Welcome To DroneVibes

DroneVibes is a COMMUNITY of drones enthusiasts. We are experts at drones for all professional and consumer applications. We welcome you to register and join the conversation.

Inspired by Inspire, DJI A2/H3-3D XY4 Quad Build with a twist

Discussion in 'Drone Builds and Kits' started by Bartman, Dec 9, 2014.

  1. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 9, 2014 #1
    Not too long ago, I built a quad-copter using DJI's NAZA V2 and an H3-2D GoPro gimbal for an XY4 quadcopter build. It used 4S battery packs for power and worked really well. The little quad saw some use in the Spring and then sat for the most of the summer before moving on to a new owner in NYC.

    When DJI's Inspire 1 recently came out there was a lot of discussion about it's capabilities compared to other products by DJI (which is natural) but it got me thinking about what a similar homebrew quad might look like if trying to get similar performance and capabilities to the Inspire. So I got to thinking about what I've got in the shop and what I could do to make a similar quadcopter.

    In the video below (the horribly produced and bad excuse for a video) we first look at the overall plan and try to get an estimate of the performance and duration we might expect. The rough parameter set that I was shooting for was to have hover power around the 65% throttle position with 30 minutes of flying time while using two Turnigy Nano-Tech 6000mah packs.

    Have a look at the video;


    Datasheet from the rctigermotor.com website
    View attachment 22053

    The H3-3D gimbal for this review was supplied by GotHeliRC.com and we'll do a review of the gimbal while we're also building the heli that will fly it.

    Regarding the Inspire 1 reference in the thread title, you might be saying, "Bartman, I don't see any retractable gear/arms or sassy white body shell".

    Well, we're not using retracts because we're going to get full 360 degree panning capabilities using something called (say it slowly with a lot of dramatic emphasis) t..e..c..h..n..o..l..o..g..y. We're going to fly it like a standard one-man heli rig and then use a switching module from Pololu.com to convert it over to a two-man rig by simply flipping a switch. No retracts necessary, the heli's standard fixed landing gear with be panning with the camera and thus remaining out of the shot.

    The module is called the Pololu 4 Channel RC Servo Multiplexer....

    http://www.pololu.com/product/2806

    ....and it allows you to input two sets of receiver signals and it will output one rx's signals or the other's based on the position of a switching channel. Two sets of heli Yaw and camera Tilt go in, one set comes out and goes to the flight and gimbal controllers depending on the position of the Carefree mode selector switch.

    So, what does this mean for you as a builder/flyer? It means you can take just about any basic quadcopter with a two-axis camera mount, and provided the flight control system has Carefree Mode (also known as Intelligent Orientation Control), you can fly it just as anyone would fly a much more complicated helicopter with one person flying and the other person panning and tilting the camera via a second remote control system.

    The system activates when the pilot selects Carefree Mode. When the switch is flipped it activates the module and causes it to send Yaw and Tilt inputs to the flight controller and gimbal from the second receiver. The pilot is flying in Carefree mode so he/she doesn't need Yaw anyway so why not let the second operator use it to Pan the camera, right? Carefree mode is easy to get used to and the pilot can switch it off whenever necessary to get full control of the helicopter back.

    Using this system your heli will be very capable yet will be simpler, lighter, and less expensive to build. After all, why have a Pan motor/axis at all and why have retracts (big $$$) or landing gear that leaves all of the loads of landing on the camera mount's Pan motor shaft. This might be especially useful for people trying to stay below a certain weight limit for certification purposes.

    Is it perfect? It might not be as good as a dedicated brushless pan axis on a really good camera mount. If your heli is well built though and if your calibrations are really good giving you a heli that is steady in Yaw then you may be on your way to a great option in a new build. We flew this setup on two different helicopters (a NAZA V2 XY4 and a Hoverfly XY8) and both worked really well, you wouldn't know the footage we shot didn't come from a dedicated three axis, 2 person rig.

    I was pursuing the idea of this kind of system a couple of years ago and, in collaboration with an electronics engineer, we designed a module to do exactly what the Pololu product will do. It was prototyped but (thankfully) before we could order a first run of the product we discovered Pololu's component and that they sell it for TEN FREAKIN' DOLLARS! We were looking at a sale price of about $60 so thank you God that we never invested the money to run that first batch!!

    Hope you like the build, feel free to discuss anything and everything about it in the thread below and thank you again to site sponsor GotHeliRC.com for providing the DJI H3-3D camera gimbal for this build.

    Bart
     

    Attached Files:

    Last edited by a moderator: Dec 16, 2014
    2 people like this.
    Tags:
  2. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 9, 2014 #2

    Attached Files:

  3. FerdinandK

    FerdinandK Member

    502
    34
    11
    Aug 7, 2012
    Eggenburg
    Posted by FerdinandK, Dec 10, 2014 #3
    Hello Bart

    What you found with the pololu multiplexer is also available at HK:
    http://hobbyking.com/hobbyking/store/__20002__Wireless_Buddy_Box_System_4CH_Dual_RX_Controller_.html

    Here how I did a 1-2 operator switch on a copter using the buddy box:
    Personally I think that you setup is a bit on the big and the heavy side. For a H3D3 with GoPro a 10" Copter is enough to reach 30min flying time. Also the A2 is nice, but the Naza V2 is just 100gr less weight.

    If you add a Lightbridge you are pretty close to the Inspire then. Looking forward to your build.

    best regards
    Ferdinand
     
  4. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 10, 2014 #4
    Hello Ferdinand,

    Yes, it appears the HK unit is similar. Can the HK unit be programmed or trained to respond for the correct action of the switching channel? The Pololu unit can be trained to switch based on high-to-low or low-to-high without having to adjust endpoints making it compatible with the channel that is turning Carefree on and off without changing the settings of the channel.

    Also, I'm trying to use everything that I have on hand while achieving my goals. I've got a lot of 6S 6000 packs, plus the motors, plus the control system, plus the frame. I didn't even try to assemble a scenario where it would be lighter because I want to use what I have. Also, the Inspire isn't exactly a GoPro only heli and mine will adapt to other loads/mounts if/when it becomes necessary. I've actually got a small two-axis mount I've designed but never wanted to try with an AlexMos board so I might get it moving using the Phobotic Centerpiece if I ever have the time and that would be good for the GoPro through about the NEX size cameras.

    Lastly, I see in your video that you are switching a standard two-man rig but the real strength of the module that I linked to in the first post, IMHO, is that you can simulate the features and performance of a two-man rig using a simple fixed landing gear one-man rig with only a two axis mount. That really opens a lot of opportunities for folks with simple rigs to use them in a much more advanced ways by only adding the switching module, a few wires, and a receiver to the helicopter.

    I don't see myself needing an HD video downlink from the heli so I'm not going to add the Lightbridge any time soon but, yes, that's a feature that my build won't have that the Inspire does have.

    Thanks for the reply!
    Bart
     
    Last edited by a moderator: Dec 10, 2014
  5. jfro

    jfro Aerial Fun

    983
    59
    11
    Aug 23, 2011
    Upstate NY.
    Posted by jfro, Dec 10, 2014 #5
    Might be worth a try. I'd probably keep the 3rd axis, just not the retracts. I like the yaw corrections when flying forward at medium to higher speeds. I've been basically flying both my 3 axis gimals with about 15-18 degrees restriction on the yaw with a little bit of dead band and quick follow. Some days yawing with the copter is better than others, but it's doable.

    If I can only have one quad, I'd go with a bigger unit based on 6s batteries. Good flight time and I've always felt more comfortable with a little more weight when there is a bit of wind. Not sure the gopro and gimbal cares, but the MR does. In my case, I have both. My small quad with 10" props carries a 3 axis gopro and I use it as a test quad for new FC's and often just fly with out gopro to fly and good around/ ie practice and gain experience.

    Anyway, sounds like something worth trying....
     
  6. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 10, 2014 #6
    Jfro, yup, there will be times when the dedicated 3-axis mount does a better job but you'd be surprised how stable in yaw a heli with good set-up can be. and for all of those fpv heli's and hobby quads with 2-axis mounts, this opens up a whole new world of operations that can be done with them.

    even a basic racing quad can be switched to a two-man rig if it has carefree mode available.
     
  7. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 10, 2014 #7
    Moving right along, four motor builds go so much faster than 8!
    Wiring harness came in at almost exactly 75g, the motor wires stayed the same lengths as they were when weighed, the arms are a smidgeon shorter....all in all she should be on target for her final ready-to-fly weigh in. And as the build is going along, with it being a public effort and all, I keep ballparking in my head where I've been conservative or liberal in my estimates, trying to maintain an optimism that the duration and performance estimates will be accurate. It occurred to me today that I won't need the gear to be as tall as it is so I can probably lose 40 or 50 grams by shortening the gear but we'll do that after the first all-up-weight can be measured.

    So here are a few photos from today's build session. If you've seen any of my builds then the details will look familiar to some degree. I put some fancy (fancy for me at least!) yellow heat shrink on the ESC's after attaching the wires. I like to pull the wrapper off the ESC's and then remove the wires so I can attach my power and motor wires directly to the pads on the ESC's.

    :) Progress!

    View attachment 22039 View attachment 22042 View attachment 22041 View attachment 22040
     

    Attached Files:

  8. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 12, 2014 #8
    The good news is the basic build is done and the H3-3D has been mounted. It's a pretty generic build that any one of us could have successfully accomplished. Here are a few photos;
    View attachment 22055 View attachment 22054

    Before we proceed onto the mounting of the H3-3D, I'd like to again say thank you to GotHeliRC.com for being a devoted site sponsor and for sponsoring this build and the H3-3D review that will be a part of it! :)

    Mounting the H3-3D is different from the H3-2D in that the camera mount cannot be mounted to any flat surface because the pan motor protrudes up through the flat mounting plate. A flat surface therefore has to have a hole cut in it where the pan motor is. To do this I attached the mounting plate to the frame and then traced the hole in the mounting plate where the pan motor would be and removed that material from the frame plate. It's the semi-circle at the front of the larger centered hole.
    View attachment 22056

    you can see in this photo where the silver pan motor protrudes up into the frame a bit
    View attachment 22057

    and then here are the H3-3D mount on the frame and the completed helicopter awaiting set-up of the A2 and H3-3D firmwares
    View attachment 22058 View attachment 22059

    OK, so now on to the bad news :(
    It seems as if burning the candle on both ends for months/years is catching up to me as I overlooked the fact that the A2 doesn't have discreet channel inputs like the NAZA and other flight control systems do. That precludes me from using my 2-axis to 3-axis trick because to do it you need to be able to tap into the Carefree Mode, Yaw, and Tilt inputs so that they can be sent from either receiver to the flight control system.

    I could just pull the A2 system and replace it with another NAZA V2 as that would be compatible with the camera mount and would let me do the trick for single-to-double-and-back-again operation but we've done that already. So, in an attempt to further the trick into uncharted territory I'm going to have to pony up and buy a DJI Dbus adapter.

    When it's all wired up it will make more sense but, and it's a big but (a big but, not a big butt), will it work? I'd hate to have to remove the A2 because it seems like DJI has finally got the thing working correctly! Plus, DJI has added a few really cool features that I'd like to be able to try and have available. A downside to this quick-fix is that there will only be eight channels available for use via the Dbus adapter so that might keep me from being able to use all of the advanced features.

    The moral of this story is that I've got a little homework to do and that I need to chill and go back to a more normal workload! To that end, I'm going to go get on the treadmill for some exercise and then get back to work on this situation.

    Bart
     

    Attached Files:

  9. Motopreserve

    Motopreserve Drone Enthusiast

    4,011
    381
    66
    Nov 23, 2013
    Brooklyn, NY
    Posted by Motopreserve, Dec 12, 2014 #9
    Damn! Seems like you have a plan, but that hiccup is a bummer.

    Burn off some steam on the treadmill and I'm sure the inspiration will come....
     
  10. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 12, 2014 #10
    back on this problem, when using a Futaba sBus adapter, the DJI dBus adapter, or JR/Spektrum radios via satellites plugged directly into the A2 you've only got eight channels so let's see what you can do with them.

    Channels 1, 2, 3, and 4 are a no brainer, throttle-elevator-aileron-rudder
    Channel 5 is flight Mode
    Channel 6 is IOC because, after all, it's necessary to have IOC (aka Carefree Mode) for the "trick" we're trying to utilize with this heli to go from one-man to two-man operations
    Channel 7 is camera tilt
    Channel 8 will be Go Home (aka, oh snap! I want my helicopter back!)

    In the future I'll have to just map Channel 8 to whichever advanced feature I want to try and plan to use IOC's Home Lock function as my Go Home function since in that mode, the helicopter will fly directly back to where it took off from by pulling the right stick backwards.

    Keep in mind whether you're planning to have Go Home save your butt, or IOC Home Lock or the built in Fail Safe function that you'll configure in the A2 Assistant, if you fall below the minimum GPS satellite count ( 6 satellites or more) none of them will work and you'll be forced back to manual mode and then maybe Atti (aka Autolevel) to fly your heli back to safety. In the A2 quick start guide it states;
    One last option to get the heli back from a bad situation, provided a sufficient number of GPS satellites are available, switching off the radio will also force Failsafe mode but that's an absolute worst case scenario and you have to have the presence-of-mind to leave the radio off regardless of what happens so the A2 can go through it's protocols for lost-signal recovery.

    Worth mentioning in all of this is that with the DJI A2 it is possible to remotely adjust the gains via one or more RC channels but with a limited number of channels I won't be able to do that. However, the hub of the remote LED module contains a Bluetooth receiver so I will still be able to make gains adjustments via an iOS device in between flights when the helicopter is back on the ground.

    When using the A2, access to the greatest number of channels comes from using the built in RC receiver but it requires a Futaba radio. While it is good to have the maximum number of channels so that you can have access to all of the A2's features, using the internal receiver prevents you from being able to do the single-operator-to-double-operator-and-back trick at the flip of a switch.

    Moving right along, I've got to get my hands on a DJI dBus adapter. Ebay here I come!
     
  11. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 12, 2014 #11
    @Tahoe Ed@Tahoe Ed
    the DJI dBus adapter only converts 8 channels but the Futaba sBus adapter can convert 10 channels. i remember reading that even with the higher channel counts, the A2 will only accept 8 channels via a Futaba sBus connection. is that correct?
    Thanks,
    Bart
     
  12. Tahoe Ed

    Tahoe Ed Active Member

    2,063
    27
    0
    Sep 14, 2011
    Posted by Tahoe Ed, Dec 12, 2014 #12
    Bart I don't think so. The A2 will support at least 12 channels according to my memory. That is based on connecting to the A2 directly not through the sBus. I am not sure that it makes a difference.
     
  13. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 12, 2014 #13
    hi Ed, thanks for the reply. I'm pretty sure that the Spektrum satellites plugged directly into the A2 will only yield 8 channels and that an sBus connection will be the same. I think the only way to get the full complement of channels is to use a Futaba radio linked to the internal receiver in the A2. The Futaba sBus adapter will convert 10 channels from any receiver to the Futaba sBus standard which is better than the DJI dBus adapter but if the A2 will only take 8 then having ten doesn't help.
    Bart
     
  14. Pumpkinguy

    Pumpkinguy Member

    967
    185
    26
    Sep 20, 2014
    Toronto
    Posted by Pumpkinguy, Dec 12, 2014 #14
    looks pretty cool. Tagged for interest. Is that just yellow electrical tape on the arms?
     
  15. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Dec 12, 2014 #15
    Polyolefin heat shrink tubing from Mcmaster.com
    http://www.mcmaster.com/#heat-shrink-tubing/=uzuw70

    it takes some heat to get it tight around the arm so you have to be careful when shrinking it onto composite or plastic parts but it works great!
     
  16. Pumpkinguy

    Pumpkinguy Member

    967
    185
    26
    Sep 20, 2014
    Toronto
    Posted by Pumpkinguy, Dec 12, 2014 #16
    Thanks. I'm Canadian. Mcmaster won't ship here anymore because of ITAR. I guess they think I may order some bolts to build my rocket launcher. Lol. Shame because they are the best resource around.

    Edit, I found some locally. Thanks.
     
    Last edited by a moderator: Dec 12, 2014
  17. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Jan 8, 2015 #17
    There's nothing worse than a heli that don't fly and right now i've got a heli that don't fly!

    To do the trick that I've been jabbering about I've got to have wires running from the receiver to the flight control system and although I'm trying to do it with the A2, I'm wondering if I'm barking up the wrong tree. I've spent the last couple of days trying to get a ZeroUAV 8 channel S-Bus converter to interface between my JR receiver and the A2 but it isn't working. I'm about to spend $60 for a Futaba S-Bus converter but I'm beginning to think I'll be better off just buying a new NAZA-M V2 because I already know that it will work great with the heli I've built and the 2-axis-as-a-sometimes-3-axis-even-though-it's-only-a-lowly-2-axis-mount trick that I've been talking about



    Anybody interested in a very lightly used DJI A2 flight control system so I can go ahead and buy a NAZA-M V2 for this project? Make me a reasonable offer and it's yours!
     
  18. Pumpkinguy

    Pumpkinguy Member

    967
    185
    26
    Sep 20, 2014
    Toronto
    Posted by Pumpkinguy, Jan 8, 2015 #18
    You make a good video. Nice clear voice and demeanor. I bet you'ld make a good teacher.
     
    2 people like this.
  19. Bartman

    Bartman Welcome to MultiRotorForums.com!!

    8,437
    709
    116
    Jan 5, 2011
    New Jersey, USA
    Posted by Bartman, Jan 14, 2015 #19
    Problem solved! Purchased a new NAZA-M V2 and it arrived yesterday. Granted, I'll lose some of the trick features of the A2 but I'll be flying sooner rather than later and I can always go back to the A2 when Futaba's 10 channel S-Bus encoder becomes available.
     
  20. Rickey

    Rickey Owner of RT Aerial Videos

    28
    9
    1
    Aug 11, 2014
    Houston
    Posted by Rickey, Feb 14, 2015 #20
    Looking forward to the next video. I've been wanting an inspire just for the dual person setup. It would be nice to do it with the quad that I already have...
     
Loading...

Share This Page

Loading...