Very simple energize timer control for 9v solenoid

Discussion in 'The Projects Forum' started by bigt8r, Feb 23, 2014.

  1. bigt8r

    Thread Starter New Member

    May 8, 2012
    2
    0
    I have searched the forums, and, while I found several posts that were similar, they weren't simple enough; typically, posters were looking for something close to this, but had a few extra functions. Any help would be greatly appreciated.

    I am working on a project with a friend, and we need a more precise fuel delivery mechanism.


    My initial thought was of trying to control a fuel injector somehow, with a potentiometer to control the amount of time the injector was open. Since injectors are typically only open for milliseconds at a time, I was thinking that a small solenoid might do a better job, as it will need to be open for somewhere between .5 and 2 seconds, and i would probably have to make the injector open a bunch of times to achieve that length of time. (Going to be trial and error to determine the exact time...) I was thinking (I know, I know... I probably shouldn't do that) that a small circuit to energize the solenoid based on what the pot was set to, would be ideal.

    I have never designed a functioning circuit, though I wish I knew more about electronics so that I could. I have some fun ideas. I have built several circuits designed by other people, and have modified some of them to be more what I needed, so I am capable of building them... But design is way outside of my league at this point. I am a noob, so hopefully you'll go easy on me;) (I do have the basic fundamental understanding of what components do, and can read "more than basic" schematics, though)

    I saw several posts about similar circuits using a 555 chip. Would I be able to vary the energize time using a pot with this chip? Or would a different route be easier?

    Any ideas or schematics would be a huge help!

    Thank you very much for your time.
     
    Last edited: Feb 23, 2014
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,507
    2,367
    An injector in an automotive application is pulsed or on for a very short duration, if you are powering it from your own circuit then you can use the same type injector but it can be your decision how long it opens based on a custom circuit.
    A 555 variable one shot could do this.
    Max.
     
  3. burger2227

    Member

    Feb 3, 2014
    190
    24
    What is the point? The OP seems to know about circuitry, but little about the injector itself except that it stays open for milliseconds. Why mess with it?

    Also messing with an injector is an alteration to an automobile isn't it?
     
  4. bigt8r

    Thread Starter New Member

    May 8, 2012
    2
    0
    Just because something might use a fuel injector doesn't necessarily mean it is being used in an automotive application. But, you're right, I don't know much about fuel injectors, other than they're only open for short durations, which is why I was thinking a solenoid would be a better option for what I am trying to do.

    Thank you, MaxHeadRoom. It looks like this will probably point me in the right direction, based on what I skimmed after searching for 555 Variable One Shot. Sorry to ask a stupid question, but I appreciate you taking the time to answer it; there are so many posts about different 555 circuits, it looked possible that I could spend weeks searching for what I'm after, and still not find "variable one shot", so I am incredibly grateful.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,507
    2,367
    You want to look for a 555 Monostable, there are many examples out there.
    Here is a bit of a long Utube video but at around 11min in, there is the explanation of such a circuit.
    http://www.youtube.com/watch?v=SX01x1z7fTY
    It shows two loads for demo purposes, but you would only need the one.
    Max.
     
    bigt8r likes this.
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