plz help to make a circuit

Discussion in 'General Electronics Chat' started by sfcd_123, Sep 11, 2008.

  1. sfcd_123

    Thread Starter New Member

    Sep 11, 2008
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    helooo...im new to this forum...i am facing a problem in making a circuit...
    i want to make a circuit in which i can control a dc gear motor of 12 volts(in both direction-clock n anticlock) using parallel port of pc...plz can anyone help me?????i will b grateful to u...thnx....
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    1,728
    You know that building projects that use the parallel port are risky, right?

    That you stand a good chance on accidentally burning it out, and the only real fix is to replace your motherboard?

    With that out of the way, what current does your motor require?

    And do you have a program that will control your parallel port, or will you have to write one?
     
  3. sfcd_123

    Thread Starter New Member

    Sep 11, 2008
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    yes..i have to write a program...i will use vc++.....is driving a stepper motor is also dangerous???
    my gear motor runs with dc current...it is 12 volts 60 rpm dc gear motor..how can i safely make a project with parallel port....?????i heard my friends ran a 12 volt dc motor and a 12 volt stepper motor using parallel port...
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    It can be done, but it's safer to use an "add on card" LPT port. That way if you accidently burn it up, you just throw the card away. They're only a few dollars at a computer store.

    It sure beats buying a new motherboard.

    Yes, you can control stepper motors and yes, you can control standard DC motors. But you can't supply the power from the port, only control the signals.

    I asked you how much current your motor draws, but you tell me what RPM it is. That does not help me help you very much.
     
  5. sfcd_123

    Thread Starter New Member

    Sep 11, 2008
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    sory i can not say how much current the motor takes...coz in our country(bangladesh) the store keepers can not say anything about the motors and they take out the label of the motor so sory.....is there any way to know the current???if not thn u can say a common current which a gear motor normally needs...sory for the pain i m giving u....:)
     
  6. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    If you have physical posesion of the motor, why not just measure current draw ? I assumed that you have multi meter & voltage source. Average of 15 small gear reduction motors [ 4 cm dia by 6 cm ] was 50 mA, larger was 1.5 A. Check no load & under load , squese output shaft between wood blocks for load. bet it will be less than 1 A.
     
  7. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,172
    397
    Does your PC output supply a variable dc signal or a PWM signal ? I used a darlington si. npn power trantistor as an emitter follower to control a med sized gear motor, driven by a single general purpose npn transistor with about 2.7 k Ω collector load. a simple rc filter to base [ 10 k Ω & .1 μF.] should take just about any variable signal of 0-5 V.
     
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