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Maiden Flight Ugly. 2nd Flight Not Bad At All!!! GPS issue though.

Discussion in 'Cinestar 8' started by Mark Melville, Jan 5, 2013.

  1. Steve Maller

    Steve Maller UAV Grief Counselor

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    I'll weigh in on this one, as others may want to, as well. I strongly suggest buying one of the PC-based flight simulators. I used RealFlight Basic ($99), which includes a USB transmitter. It has several copters built into it, and will definitely acquaint you with flying "nose in" (bird pointed at you, and all controls are reversed) and other complicated orientations. Andy and I agree that you should avoid "CareFree" mode (which might appear to be the answer to this issue) because it can cause disastrous consequences in a variety of situations. Basically, there is no substitute for experience. You really need to spend time practicing, and using a simulator is the safest way. You might also want to get a small quadcopter (like the mQX blade which many folks fly). Again, putting your big bird at risk is not recommended until your skills and confidence are sufficiently high.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The amount of magnetic variation changes from place to place -- sometimes within just a mile or so. Whether it's enough to cause problems, I don't know, but I recalibrate every time I go to a new location.

    That's recalibrating the 3-axis accelerometer and you only need to do that when you first build the bird, when you upgrade the firmware, or if you make any changes in orientation of the flight control board.

    Yes. Do that every time before you take off. Use that as a reminder to check that you have a GPS fix before you start the motors -- to ensure that you have a good value for "Home," in case you want to use Come Home.

    Really? I should have just calibrated the ACC (left stick to 1:30 on the clock) once.
    Then recal'd the gyros before take-off.

    No. Yes. No. No. :)

    They're independent, so you can use them independently or in together, depending upon what you want to do.
    If you have enabled Vario AH in MK Tool, then you can use the throttle or a POTI to vary the "set point" (the held altitude).
    If you have enabled Dynamic PH, then you can vary the lat/long of the hold point.

    The idea is that in both cases the bird is held in position, but you can move the position it holds. AH affects the Z-axis, PH affectss the X and Y axes, if you want to think of it that way.

    Very badly. :)
    My landings cause total strangers to gasp and clients to wince. Nearby dogs hide.
    :)

    Actually, not badly. I've flew a full-sized self-launching sailplane for about 15 years. Getting used to RC was interesting, but not an impossible problem to solve.

    AerosimRC is the best advice I can give you. Practice new maneuvers on it. e.g. Fly a figure eight at constant altitude with boom #1 pointing to your left. Then try it with the boom pointed to your right, and so.

    As to FPV, I combine the two. I want to watch the bird line of sight when I can, but glance over at the FPV (or down when I use the Cinemizers) so I can get the benefit of the Smart On Screen Display. If the bird is more than 150 meters away, I'll tend to spend more time on the FPV because the line of sight doesn't tell me too much....

    Your stereoscopic vision is basically useless at about 20 meters or beyond (or even closer), so I use FPV to augment my situation awareness. I have two FPV cameras -- one looking forward and tilted down (but I can see the underside of boom #1) and the other looking straight down so that I can hover directly overhead of things if that's what the cameraman wants. I use an RC channel to switch between the cameras.

    Hope this helps.
    Andy.
     
  3. Mark Melville

    Mark Melville Member

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    I have an experienced pilot flying this. I'm slowly learning on the simulator and in no rush to fly this. I'm a DP and more than happy to do my job and let an expert to theirs.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Wise move to take your time, Mark.
    Also being DP gives you credible deniability if there's "an incident." :)

    Andy.
     
  5. Dave King

    Dave King Well-Known Member

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    Yes, thanks as always
     
  6. Dave King

    Dave King Well-Known Member

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    Thanks the reply. I just got aerosim.
     
  7. Dave King

    Dave King Well-Known Member

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    Andy what do you mean you use an RC channel to switch between the cameras? What is the actual device you use? Is that a switcher that takes both TX signals as inputs and takes the switched signal to the output for the video monitor? When you use two cameras are they both 5.8 or is one 1.3? I would assume that it would be hard to switch between transmitter signals if they are not the same bandwidth frequency but I don't know how you can have two 5.8's running at the same time without interferring with each other.
     
  8. Steve Maller

    Steve Maller UAV Grief Counselor

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    I believe Andy uses two cameras that go into a servo/relay/switch on his copter, which in turn feeds the video TX. He controls which camera is transmitting using a switch on his Graupner transmitter.
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Steve's correct, Dave. I use one of these: Two channel video switch:
    http://www.dpcav.com/xcart/R-C-Controlled-Dual-Video-Switch-2-Way.html
    to do the switching.
    The output of the switch goes into the Lawmate 1.2Ghz Tx., so I have an MX-20 switch for the two views: "Here's what I will hit if I go forward" and "Here's what I will hit if I plummet." :)
    Andy.
     
  10. Dave King

    Dave King Well-Known Member

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    Andy thats really clever what servo on the graupner do you have the switch hooked up to? Are you taking lipo power to the Cam + connectors?
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yeah. The switch has a pass through for ground and power.

    Edit: Sorry, forgot to answer the switch question: Switch 3. :)

    Andy.
     
  12. Dave King

    Dave King Well-Known Member

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    Sorry to be a pain in the neck but can you walk me through this? I have the wiring diagram for it. It looks like P1 goes to the GR-24 (I guess it can go to any servo on the bottom except 8) , and the 3 pin header below it goes to the RX transmitter as it is the output of the switch. Then on the right side of the board is the 2 header pins for the 2 AV sources. You have Cam ground, cam + and Cam signal. If you are just using battery power for the camera do you not need a Cam + at the header or is that how the board is getting power?
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Dave:
    The video switch board gets its power/gnd from the RC connector, P1.
    The Vid+/Gnd at C feed power out to both cameras Cam+/Gnd simultaneously -- so both cameras are "hot" all the time.

    It's really the same setup as if you only had one camera -- you provide Vid+ and Gnd to the camera, and it provide Vid Sig back to you. You feed Vid sig and Gnd over to the downlink transmitter. In this case, you feed the same signals to the video switch and it passes +/Gnd to the camera and feeds you back the Vid sig for whichever camera you have selected.

    Hope that helps
    Andy.
     
  14. Dave King

    Dave King Well-Known Member

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    Andy: Sorry to hijack this thread but I think you would want me to put in public in case other newbee's have the same ignorance I do. I haven't wired up my FPV system yet but here's what I was planning on doing.
    1. Use the battery in the Go pro for camera power.
    2. Wire up a 1200 mah cell lipo to power the transmitter.

    Are you not using a lipo to power the switchc or your transmitter?
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Don't worry about hijacking the thread....people will find the info via the Search if they need to. :)

    I use a 3S 1200 mAh LiPo for approx. 12v for the camera and downlink Tx, a BEC 5v for the Receiver/Radians/Servos, and the video switch gets its power from the servo connection to the Receiver. Make sure everything has a common "ground" (including the GoPro -- via the video cable).

    Hope that helps.
    Andy.
     
  16. Dave King

    Dave King Well-Known Member

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    Andy
    Wouldn't you want the 3S Lipo to provide power to the video switch since the switch provides power to the cameras and the FPV RX? This way everything would have the same ground point as well. See attached pic. Plus the switch wouldn't take power away from the 4S Lipo for the bird if the GR24 isn't powering it??

    thanks
     

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  17. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Dave:
    Aha....I think I see where some confusion has crept in. I'm using a 3-Axis gimbal so there is no connection between the receiver for flight control and the receiver for the gimbal control.

    The 3S Lipo thus does power the gimbal receiver, and thereby, the video switch too.

    Andy.
     
  18. Dave King

    Dave King Well-Known Member

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    OK, so my circuit looks like it would work? I just bought the switch and plan to install this weekend.
     
  19. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I'd make sure that the Servo lead from the GR24 shares a ground connection with the LiPo that you show otherwise there might be problems.

    Andy.
     
  20. Mark Melville

    Mark Melville Member

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    On the GPS issue. My pilot plugged in the coordinates from the GPX file from the navi board. The coordinates that MK established as our location was actually about 200 to 300 meters from where we were according to google earth. How could the MK GPS be that far off? That might explain when we engaged position hold it took off on us..
     

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