Introduction: Foldable 3D Printed Quadcopter

Hello everyone!!

Surfing the web i've seen some videos about Quandcopters that autofollow you, filming yourself doing sport or whatever you want. Searching around the price for a Ready to Fly quad I realized that it's too expensive for my DIY mind, so i started to learn how to build one for on my own.

I've spent a lot of time searching proper combination of components, then i started to think about the frame and a foldable design, because I can't go arround with a box of 0.5x0.5 meters bound on the back of my motorcycle. There is a lot of ready frame out there, but i don't really like them, and with a 3D printer on my desktop i can easly draw what i desire and print it in a couple of hours.

I've built a 1.0 version of the quadcopter, just for assemble all the components and see if it flies: YES!

After a little crash (indoor flight is not a good choise if you have to tune a quadcopter :D), i've started to think about the version 2.0 of the quad, really foldable, much stronger and better assembled, here there is the result of that work. It's not finished, I have to build the gimbal (i'm waiting for the motor and controller), and maybe tweak some printed parts, but this version flies, and not bad, I'm pretty proud of it and i want to share with you all the design!

This is my first "instructables", made when the quadcopter was already build, I hope it is understandable at least for the frame assembly part (it's such a simple design, a couple of m3 screws :D), for the electronic part I have just write a guideline because the web is full of videos, guides and information about this.

If you need explanations, or give an advice just write it in the comment.

And don't forget to vote if you like my quad :D

Greetings, Christopher.

Step 1: Tools and Materials


  • 3D printer (200x200 area)
  • Scissors
  • Cutter
  • Soldering Iron
  • Screw drivers
  • Allen key
  • Shrink tubes
  • Glue
  • Maybe something else...


  • -4x brushless motor 920KV

examples: multistar elite 2216

DYS 2212 (<-----djs phantom clone i've used this but I think that every motor with 28mm diameter i think could work)

  • -1x QBRAIN 4x25 ESC

example: Qbrain (just four in one solution instead of 4 indipendent ESC)

  • -1x Turnigy BESC programmer

example: BESC programmer (for program the ESC, easy and fast)

  • -1x Turnigy 9x

example: RC transmitter 9CH (i've read it's a good transmitter for beginners, cheap and costumizable)

  • -1x PPM encoder

example: PWM to PPM encoder (it converts the PWM signar from the RC to a PPM signal readable from our flight controller)

  • -1x HKpilot32 SET

example: SET with 433Mhz telemetry (be careful about the frequency of the telemetry, 433Mhz for EUROPE, 915Mhz for other countries)

another similar SET (i've bought this, but i think it's the same)

this set includes a lot of usefull things:

  1. -Flight controller FC (pixhawk equivalent, it can be used with ArduPilot firmware)
  2. -GPS with compass
  3. -Telemetry (433 or 915 Mhz <----- be careful)
  4. -Buzzer
  5. -Switch button
  6. -Power module (for battery monitor and FC power supply)
  7. -I2C splitter (for extension hardware)
  8. -Cable
  • -2x Propeller pair (djs phantom clone will work 9.4" x 4.3 pitch, but i think 10" will be the same)
  • -1x or more Battery 5000mAh

example: 5000mAh 3S 25C (i've designed the battery cage for this battery, but if you need you can print an adaptor for your battery)

  • -1x Lipo battery charger

example: one of many

  • -4x vibration damping ball (for the FC support)

example: antivibrating for FC

  • -1x Male to male servo lead

example: this kind of cable (for connect the RC reciever to the PPM encoder)

  • -XT60 connector a pack of 10 (5 male 5 female) will be enough (for shorten the cables)
  • -4x 155 millimeter alluminium square profile for arm (i have find on local store a square profile of 11.5x11.5mm the arm support and motor support are designed for this measure)
  • -3x 100millimeter round profile for legs (always on local store 7.6mm of diameter)
  • -2x velcro strap (100mm? i don't know because i have not bought it) :D
  • M3 screw (not sure about this list)
  1. -20x M3x10mm
  2. -3x M3x20mm
  3. -4x M3x40mm


  • Lower frame
  • Upper frame
  • Canopy
  • Battery holder
  • 2x Front arm support
  • 2x Rear arm support
  • 4x Motor support
  • Front leg support
  • Rear leg support
  • Flight controller support (thinkinverse file)
  • RC and telemetry support
  • Telemetry holder
  • GPS box (optional, you can use the original coming with the GPS)

Step 2: Configuring Electronic

First of all it's better to configure part of the electronics, it can be divided in 3 group:

  1. configure the Turnigy 9x for quadcopter
  2. install the Ardupilot firmware into the Flight controller
  3. setup the QBRAIN with the BESC programming card, and calibrate the throttle

I will not explain in deep this step because the www it's full of information about this procedure, just google like me :D

Turnigy 9x:

There are 3 settings you have to change for use the RC with the FC (Flight controller), first of all is set the auxiliary channel CH5 to GEAR, so you can change the flight mode with the switch on the back of the transmitter.

(you can find the menù for set the aux channel under FUNC SETTING)

Then you have to change the MODE TYPE to "ACRO" (otherwise the FC will not understand the command from the transmitter), for doing this you have to enter the SYSTEM SETTING.

There you can change the name of your setup and other things like the MODE of the stick (MODE 1 throttle on right, MODE 2 throttle on left) this choise is the last to make the Turnigy 9x usable.

in the last step of this section we will bind the transmitter with the reciever

Ardupilot firmware:

Now you have to install the ground station (just a program for monitor your quadcopter), the program is Mission Planner, from there you can download the latest firmware and upload it into your FC.

After you have installed the program go into the "INITIAL SETUP" tab and click on "INSTALL FIRMWARE" on the left and select the quadcopter firmware.

The wizard for set up the accelerometer, compass, transmitter can be done after via telemetry.

QBRAIN setup:

Last step for this section is the configuration of the ESC through the Turnigy programmer card, and the throttle calibration.

Connect the 4 motor cable to the HUB (from 4 connector to 1), then connect it to the programmer, finally connect the battery to the QBRAIN, the programmer will power up, and you can set it like this:

  1. Brake: OFF
  2. Battery type: Li-xx
  3. Cut off type: Soft cut
  4. Cut off voltage: Middle
  5. Start mode: Very soft
  6. Timing mode: High
  7. Music/Lipo cell: look at instruction for music
  8. Governor mode: OFF

then press OK for upload the setting.

Now disconnect the programming card connect the binding cable on the reciever and connect the cable of the HUB into the channel 3 of the reciever, it will power up the reciever, then power up the transmitter, if the red led on the reciever is solid then the transmitter is already bound, otherwise turn off transmitter, press and hold the "BIND RANGE TEST" on the back and power it on again.

Now turn off the QBRAIN (disconnect battery), move the throttle stick to MAX on the transmitter, turn on the QBRAIN, after the music the QBRAIN will make another sound, at this point put the throttle stick to MIN. Now you have the ESC calibrated to your throttle stick.

As I've said before there are a lot of information on internet for doing this step, and it can be done after you have assembled the quadcopter (before closing it with canopy) but you have to play a little with the cables in little space.

Step 3: Frame Assembly

After you have print the parts you can start to build the frame:

Start with the Upper frame, you have to cut and solder again the power cable of the QBRAIN and the Power module to fit into the designed housing, then pass the signal cable into the hole and put everything in its place.

Take the Lower frame, pass the cable for the motor in the holes, the velcro strap and close the 2 half of the frame with the 2 front screws and the 2 middle screws.

Place in position the Battery holder and secure it with 4 screws.

(NOTE: for the Arm assembly consider to have 2 front arm with 1 motor CCW and 1 motor CW, and the same for the rear arm. Every printed Arm support have 3 hollow for mantaining the position when you tighten the 4 arm screws, these hollows have to stay upward)

Now assembly the Arm, secure the motor with the 4 screws on the Motor support, insert the alluminium profile into the square hole (you can use some glue or drill the profile for a security screw), then insert the Arm support on the other side of the profile (drill and place security screw, care about the position of the screw, place it externally from the frame, don't glue now if you want to use the cable blocker).

Insert the assembly in the frame anche thighten the 4 screws of the arm (i suggest to use screw with Allen head, easier to tight and loose for clamping the arm open or close)

You can now shorten the QBRAIN cable (only this, because you have to test motor rotation before shortening the motor cable) look at the photo, you can cut it as much as you want (just check the lenght for closed and open arm), but in this case i can't reverse the motor cable if i disconnect them. I have tried to design a easy cable blocker (not included)but i'm not really satisfied, maybe a simpler ziptie will do the work better

Next: print the FC support, and on the lower part cut a square hole (use a cutter heated by a lighter) in proximity of the hole for the signal cable of the QBRAIN. Pass the cable through the hole, and secure the FC support with 4 screws, mount the damping ball, and the upper part.

Last step is mount the RC and telemetry support just put in place and tight a screw on the back, on the front will be the Rear Arm screw to clamp everything with the canopy.

Step 4: Electronic Connection

Using the biadhesive you can secure the FC on the FC support, the Buzzer on the right, and the I2C splitter on the left, connect the relative cable to the right place

Then connect the motor signal cable to the FC like in the photo

  1. brown
  2. orange
  3. white
  4. red

but you will check if it's all ok later.

Extend the Power monitor cable and connect it

Use the Male to male servo lead to connect the reciever to the PPM encoder then secure it to the reciever with some adhesive.

Extract the Telemetry from his plastic box and insert it in his place, loose the screw, place the telemetry holder and tighten again, connect to the FC.

Place the Reciever in place between the telemetry and the FC and connect the cable from the PPM encoder to the FC RCin.

Use the biadhesive for secure the GPS box to the canopy, pass the cable into the hole, fit the Switch button into his place. Connect all to the FC and push the reciever antenna into the rear hole of the canopy.

Now it's time to finish to setup the FC, so don't close the canopy.

Step 5: Lets Fly... No Wait.. Not Yet...

I think the simplest way to finish the configuration now it's to setup the Telemetry, so you can do it wirelessly:

open Mission Planner, in the "initial setup" tab, on the left select "mandatory hardware" then "3DR radio", insert the Telemetry in the USB of the computer, (obviously find and install the driver), select the COM port on top right and set the baud rate to 57600, click connect.

(NOTE: power up the FC with the usb cable or the battery)

click on "load setting" below, check if settings in the 2 windows (local and remote) are the same then click on "save setting" for bound the 2 radios.

Close the canopy with the 4 screws of the arm.

Now you can power up the quadcopter with the battery and connect to Mission planner via radio telemetry, run the Wizard for setup the last thing.

After the Wizard you can try the rotation of the motor, and check the motor number, in Mission planner under "initial setup" and "optional hardware" click on "motor test". When you find the right combination of motor cable you can shorten them (if a motor spin with different rotation just swap 2 cable, no matters what).

(NOTE: for testing the motor you have to press the Switch on the canopy for activate the QBRAIN)

Then make some test without the propeller.

And if i haven't miss anything (or you :D) you are ready to do the maiden flight (i suggest to prepare 2 flight mode "stabilize" and "alt hold" because the first time it's difficult to hover the quadcopter without send it to the moon or crash it to the ground, you will have to calibrate the throttle middle)

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