Newbie Needs help with Creating Variable Speed Motor

Discussion in 'The Projects Forum' started by pixelatednoise, Jun 1, 2011.

  1. pixelatednoise

    Thread Starter New Member

    Jun 1, 2011
    1
    0
    Hello all,

    I am currently trying to make a variable speed DC Motor that I can attach to a camera slider and use it to automatically pan my camera. (see a larger example here http://vimeo.com/15517603 )

    I will admit I have the circuitry knowledge of a 5th grader but I am now engrossed in figuring this out. I just need some help. I bought the following parts from radioshack:
    -9V motor (http://www.radioshack.com/product/index.jsp?productId=2911245)
    -100k ohm Potentiometer (http://www.radioshack.com/product/index.jsp?productId=2062354)
    -9V battery

    I hooked everything up in a complete circuit and to my surprise it actually somewhat worked. The potentiometer was tricky in that it went to extremes it would go either off or on and you had to minutely rotate it to get speeds in between. I also noticed that as I was playing around with it I burned the Pot out as it started to smoke. I already invested about $30 on this little project and Im hoping to get some results. Any ideas on how I can achieve this?
     
  2. #12

    Expert

    Nov 30, 2010
    16,343
    6,828
    I think the usual way is to use PWM...pulse width modulation. This method applies the full 9 volts to the motor in very short bursts so the motor has full power for a percentage of the time, and the percentage is adjustable.

    The 555 timer chip is often used to make this kind of circuit.

    This is enough information to guide you to look up 555 PWM circuits and start learning how to build them and make them work for your application.

    Go to the "chat" forum and look at "Working with comparator LM393" post number 8.
     
    Last edited: Jun 1, 2011
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