• ardupilot doc
• Connecting the Flight controller and RPi Hardware
• Setting up the flight controller
• Configure the serial port (UART)
• Configure the Wifi
• Setup the RPi Software
  • APSync
  • MAVProxy
  • Mavlink-router
  • DroneKit
  • Rpanion-server
• Connecting with the Mission Planner
• Example projects
  • use case with fpv

ardupilot doc

.. _raspberry-pi-via-mavlink:

=========================================== Communicating with Raspberry Pi via MAVLink ===========================================

This page explains how to connect and configure a Raspberry Pi (RPi) so that it is able to communicate with a flight controller using the MAVLink protocol over a serial connection. This can be used to perform additional tasks such as image recognition which simply cannot be done by the flight controller due to the memory requirements for storing images.

Connecting the Flight controller and RPi Hardware

.. image:: ../images/RaspberryPi_Pixhawk_wiring1.jpg :target: ../_images/RaspberryPi_Pixhawk_wiring1.jpg

Connect the flight controller’s TELEM2 port to the RPi’s Ground, TX and RX pins as shown in the image above. More details on the individual RPi’s pin functions can be found here <http://elinux.org/RPi_Low-level_peripherals>__.

The RPi can be powered by connecting +5V source to the +5V pin or from USB in.

Addon boards such as the Pi-Connect <https://www.rpanion.com/product/pi-connect-lite/>__ can simplify the connection of the RPi by providing a power supply and telemetry port.

.. tip::

Depending on the model of RPi used and internal/external peripherals used, +5V power requirements can vary from 80mA to close to 2.5A. The power budget for the particular system configuration should be assessed to determine the requirements for the +5V supply current. It is usually not recommended that +5v be supplied via the flight controller’s TELEM port connector.

.. _raspberry-pi-via-mavlink_setup_the_rpi:

Setting up the flight controller

Connect to the flight controller with a ground station (i.e. Mission Planner) and set the following parameters:

• :ref:SERIAL2_PROTOCOL <copter:SERIAL2_PROTOCOL> = 2 (the default) to enable MAVLink 2 on the serial port.
• :ref:SERIAL2_BAUD <copter:SERIAL2_BAUD> = 921 so the flight controller can communicate with the RPi at 921600 baud.
• :ref:LOG_BACKEND_TYPE <copter:LOG_BACKEND_TYPE> = 3 if you are using APSync to stream the dataflash log files to the RPi

Configure the serial port (UART)

If not already configured, the Raspberry Pi’s serial port (UART) will need to be enabled. Use the Raspberry Pi configuration utility for this.

Type:

::

sudo raspi-config

And in the utility, select “Interfacing Options”:

.. figure:: ../images/RaspberryPi_Serial1.png :target: ../_images/RaspberryPi_Serial1.png

RasPiConfiguration Utility

And then “Serial”:

.. figure:: ../images/RaspberryPi_Serial2.png :target: ../_images/RaspberryPi_Serial2.png

When prompted, select no to “Would you like a login shell to be accessible over serial?”.

When prompted, select yes to “Would you like the serial port hardware to be enabled?”.

Reboot the Raspberry Pi when you are done.

The Raspberry Pi’s serial port will now be usable on /dev/serial0.

Configure the Wifi

howto_official

If desired, the Raspberry Pi’s Wifi can be configured to create a Wifi access point. This will allow other clients to connect to the RPi and stream telemetry. See the official RPi documentation <https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md>__ for details.

.. tip::

The built-in Wifi on the Raspberry Pi does not have a large range. If range is an issue, consider a USB Wifi adapter with external antenna.

Setup the RPi Software

There are a few different software options for communicating with the flight controller. All use the MAVLink protocol for communication.

APSync

The easiest way to setup the RPi is to flash one of the existing :ref:APSync <apsync-intro> images:

• Purchase a formatted 8GB or 16GB SD card (16GB is better because some 8GB cards will not be quite large enough to fit the image) and insert into your laptop/desktop computer’s SD card slot
• Download the latest image from firmware.ardupilot.org <https://firmware.ardupilot.org/Companion/apsync>__. Look for the file starting with “apsync-rpi”.
• Use the Etcher <https://www.balena.io/etcher/>__ software to load the image onto the micro SD card.

• Insert the micro SD card into into the Pi’s micro SD card slot

  .. note::

  There is a more recent APSync build for the RPi in the forums <https://discuss.ardupilot.org/t/new-apsync-build-for-raspberry-pi/49528>__.

The APSync image will have the serial port (UART) already enabled.

MAVProxy

MAVProxy can be used to send commands to the flight controller from the Pi. It can also be used to route telemetry to other network endpoints.

This assumes you have a SSH connection to the Pi. If not, see see the the RPi Documentation <https://www.raspberrypi.org/documentation/remote-access/ssh/>__.

See the :ref:MAVProxy Documentation<mavproxy:mavproxy-downloadinstalllinux> for install instructions

To test the RPi and flight controller are able to communicate with each other first ensure the RPi and flight controller are powered, then in a console on the RPi type:

::

python3 mavproxy.py --master=/dev/serial0 --baudrate 921600 --aircraft MyCopter

Once MAVProxy has started you should be able to type in the following command to display the ARMING_CHECK parameters value

::

param show ARMING_CHECK
param set ARMING_CHECK 0
arm throttle ![RaspberryPi_ArmTestThroughPutty](https://user-images.githubusercontent.com/42961200/150961322-d2749c4b-b646-4794-b192-5e38fd547a08.png)

.. figure:: ../images/RaspberryPi_ArmTestThroughPutty.png :target: ../_images/RaspberryPi_ArmTestThroughPutty.png

.. note::

If you get an error about not being able to find log files or if this example otherwise doesn’t run properly, make sure that you haven’t accidentally assigned these files to another username, such as Root.

Mavlink-router

Mavlink-router is used to route telemetry between the RPi’s serial port and any network endpoints. See the documentation <https://github.com/intel/mavlink-router>__ for install and running instructions.

After installing, edit the mavlink-router config file’s /etc/mavlink-router/main.conf UART section to:

::

[UartEndpoint to_fc]
Device = /dev/serial0
Baud = 921600

You will also need to add an additional UDP endpoint allow other ground stations on the same network to connect to the Pi. Edit the mavlink-router config file /etc/mavlink-router/main.conf to include:

::

[UdpEndpoint to_14550_external]
Mode = eavesdropping
Address = 0.0.0.0
Port = 14550
PortLock = 0

DroneKit

The most up-to-date instructions for Installing DroneKit <https://dronekit-python.readthedocs.io/en/latest/guide/quick_start.html>__ on Linux are in the DroneKit-Python documentation.

Rpanion-server

Rpanion-server <https://www.docs.rpanion.com/software/rpanion-server>__ is a web-based GUI for configuring flight controller telemetry, logging, video streaming and network configuration.

Installation is via a disk image:

• Purchase a formatted 8GB (or larger) micro SD card and insert into your laptop/desktop computer’s SD card slot
• Download the latest image <https://www.docs.rpanion.com/software/rpanion-server>__.
• Use the Etcher <https://www.balena.io/etcher/>__ software to load the image onto the micro SD card.
• Insert the micro SD card into into the Pi’s micro SD card slot

The Rpanion-server image will have the serial port (UART) already enabled.

.. _raspberry-pi-via-mavlink_connecting_with_the_mission_planner:

Connecting with the Mission Planner

The flight controller will respond to MAVLink commands received through Telemetry 1 and Telemetry 2 ports (see image at top of this page) meaning that both the RPi and the regular ground station (i.e. Mission planner, etc) can be connected. In addition it is possible to connect the Mission Planner to the MAVProxy application running on the RPi :ref:similar to how it is done for SITL <setting-up-sitl-on-windows_connecting_with_the_mission_planner>.

Primarily this means adding an --out <ipaddress>:14550 to the MAVProxy startup command with the being the address of the PC running the mission planner. On windows the ipconfig can be used to determine that IP address. On the computer used to write this wiki page the MAVProxy command became:

::

mavproxy.py --master=/dev/ttyAMA0 --baudrate 57600 --out 192.168.137.1:14550 --aircraft MyCopter

Connecting with the mission planner is shown below:

.. image:: ../images/RaspberryPi_MissionPlanner.jpg :target: ../_images/RaspberryPi_MissionPlanner.jpg

Example projects

FPV with raspberry Pi <https://diydrones.com/profiles/blogs/fpv-setup-with-raspberry-pi>__

Can’t get it to work? Try posting your question in the Companion Computer discussion board <https://discuss.ardupilot.org/c/apsync-companion-computers>__.

use case with fpv

After much chasing, and testing, I have found this to be an efficient way of getting low latency high quality HD video out of an Aircraft. The latency is around 0.4 seconds at worst which would be OK for an FPV with an APM doing the hard work.

I will continue to search for methods to drop the latency down further, but this is a lot better than the 6-12 seconds I was getting on my first attempts.

Any comment (with useful instructions) would be appreciated.

For the wireless link, I am using two UBIQUITY ROCKET M 900 with Australian ACMA approved firmware, at the base station, I am using a tracking (yet to built the tracker…) 1.5 meter long X and Y polarised Yagi, and on the plane, two RF Design flexible strip antennas, placed at right angles to each other.

but how you do that bit is up to you…..

the critical bit is getting the Raspberry Pi’s to chat to each other.

I have tried to make this as user friendly as possible… good luck.

Setting up IP video for Raspberry Pi 1080p video (FPV)

You will need 2 B model Raspberry Pi’s and 1 Pi Camera. (Element 14, or RS components)

Preparing your Raspberry Pi for first boot…

Follow the instructions at http://www.raspberrypi.org/wp-content/uploads/2012/04/quick-start-guide-v2_1.pdf

Install the prepared SD card in the Pi and boot.

Setting up your Pi Connect the Pi to your router with a network cable.

On Start-up it will resize the FAT partition and present you with a menu.

Set your language, and keyboard layout.

Select Raspbian… then click install.

After this has extracted (will take a while….) it will reboot into the configuration screen (again will take a while for this first boot.)

The important things to change here are

Enable the camera In advance options….. Set the host name (camera, for the camera end, receiver, for the viewing end) Memory split, set the memory for the GPU to 256 Enable SSH ( will come in handy later, as you may need to talk to the Pi in the air….. Then finish and reboot.

First login Username: pi

Password: raspberry

Setting up the required programs for video streaming

Install the dependencies by running the following in a terminal:

sudo apt-get install mplayer netcat

cd /opt/vc/src/hello_pi

make –C libs/ilclient

make –C libs/vgfont

cd /opt/vc/src/hello_pi/hello_video

make

cd ~

Now repeat this for the other Pi….

Streaming… First set up the receiver…. Ensure the receiver is connected to your network and run

ifconfig

after you press enter, you can find your ip Address. Note this down.

Then run the following.

mkfifo buffer

the Pi will now wait for the feed.

On the Camera Pi Ensure camera is connected to the Pi

Ensure Pi is connected to the network (you can confirm this with ifconfig)

(see instructions at http://www.raspberrypi.org/camera for how to connect the camera)

In the following command, replace the ip address with the one you just noted down.

if all goes well you should be streaming 1080P video at 15fps with less than 0.5seconds of delay..

now add your wireless bridge between the two, and away you go J

This information has come from the Raspberry Pi foundation website, and other sources, tested and proven by myself..

The following wiki, pages and posts are tagged with drone