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Some basic questions

Discussion in 'General Discussion' started by jdjeff, Mar 24, 2013.

  1. jdjeff

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    As I wait for my replacement Phantom, I have been continuing trying to learn as much about this bird prior to getting mine off the ground for the first time. Please excuse the possibility that I might be over complicating something here:

    1. The information I have up to this point is that GPS mode is optional but highly recommended. That being said, if the Phantom should lose GPS signal for whatever reason, can you switch to another mode to manually (attempt) to bring it home? I've seen some of the horror stories about Phantoms running away and it appears related to lost or corrupted GPS signal. When it decides to run away, can you intervene and override that decision?

    2. Relative to question #1, is a GPS signal required for successful flight? In other words, can this be flown without a GPS signal?....Like manually indoors in a gym for example when a GPS signal may not be present? Do you need to calibrate it to just hover or fly?

    3. I'm reading and seeing videos relative to GoPro. They all seem to suggest to turn off GPS to eliminate all the micro corrections that show up as unstable video. With Q #1 and #2 in mind, then is the Phantom at risk at this point?

    4. If you bring the Phantom down to replace the battery, can you change the battery on the fly? Or do you need to go through the whole calibration process again?

    I'm just a little confused about some of the standard flight preparations. Seems like this is dependent on GPS 100% of the time from what I can see. Or am I missing something?

    Just a little commentary, this 'running away' issue that people are experiencing is what scared me away from the AR drone. I personally also had an issue with anything flying over a WiFi signal. So I backed out. I didn't find this forum until after I received my first Phantom. (I sent it back because the props didn't fit). But I didn't think this issue would come up with an RC grade transmitter/receiver. Now I'm second guessing my decision to go ahead with this. I bought Hero 3 and have some bucks tied up in this. And after checking out the instructional videos, I'm scratching my head a little at all the hoops you have to jump through to calibrate. It just seems a little hokey to have to go through all those gyrations spinning around in circles and whatnot for such a high tech device. Can someone give me a warm and fuzzy about this? Thanks.
     
  2. IamWill

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    1- not sure, I haven't had any negative experience with GPS, and I do the lions share of flight in GPS. I don't want to speculate, so maybe someone else can chime in.

    2 - no, GPS is not required (and probably not even preferable for an experienced pilot). You probably want to do the initial calibration out of the box though.

    3 - not sure what you're asking. GPS on the GoPro? Do you mean wifi? If so, it's inadvisable to run the wifi as I have heard it can screw with the Phantom's mojo.

    4 - there is no on/off switch on the Phantom, so changing the battery does require a complete power-down. You shouldn't have to calibrate after each flight, and the warm-up period is greatly reduced or eliminated entirely.

    I had a hard time fitting my props on - but kept at it. They are a tight fit (well, two of them at least), but I seem to have lucked out and have incredibly stable flight out-of-the-box. No prop or motor balancing. I've posted a couple vids in the video section.
     
  3. jdjeff

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    Will...I was referring to GPS on the Phantom. People seem to be saying that GPS mode induces constant little corrections on the Phantom which manifest as wobbly video...not Jello...but an unstable looking video. But you pretty much answered my question saying GPS is not needed.

    So if I have this correct, when you do a calibration, you are calibrating the compass? And not the GPS?
     
  4. IamWill

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    Gotcha I could see that, as GPS will made adjustments to maintain it's position (and stop it's movements when you cease to make them). I could see some give and take, as flying in ATTI mode will be smoother because it maintains the momentum. I prefer GPS because when I'm flying and want to (or need to) STOP zeroing the throttle/direction STOPS it (albeit abruptly).

    Yes, I believe when you do the calibration it is exclusively for the compass. The GPS sync's up when you are warming the Phantom up, and will indicate via the LED light when it has sufficient satellite communication.
     
  5. jdjeff

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    Thanks Will...I do remember the guy in the video talking about that now. I'm getting a little tangled up reading this stuff, thus overcomplicating things maybe. But that clears up alot of my questions. It seems to logically make sense that you can switch out of GPS mode if it decides to run away. I would hope it works that way.
     
  6. pwright

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    In regards to changing batteries you should make sure it reacquires the home location ago before it takes off. Watch for the multiple quick green flashes.

    Redoing the compass calibration won't hurt either and the 30 seconds are well spent if it keeps your Phantom from flying off over the horizon.
     
  7. Boosted2000si

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    I would suggest the advance calibration out of the box.

    Do the one in the Naza software then go do the compass calibration. Once calibration is completed you won't need to recalibrate unless you crash hard or it starts to act up.

    The fly off issue had me concerned as well but I have only read one real story about it. All in all the amounts of happy problem free users seem to out weigh the few horror stories you will hear, and that goes with almost all hobbies.

    GPS mode will make the video a little more shaky due to it trying to maintain its spot in space but I recommend you stay in GPS mode until you get the hang of flying the copter.

    Also take it to a large field for the first flight.
     
  8. auck

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    heya -

    1) GPS signal is NOT required for the Phantom to operate. It IS highly recommended to have a strong GPS signal because the RTH function is dependent upon GPS. GPS tells the craft where it took off from (home) and where it is relative to home when it needs to return. Also, the GPS function is great for noobs like myself.

    2) A "run away" Phantom is NOT due to GPS signal loss, but rather caused by TX signal interference. That is why you see posts about 2.4 Ghz WiFi on GoPro3 as being a possible cause. Even the FAQ on DJI's Phantom page states "the WiFi signal may interfere with the signal of the transmitter and affect your flight."

    3) Yes, turning off GPS will help with video shots, but this will put your Phantom at risk because the RTH function will not be available. If you loose signal between the TX and Phantom, the Phantom will most likely continue with the last signal it received, thus the "run away" Phantoms. If you are lucky enough to re-establish connection between your TX and the Phantom, then you can bring it back to you.

    4) The calibration process only needs to be done once unless you travel to a different region, ie another time zone. The calibration only requires that the Phantom itself be rotated. I thought the same thing of having to do the Hoky Poky dance to calibrate the Phantom when I saw the first video, but in a later video, they show that only the Phantom unit needs to be rotated. Also clarification is in the manual itself. After you change batteries, you just need to make sure that the indicator light is green.

    hope this helps
     
  9. Gizmo3000

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    Hold your horses! there seems to be some major confusing between flying GPS and RTH here
    DJI doesn't really make it clear, that's for sure, so it's kind of been up to us users to figure things out and learn from each other just what does what.

    - when you first connect the battery and the phantom warms up and indicates a single green blinking light, it means it's locked in with more than 6 satellites and when you first give it throttle it'll blink 6 times indicating that it's recorded a Home position.
    from then on out, if the Phantom loses contact with the Tx, (provided there's no Wifi interference or gremlins) it will then go into Enhanced Failsafe mode and will RTH to that set location.
    *REGARDLESS* of what mode you're flying in!
    (I asked this question myself and some brave souls over on the facebook page tested out RTH while flying in ATTI mode)...
    .which was a relief to hear!
    but apparently you can reconnect and take control again if you turn the Tx back on , put the throttle at greater than 50% and switch to ATTI mode from GPS mode (dunno who 's tried that tho).

    Now as for flying in GPS mode, think of it as if you're driving a car. ATTI mode is kind of what it's like when you merely take your foot off the gas and the car continues to cruise.
    GPS mode is akin to putting your foot on the brake the moment you take your foot off the gas.
    Basically when you let go of the right joystick and it centers itself, the Phantom then tries to stop and hold and will do everything to stay in that position. so you can imagine what the video might look like.

    but as a newbie flyer, the GPS hold is awesome to have

    -once you bring the Phantom down and swap out a new battery, you merely have to wait a minute or so for it to reboot and you're ready to fly again.

    -you only really should need to calibrate the compass once, just prior to your first flight.
    after that you'll only need to do it again if you move many miles away, or if you accidentally place the Phantom near a magnetized surface. (which might also require using a magnet to fix things).
     
  10. Ali in Austria

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    I'm a complete Newbie and haven't even had a chance to get airborne yet but I have done a lot of research so take from this what you will.

    From what I have gleaned and witnessed in the many videos I have watched is that provided the Compass is calibrated (only required once unless you change geographic location by some distance but take care where you do it) and you have secured the Home Lock then it is pretty much reliable. Lets face it, Home Lock doesn't take long to achieve and if it does take an inordinate period of time maybe it is an indication something isn't right and perhaps you shouldn't fly.

    The flight mode selections can be toggled at will. I have seen pilots fly it way in the distance, turn their TX off and watch it come back. I have seen Pilots with the TX turned off, catch it as it starts to land and throw it away repeatedly and it recovers and returns. I have seen Pilots turn the TX back on prior to landing and continue flying. Switching between flight modes at will isn't an issue. It may be an idea to have a visual reference on the Toggle Switches in the event of an emergency so that you can immediately select the correct combination.

    Of course there is always the possibility of a component failure. May be a TX can give an incorrect signal but turning it off should overcome that. There is always the possibility the controller,GPS or Compass will fail but that is life. At least with the low power functions it will try to land normally and not just fall out of the sky. You have to be mindful that the return to home function does have draw backs. If there is something between you that is higher than the altitude the Phantom climbs to in that scenario then it is going to hit it, like wise if there are overhead obstructions such as tree canopies, power lines etc it will climb in to them.

    Perhaps I have got it all wrong, I'll find out soon enough, but it appears most failures are probably down to human error.

    As for the Camera and GPS Mode. You may or may not be aware how a modern video camera actually records. It doesn't take a whole frame at a time but many sections of that frame and then puts them all together as one. Any vibration between each section will affect the smooth appearance of the assembled frames. There are many relatively cheap solutions offered to minimise the Jello effect which can be worse in brighter conditions. When the Phantom is in GPS mode it is constantly making tiny adjustments. The windier the conditions the more adjustments that are needed. This will show up as jerky movement on the footage and can cause Jello. The higher the quality and the higher the frame rate you record at, the better the results are. To this end by far the best camera for the Phantom at the moment would be the GoPro H3 Black (WiFi disabled of course). It would also appear that image stabilisation on these small Action Cameras isn't necessarily a good thing when hooked to a Quad Rotor (Sony & JVC)

    My anticipated use is to film particular scenery rather than the flight itself and to that end I anticipate turning the GPS off for the shots I want and re establishing it in between and to get in position. Then I only use particular sections of the recording. Recording a whole flight in GPS, especially at a hover may show up as jerky footage. A Gimbal appears to be the answer. There are already a few out there with what appears to be a raft of brushless servo models about to hit the market, all designed with The Phantom and GoPro in mind. Results I have seen of footage from them are very impressive for the equipment being used. I will probably invest even for the scenarios I want it for.
     
  11. jdjeff

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    Ok...I've read over the helpful replies, but there seems to be some conflicting information. I see that 'run away' mode is triggered by a corrupted TX signal? A loss of TX signal would pretty much mean that the bird will return as long as GPS mode has acquired satellites and is turned on or even off....yes?

    If that is indeed the case, let's say you have acquired satellites, GPS mode is turned off, the transmitter signal incorrectly tells the Phantom to fly away. Could you just turn off the transmitter, and wait for it to come home?
     
  12. MX45OR

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    Not if the other signal is telling it to do something else. If the Phantom flies away uncontrolable, it recieved a signal to do so. Wether it was some strong wifi (also on 2.4Ghz) signal, another controller,solar flare, or just a bad glitch. The controller(TX) will override all GPS signals. Flying away has Nothing to do with the GPS, GPS doesnt control the Phantom where to fly (except for home). That being said, make sure you record a new home position EVERY flight. This will cut down on confusion with you and the Phantom. You can also set home through the "CL" and "HL" switches by switching between the two 6 times. If this is done correctly the LED will blink green fast 7 times. I would not try to turn off the controller unless you have absolutly no control at all. I have yet to try this RTH feature, because I'm kindof leary with anything going wrong. Do what most of us did and Sharpie your name and number on the side of the Phantom. The only other thing i would say to keep from a Phantom from running away, would be to change TX to one with an extra channel to cut battery power. A smashed Phantom is better than no Phantom.
     
  13. Gizmo3000

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    Writing your name (multiple times) is a must-do, I know of at least two instances now where fellow flyers have recovered lost Phantoms.

    RTH is indeed a bit intimidating , because of the uncertainty of it all.
    But it really does work when you get into trouble. (unless the trouble is a runaway being caused by another wifi taking control in the first place). twice I've had to use it, and twice my Phantom has come back to me. first time i was flying FPV and lost my bearings.
    and the 2nd time might have been user error, or high winds, but for some reason HL wasn't bringing it back to me and it seemed my Phantom was flying farther and farther away (might have been high altitude winds). But it really is a great feature to use when all hope is lost.
     
  14. Sac D

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    I just wish DJI would implement RTH so that it can be used in a less desperate manner.
     
  15. jdjeff

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    Will the Futaba transmitter/receiver upgrade minimize this possible runaway situation? Seems that people get more flight distance out of that upgrade which tends to suggest the DJI transmitter or receiver is kinda weak....or weak-ER. Could that be why the Phantom can be taken over by a Wifi signal? Or are they not using the typical hobby grade technology? I don't know...I'm just askin'
     
  16. Gizmo3000

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    Yah, it would, but really the only possibly switch on the Phantom transmitter that's open would be the third spot on the GPS/ATTI switch, which would make it far too easy to accidentally switch to while flying. (and they leave that there for enabling manual mode)

    Technically, unless there's interference over-riding things, if you're a safe flyer , there would be little need to enable RTH, as one should calmly switch to GPS and HL .. and pull back on the right joystick and the Phantom *should* fly back towards home.

    But the current way to manually trigger RTH is actually a smart way to do so, since the transmitter is turned off there's little chance of the user messing things up trying to re-gain control.
     
  17. jdjeff

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    Ok...I just got my phantom assembled and installed drivers/software on my computer. I am following the instructions to the letter and they are letting me down. This is very counter intuitive. I finally figured out I need to have the transmitter powered up since there is a stick cal and switch position cal. I got the sticks cal'd ok. Now the instructions on the switch cal are telling me to adjust subtrim to get the GPS, ATTI, and Fail Safe to turn blue. GPS, ATTI turn blue but the fail safe doesn't. The black slider moves over but I see no blue. What the heck? They warn not to use a third party transmitter but they are telling you to use sub trim? Anyway, am I to assume that no blue color in fail safe is normal and can't be adjusted with the stock transmitter? Or is subtrim buried some place where I can't see it?

    In a previous post, someone recommended advance calibration out of the box. Is that IMU? I checked IMU status in basic and it said calibration not needed. Do I do an advanced calibration anyway? What will that look like as they only give a button to calibrate and no explanation. Was this stuff written in another language and translated without good old American logic?

    I watched all the videos and the guy goes right outside and calibrates the compass. What am I missing here? I'm going off of 2 sets of instructions....one for the NAZA and one for the Phantom. One refers to the other and it's got me bouncing off the walls. Can someone help simplify this a little?

    p.s. It also says, "If the communication indicator is on, please double check the connections and driver installation, otherwise if the indicator is blinking, go to the next step." What are they talking about? The blue indicator? It's the only thing I see blinking. I see a green one that is on solid. There is nothing telling you which indicator is which. Aaaargh...I hate stuff that's written like this.
     
  18. tanasit

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    jdjeff,

    I just want to add that when you fly with GPS on and if later NAZA somehow lost the satellites signal (lees than 6), you are then in ATTI mode without flipping the switch from GPS to ATTI.
    The possible scenario is when someone flies from outdoor to indoor, thus he doesn't need to turn off GPS once indoor to avoid jerkiness caused by GPS mode.
     
  19. jdjeff

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    Well I decided to just go ahead and do the IMU advanced calibration. It barked at me telling me to power off the MC for 10 minutes before continuing. So I guess that meant disconnect the battery. I waited 10 minutes, plugged it back in and it did its thing. No message that it was done or anything. I still can't get the fail safe to turn blue.

    So I went ahead and performed a compass cal...successfully. I spooled up the motors in my basement then took it out in the yard. Began a hover in atti mode and when up about 5 ft I put it in GPS. Had good lights prior to that. It was very stable and responded well to all my inputs. So I'm assuming this thing is set up right. The only thing I failed to do was note whether the warm up lights were done...but I had the phantom powered up already for a few minutes prior to walking outside. Once outside, I saw the >6 GPS light so I figured I was good to go.

    But now that I see this thing in action, switching back and forth to GPS to ATTI...testing a little with no stick input, It's beginning to make a little more sense.
     
  20. auck

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    here's the video on how to do calibration / advance calibration with the IMU. you really don't need to do any advance calibration with the IMU out of the box unless it is not flying right after you calibrate the compass.

    http://www.youtube.com/watch?feature=pl ... WWinX3m23A

    EDIT : MC is the TX. according to the video you don't have to worry about it, but I always turn off my controller when i do an advance IMU calibration just to be on the safe side (usually after I crash my phantom).