or 400rpms to 2500rpms.the box im trying to copy had a 9v battery with a pot switch a on/off switch a l.e.d light and a 14gage wire that loops from the project box that messures 4inx4in.Wen i turn the pot switch the light blinks faster acording to the amount off volume i give it. If i connect a timing light to the wire loop it reads pulses to rpms.
     
    Last edited: Sep 29, 2009
  7. SgtWookie

    Expert

    Jul 17, 2007
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    OK, so a pretty simple 555 timer oscillator. Since a timing light fires using just one spark plug wire, it really doesn't matter how many cylinders a 4-stroke Otto cycle engine has. It fires each spark plug once every other revolution, so your frequency range is 200Hz to 1,250Hz.

    The only thing you really need is a very short pulse of current through that loop wire to trigger the timing light, which has the tachometer built in.

    Sounds like a job for Bill_Marsden, our resident 555 Timer Guy!
     
  8. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    @ SgtWookie: I think you mean 200/60 to 1250/60 Hz (3.3 to 21 Hz), respectively.

    The real issue is what type of device will be reading the signal. For example, I made an RPM simulator to simulate a Hall-detector signal to test the advance/retard function of a CDI ignition. That output might be unsuitable for ignitions using other types of pickup or for other purposes.

    John
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    Yes John, that's exactly what I meant.

    One of the big reasons I didn't try to continue with that train of thought was because it was late and I was tired!
     
  10. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Sometimes I may get up at 0230 ET. :D

    Back to the OP...

    It would help to see the inside of the box, if he still has it. The question I have is whether the pulse in the loop is low voltage/current, or high voltage and/or high current, as one would get from a CDI. The loop looks superficially like ignition cable. If a picture inside the box shows just an IC (possibly a 555), then it is likely the former. If there is a small transformer, then I would suspect it is the latter. It would also show how that cable is connected.

    John
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    OK, here's a circuit using a 555 timer, a cap, a few resistors, a diode and an LED. You can get the stuff from your local Radio Shack store.

    [​IMG]

    You will also need a 220uF capacitor to go from pin 1 to pin 8 of the 555 timer, the negative lead on pin 1.

    The the pulsewidth when current flows through the loop is fixed at roughly 5mS. If that time isn't long enough, you can increase R3. 3k will give you a roughly 9.5mS pulse. Don't decrease it below 1.5k though.
     
    Last edited: Sep 29, 2009
  12. SgtWookie

    Expert

    Jul 17, 2007
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    Good points, John.
    If it does contain a transformer, not a big deal. It could be added to the circuit I posted, but the primary will need a diode across it.
     
  13. hondatech

    Thread Starter New Member

    Sep 24, 2009
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    hello felas. the pic is a sample of what the box looks like. I never saw the original from the inside. thats how it looks on the outside. Let me know if you could come up with some thing close to that or if i need more parts.
     
  14. SgtWookie

    Expert

    Jul 17, 2007
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    Hondatech,
    That's what the schematic I posted is; my guess of what is inside the box.

    If you could take a photo of what is inside the box, that would help.
     
  15. hondatech

    Thread Starter New Member

    Sep 24, 2009
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    thanks SGt.WOOKIE ill try those components tonight, ill let youknow hw it works!
     
  16. SgtWookie

    Expert

    Jul 17, 2007
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    Good luck.
    I won't be back on AAC for several days; going out of town.
     
  17. erndog

    New Member

    Oct 30, 2011
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    Wow I know i am Resurrecting an old thread but I wonder if the OP got the RPM Sim. to work? I seen a similar one awhile back but now that I need one I cant find one. lol Thanks for the Info, hopefully I can make this work.
     
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