I finally received my Raspberry Pi Zero,  just in time to get into the DIY challenge of building a smart drone with the Pi Zero and APM under 100$. I called this project: MINI-Zee


How this can be done?

Well first of all, thanks to Victor and the team at Erle Robotics for releasing the plans and software of their PXFmini.  This is a real inspiration for building my own board, because all the parts are available at a cheap price and are relatively easy to assemble and interconnect using through-hole breadboard, providing you are very experienced with this type of build.  Thanks to Mirko as well, for having introduced a real DIY autopilot project that allows us to experiment with a fully working and well supported BeagleBone  based  ArduPilot  Cape called the BBBMINI.


Bill of Material (US$ - Transport & taxes excl.):

Raspberry Pi Zero                                      5.

MPU 9250 (SPI 9 dof IMU)                         8.

MS 5611 (SPI Baro)                                   9.

PCA 9685 (16 channel PWM Servo Driver)  5. 

3.3 v. regulator                                          1.

BEC 3 amps                                             3.

Breadboard, Resistors, Connectors, Misc.   7.

                                               AutoPilot:  38.

HobbyKing Spec FPV250 V2 Quad Copter

ARF Combo Kit - Mini Sized FPV         60. 

                                                     Total:  98.

*This is Banggood price; I had an ADAFRUIT –PWM on hand, and I really recommend going with ADAFRUIT, because of all the effort  they put on making a great tutorial and drivers for this product. Note: Just like Erle , the USB WIFI, GPS and the Radio Control are excluded.


A) Hardest part: Get a  RASPBERRY PI ZERO (Where is my Zero site)
B) Hardware - See BOM
C) Board Schematics : Erle pxfmini
D) Board Software: Erle pxfmini

E) LOAD LATEST Raspbian-Jessie

Disable serial Login (Allow GPS on serial Port)
Enable , I2C, SPI , Serial
Disable Console = Auto Log on a shell

Load Test Result: TEST: T: 0 ( 1136) P:80 I:500 C: 100000 Min: 16 Act: 31 Avg: 32 Max: 157

G) MAKE ArduCopter

Special MINI-ZEE release:
1) The MPU 9250 is mounted on the Z-Axis, so we need to change : 

, _default_rotation(ROTATION_YAW_270)  = to ROTATION_NONE

2) The PCA9585 has no external clock, and the ESC are connected to ports 1-2-3-4, so we need to change: 

static RCOutput_PCA9685 rcoutDriver(PCA9685_PRIMARY_ADDRESS, true, 3, RPI_GPIO_27);      -to-

static RCOutput_PCA9685 rcoutDriver(PCA9685_PRIMARY_ADDRESS, false, 0, RPI_GPIO_27);

H) Fly the MINI-ZEE == Add these to /etc/rc.local

#wait till network is up and DHCP assigned address

while ! ifconfig | grep 192.168.2. >> /home/pi/bootlog; do
echo “no network, waiting…” >> /home/pi/bootlog
sleep 5
echo “Starting ArduCopter” >> /home/pi/bootlog

sudo /home/pi/ardupilot/ArduCopter/ArduCopter.elf -A udp:192.168.gcu-address:14550  -B /dev/ttyAMA0 > /home/pi/startup_log &

exit 0



Thanks to the damping platform, the vibration level is within specs. Video is available for anyone interested..;-)


This project took about 20 hours to complete. As you can see, I really enjoyed  doing some hardcore DIY to demonstrate that it is still possible to build your own flight controller from a Linux Based system.  I do not recommend to try this as a first project, but if you are interested, get a BBBMINI, this is the best introduction to DIY  and if you want to fly a Raspberry Pi Zero, it is much  easier to buy a PXFMINI.

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  • Here is release 2 of the Mini_ZEE

    I finally received the RPI Zero with Camera and decided to upgrade the motors as well.

    Still need some adjustments since the camera induces some noise on the GPS and now the Wifi Dongle need its own power. 


  • understood.

    thanks for taking the time to answer

    regards, Matic

  • Thank You 

    There are 2 reasons:

    A) This build is based on the pxfmini that has a lot of similarities with the Navio, and both are using the PCA9685 for PWM.

    B) There is no consensus in the community as if the RPI can generate stable PWM using its own resources  (see some discussion here: PIGPIO ) . So instead of going on the unknown I decided to stick with 2 generation of working autopilots and adapt the pxfmini code for my particular build.

  • hello,

    Great work

    I have one question tho, why do you need PCA9685?


  • Hello Victor, 

    You can use the main repository, https://github.com/ArduPilot/ardupilot

    ArduPlane, ArduCopter, ArduRover source. Contribute to ArduPilot/ardupilot development by creating an account on GitHub.
  • Hello Patrick.

    D) Board Software: Erle pxfmini, this is "https://github.com/erlerobot/ardupilot", it is right?. Thank


    APM Plane, APM Copter, APM Rover source. Contribute to erlerobot/ardupilot development by creating an account on GitHub.
  • Hello Patrick, Thank you!


  • Hello Radioelf

    Once I had modified the sensor files for my particular setup;

    ardupilot/libraries/AP_InertialSensor/AP_InertialSensor_MPU9250.cpp  = for the IMU

    ardupilot/libraries/AP_HAL_Linux/HAL_Linux_Class.cpp = For the PWM

    Lauched the MAKE process (no cross compile , just build straight from the PiZero):

    cd ~/ardupilot/ArduCopter
    make pxfmini


  • Hi Patrick, you can comment a little more: G) MAKE ArduCopter. (requirements)


  • Hi.

    Very interesting ... I'm starting a similar project, right now i am with PCB design with Kicad.


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