Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Add Servo solution, other than the retract legs option?

Discussion in 'Pro/Adv Discussion' started by DiluxEdition, Feb 17, 2016.

  1. DiluxEdition

    Joined:
    Jun 30, 2015
    Messages:
    200
    Likes Received:
    50
    Anyone figure out how to add a servo without the retract kit? I'm guessing that flipping the P A F switch does something on the P3 and they took advantage of it. I just learned about transistor switches (mosfets) and how they work and perhaps when using the switch like they do it changes voltage somewhere which would allow you to use a mosfet and some sort of servo controller to get it to open and close...?
     
  2. N017RW

    Joined:
    May 2, 2014
    Messages:
    6,241
    Likes Received:
    1,613
    Location:
    Palm Beach Co.- FL
    Most (never say all) hobby servos require PWM to control their position. This cannot be achieved with simple switching.
    The general understanding, regarding the retract kit, is that the PAF channel is monitored by a small processor (PIC or similar) and when the appropriate transitions occur (PAF toggling) the PIC responds and generates/sends the PWM signal to the servo.
     
  3. DiluxEdition

    Joined:
    Jun 30, 2015
    Messages:
    200
    Likes Received:
    50
    I never meant for the transistor to move the servo, but for the transistor to enable a servo driver to go from open to closed. I doubt that the retract kit gets a pwm signal from the p3 itself. It likely does something similar to what I mentioned...
     
  4. N017RW

    Joined:
    May 2, 2014
    Messages:
    6,241
    Likes Received:
    1,613
    Location:
    Palm Beach Co.- FL
    You need to reread my posting.
    Simply put again,
    The HobbyDepot kit uses a small uP to monitor the buss for activity on the PAF channel (X1 or X2 I don't recall) and generate PWM accordingly.
     
  5. DiluxEdition

    Joined:
    Jun 30, 2015
    Messages:
    200
    Likes Received:
    50
    yea, I guess that's another way of doing it, but would likely require some programming skills instead of just electronics...
     
  6. N017RW

    Joined:
    May 2, 2014
    Messages:
    6,241
    Likes Received:
    1,613
    Location:
    Palm Beach Co.- FL
    Yes,

    HobbyDepot has done that [programming] for 'you'.

    The architecture of these systems is digital between the Rx and MC (Futaba S.bus clone/compatible) so there is no switching/swinging voltage to use.
     
  7. rene van der meer

    Joined:
    Oct 16, 2015
    Messages:
    377
    Likes Received:
    70
    You need preferably a spare signal in the AC that can be controlled with the RC.
    I do not expect that the PAF switch changes a signal that can be used. It is likely an internal signal.
    Maybe there are other signals or ports that can be used. I would like to know this as well. Ideally this signal can be controlled with the programmable switches (C1 or C2) on the back of the RC.
    See customizing-your-c1-and-c2-functions
    Another idea is to use for instance the LED control of the AC. If the LEDs are switched off more than a certain period (5 s) you could use this to control a (electronic) switch.
     
    alokbhargava likes this.
  8. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,132
    Likes Received:
    1,655
    Location:
    San Francisco, CA
    It is not necessary to give a PWM voltage to servos. That is just a way to vary a voltage to servo to change its speed.
     
  9. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,132
    Likes Received:
    1,655
    Location:
    San Francisco, CA
    It is not necessary to give a PWM voltage to servos. That is just a way to vary a voltage to servo to change its speed and easy to implement.
     
    rene van der meer likes this.
  10. John Locke

    Joined:
    Jun 26, 2015
    Messages:
    2,934
    Likes Received:
    1,105
    Location:
    Yorba Linda, CA
    What are you trying to do with a servo?
     
  11. N017RW

    Joined:
    May 2, 2014
    Messages:
    6,241
    Likes Received:
    1,613
    Location:
    Palm Beach Co.- FL
    Don't be ridiculous.
    A PWM generator would be required to use a varying voltage as the source of input.
    Hobby Servos do not use a varying voltage for positional control and the speeds are typically fixed.


    This so easily confirmed by simply doing a Google search.
     
  12. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,132
    Likes Received:
    1,655
    Location:
    San Francisco, CA
    Please read my post clearly. Thx
     
  13. N017RW

    Joined:
    May 2, 2014
    Messages:
    6,241
    Likes Received:
    1,613
    Location:
    Palm Beach Co.- FL

    I have read this:
    "It is not necessary to give a PWM voltage to servos. That is just a way to vary a voltage to servo to change its speed and easy to implement."

    It's still wrong.
     
    rene van der meer and dirtybum like this.