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DC motor smart wifi control?

Discussion in 'Sensors and Actuators' started by Mike Bonheim, Feb 14, 2018.

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  1. Mike Bonheim

    Mike Bonheim

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    Feb 14, 2018
    This is hopefully not going to be overly convoluted, or difficult, or or even impossible.

    My wife is a chicken keeper, and we have a door that we must open in the morning to let the chickens out and close at night to let the chickens back in. This has to be done manually so we need to be home by nightfall each night to keep predators out.

    I'm trying to design a system where my wife can control the door from her smartphone wherever she may be.
    I have a small DC motor that that can do the job of raising and lettingl the door, and i know that I can reverse the direction of the motor by switching polarities.

    I also have two outlets that are WiFi controlled. So my thought was to plug a DC converter into each WiFi plug and have them feed to the motor with opposite polarities. Of course I realize that we cannot have both on simultaneously but I need some way to ensure that when Outlet A (+/-) is powered up, the current doesn't flow back to outlet be which is off (-/+).

    Is there a simple way to ensure that the two lines only feed the current one way, so when the other is on I don't get a backflow problem?

    Or is there a simpler more elegant solution that I don't know about?

    Thanks in advance for any advice for this truly ignorant newbie.
     
  2. Nanren888

    Nanren888

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    Nov 8, 2015
    Interesting task & interesting approach. You could go about this several different ways.
    I'm interested.
    The "small DC motor", how small?
    When you switch on the wifi socket, how will you know when it is fully closed, er when to turn it off again?
    .
    I guess, I think of either cunning mechanical mechanisms, or like the car window, where a limit switch of some form stops the window at the top or bottom.
    .
    If you've got the mechanical stuff sorted out, maybe there's a mechanical way to have just one drive do it, given its current state?
    .
    Otherwise. Maybe another way would be to have one socket energize the motor & the other reverse the direction.Hence, A on means open & A&B on means close. Just a thought.
    This would need only a relay or similar, double pole, double throw, to swap the polarity of drive from the other to the motor.
    .
    There are some small & cheap IOT (internet of things) devices that are wifi ready, that have relay outputs. If you don't mind a little setup. Maybe not much more than the setup for the smart switch, depending on which ones you're planning to use. Choose relay outputs that are good for the voltage & current you're going to switch. More of an IT/IOT solution.

    Hope this helps :)
     
  3. Mike Bonheim

    Mike Bonheim

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    Feb 14, 2018
    I actually decided to go a completely low tech mechanical route. Since need to raise and lower the door around 10", I'm going to simply have the motor drive a 10" disc with a cable attached to one side of the disc, and the other end to the door.

    As the disc rotates, it will pull the cable around it' 10" diameter to raise AND lower the door with the same rotational direction...

    She'll just have to switch it off at the right time when it's pretty much all the way closed.

    [​IMG]
     
  4. Mike Bonheim

    Mike Bonheim

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    0
    Feb 14, 2018
    And, I meant also to say thank you for the response and thoughts!
     
  5. Nanren888

    Nanren888

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    Nov 8, 2015
    Which sort of leads back to my question about how it knows when to stop? Somewhat of an issue, remotely. MAybe a wifi camera? :) Mechanical? Limit switch? Maybe if you make the cable fixed & the disc a cunningly-shaped cam, pushing the cable length out, you might be able to have a system that spends a long time open & a long time closed, but not much time in between? :) That way increasing the margin of error for stopping in the right place?
    .
     
  6. Mike Bonheim

    Mike Bonheim

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    Feb 14, 2018
    Ah... yes, there is a webcam already out there - my wife likes to be able to check in on the chickens when we're away.

    Yes, she's crazy. But I have since learned that all backyard chicken keepers are nuts. I just happen to live with one of them!
     
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