215 Hopper FPV Airborne

Over the weekend just past I got my first solid session flying FPV under my belt. This of course means, as the title of this post also states, that my FPV build of my 215 Hopper design is complete.


The build wasn’t quite as smooth as I had hoped for a few of reasons:

  1. The new routing for the motor wires, through the arms, came up short. An extra 10mm or so and I would have run them as they were. As it is though I ended up extending the wires. This also made soldering them to the ESC’s a simpler task so it was a good move in the end. Despite the extra complexity in the build I am very pleased with how this aspect of the design turned out.
  2. My initial design for the base plate of the camera mount fouled on the zip ties that hold the ESC’s in place. I had to shorten that and print the new design.
  3. My initial design for the video transmitter carrier fouled on the heads of the screws  that mount the flight controller. This was actually 2 errors rolled into one. I absentmindedly assembled the frame back to front with respect to the flight controller. i.e. the flight controller is in the front half rather than the rear half. This doesnt make any difference flight wise but it would have meant the carrier wouldn’t have fitted up even if I had accounted for the flight controller screws.

The second failure with the video transmitter carrier design is also the same failure as with the camera mount. It is a lesson that I have learnt the hard way on to many occasions and it is thus; If you are using CAD use it fully, every detail should be represented in your model. If you leave something out, either intentionally or inadvertently it will come back to bite you at a later stage of the project. In the case of the camera mount I didn’t even have the holes for the zip ties let alone the zip ties themselves. For the transmitter carrier I didn’t have the screws in my model. Thankfully having the 3D printer on hand meant that I could correct these errors in the space of an evening and was ready to fly on saturday morning.


With the new build came new batteries, I am now flying on 4S 1400mAh batteries (hobbyking) and loving it. I went with the higher discharge rate option, it is perhaps overkill but it means I get much further through the capacity of the battery before voltage sag starts hitting my warning levels.


Other than the mentioned hiccups the build was much the same as the ‘base model’ 215 Hopper as I detailed here. I will put together a similar writeup for the FPV model in the near future. The design files will also be available. On top of that I now have a big stack of PCB’s for the build which I will make available for purchase. A full frame kit with hardware and 3D printed parts may also be an option.

215 Hopper FPV Build

After the mad rush of getting my ultimaker operational and making my Iron Man mask I have finally been able to get back to my FPV build of the 215 Hopper. I now have all the frame components made and there are some significant changes from the original.


To start off with though, a tale of my first FPV session. As soon as I had all the pieces needed to fly FPV I had to try it. Knowing that my dedicated FPV build was still a couple of weeks away I rigged up the Hopper, mostly with cable ties and temporary wiring but also my first iteration of the camera mount/crash protection. The first couple of batteries were trouble free. Landings were rough but I was mostly taking things very easy, it was certainly a cool experience and all the gear performed flawlessly.

On the third battery I hit the ground quite heavily. Looking back at why I have realised that I basically flew it into the ground forgetting that maximum lift (i.e. quadcopter level) is going to be achieved with the camera pointing mostly towards to sky. When I came down I was looking mostly at the ground despite thinking I was pulling up. As can be seen below the airframe itself suffered no real damage. The motors all twisted on their tubes but that is easy to correct. Unfortunately one of the motors also came off its tube, the spinning prop cut one of its wires and pulled it out of the motor at the same time. The VTx also collected a lot of dirt given that it is exposed beneath the airframe. The roll hoop around the camera snapped as the quad tumbled, I guess this means it did its job of preventing the camera being a point of impact. All these factors combined meant that I decided not to fly with this cobbled together rig, I would wait until everything was in its proper place.215H-24

To address the wire cutting issue I have decided to route the wires through the tubes rather than hanging them loose around the arms. To achieve this I have had to redesign the motor mount. Previously the 2 parts of the motor mount and the motor were all clamped to the tube using the motor mounting bolts however the spacing meant that they could only just fit around the 12mm tube. This forces the wires to exit at 45° to the tube, in reality this would probably be fine but my sense of details told me to rotate them so the wires exit parallel with the tubes. To do this the new motor mounts incorporate their own M3 clamping bolts with captive nuts. To assemble them the top half of the tube clamp is bolted to the bottom of the motor (now using all 4 M2’s) before the two halves are clamped around the tube. The new mounts also include a slot on the end for passing the wires in to the tube.


As mentioned in one of my design posts the rear motor mounts now also incorporate a small pocket for LED tail lights. I haven’t designed the tiny PCB for that yet but the image below shows where they will be with the power supply wires hanging out. I’ve been really impressed with the detail I have been able to model in to these parts. The wire grooves through the middle of these are only 1.5mm wide but are reproduced in perfectly useable fashion without needing to make any adjustments to my default print settings.


At the rear the modified tube clamp for mounting the antenna has come up nicely but I may need to make a counter bore for the nut. The antenna itself is only just getting tight. All of the tube clamps are also modified on the inside with a hole for the motor wires to come through.


Underneath I am very please with the VTx housing. I completed the details of its design after receiving my Lumenier TX5GPro Mini 600mW (GetFPV). It now sits inside the housing with no extra support required and is protected by thick ribs on the inside of the housing. The wires will be routed through the PCB rather than coming out the front as in the photo below.


And finally the camera mount. There are a few pieces to the current solution but it allows for a lot of flexibility and feels much more robust than my first attempt. The camera is held in place by the clamping effect of the bolts in each side, it can be adjusted from 0° to 45° above horizontal.  To install it the base plate is attached to the airframe clamping the two posts in place before the threaded standoffs are inserted and each side of the housing is clamped around the camera.215H-FPV-7

I also decided that the less conspicuous look of black was better than a big red blob on the front.


Next up is all the internals. I already have everything on hand so it won’t be too long before this is in the air.

Ultimaker Operational

It has been a bit longer than I would have liked since my last update. A lot has been going on, most of it to do with 3D printing. As the headlines states my Ultimaker tribute is now operational, so far I am very happy with its performance. There is however still room for improvement, particularly on the reliability front, and I certainly wouldn’t call it finished yet. At my last update on progress for this build I was still waiting for the electronics to arrive.

Once I finally had all the parts on deck I dived in to wiring everything up so that it was basically functional. Beyond a general excitement to see it functioning I now had a deadline hanging over my head, in just over 1 week a friend was celebrating a birthday with an ‘at the movies’ theme and I had come up with a costume idea that resonated with me that would required a lot of 3d printing to pull off. I still had the Steelcity Electronics printer on my bench but I was running it flat out printing bits for his costume. I also wanted to use PLA for its improved stability and the DaVinci is not yet set up to cope with that. So I had put myself in this crazy position of needing my new and untested printer to function really well straight out of the gate.
Thankfully it generally didn’t disappoint! More on that project at the end of the post for now though the printer build itself.


My first order of business was to get all the electronics in roughly the right place so that I could measure wire lengths and terminate them with the appropriate connectors. Unfortunately this is also where I hit my first stumbling block. The contacts I purchased for the JST connectors used for the limit switches and motor connections to the control board where the wrong series. I had the correct housing but the wrong crimp. Thankfully the spacing on the pins is 0.1″ so for now I have rigged it up using terminal strip connectors. The only significant change I have made to the wiring layout compared to an official ultimaker is to run the hot bed connections off the other side of the build plate. It is not yet installed but I will be running a cable chain on this side tucked in to the back corner rather than in the more traditional left side position.

With the wiring mostly sorted (if only in a temporary sort of way) I had to tidy up the last critical mechanical details which were:

  1. Drilling out the build plate to accept the larger diameter POM nut supplied with the Z-axis screw I am using. I also tapped holes for it’s fasteners however only 2 of the 3 would fit without overlapping any of the existing holes. I have however installed the nut in its self supporting orientation so I am not concerned about this.
  2. Drilling holes so that the fasteners on the 90° brackets could be tightened. As mentioned in the previous post I have forgone the Plastic corner joiners in favour of full metal joints. This is achieved by a combination of the angled brackets shown here and the previously discussed end tapping of the perpendicular members.
  3. A full frame and gantry build up with threadlocker throughout. This was more time consuming than anticipated, applying threadlocker seemed to slow things down markedly however everything went together without much drama. After a couple of hours of assembly I couldn’t get the frame to sit perfectly square and true but it was very close so I forged ahead and locked down all the gantry pulleys and sliders.

With everything mechanical in place I want back to the wiring and connected everything in it’s temporary but functional state and fired it up for the first time. No magic smoke so I was of to a good start. It was here that I faced my first significant frustration and it was all to do with my long Z-axis. I had assumed that simply changing the upper Z-axis soft limit in Marlin and uploading the recompiled firmware would be all it took however something there is slightly amis and I’m not entirely sure what just yet. To get it running I had to disable the lower Z-axis soft limit (i.e. the end with the limit switch) so that the bed would come all the way home without reporting a Z-axis limit switch error. Even still though the firmware doesn’t seem to properly understand its build envelope at all times. It will start in the right spot though so that is all I need for now.

The last piece of the puzzle was a way to hold a spool of filament. I have seen plenty of fancy bearing mounted spools on thingiverse but in the end decided that to get things started I would knock up a quick solution using a piece of leftover 2020 extrusion. I came up with a very simple beam clamp to hold a short section of extrusion on top of the rear mid member (which doesn’t exist on the standard size version) and a small bracket to stop spools sliding off. Both pieces can be found on my updated remix of Jason’s design on thingiverse.



With that in place it was time for some heat. I manually set some temperatures for both the build plate and the hot end so that I could verify they were both working, all was as expected. I tightened the hot end whilst it was hot and then ran the auto tune sequences for both the bed and the hot end, the hot end being most important since I am using the E3D v6 rather than the standard Ultimaker unit. Once an updated copy of the firmware was in place, containing the new PID values, I checked the extruder was performing as expected and decided to jump right to a test print.

The first signs were not good. Bed adhesion was poor and there were big gaps between lines. By this stage it was in to the early hours of the morning so I decided to leave it and come back to it with a fresh perspective the next day. This proved a wise decision as it took me only minutes when I was next in front of it to realise I never changed the default filament size from 3mm to the 1.75mm that I am using. Changing that obviously made a world of difference and the new test print was going down very nicely. After 30 odd minutes of solid printing I cut the test piece off and decided to jump head first into my urgent project, fine tuning be damned, I didn’t need precision and the quality was looking better than good.

Turning into Iron man

If ever there was a movie character that I could see myself as it is Iron Man/Tony Stark. Genius billionaire playboy philanthropist, that’s my sort of jam.
Unfortunately I don’t have a great deal of photos of this process as I did it all into just a few days. I started printing parts for my Iron Man helmet, as supplied by MIPRESIDENTE on thingiverse (my make of it is here), on the tuesday night, the party was the following Saturday. Ultimately I was a long way off a complete helmet but I made enough parts for a complete mask which was all the identity I needed. I glued the parts I did have finished to a cap with the brim cut off so that it could easily be worn.


Also from thingiverse was the Wearable Arc Reactor by MishaT. It was not 100% complete either so I chose to wear it hidden under my T-shirt with only the lighting effects shining through.

The finish quality is a long way from perfect but from a distance looks very convincing. To get from the raw print to the finished product, involved:

  1. Breaking away support structure.
  2. Sanding raw plastics to remove significant layer lines.
  3. Coating with XTC3D. (I will have to experiment with this more as I don’t feel like I saw the full benefit from it)
  4. Sanding.
  5. Spraying with plastic primer
  6. Sanding.
  7. Spraying with black base coat in the hope of a deeper colour.
  8. Spraying with gold and/or red (the jaw piece has both colours on it if not separated before finishing).

As an indication of what I was working with shown below are the two side panels (which I didn’t end up using) still on the bed but almost complete. I think I added a lot of time to the print with excess support material but when I started the print it was a case of ‘just make sure it works’.


There was one very significant problem I faced whilst printing these parts and that was a feeder which kept grinding the filament causing extrusion to stop. At one point this happened when I was more than 12hrs deep on the 3rd attempt on the face plate and jaw piece print. This was a make or break moment. If I had to start it again I probably wouldn’t have been able to make the mask work. Thankfully with a little bit of trickery I was able to save the print by restarting it at the layer at which it had failed. This post is long enough as it is without details on that so look out for a how to on restarting a failed print with some manual G-code magic in the future.

I do intend to complete the helmet print. If not to be worn then at least as a show piece. I will also strip it and refinish it to a higher standard, hopefully with a more accurate red on it too. With the pressure of the party deadline behind me now though I will finish the printer itself first (whilst printing the 215 Hopper FPV parts, I just can’t help myself). The three big items to tick off the to do list are:

  1. Terminate all of the wiring correctly and generally tidy that up.
  2. Install the cable chain for the hot bed wiring.
  3. Have the enclosure panels made (for improved thermal stability whilst printing ABS).

There are also several other odds and ends like lighting which need to happen but they will come further down the track. I will at some point also replace the vertical frame members and Z-axis rods as it turns out there is still more than 80mm of thread left on my Z-axis when it reaches the print head.

For now I will leave you with this teaser on what I am planing for the enclosure.



215 Hopper FPV Details

Working from the concept layout for carrying FPV gear on the 215 Hopper which I wrote about previously I have developed a few new parts which can be 3D printed. I have come up with a camera bracket with an integrated ‘roll cage’. The camera angle is set with a 3D printed wedge behind it.


On the bottom I have created something of a streamlined housing to go over the video transmitter. Of particular note in this area; when I dropped the model of the ImmersionRC transmitter in place I was quite surprised how large it actually was. As such I went looking for a smaller unit. I have consequently also picked up a Lumenier Tx5GPro mini 600mW TX (GetFPV). I will compare the two when they both arrive but suspect I will run the Lumenier rather the the IRC and as such that is what I have designed the pod to fit around. When I actually have the transmitter in front of me I will be able to flesh out the internal details of the pod so that the TX is a nice snap fit inside.



At the rear I have modified one of the central tube clamps to include a bracket for screwing the SMA 90° connector to. The antenna is then subsequently connected on top. Hopefully this provides enough support and isolation to prevent any damage to the transmitter in the event of an antenna strike. Also of note here is the addition of tail lights. As I can’t run the traditional WS2812b LED’s with the telemetry on a soft serial port these will just be on whenever the battery is connected. I am adding them for LOS flying visibility as much as anything. There have been a couple of occasions  with the 215 Hopper (including when I lost the first build) where I have struggled to orient the craft even at relatively close distances. The hope here is that with a few super bright LED’s pointing in one direction such problems will be easier to resolve.


And finally, I have made a decision on goggles and decided to go with the FatShark Dominator V3 (NextFPV) running a NextWave race band module (NextFPV). I haven’t received them yet (only ordered yesterday) but will make some comments on them when I do. In the same order I picked up another Naze32 and a set of esc’s so I can build this ‘215 Hopper FPV’ up as a new a rig and keep the other one flyable.

215 Hopper FPV

Recently I flew with a couple of other pilots for the first time, one of whom had an FPV rig. As soon as he flew off in to the distance I knew that I had to get into FPV as soon as possible. So now I have bitten the bullet and started to put together and FPV kit. I haven’t purchased a set of goggles yet as there is some internal debate about starting at the cheap end with something like the Eachine VR-007 or spending the money upfront and getting the Fatshark Dominator V3’s. I’m currently leaning towards the latter option.

To get the ball rolling I’ve started off with the airborne end:

  • Camera – Foxeer HS1189 XAT1200M (NextFPV) – Primarily chosen for the 16:9 aspect ratio.
  • Transmitter – ImmersionRC Race Band 200mW 5.8GHz A/V Transmitter (Hobby King)
  • Antenna – ImmersionRC 5.8GHz Circular Polarized SpiroNet Antenna V2 (Hobby King)

To start with I will keep things as simple as possible so no OSD or any other extra bits, just this basic video system.

So far I have only received the camera, I am still waiting for my Hobby King order, however I decided I would start roughing out a layout to see how all the parts are going to fit onto the 215 Hopper platform. My progress can be seen below.  Obviously I need to design brackets and housings for the various parts but this shows how it might be laid out. To differentiate the FPV version I thought a colour change was in order (I’ve also just bought red filament, the orange will go go back to Steelcity Electronics before too long).


UIltimaker 2 Tribute Build

When the Steelcity Electronics DaVinci 3D printer landed on my workbench for a short stay I got to browsing Thingiverse. Initially this was more out of curiosity than with an intent to find a printing project. My day job involves a lot of CAD work with Solidworks so I am quite capable of developing my own designs and I did have a couple of projects in mind. However I soon discovered the Ultimaker 2 Aluminium Extrusion 3D Printer by  jasonatepaint.


Since the very early days of 3D printing I had my eye on Ultimaker as an excellent option for an FDM style printer and now here was a chance, in true RepRap style, to use the 3D printer I had on loan to print myself a 3D printer using all the best bits of the Ultimaker 2. I must also say that specific use of the Ultimaker parts is only possible due to the great attitude and continued openness that Ultimaker the company maintains for the community it was born out of. If I could support them directly with the purchase of one of their printers then I would but the value proposition here in Australia is just not there for me presently.

For my build I decided to make a couple of changes to the default spec. Firstly and most obviously I am building an ‘extended’ version. At the moment I am not sure exactly how much Z-axis travel I will have but it will be even more than the official UM2 extended model. The screw I purchased is 500mm long, useable travel I expect will be about 450mm. Exactly why I have made it so long has no good reason other than the price difference being negligable. Hopefully there are no ill effects from the extra height.


The second change I have made is to the hot end. I am using the E3D V6 rather than the standard Ultimaker hot end. I’ve got no immediate requirement for this but decided that it would be good to have the extra flexibility that the all metal hot end offers in place from the start. To mount this I am using the E3D Custom UM2 Mount by lions3.

Not discussed in Jason’s build guide is the possibility of screwing the frame members directly to each other rather than relying on the plastic joiner pieces for a solid corner. This is achieved by tapping the center hole in both ends of every cross member. A clearance hole for the hex drive required on an M6 button head socket screw is then drilled through the vertical member at the point at which the member is to be positioned. The M6 button head is then screwed in to the end of the extrusion before sliding the head into the v-groove of the vertical member and tightening it at the appropriate position. On top of this I also have aluminium corner fittings which I picked up cheaply with my order from RobotDigg. These are not installed in the photos here but will provide an even stronger joint. This approach actually makes a lot of the plastic joiners redundant but I have kept them in place for now. I will print some cosmetic replacements when the machine is operational.

I have already made modifications to some of the printed parts. STL files for each can be found on my remix of Jason’s design on Thingiverse.

  • Gantry spacers
    When initially printed I found the gantry spacers quite inconsistent due to warping and shrinkage. This could probably have been addressed with print settings but instead I created more bulky gantry spacers with larger through holes. The fit is now a little loose but they can be installed straight from the printer. The tapered end goes towards the bearings and the flat end against the pulleys.
  • X-axis motor mount
    As initially designed mounting the motor required the used of spacers to position the motor correctly. Upon examining this situation I could not determine any reason why these spacers could not be integrated in to the bracket itself. I modified and reprinted the bracket to achieve that.
  • Y-axis motor mount
    Modified to include motor mount spacers in bracket as per X-axis motor mount.
  • Z-axis lower support and motor mount
    I was concerned that this part was not stiff enough. Given that the threaded rod and hence the motor and its mounting bracket supports the entire weight of the build platform and print I felt it would be wise to stiffen this part of the assembly. My solution is a two piece lower Z-axis support which braces the motor mount to the lower rail. At the same time I took the opportunity to integrate the Z-axis limit switch as accessing the screws for the original bracket design was impossible whilst the frame was assembled. Note that this new bracket requires the modification of the screw tab on the inside of the main board tray. I have not modified the model for this part as I simply trimmed the excess off and drilled a new hole, (not perfect but good enough to support the tray).

Currently I have all the mechanical parts in place for a temporary fit and alignment checking build and everything is looking good. I am waiting on the last couple of parts to arrive from China, specifically the electronics. When they arrive I will check they fit before striping everything down and rebuilding it in a functional state. After wiring it up it should be basically functional. Before I call it complete though I will also make acrylic panels to enclose the build space (primarily for improved thermal stability), add LED’s and change the joining pieces as previously mentioned.

Building the 215 Hopper

As promised supplied here in is everything required to put a 215 Hopper together exactly as I have built it.

Please see the end of this article for an update regrading a mistake with the originally supplied brd file.

The digital assets can be found on YouMagine or Thingiverse.
There is nothing specific about the 3D printing requirements, 15-20% infill will do the job and a typical 0.2mm layer height is ok.
For the PCB’s I typically use Dirty PCB’s from Dangerous Prototypes. The brd file to submit is included with the digital assets. Options you will need to specify are 1.6mm thickness, color black (or your preference) and ’10×10 max’ for the size. Note that I have found some flexibility with this limit as this board is actually larger than 10cm in one direction, I got no questions when ordering my first batch (of which I still have 8 unused). The cost they offer can’t be beaten but do note that they are a bare bones sort of service so support is limited, what you submit is what you get.

Purchased Items

  • Naze32 Rev 6 Flight Controller (NextFPV)
  • FrSky x4r Receiver (NextFPV)
  • DYS BE1806-2300KV BE Series Set of Four CW/CCW Motors (NextFPV)
  • 4x ZTW Spider Series 18A Opto Lite (NextFPV) This could be considered overkill from a power point of view, I chose it for its svelte size and preloaded blheli.
  • MultiStar Racer Series 1400mAh 3S 40-80C LiPo (Hobby King) I usually start with 3 of a particular battery size but the more you get the more you can fly.
  • 5×4 Propellers (NextFPV) I like to use a bright colour (usually orange or green) on the front and black on the rear to help with orientation. 4 propellers are required, 2 CW and 2 CCW, but buy plenty of spares.
  • 500mm x 12mm x 10mm carbon tube (ebay) Cut in to two pieces, both 183mm long, there will be a short piece left over.
  • 5V, 500mA Step-Down Voltage Regulator D24V5F5 (Pololu)
  • 20x M3x8mm hex socket button head screw (ebay)
  • 8x M2x16mm torx socket screws (ebay) A generic M2x16 cap or button head will also work however for anything smaller than an M3 I find that a torx socket is more reliable than a hex.
  • 8x M2 Washers (ebay)
  • 8x M3 nylon nuts (ebay)
  • 8 M3x15mm nylon screws (ebay)
  • 10x 15mm round threaded standoffs (ebay)
  • Battery strap (Hobby King)
  • 16 AWG silicone wire (Black Hobby King, Red Hobby King) This size wire is the largest size that will fit through the wire slot on the power distribution board. It is also the same size as the leads on the battery.
  • XT60 male connector (Hobby King)
  • XT60 female connector (Hobby King) Purchase 1 for every battery. I managed to fuse the XT30 connector together, admittedly whilst running 5 motors on a heavier rig, however I think the upgrade is still a worthwhile precaution.
  • 2x JST-PH pre-wired plugs with sockets (ebay) for Vbatt and 5v connections on power distribution PCB.
  • Self adhesive rubber feet 25mm(L) x 5mm(W) x 3mm(H) (Aliexpress) These seem a very uncommon size but are available if you are prepared to wait for delivery. Alternatively anything that is 3mm thick can be used as a spacer. They are required as the battery wire penetrates the top plate below the battery.
  • 9x 160mm x 2.5mm cable ties (Hobby King)
  • 20mm heat shrink tubing (Hobby King) for the modified receiver
  • 10mm heat shrink tubing (Hobby King) for the modified ESC’s
  • 1x 1 pin crimp connector housing (Pololu) For SBus connector to Naze32
  • 3x 2 pin crimp connector housing (Pololu) For receiver power, SmartPort and Vbatt at Naze32.
  • 2x 3 pin crimp connector housing (Pololu) for receiver connection and 5v connection to Naze32.
  • 13x Female crimp pins (Pololu)

Note that a lot of the links provide, particularly for small parts, direct you to sources that are sold in bulk lots. For example the M3x8mm hex socket button head screw I have linked are sold in a lot of 100. As you only need 20 do not purchase 20 of the linked item, 1 bag will give you enough to build 5 215 Hoppers.

Custom Parts

  • 1x Left side pannel (215H 103)
    215H 103
  • 4x Motor mount bottom (215H 104)
    215H 104
  • 4x Motor mount top (215H 105)
    215H 105
  • 4x Tube clamps (215H 108)
    215H 108
  • 1x Right side pannel (215H 111)
    215H 111
  • PCB

Optional Parts

  • 1x GoPro session mount (215H 113)
    215H 113

Build Notes

This is not an exhaustive step by step for building the 215 Hopper but rather a collection of build notes in the basic order of construction.

  1. 3D printed holes for fasteners should be drilled out to their finished size after printing. This includes the 5mm holes for the frame standoffs (parts 103, 108 and 111) and the 2mm holes in the motor mounts (parts 104 and 105).
  2. Depending on the quality and accuracy of your prints you may also need to clean up the counter bore for the head of the M2 fasteners. This detail can be particularly critical as there is very little thread engagement in the motors and getting the thread started can be challenging. If you are using a hand drill for this process take it very slowly and carefully. It is easy for the drill to bite and get pulled in too far. Grinding a flat point on to a spare drill bit can minimize this biting problem.
  3. The PCB needs to be split in to its two pieces along the tabs. Side cutters and a file will quickly tidy up any leftover material. Also round over any sharp edges where wires, zip ties and the battery strap rest.
  4. Clean up any edges on you 3D prints the prevent the parts fitting together nicely. Likely areas that can cause problems in this regard are the knobs that fit into the slots on the PCB’s and the wedge between the side panels and tube clamps. The holes in the side panels should be a loose fit around the tubes.
  5. Solder the 5v regulator and JST sockets in place on the power distribution board.
  6. Shorten the signal/ground connectors from the ESC’s. I found if left as they are supplied there is simply too much bulk in the tight confines of the 215 Hopper.
  7. Solder the motor wires directly to the ESC’s. This will mean that the wires must first be threaded through the last window in each end of the side plate. As previously mentioned this is a bit awkward and one of the shortcomings of the design. You will want to have a rough layout with arms and motor mounts in place to determine the length of wire required.
  8. Once the two previous adjustments have been made to the ESC’s reseal them with heat shrink tubing before cutting the input connections short and soldering them directly to the pads adjacent to the mounting points. Ensure you have the ESC up the correct way to match +ve and -ve connections. The ECS’s can be secured in place with zip ties. As there is no support for the signal wires a dab of hot glue will prevent them moving and possibly breaking.
  9. Solder 16 AWG wires on to each battery terminal and route the wire out through the rear slot. Trim the wires such that there is about 10-15mm of overhang past the end of the board. Attach the XT60 male connector to the end being careful with polarity. You may wish to position a battery to determine exactly how long you would like the battery connector to be.
  10. Prepare the SBus and SmartPort interconnects. The SBus interconnect should have a 3 pin connector at the receiver end. At the Naze32 end, 5v and GND should be on a 2 pin connector with the signal wire on its own 1 pin connector. The SmartPort interconnect need only connect the signal wire to both pins of a 2 pin connector. Use the breakout wire supplied with the X4r, remove excess wires and add a short loop between the two pins.
  11. Prepare the Vbatt and 5v interconnects. The Vbatt interconnect (pictured at top) should have a JST-PH connector on one end and a 2 pin connector at the other. The 5v interconnect (pictured at bottom) should have a JST-PH connector at one end. At the other end either a 3 pin or a 2 pin connector will work, on the Naze32 I connect it to motor port 5. Double and triple check voltages and polarity are correct before plugging either of these in to the flight controller. I damaged a receiver because on the initial board revision polarity of the 5v was reversed at the JST socket. This has been corrected on the supplied board layout.
  12. Use the nylon fasteners to attach the flight controller to the appropriately marked PCB. Each screw comes through from the outside and is secured to the plate with a nut. The Naze32 is then stacked on top and secured with another screw. Prior to attaching it to the PCB install pins on the Naze32 rev 6 as follows:
    • Motor ports – 90° header on top side and pointing away from centre.
    • Digital ports – 90° header on bottom side and pointing towards centre.
    • Auxiliary ports – 90° header on top side and pointing towards centre. This header will also need to be a little higher than usual to clear components on the board. The easiest way to achieve this is to attach a connector before positioning the header strip.
  13. Positioning of connectors dictates that the x4r must be modified to fit correctly. For me this is not a concern as I only use SBus and usually dedicate a receiver to each model. After removing the cardboard housing trim to remove the top row of servo connectors (i.e. the row which SBus is NOT on). Snip the wires before the plastic so that the plastic can give whilst you are cutting it, this will prevent splitting through the bottom row. The remaining connectors may need to be bent down slightly to dip under the ESC connectors on the flight controller. Once modified seal the receiver with heat shrink, you may need to cut a small window for the Smart Port connector. Zip tie it in place on the same board as the flight controller.
  14. It is easiest to assemble the frame upside down. The power distribution board is the top panel, the receiver and Naze32 are on the inside of the bottom pannel.
    Put the battery strap in place around the power distribution board
    Push the standoffs in to their holes and loosely fasten them to the power distribution board with screws. Put the arms roughly in place, the friction on the standoffs should be enough to keep everything in place.
  15. I found the easiest way to get the motor mounts on to the tube was to first screw the two pieces on to the bottom of the motor (do not tighten but ensure there is a couple of turns of thread engaged) before sliding the clamp on to the end of the tube.
  16. Connect the ESC’s, 5v and Vbatt to the flight controller then roll the bottom board over on to the bottom of the frame, poke the antennae out a couple of the side windows whilst tucking all the wires into the frame.
  17. When closing up the body be careful that no wires are pinched between the side panels and the PCB’s. Before locking everything down ensure that the arms are centered (measure from the side of the PCB to the inside of the motor mount) and that the motors are vertical. Rather than simply eye balling this put your propellers on and ensure the tips meet at the same level. Remove your propellers before connecting any power.
  18. Position 4 sticky feet around the battery wire penetration slot and battery strap to support the battery.



My flight control software of choice is CleanFlight. When you first connect to CleanFlight there will be a number of setup changes to make. As a starting point change the following:

  • Enable Serial RX on UART2
  • Receiver Mode RX_SERIAL
  • Serial Receiver Provider SBUS
  • ESC/Motor Features Enable ONESHOT125
  • Minimum Throttle 1040
  • Maximum Throttle 1900
  • Battery Voltage Enable VBAT
  • Other Features Enable SOFTSERIAL and TELEMETRY
  • Enable SmartPort and SOFTSERIAL1.

On the PID Tuning tab:

  • PID Controller MultiWii (I found that the Naze32 was struggling with LuxFloat whilst SoftSerial was enabled)
  • ROLL rate 0.4
  • PITCH rate 0.4
  • YAW rate 0.52

Setup auxiliary switches on the Modes tab as you would like. I typically assign a switch to ARM and a 3 position switch to ANGLE/HORIZON/RATE.

You will then need to connect a battery (no propellers attached!) to ensure everything on the receiver tab is coming through correctly.

From here all the usual maiden flight checks and safety procedures apply.

If you have any questions about the build or would like more images or information about something specific feel free to leave a comment here, visit the contact page or leave a comment on either the YouMagine or Thingiverse pages.

If you build a 215 Hopper I would love to see the results. I have set up a form where you can tell me how it went and let me know where I can find some photos of your work.
Build Form

Update 1:
It has been brought to my attention that the original brd file that I upload had a fault on the vbat connector. The ground trace from said connector did not reach the main ground plane. Now uploaded is revision 2 of the board with this problem corrected.
My apologies to anyone who has already made the board. You will still be able to fly with it but you will need to forgo the connector for vbat and connect wires directly to the same pads as the battery leads (mind the polarity), or leave them off all together (mind you don’t over discharge your batteries). I have ordered a new batch myself so if anyone has already made boards and would like a corrected replacement get in touch.