[PROJECT] Heavy Lift Hexacopter scratch build

Discussion in 'Other Toys/Hobbies' started by ShadowBurger, Oct 27, 2016.

  1. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Still back and forth with Slobbyking trying to get my darned motors. Between them self-destructing their company with a broken website and providing only "copy-paste" customer service I think I can safely say I'll never be buying anything from them again.

    While I wait for the key ingredients, I'm sneakily putting something else fun together. This little feller runs 4" propellers.... :Pirate:

    [​IMG]
     
    Last edited: Jan 9, 2018
  2. Andres

    Andres Motor Admin

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    Do you reckon you may run into any issues with vortexes or the like having the props that close?

    I've a little over killed on my ESC (in the general quad thread).

    I've generally found HK ok. Especially nice and quick when it's in there Aus warehouse. But I can only imagine the pain with dealing with any of these online retailer's returns department. :wired:

    Seriously considering the Pixhawk based on your thread now. :thumbup:

    Edit: Forgot to ask - what running time are you expecting before adding any additional load or jsut with camera + gymbal.
     
    Last edited: Nov 9, 2016
  3. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Vortexes... I hope not, but don't know. I'm not an engineer by any means. If I do have issues, it should be a "simple" case of using longer sections of aluminium for the arms to space them further apart

    I think actually your ESCs are about right. They are 2 amps over the max rating for that motor, so they should be OK.

    Glad you're considering the pixhawk! Maybe a challenge to learn, i had the benefit of being introduced to it by someone in the know

    Hard to guess at the run times. Very good, I hope. 20 minutes would be nice, although I tend not to push my batteries too close to flat - at $200 per set (2x 8.0ah 6S) for this hex I can't afford to. I am building a very powerful multirotor for such a tiny gimbal carrying only a gopro, and each motor has a max (theoretical) thrust of 4kg, so I have 24kg of thrust to play with on a multirotor that weighs somewhere around 4kg (my latest guesstimate) including the gimbal. The motors are supposedly most efficient at around 500g of thrust each so I should be right around the efficiency sweet-spot :thumbup:
     
    Last edited: Nov 18, 2016
  4. OP
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    ShadowBurger

    ShadowBurger Member

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    Spent a few hours on the beast last night. I connected up the Pixhawk, wired in the backup UBEC (redundant power for the pixhawk) and mounted the dragonlink receiver and video transmitter.

    [​IMG]

    I mounted the 1.2GHz video antenna upside down to one of the arms. There's a 90deg adapter and a 1.4GHz low pass filter in line there.

    [​IMG]

    Out this morning ready for first flight!

    [​IMG]

    You can see the twin 3S 5.0ah batteries underslung. I have ordered 6S 8.0ah batteries which be used in future. I got about 8 minutes flight time on the 3S's. The white thing on top is literally just a temporary button, as I needed one for the pixhawk

    [​IMG]

    And here's the maiden flight! It went excellently and I am super impressed with the power of this hex. I used a maximum of 84% throttle according to the flight data. RTL was spot on... I'm very impressed with this GPS module, it was able to get a lock indoors which none of my others have been able to do.

     
    Last edited: Jan 9, 2018
  5. tasmik

    tasmik Member

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    what ball park price are you at for the build so far?
     
  6. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Frame:
    • Carbon fiber: $210
    • Aluminium: $30
    • Screws / Standoffs: about $40 - i bought in bulk from aliexpress and have enough for a few frames
    • Cloth tape: $15
    • A pool noodle: $3 :)
    • ...plus tools bought to build it.

    Parts:
    • Motors: $240 ($40 ea)
    • ESCs: $78.84 ($13.14 ea)
    • Pixhawk PX4: about $260aud for a non-genuine eBay special like the one I'm using. I got mine for free after I thought the one I bought (and sold with the HAL) was faulty but it wasn't :thumbup: So I've had to build or buy the other accessories, like the GPS module and wiring etc.
    • Batteries: about $100 each for 6S 8.0ah from Banggood
    • PDBs: about $12ish
    • 5V 3A BEC: $14
    • Battery Straps: $8
    • Extra silicone wire: $12

    Extra Equipment:
    • Taranis X9D Plus: $300
    • Dragonlink V3 Advanced: $460
    • Tarot T4-3D GoPro Gimbal: $80
    • Video transmitter/receivers/antennas: $180
    • Video Goggles: $350
    • Other stuff, charger, leads, tools, GoPro, extra batteries etc.... $???

    In summary, you could build this exact frame for about $300, but it's a little extravagant with carbon fiber and you could potentially do it for a lot less with some more efficient design. All up, you could probably get a hex like this one in the air for about $1000 depending on how much variation you get in the prices and assuming you have all the necessary equipment already.
     
  7. Andres

    Andres Motor Admin

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    That RTL is so cool! Looks pretty impressive in the air, plenty of punch!

    I'm still struggling to pull the trigger on the FC for my build. It seems like there's about to be a Pixhawk 2 released, but can't for the life of me really work our the benefits - not to mention it looks like an 'add-on' cube to the 'normal' Pixhawk??

    I did some reading about the HobbyKing HK32 - which looks like a clone of the Pixhawk, but for more less $$$s. Says it uses different connectors though :tired:

    Also seems like the usual retailers for a genuine Pixhawk are out of stock or waiting for Pixhawk 2. :Paranoid:

    Need to pull the trigger asap so I can complete build prior to Xmas... Sorry to derail!
     
  8. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Thanks! It seems like it'll have plenty of power for my needs and after a quick flight FPV yesterday, I can say it handles really really well - and I haven't tuned it at all. It flew like a racing quad! :D:D

    I suggest just grabbing a chinese pixhawk PX4 copy off eBay. The genuine ones are too difficult to get (from the US) and the australian retailers that actually have them in stock have inflated the price by almost 100%. The chinese sellers are usually pretty good and if there's an issue they'll just ship another no questions asked as long as you can take a photo of the problem.

    As far as the HK unit goes... It doesn't come with a GPS, remote USB port / LED, or a radio link. Note that you'll absolutely need the GPS to use it, and as you'll probably want to interact with the mission plan or receive mavlink telemetry during flight and you will need either the 433/900mhz telemetry radio or a dragonlink setup like mine to do so

    EDIT: This HERE comes with GPS, 433mhz radio, a MinimOSD, remote USB / LED, and all the other usual bits. You'll have to buy an SD card - don't even bother trusting the one it comes with - but any 4GB will do, it's mostly just for logging. They can't work without an SD card though so treat it as an important component and buy a good brand.
     
    Last edited: Nov 14, 2016
  9. Andres

    Andres Motor Admin

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    Awesome - thanks SB -will pull the trigger on this today.

    Keep putting up the videos as you go, they're oddly interesting seeing the automated flight modes.
     
  10. Andres

    Andres Motor Admin

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    What brand batteries are you buying from Banggood and have you given them a run yet?

    Tempted to get some ZOP batteries, but the interwebs has mixed reviews.

    Ordered the Pixhawk :Paranoid: so should have all components ready to go within a fortnight.

    Have you got vids of your beast with cam and gimbal mounted (and any vids taken with said cam and gimbal?)
     
  11. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    hey mate

    Glad you got the pixhawk.... :thumbup: It's a complex beast but super powerful. I really want to order the PX4 flow sensor with the sonar add-on :leet: Yeah I've ordered ZOP batteries. They are cheap, but the difference between an 8.0ah 6S ZOP and a reputable brand like Tattu is something like an extra $200. I figure (i hope) they are like any battery, just don't let any of the cells go below the threshold voltage and it will serve well. Probably has over-rated capacity ratings, but I'm not too concerned. Worth a shot at least.

    [EDIT: 1 year later, these cheap banggood batteries are still serving really well!]

    Another update:

    Just the last few days I've put some hours into properly setting up my Taranis with the Pixhawk. It's a bit of a challenge because APM only allows you to use a single channel to select flight mode. To get around it, I have set up two three position switches to control five possible positions on the single channel, with a third switch used solely to activate RTL. Getting one switch to override the other and the RTL switch to override them both required some delving into the Taranis' Logical Switches and Mixers, which is new to me and pretty complex, but in the end it works really well and I have the added bonus of the Taranis LCD displaying the currently active flight mode. Alternatives to this include just using one of the pots, or swapping a pot with a 6 pos rotary switch. The pixhawk does let you assign another two channels, but only to one flight mode each. The way I've done it lets me have 8 flight modes.

    Because of not having set all this up already, I haven't been totally confident that the hex was flying safely or that I had a good chance of landing if it ran into an issue, so I haven't put the gimbal on it yet. I still have to test out the flight modes, test the autopilot, swap out a dead 12V BEC, and set up all the failsafe settings. When I do, I'll have a few more test flights before I go putting the gimbal on as it's super fragile. Video will come soon :)

    I need a new lens for the GoPro at the moment as well also (landed it on its face with the race quad)... Strongly tempted to suck it up and buy a Hero 5 but I'm about to move house to have to save moneys :upset::upset::upset::upset:
     
    Last edited: Jan 9, 2018
  12. eukaryote:)

    eukaryote:) Member

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    I've used a function built into pixhawk to disable motors on command. A kind of kill switch if you will. You should allocate a channel to this, because i've had one catastrophic failure due to bad gps and compass which led to the drone going crazy. The motor override is what saved my day.

    If you want more fancy stuff, check out craft and theory. I'm using their mavlink powered telemtry system on the taranis, and it works a treat.

    http://www.craftandtheoryllc.com/wp-content/uploads/2016/10/3.4-rc6-984x515.jpg

    You can save yourself some money and get the hardware parts from banggood and save yourself some money.
     
  13. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Cheers eukaryote, i think I might just do that. Might set up a mixer to require two switches though so I don't accidentally drop it out of the sky :Paranoid:

    put some red LEDs on the hex and cut out a plastic cutting mat as a background for the cover plate. One of the silicone shock mounts worked well as a grommit for the GPS cable. The lighting isn't as even as I'd like, so I've ordered some red LED strip to put in and will find something to use a diffuser. The red button on the left is the PX4 "safety switch"

    [​IMG]

    I'll get some more red cutting mat and make covers for the sides as well, to hide the wiring and protect the bits inside a little.

    [​IMG]

    Not much other progress, and haven't had a chance to get it in the air again yet. I've ordered an 8 amp 12V regulator to replace the busted PDB. Done a lot of tweaking the configuration and setting up the failsafe and other behaviour to keep it safe. Played around in Mission planner and set up some waypoints ready for trying a longer autonomous flight.
     
    Last edited: Jan 9, 2018
  14. alch

    alch Member

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    Didnt see video on page 1.. tl;dr!
     
  15. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    it's a project log... I didn't have a video when page 1 was being posted :confused:

    EDIT: there you go, updated OP :p
     
    Last edited: Nov 21, 2016
  16. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Built this previously to use with a battlebot. Modified it to suit the UAV: http://noobs.wtf/hud/

    [​IMG]

    I'll have an arduino on board the Hex with temp sensors attached, which will add data to the MavLink stream. At the transmitter side, an ESP32 or an ESP8266 hidden in the module bay of the Taranis will host a wifi AP and decode the MavLink which I can connect to my tablet to display the page :thumbup:

    As you can see it gives a clear visual indication of anything out of the ordinary:

    [​IMG]
     
    Last edited: Nov 21, 2016
  17. mad_mic3

    mad_mic3 Member

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    Good to watch your journey, so much use full info:thumbup:
     
  18. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    cheers :)

    Last night I did a stack of soldering. I installed the replacement power module, which is an AttoPilot 180 amp, 50V unit. This replaces the stock Pixhawk power module which can only operate at a maximum of about ~16.8v (4S LiPo) and 45 amps. The new power module doesn't have a 5V BEC built in, but that's not needed as I'm using a standalone 3 amp unit.

    This is the power module. My camera is shithouse so I nabbed this pic from sparkfun's catalog. It's a tiny tiny little unit, hard to believe it can handle 180 amps.

    [​IMG]

    Soldering was difficult given that the wiring is as thick as the solder pads. I have attached two XT60 plugs to run two batts in parallel.

    These are the new ZOP LiPos from Banggood. I wouldn't say they look like amazing quality, and the actual performance remains to be seen, but the inclusion of XT90 connectors and 10 gauge wiring is nice. They are 6S2P configured packs and judging by the weight the capacity rating seems about right. Didn't realise they have XT90 connectors so I think I better order some! I had to get creative with the battery straps, will have to order longer ones

    [​IMG]

    That's not a LiPo... This is a LiPo! :Pirate:

    [​IMG]
     
  19. eukaryote:)

    eukaryote:) Member

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    I see you have a large lipo and raise you one

    :Pirate:


    Click to view full size!


    Just kidding. They're probably the same as yours.

    6S 10,000mah
     
  20. OP
    OP
    ShadowBurger

    ShadowBurger Member

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    Nice! What do you use em for?

    Last night I put together a re-transmit station so I dont have to keep swapping between 1.2ghz and 5.8ghz modules in my goggles. I used the 1.2ghz module from my goggles to build it. That requires 5V so I installed a spare power distribution board with built in 5V and 12V regulators. I used a spare platic box which I covered in cloth tape to house it

    Soldering the pdb
    [​IMG]

    The pdb installed next to the 600mW 5.8GHz transmitter. The 1.2ghz module is adhered to the top of the pdb
    [​IMG]

    The pdb and vtx gets fairly warm, so I took advantage of the 12V regulator and installed a small fan. The channel on the 1.2GHz receiver is set by grounding one of three pins.

    [​IMG]

    Finished! I dremeled some slots for the airflow to escape as well
    [​IMG]

    EDIT: works great! I set up my tablet as an FPV screen using one of those USB capture devices. The video quality is woeful, so this screenshot doesn't do it justice, but it gives an idea of what my FPV display looks like

    [​IMG]
     
    Last edited: Nov 27, 2016

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