Need help creating a mini "Garage door opener"

Discussion in 'The Projects Forum' started by SLBAZ, Nov 19, 2006.

  1. SLBAZ

    Thread Starter New Member

    Nov 19, 2006
    1
    0
    As the title states, I'm essentially trying to figure out how to create a miniature garage door opener. I'll say right up front I know very little about electronics beyond the most basic components, so my dilemma is knowing what I want to do but not what components I need to do it.

    The basic premise of the project is to use a small electric DC motor, 6-12v depending on what's required, to move a small plastic panel up and down the front of a cabinet. The panel itself only weighs 4-6 ozs. I'd like to have this set up such that the motor is activated by pressing a momentary switch and starts the panel moving, we'll say up to start. When the panel reaches the top of it's path, approximately 8 inches, the motor should stop, holding the panel in place. The next time the momentary switch is pressed the motion should be reversed so that the panel moves down to it's original starting position. Power for the motor will be supplied by a standard computer PSU.

    With my limited knowledge of electronics I don't know if I'll need some kind of control unit to to stop the panel in the appropriate position and reverse the direction of the motor or if this is something I can accomplish with a series of switches and relays. The intent is to keep this as simple and cheap as possible. I don't need any complicated control scheme, just push the button the panel goes up, push it again the panel goes down......garage door opener. Thanks in advance for any help you can provide.
     
  2. Gadget

    Distinguished Member

    Jan 10, 2006
    613
    0
    If its just a low wattage motor, then a simple timer setup should work fine.
    If you want to get a little more complex, then you could possibly work out a upper and lower limit setup using opto interuptors or similar.
    The real thing also monitors motor current to sense a door obstruction and uses mechanical limit switches.
     
  3. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    You just need a circuit that can turn the motor forward and reverse with something to stop it from moving at the ends of it's travel.

    If you just want a manual system wire the up switch as a normally open push button in series with the normally closed upper limit switch. The up direction will stop when the upper limit switch is open.

    Then the normally open down button is in series with the normally closed lower limit switch which. The down direction will stop when the lower limit switch opens.

    To be able to 'push and forget' you'd want a double throw, single pole toggle switch or two latching push button switches. Limit switches would be momentary button switches. http://en.wikipedia.org/wiki/Switch Some of the push button switches have levers already installed which can make them easier to use in this application.

    All of this can be done with zero semiconductors.
     
  4. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    Difficult to get useful power transfered to a different frequency system. The simplest method is to use an AC motor and couple that via shaft to an AC generator. This does have losses but it's much less than other systems. One use of it has been to convert the standard 400HZ aircraft power to 60HZ power and vice versa. It's pricey and lossy but not the worst.

    If you were to rectify the output, chop it at the desired frequency and then feed that to another transformer you would get a higher frequency but the cost in material and energy loss would be substantial.

    I don't think a Tesla coil would have the current capacity but it would be showy.
     
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