Surfing - cs8, freefly 3axis w/ home made brushless conversion

Discussion in 'CineStar Showcase (Photo/Video)' started by Steve Galle, Jan 27, 2014.

  1. Steve Galle

    Steve Galle New Member

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    Hi, a friend and I went out on Saturday and shot a few flights worth of surf footage. We're pretty happy with the results, so I thought I'd share. Hope you enjoy.



    -Steve
     
  2. Jason Smoker

    Jason Smoker Active Member

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    Awesome Steve!!
     
  3. Steve Maller

    Steve Maller UAV Grief Counselor

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    Simply gorgeous!
    Any more details about your setup? Camera? Gimbal specs?
    What altitude were you maintaining? I assume you had camera op, right?
    I love the perspective of the 50mm lens...such a difference from all the wide angle footage out there!
     
  4. Jason Herring

    Jason Herring Member

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    Amazing work,
     
  5. I grew up in Hawaii and am a sucker for great surf footage...this definitely qualifies. Nice work! Love the closing sunset shot.
     
  6. Steve Galle

    Steve Galle New Member

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    Thanks, we're jazzed with the results; it's taken a lot of tinkering to get things worked out.

    Steve, yep, I've got a buddy who operates the camera. We're shooting on a 5DmkIII, and using the magic lantern firmware so that we can shoot the video raw. That gives us something like 7 minutes on a 32GB card, so there's lots of card swapping, rebalancing, and offloading of data, but having the raw files allows for a bit of extra latitude to push things around in post. We're currently shooting with the 24mm f/2.8, and the 50 f/1.4. I wish I had the 50 1.8, it's much lighter, and we're never shooting wide open anyway. The gimbal is a bit of a monstrosity... it started life as a freefly 2 axis with servos and radians. Not too long after I picked it up the alexmos controller became available, and I began the process of converting it for brushless operation. Many evenings in solidworks and more versions of bits and pieces than it probably should have taken, the gimbal was working nicely. It used to be hanging on a hex with much less lifting capacity, so the motors aren't beefy at all (just the rctimer 5010). Due to the low power, balance is super critical, but as long as I pay attention to that they work fine. After that was done I pretty much instantly realized the third axis was not optional, and ordered a clone from China. Brushless craze was still new, so there were no natively brushless options at the time, so I went on another solidworks binge designing a setup using the ipower 5108. The parts to adapt the gimbal are all 3d printed; I keep telling myself I'm going to get around to milling replacements, but in reality I'll probably wait until I'm upgrading the motors to bother, for now these parts are working fine. Direct drive all around, but I have toyed with experimenting with some reduction. I'm using two seperate alexmos boards (the 3rd axis expansion was not available at the time), on 4S. I really need to apply the mod that allows for battery monitoring, as I have puffed a couple of packs on the gimbal.

    Of course now that I've done this work, you can just go to brushlessgimbals.com and order up just about anything you need... the building was fun though, and good practice for the next project, which will be a ground up copter and gimbal build. Just about ready to order the carbon :)

    Anyway, sorry to ramble, but that's the story!
    Steve
     
  7. Jason Smoker

    Jason Smoker Active Member

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    Can you post some pics of your gimbal I would like to see!
     
  8. Steve Maller

    Steve Maller UAV Grief Counselor

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    Fantastic info, Steve. And the results speak for themselves! :D
     
  9. Steve Galle

    Steve Galle New Member

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    Jason, I'll post some pics when I get home. In the mean time you can see the tilt axis parts pretty well in a video we shot from a gopro on one of the hex's (listen to the poor hex scream!) arms while range testing the Arrow (I turned around at signal loss if anyone is curious about range). Since this was shot the bit that couples the roll motor output to the gimbal (which you can't see anyway) was replaced, as was the yaw axis (it was belt drive at this point, and I wanted to try direct drive, there are some yaw jitters I'm battling that have been a real nightmare to get rid of). As you can see the tilt axis is supported opposite the motor by a slip ring. Seemed great in theory, but it got the best of me by slowly degrading, introducing i2c errors and jitters on roll and pitch that drove me absolutely bonkers until it finally failed decisively and solved the mystery. Never again.

     
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