12v dc motor control - timer

Discussion in 'The Projects Forum' started by ozioho, Jan 20, 2014.

  1. ozioho

    Thread Starter New Member

    Jan 20, 2014
    15
    0
    Please understand that I am not a electrical guru at all. I play around with a few projects in my garage as a hobby.

    I have a 1-1/2 x 1-1/2 inch 12v dc motor that I am controlling from a momentary remote contol button. (car alarm type button). What I would like to do is push the remote button and let off and have the motor run for 3 or 4 seconds (or whatever I have set up) and then shut off on its own. I there a small timer that could do this. The motor using .25 amps is all and smaller the better since I have not much room.

    Thanks
     
  2. #12

    Expert

    Nov 30, 2010
    16,346
    6,833
    It's called a 555 one-shot.
    How far away is the button from the motor?
    Where is the power supply? At the motor end or the button end?
    By, "remote control, do you mean you want a wireless communication?
    (Very much more difficult that a wired connection.)
     
  3. NFA Fabrication

    Member

    Aug 12, 2012
    104
    3
    A simple 555 timer will control what you need. Here is a basic diagram using a 555 timer with needed add ons to get what you need:

    [​IMG]

    You will most likely want to use a 5m or 10m potentiometer for the "3.64M" resistor to adjust to your needs more accurately. The 555 with run a 12V relay directly as long as you use a protection diode across the relay coil (A common 1n4001 works well).
     
  4. #12

    Expert

    Nov 30, 2010
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    I'd use a bigger capacitor to get the potentiometer down to a resistance that is easy to buy.

    Like, 10 uf tantalun, a 330k resistor, and a 1M pot.

    3.6 seconds to 14.6 seconds, adjustable.

    LM555 can only do .2 amps so you're going to need a transistor added on, especially if the start-up current is more than the run current.
     
    Last edited: Jan 20, 2014
  5. ozioho

    Thread Starter New Member

    Jan 20, 2014
    15
    0
    Great, thanks for the help. Now I need one more addition. Is there a way to add a digital timer (lap type counter) that can monitor how many times I push the button. I am trying to monitor how many times the button is pushed. Preferably a countdown timer. Also, the button is not what I am monitoring, it is how many times the motor comes on, so whatever would be easiest application, read the momentary button or read how many times the motor came on. only be counting to 99 or less, do not need 3 digits. Not sure if that mattered

    Thanks
     
    Last edited: Jan 20, 2014
  6. #12

    Expert

    Nov 30, 2010
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    "counting motor starts"? "counting motor run time"?
    A counter and a time accumulator are two very different things.
    You need to be clear about that.
    There are many ways to do a counter and it's not so easy as adding a "run persist" timer.

    Ideas, guys?
     
  7. ozioho

    Thread Starter New Member

    Jan 20, 2014
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    Motor run time is not important, how many times the button is pushed is what I need to monitor.
     
  8. inwo

    Well-Known Member

    Nov 7, 2013
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    Last edited: Jan 20, 2014
  9. #12

    Expert

    Nov 30, 2010
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  10. ozioho

    Thread Starter New Member

    Jan 20, 2014
    15
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    inwo,

    this is exactly what I was looking for. Ebay and google is great, but if you don't know what you need to type in, it doesn't do much good. A "delay timer switch module" is what I needed.

    Thanks too everyone for the help
     
  11. #12

    Expert

    Nov 30, 2010
    16,346
    6,833
    We had the delay timer done by post #4. You just need to answer the questions in post #2 to get from theory to application.
     
  12. inwo

    Well-Known Member

    Nov 7, 2013
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    Sorry I jumped ahead.:p

    It was looking like OP was not following the theory enough to answer.

    I know this is AAC not all about "buy something on Ebay".
    I'm new and don't always know what's appropriate. :(
     
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