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Crazy Question -How keep IMU warm while waiting for the Shot

Discussion in 'General Discussion' started by Videoguy, Sep 13, 2014.

  1. Videoguy

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    Hi, does anyone have any tips on how to keep the IMU warm for long periods of time, while I'm waiting for the shot? Or hwo to get the IMU to warm up really fast? I'm going to be doing a video shoot in a week of whitewater kayakers coming down a river, (I'm a professional Director so this is a pro shoot) at a location thousands of miles from my house, so I won't have a lot of time to actually scout the river very much. The challenge is, from the time I see them coming around the bend, I probably only have about 10-20 seconds to get airborne and line up for the shot. One way is to put a Camera Assistant about 1-3 minutes up the river... which may or may not work, if he can get access to an overlook. But there has to be a way to keep the IMU warm on another battery...?

    I tried plugging a spare battery into the Phantom, and waiting for a few minutes, well after it's take-off ready. Then I disconnect the spare, and quickly plug in the onboard battery. At that point I get alternating green/red flashes for about 3 or 4 sequences, then a sequence of 3 green flashes, and those 3 greens repeat indefinitely. I haven't tried flying at that point, I'm too worried about a fly-away, especially since my shoot is in a week. And after poring over the LED codes, I can't find anything that matches those sequences.

    If I wait about 1 minute after disconnecting the spare, and connect the onboard battery, It's ready to go in about another 45 seconds. So that's 1:45 total ... way too long.

    I'm going to try some tests on how much battery I burn by letting it just sit there in "ready to take-off mode", but I would think that waiting for any period of time, such as 20-40 minutes or more, I'd lose some significant flight time on battery. FYI I'm using a 3300mah battery and a Sony Rx-100, so I normally get just about 7-8 minutes of flight time (but the Sony makes it worth it!!!) I know, I'm beyond the specified payload, but it actually gives me some amazing, professional results. Any ideas would be appreciated!
     
  2. thedjiguy

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    Re: Crazy Question -How keep IMU warm while waiting for the

    If its cold outside, place the phantom in your car until showtime. Otherwise, in my experience, if you were flying about 10-15 minutes ago, IMU is all flashing green in about 15 seconds. Just run some tests in your backyard.
     
  3. N017RW

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    Re: Crazy Question -How keep IMU warm while waiting for the

    If I may assume... I believe you want to have GPS lock and be ready to go.

    The IMU has no indication of it's temperature.

    If my assumption is wrong, with all due respect, the P2 will sit and wait for CSC for hours with a fully charged battery.

    Why not test it to satisfy your concerns ahead of time?
     
  4. CaptMike

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    Re: Crazy Question -How keep IMU warm while waiting for the

    Can you not give the "subjects" a Walkie Talkie and when they get within 2 or 3 minutes from you give you a call? or what the Above Poster said. Run some tests on just sitting. I'm betting the Quad will time out like the Controller after 10 minutes of being idle.
     
  5. Videoguy

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    Re: Crazy Question -How keep IMU warm while waiting for the

    Thanks for the info. Yes, as I said, I'm going to run another test. And I'm going to try to position a Cam asst. up the river, which is a huge variable dependent on a number of factors. It's just such a pain that you can't just swap the battery and be ready for take-off quickly. Maybe I can rig something that will add a 2nd battery in parallel while on the ground, then disconnect only the 2nd battery right before take-off. So voltage stays the same, the IMU is still warm and ready to go, and the P1 will think it's still ready for take-off. Because the only thing that changed is battery capacity. That seems like the best option... has anyone tried that?
     
  6. Uncle Meat

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    Re: Crazy Question -How keep IMU warm while waiting for the

    Why not run an external parallel connection that would allow you to hot swap batteries? Something like this:

    [​IMG]

    Keep one battery plugged in and the quad powered up while you wait for the shot. Then when you see them come around the bend just plug in fully charged battery #2, remove battery #1 and take off immediately. GPS/IMU would never get powered down.

    U.M.
     
  7. lake_flyer

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    Re: Crazy Question -How keep IMU warm while waiting for the

    {edit} +1, you beat me :)

    I do that all the time, with a T splitter cable. I can choose to fly one or two batteries, one in the bay or two on sleds on the side. If you connect a 2 dollar Lipo checker to the flight battery (ebay) you can monitor the voltage while you wait for take off. On the other hand, if you use a T-splitter, you just hook up the flight battery just before take off and disconnect the 'stationary' one. The P1 will never know you changed batteries.
     
  8. Videoguy

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    Re: Crazy Question -How keep IMU warm while waiting for the

    Great ideas, and I will definitely rig the T splitter. In case anyone's interested, here's what I found:
    I lost about 10% of capacity for every 10 minutes of just sitting on the ground.
    When switching from a spare battery to the onboard battery, i was getttng a wierd LED code... 3 green, then about 10 green, then repeated continually... it never cleared to normal status. couldn't find that code on any DJI info. With only 3 days until my shoot I was running out of time and didn't want to risk a crash, so I then discovered this. If I waited 30 secs after disconnecting the spare battery, i'd be ready for takeoff within another 20 secs... total 50 secs, not too bad.

    I did position a Cam Asst. upstream, but as I suspected, without time for a full blown test it was faulty. According to the river guide I should have had 4 minutes warning. It was more like 1:20. So I'd just taken off and got in position when they came around the bend and hit the rapid.

    Got the shot, that's all that matters!

    Thanks for all the great advice!
     
  9. BostonPhotog

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    Re: Crazy Question -How keep IMU warm while waiting for the

    So where is the video? We're all dying to see the shot! :p
     
  10. Uncle Meat

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    Re: Crazy Question -How keep IMU warm while waiting for the

    After reading and commenting in this thread I opted to get one of these so I could have my hex in "standby mode" should the need ever arise again. I could have used this modification when I was filming the dragon boat races a few weeks back.

    U.M.

    http://www.amazon.com/gp/product/B00KXV ... UTF8&psc=1
    [​IMG]