DC polarity switching circuit for motorized toy

Discussion in 'The Projects Forum' started by mechanical_guy, Mar 4, 2011.

  1. mechanical_guy

    Thread Starter New Member

    Mar 4, 2011
    2
    0
    As my username implies...I may be too far out of water. I have located a similar thread, but there was not a response. Here is my simple project goal:

    Small DC motor that runs with 6V battery pack. I would like to have one button (when pressed) run the motor CW, stop when released (i think this is a momentary switch?) The second button, when pressed, runs the motor CCW until released. I can easily do this by swapping the terminals on the battery pack, but I am looking for a little more "elegant" solution for integration into an elevator-like toy project that I am building with my 7yr-old. Position of the motor is not required for the sophistication level of this project. Integrating a limit switch to break the circuit at each end of travel is my plan, if I have space. Ultimately, I would like to get to a continuous operation mode (push a different button, device stays on and automatically reverses when it hits the limit) - I'm guessing that there are some relays involved...but I am way outside my wheelhouse.

    I apologize in advance if this is not the right forum for this question...and if there is a "cookbook" solution out there, please point me in that direction. I realized after I started into this project that I am essentially emulating a low voltage drill driver that has a forward/reverse button...had I had one to cobble from, I would have started there...I am now looking for some guidance on a shopping list from Radio Shack and a quick schematic....

    Thanks in advance for your time and consideration!
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,120
    3,046
    Welcome to the AAC Forum!
    So far, very simple. Just use two momentary switches. A single, 3-position toggle switch would have the advantage of not being able to activate both directions simultaneously, which could be a problem with two buttons and a 7-year old.

    Yes, this is quite a bit more complicated but many here can help you with this.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    This should pretty much do it for you:

    [​IMG]

    See if you can find 6v relays. If not, you could use 5v relays with diodes in series with the coils.

    [eta] You can use just about any diodes; the 1N400x series should be fine.

    If this is going to be battery operated, you don't want it to run continuously - unless you really like buying batteries.
     
    Last edited: Mar 4, 2011
    mechanical_guy likes this.
  4. mechanical_guy

    Thread Starter New Member

    Mar 4, 2011
    2
    0
    Thanks for the great (and quick responses) wayneh and SgtWookie - I am off to the 'Shack to give this a try. I agree with the battery comment. If this works well, I would likely use a discarded power supply/ wall wart.
     
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