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The interesting corner

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Control drone with raspberry Pi


Set wifi on raspberry pi from SD card: add this to /boot/wpa_supplicant.conf:

            country=NL # Your 2-digit country code
            ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev

use GPIO on ubuntu on pi

use UART on GPIO on ubuntu on pi


control pixhawk met rpi:

Mavlink op rpi:

APSync voor op rpi

Ardupilot op drone aansturen met python: dronekit python api

PX4 op drone aansturen met software: MAVSDK (verschillende versies, Python ). Op de PX4 wiki is ook een artikel te vinden over using a companion computer with pixhawk controllers (meer info: Companion Computers).

MAVlink documentation

Je kunt ook een drone simuleren met [VIDEO] SITL. (Deze video gebruikt mavproxy)

PX4 gebruikt uORB messaging om berichten te sturen. Dit is een publish() en subscribe() protocol. Er is een tutorial voor hoe je dit in C++ kan doen. ROS2 is nog wel under development.

Pixhawk 4 Mini heeft maar 1 telemetry port (TELEM1), om de functie hiervan aan te passen kan je de Serial Port Configuration gebruiken. De Pi kan ook aan de TELEM/SERIAL4 port

New raspberry Pi with 8GB of RAM

Nieuwe raspberry pi met 8GB ram besteld omdat het builden van de px4_ros_com niet lukte met 2gb. Hierna werkte het wel gelijk

5G dongle

5G modem connected with USB C to Raspberry Pi that is getting powered by an STM32F446RE.

Link: Askey 5G NR USB dongle

use raspberry pi usb c port as host

config.txt on ubuntu is in /boot/firmware/

When attaching with usb to usb c dongle:

Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 05c6:9057 Qualcomm, Inc. SDXPRAIRIE-MTP _SN:0FCDAC25
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub 

Used the fix from here, the line to change was dtoverlay=dwc2,dr_mode=host. The raspberry config file is located here. After that, usb output when powered with 5V line and 5G modem attached with dongle:

ubuntu@raspberrypi-5g-drone:~$ lsusb
Bus 003 Device 002: ID 05c6:9057 Qualcomm, Inc. SDXPRAIRIE-MTP _SN:0FCDAC25
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

When disconnecting and reconnecting the modem, the output is this:

[  703.735276] usb 3-1: USB disconnect, device number 2
[  703.735551] rndis_host 3-1:1.0 enxa49733070111: unregister 'rndis_host' usb-fe980000.usb-1, RNDIS device
[  716.835194] usb 3-1: new high-speed USB device number 3 using dwc2
[  717.156418] usb 3-1: New USB device found, idVendor=18d1, idProduct=d00d, bcdDevice= 1.00
[  717.156456] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  717.156473] usb 3-1: Product: Android
[  717.156487] usb 3-1: Manufacturer: Google
[  717.156500] usb 3-1: SerialNumber: fcdac25
[  719.359444] usb 3-1: USB disconnect, device number 3
[  735.263348] usb 3-1: new high-speed USB device number 4 using dwc2
[  735.474230] usb 3-1: New USB device found, idVendor=05c6, idProduct=9057, bcdDevice= 4.14
[  735.474264] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  735.474280] usb 3-1: Product: SDXPRAIRIE-MTP _SN:0FCDAC25
[  735.474294] usb 3-1: Manufacturer: QCOM
[  735.474307] usb 3-1: SerialNumber: fcdac25
[  735.486798] rndis_host 3-1:1.0 eth1: register 'rndis_host' at usb-fe980000.usb-1, RNDIS device, a4:97:33:07:01:11
[  735.594839] rndis_host 3-1:1.0 enxa49733070111: renamed from eth1                            

at 703 the modem is unplugged, at 716 it's plugged back in and recognized as a Google Android device, but lsusb doesn't yet show anything. At 735 it's recognized again as a QCom device and then lsusb does recognize it.

The modem is recognised as a RNDIS device. It gets assigned the eth1 interface, but that changes to enxa49733070111. When running the command ifconfig enxa49733070111, the output is:

ubuntu@raspberrypi-5g-drone:~$ ifconfig enxa49733070111
enxa49733070111: flags=4098<BROADCAST,MULTICAST>  mtu 1500
        ether a4:97:33:07:01:11  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0                            

Laatste regel config.txt aangepast naar:


Installing Ubuntu Server 22.04

Ik heb deze tutorial gevolgd en Ubuntu Server 22.04.1 LTS geïnstalleerd.

Preparing the SD card:

change ownership:

sudo chown sem:sem /dev/mmcblk0

Daarna bij schrijven error dat de FAT32 partition niet gemount kon worden, opgelost door eerst 0 te schrijven

sudo dd if=/dev/zero of=/dev/mmcblk0 bs=8192
dd: error writing '/dev/mmcblk0': No space left on device
1944769+0 records in
1944768+0 records out
15931539456 bytes (16 GB, 15 GiB) copied, 1219,99 s, 13,1 MB/s

Setting up the Linux installation:

Dit werkte, daarna ingelogd met default username:password ubuntu:ubuntu.

[$ | ~ (4) > ssh ubuntu@
ubuntu@'s password:
Welcome to Ubuntu 22.04.1 LTS (GNU/Linux 5.15.0-1012-raspi aarch64)

 * Documentation:
 * Management:
 * Support:

  System information as of Thu Feb 16 13:39:31 UTC 2023

  System load:  0.17333984375      Temperature:           44.8 C
  Usage of /:   15.7% of 14.28GB   Processes:             141
  Memory usage: 12%                Users logged in:       1
  Swap usage:   0%                 IPv4 address for eth0:

0 updates can be applied immediately.

The list of available updates is more than a week old.
To check for new updates run: sudo apt update

Last login: Thu Feb 16 13:38:20 2023
To run a command as administrator (user "root"), use "sudo ".
See "man sudo_root" for details.

Pi geüpdate en geüpgrade.

Wifi ingesteld via deze tutorial. Ook static IP ingesteld. De local IP was, en daar heb ik hem ook op vastgezet. Ik heb /etc/netplan/50-cloud-init.yaml aangepast naar:

The config.txt is available here and here.

I installed Ubuntu 20.04 after building the PX4-ROS 2 bridge failed.

setting up the display

I connected the 4 inch HDMI display to the pi. Tutorial for writing to display without desktop environment The tutorial links to this blogpost about querying the framebuffer. I tried to install LXDE but got an error stating the session could not be started. this post explains the fix.

Settings for Ubuntu 20.04

Installing raspi-config didn't work, so I used this post to disable serial login and bluetooth.

connecting to the flight controller

I connected the rpi and pixhawk physically. Then I executed the command --master=/dev/serial0 --baudrate=57600 to start the connection. When trying to arm, I got an error on QGroundControl arming denied.

ubuntu@ubuntu:~$ --master=/dev/serial0 --baudrate=57600
Connect /dev/serial0 source_system=255
Log Directory:
Telemetry log: mav.tlog
Waiting for heartbeat from /dev/serial0
MAV> Detected vehicle 1:1 on link 0
online system 1
fence breach
Received 874 parameters
Saved 875 parameters to mav.parm

MANUAL> arm throttle
AP: Arming denied! manual control lost                            

I replied to a question on the PX4 forums where someone asked how to take off without RC. I also made a topic on the forum asking if anyone can help.

I also found this issue regarding the problem.


Voor pi aan pixhawk is een JST-GH 6 pin to jumper wires connector nodig. Er is er een nodig voor UART & I2C en eentje voor TELEM1. Ik heb female jumper wires besteld die ik aan de bijgeleverde kabeltjes kan solderen.

connectie van pixhawk naar rpi (gwn met uart):

uart connectie tussen pixhawk en pi

Connectie gemaakt van pixhawk naar pi. Pinout:

pixhawk raspi

De volgorde van aansluitingen:

PilotPi is een shield en software om autopilot op de rpi uit te voeren. Dit is niet nodig voor ons omdat we de pixhawk hebben.

Connectors aan elkaar gesoldeerd in testing esc motors

Foto test van camera met fswebcam -r 4656x3496 web-cam-shot.jpg:

webcam shot

Voor ROS 2 is een camera node. You can use the image_tools package.

Camera ingesteld via windows 10 VM. De camera kan in 4K resolutie maar met 10 FPS filmen

camera setup through windows vm 1 camera setup through windows vm 2

Camera node gemaakt met OpenCV2, alleen dan kan ik geen 4k resolutie selecteren.

Python sockets video versturen

Testing the TeraRanger Evo Height Sensor and Multiflex Object detection sensor

I used this video and tried this example to test if the sensor works, the results were positive:

ubuntu@raspberrypi-5g-drone:~/teraranger_evo_mini/Python$ python3
Evo Eco found on port /dev/ttyACM0
Sensor succesfully switched to binary mode
Sensor succesfully switched to long range measurement
Sensor succesfully switched to single range measurement

Er is een ROS node voor de TeraRanger Evo Mini, maar dit is voor ROS 1.

Ik heb de TeraRanger Multiflex getest en deze werkt ook. Ik heb de 1e 4 aangesloten:

1st 4 sensors of TeraRanger Mini

Testing the TeraBee Tower Evo LiDar

TeraBee heeft een Sensor API om met al hun sensoren te interfacen.

Testing the beacons Robot Positioning System

I tested the setup according to the user guide, with the AAP mode. This didn't work because the power adapters couldn't all get powered. I did configure all the anchors and trackers with the following info:


  • AAP mode on
  • z position 50 mm
  • LED mode on
  • priority x for anchor Ax
  • short message mode
  • LED mode on
  • priority x for tracker Tx
  • long message mode

test setup beacons 1 test setup beacons 2


Pi would not boot with Pixhawk connected to uart, solution is here. Fixed by putting relais in between RX and TX pins and turning on after pi has booted.

import rclpy
from rclpy.node import Node

    import RPi.GPIO as GPIO
except RuntimeError:
    print("Error importing RPi.GPIO!  This is probably because you need superuser privileges.  You can achieve this by using 'sudo' to run your script")

from drone_services.srv import ControlRelais
class RelaisController(Node):
    def __init__(self):
        self.srv = self.create_service(ControlRelais, '/drone/control_relais', self.control_relais_callback)

        self.relais1_pin = 17
        self.relais2_pin = 27

    def init_gpio(self):



        GPIO.setup(self.relais1_pin, GPIO.OUT)
        GPIO.setup(self.relais2_pin, GPIO.OUT)
        self.get_logger().info("GPIO initialized")

    def turn_relais_on(self):
        GPIO.output(self.relais1_pin, GPIO.HIGH)
        GPIO.output(self.relais2_pin, GPIO.HIGH)
        self.get_logger().info("Relais turned on")

    def control_relais_callback(self, request, response):
        if request.relais1_on:
            GPIO.output(self.relais1_pin, GPIO.HIGH)
            response.bits = response.bits | 1
            GPIO.output(self.relais1_pin, GPIO.LOW)
            response.bits = response.bits & ~(1 << 0)
        if request.relais2_on:
            GPIO.output(self.relais2_pin, GPIO.HIGH)
            response.bits = response.bits | (1 << 1)
            GPIO.output(self.relais2_pin, GPIO.LOW)
            response.bits = response.bits & ~(1 << 1)
        return response

def main(args=None):

    relais_controller = RelaisController()


    # Destroy the node explicitly
    # (optional - otherwise it will be done automatically
    # when the garbage collector destroys the node object)

if __name__ == '__main__':

Optical flow sensor

GPS works but not great, ordered a optical flow sensor for indoor positioning

Sensor: Here Flow

optical flow sensor parameters

Flight autotuning

Flight PID tuning guide