How does a Transmitter/Receiver work on a Multi-copter

Discussion in 'The Projects Forum' started by rhekj, Sep 6, 2014.

  1. rhekj

    Thread Starter New Member

    Sep 6, 2014
    9
    0
    Hello. I am doing some research for a project that pertains to multi-copter drones and their transmitters/receivers. The specific model that I am using is the DJI Phantom 2.0

    So basically, I would appreciate some guidance/clarification on how the controller communicates with the drone itself. I know the controller has a transmitter that sends out pulse waves to the drone and the receiver that is installed onboard the drone will read these waves and do what the pilot wants it to do. My question is how do the waves carry this information to the drone? The transmitter and receiver must be functioning on the same frequency, but does it use Frequency Modulation, Amplitude Modulation, or Pulse Modulation? I figured it communicates with FM…

    For example, if the pilot uses the controller to make the drone go down and to the left, what do the signal pulses that propagate out to the drone look like?

    I know the basics of how a transmitter and receiver work and how each of them must have antennas to operate on the certain frequency. Any advice/knowledge/guidance on HOW the controller communicates with the multi-copter would be much appreciated!

    Thank you in advance.

    (PS: if anyone has any schematics for the DJI Phantom 2.0 or any similar multi-copter, I would appreciate it! I am assuming that most multi-copters have similar schematics for the controllers and drone body.)
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,562
    2,378
    You may want to look up RC Digital Proportional control.
    Max.
     
  3. alexfreed

    Member

    Oct 8, 2012
    72
    10
    Old school used mostly pulse width modulation to control things like rudder position or thrust. These days it may well be digital codes.
     
  4. jlatshaw

    New Member

    Jul 20, 2013
    28
    0
    Check this out:


    Look into the "synchronization segment" and the "pulse segment."
    From what I understand, the synchronization segment is a pule running at the desired frequency for a certain period of time. Its job is to inform the transmitter to get ready for instructions.
    After that, pulse segments are sent with instructions for operation (such as moving left, right, etc).

    For your project, you should look into what the actual synchronization and pulse segments are and then which pulse segments correspond to what operations.
    Then you could look into designing a circuit to do that.

    However, this is assuming the DJI is running on pulse width modulation and not digital codes.

    Hope this helps,
    James
     
  5. jlatshaw

    New Member

    Jul 20, 2013
    28
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  6. jlatshaw

    New Member

    Jul 20, 2013
    28
    0
  7. rhekj

    Thread Starter New Member

    Sep 6, 2014
    9
    0
    Very interesting, James. Thanks for all of the info!
     
  8. rhekj

    Thread Starter New Member

    Sep 6, 2014
    9
    0
    Thank you for all of the help everybody. I appreciate it!
     
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