Flying BeagleBone Green

BBBmini is a state of the art Linux autopilot / flightcontroller Cape for the BeagleBone. It can be used for Copter, Planes or Rovers.

Categories: Intermediate

Originally published at https://www.hackster.io/mirkix/flying-beaglebone-green-448b60.

About BBBmini

BBBmini is an autopilot / flightcontroller Cape for the BeagleBone Green. BBBmini + BeagleBone Green can be used as a state of the art Linux autopilot / flightcontroller for Copter, Planes or Rovers. BBBmini can be used with
ArduPilot
(open source unmanned aerial vehicle flight stack. BBBmini is a DIY project using widely available IMU and barometer breakout sensor boards, there is no SMD soldering necessary. The design is made that everybody can build a BBBmini by himself. In flight internet connection is done via WiFi link.

What does BBBmini offer:

  • DIY state of the art UAV autopilot / flightcontroller
  • Easy to build, no SMD soldering necessary
  • Free hardware, free software
  • Autopilot / flightcontroller software is running on Real-Time Linux
  • DIY friendly connectors 0.1” pin header
  • 12 x PWM out with individual frequency for each channel
  • RC in connector for PPM, S.BUS or spektrum satellite input
  • MPU-9250 IMU 9 x DOF
  • MS5611 barometer
  • HC-SR04 ultrasonic rangefinder
  • GPS for full autonomous flights
  • Voltage and current sensing
  • I2C / GROVE connector for Status display and additional sensors
  • SPI connector for second redundant IMU
  • U
    ART / GROVE connector for GPS
  • UART / GROVE connector for telemetry
  • CAN connector with on board CAN bus transceiver
  • USB connector used for WiFi, Laser rangefinder or cameras
  • Excellent cost-performance ratio

The BBBmini project development includes:

  • BBBmini documentation / how to
  • BBBmini PCB design done with
    Kicad
    all sources free available on
    Github
  • Device tree file for BBBmini hardware
  • PRU firmware: 12 x PWM OUT with better than 1us accuracy, separate frequency for each channel. RC input capture with 5ns accuracy, can be used to capture PPM, S.BUS or spektrum satellite
  • PRU firmware: HC-SR04 Ultrasonic Rangefinder device driver
  • Commits to ArduPilot project to get BBBmini supported by ArduPilot
  • Development of status display device driver for ArduPilot
  • Add redundancy sensors via SPI / I2C or UART
  • Lots of test flights and fine tuning in hardware and software to get a stable and reliable BeagleBone Green flightcontroller

BBBMINI PCB

See the BBBmini flying

Why BeagleBone Green

Once I had the idea to develop an flightcontroller, I have examined on the market available computer for their suitability. The following criteria should be met by the computer being used.

First, the computer should be very well supported by the community. As a result, a Raspberry Pi or BeagleBone could be used. 

In addition, the flightcontroller should be set up with as little as possible external components.

The decision was made for the BeagleBone. With the Programmable Real-Time Units of the BeagleBone, it is possible to create the BBBmini with only a few sensor breakout boards. In addition the BeagleBone offers many interfaces such as UART, SPI, I2C, CAN, USB and ADC. All these interfaces are used by the BBBmini.

BeagleBone Green parts used for BBBmini

  • Main CPU running Linux
  • PRU0 device driver for HC-SR04 ultrasonic rangefinder
  • PRU1 to generate 12 PWM signals and receive PPM, S.BUS or spektrum satellite input
  • Grove / I2C for communication to the status display, external compass or Laser rangefinder
  • GROVE / serial 2 for sensors like Laser Rangefinder
  • Serial 4 for telemetry radio
  • Serial 5 for GPS
  • ADC for voltage and current sensing
  • SPI1 for high speed data transfer from IMU and Baro sensor
  • SPI0 for high speed data transfer from second redundant IMU or other hardware
  • CAN for communication with ESCs and additional hardware
  • USB for WiFi and camera connection for life HD video transmission
  • Ethernet for communication on ground

Assemble BBBmini

Step 1:
Solder resistor R4 and R5.




























For 3.3V RC input signal use R4 = 0Ω (bridge) and R5 = open (see picture)

For 5V RC input signal use R4 = 1kΩ and R5 = 2kΩ

Solder R4 and R5

Step 2:

Solder resistor

R1 = 120Ω

R2 = 1kΩ

R3 = 2kΩ

R6 = 20kΩ 0.1%

R7 = 10kΩ 0.1%

R8 = 20kΩ 0.1%

R9 = 10kΩ 0.1%

to the bottom layer. 


Solder R1, R2, R3, R6, R7, R8 and R9

Step 3:

Solder CAN transceiver on the top layer


Solder CAN transceiver

Step 4:

Solder male pin-header on top layer

P1, P2, P3, P4, P7, P10, P11, P12, P13, P14, P15, P16, P17, P18, P19, P20, P21

Solder P1, P2, P3, P4, P7, P10, P11, P12, P13, P14, P15, P16, P17, P18, P19, P20, P21

Step 5:

Solder C1 and C2

Solder C1 and C2

Step 6:

Solder female pin-header P5 and P6 on top layer

Solder P5 and P6

Step 7:

Solder male pin-header P8 and P9 to bottom layer

Solder P8 and P9

Step 8:

Solder male pin-header to bottom layer of GY-9250 and GY-63

Solder pin-header to GY-9250 and GY-63

Step 9:

Mount spacer to BBBmini

Mount spacer

Step 10:

Mount GY-9250 and GY-63

Mount GY-9250 and GY-63

Finish! BBBmini is ready to use for Copter, Planes or Rover.

BBBmini + BBG

Prepare BeagleBone Green

Prepare microSD with your host computer

Step 1:

Download Debian image to host computer






 

wget https://rcn-ee.com/rootfs/bb.org/testing/2016-03-13/console/BBB-eMMC-flasher-debian-8.3-console-armhf-2016-03-13-2gb.img.xz

Step 2:

Decompress image






 

unxz BBB-eMMC-flasher-debian-8.3-console-armhf-2016-03-13-2gb.img.xz

Step 3:

Copy image to microSDcard (>= 2GB)

/dev/sdX point to your microSD, be careful here!!! Use
lsblk
to figure out, which is your mircroSD. The process can take 15-30 minutes depending on the speed of your microSD card.






 

sudo dd bs=4M if=./BBB-eMMC-flasher-debian-8.3-console-armhf-2016-03-13-2gb.img of=/dev/sdX

Step 4:

sync
and remove microSD






 

sync

Install Debian to your BeagleBone eMMC

Step 1:

Plug prepared microSD into BeagleBone

Step 2:

While holding down the boot button, apply power to the board. If there is a newer Debian installed, holding down the boot button is not necessary.

Step 3:

Wait some minutes until Debian is installed (all four LEDs turned on).

Step 4:

Remove power.

Step 5:

Apply power again.

Step 6:

Connect to the BeagleBone (password =
temppwd
)






 

ssh debian@beaglebone

Step 7:

Update Software






 

sudo apt-get update && sudo apt-get upgrade -y

Step 8:

Install software






 

sudo apt-get install -y cpufrequtils g++ gawk git make ti-pru-cgt-installer device-tree-compiler screen python

Step 9:

Update scripts






 

cd /opt/scripts && sudo git pull

Step 10:

Install RT-Kernel






 

sudo /opt/scripts/tools/update_kernel.sh --bone-rt-kernel --lts-4_1

Step 11:

Add BBBMINI DTB

sudo sed -i 's/#dtb=$/dtb=am335x-boneblack-bbbmini.dtb/' /boot/uEnv.txt

Step 12:

Adjusting the BeagleBone clock

sudo sed -i 's/GOVERNOR="ondemand"/GOVERNOR="performance"/g' /etc/init.d/cpufrequtils

Step 13:

Reboot system






 

sudo reboot

Step 14:

Login again






 

ssh debian@beaglebone

Step 15:

Clone overlays






 

git clone https://github.com/beagleboard/bb.org-overlays

Step 16:

Change dir






 

cd ./bb.org-overlays

Step 17:

Update DTC






 

./dtc-overlay.sh

Step 18:

Build and install overlays

./install.sh

Step 19:

Add ADC DTBO

sudo sed -i 's/#cape_enable=bone_capemgr.enable_partno=/cape_enable=bone_capemgr.enable_partno=BB-ADC/g' /boot/uEnv.txt

Step 20:

Reboot system






 

sudo reboot

Step 21:

Login again after reboot






 

ssh debian@beaglebone

Step 22:

Clone ArduPilot sourcecode

git clone https://github.com/diydrones/ardupilot.git

Step 23:

Change dir

cd ardupilot

Step 24:

Init submodule

git submodule init

Step 25:

Clone submodule

git submodule update

Step 26:

Change dir

cd Tools/Linux_HAL_Essentials/pru/rangefinderpru

Step 27:

Build Rangefinder firmware

make

Step 28:

Install Rangefinder firmware

sudo make install

Your BeagleBone is now ready to use.

Build ArduPilot software

BBBmini uses
ArduPilot
as flight stack. I contribute patches to the ArduPilot that BBBmini is supported by
ArduPilot
software.

Compile ArduPilot native on BeagleBone

Step 1:








 

cd ardupilot

Step 2: 

alias waf="$PWD/modules/waf/waf-light"

Step 3: 

waf configure --board=bbbmini

Step 4:
(take about 1h20) 

waf

Step 5: 

 cp build/bbbmini/bin/* /home/debian/

Cross compile ArduPilot (faster)

To compile ArduPilot for BeagleBone on an Ubuntu computer the following packages are required:

sudo apt-get install git gawk g++-arm-linux-gnueabihf

Get the source code and build ArduPilot:

Step 1:








 

git clone https://github.com/diydrones/ardupilot.git

Step 2: 

cd ardupilot

Step 3: 

git submodule init

Step 4: 

git submodule update

Step 5: 

alias waf="$PWD/modules/waf/waf-light"

Step 6: 

waf configure --board=bbbmini

Step 7: 

waf -j8









Step 8: 

scp build/bbbmini/bin/* debian@beaglebone:/home/debian/

BBBmini Test

For safety reasons dismount all propellers when testing BBBmini.

Step 1:
 Check connection to sensors

1. Connect BeagleBone Green via Ethernet to Network

2. Supply power to the BBBmini

3. Connect to BeagleBone Green from host computer with ssh








 

ssh debian@beaglebone

4. Start arducopter

Parameter description:

-B /dev/ttyO5
GPS connected to serial port 5

-C /dev/ttyO4
telemetry radio connected to serial port 4 

sudo ./arducopter-quad -B /dev/ttyO5 -C /dev/ttyO4

5. Check if startup is successful

nit APM:Copter V3.4-dev



Free RAM: 262144



FW Ver: 120



----------------------------------------



load_all took 210us



0 0 0 DataFlash_File: buffer size=16384



� Q}�HMC5843: Could not detect version



� Q��Init Gyro*� Q� ***



Ready to FLY

The output should look like this.
HMC5843: Could not detect version
does not matter, because there is not a HMC5843 connected. The non ASCII symbols are MAVLink messages, that is alright. 

Step 2:
Add arducopter to automatic start at boot time

1. Edit rc.local

sudo nano /etc/rc.local

2. Add automatic arducopter startup

Parameter description:

-B /dev/ttyO5
GPS connected to serial port 5

-C /dev/ttyO4
telemetry radio connected to serial port 4
 

#!/bin/sh -e

#

# rc.local

#

# This script is executed at the end of each multiuser runlevel.

# Make sure that the script will "exit 0" on success or any other

# value on error.

#

# In order to enable or disable this script just change the execution

# bits.

#

# By default this script does nothing.

/home/debian/arducopter-quad -B /dev/ttyO5 -C /dev/ttyO4 &

exit 0

Save and exit: Strg + o and Strg + x 

Setup BBBmini Quadcopter

Step 1:
Assemble frame

Step 2:
Connect motors and ESC

BBBmini ESC wiring

Step 3:
Connect power distribution 

  • Connect each ESC to the power distribution board
  • Connect the 5V power distribution board output to BBBmini P11 power input
  • Connect the voltage and current sensing power distribution board output to BBBmini P21 voltage and current sensing pins

BBBmini power distribution wiring

Step 4:
Connect RC receiver

BBBmini RC receiver wiring

Step 5:
Connect display

Connect your SSD1306 OLED display to P15 or I2C GROVE port

P15 or GROVE +3.3V to display VCC

P15 or GROVE GND to display GND

P15 or GROVE SDA to display SDA

P15 or GROVE SCL to display SCL

BBBmini display wiring

Step 6:
Connect GPS

Connect your GPS to P10.

P10 +3.3V to GPS VCC

P10 GND to GPS GND

P10 RX to GPS TX

P10 TX to GPS RX

BBBmini GPS wiring

Step 7:
Connect telemetry

Connect your telemetry radio to P7.

P7 +5V to telemetry radio VCC

P7 GND to telemetry radio GND

P7 RX to telemetry radio TX

P7 TX to telemetry radio RX

BBBmini telemetry wiring

Step 8:
Connect HC-SR04

Connect your HC-SR04 ultrasonic rangefinder

P19 +5V to HC-SR04 VCC

P19 GND to HC-SR04 GND

P19 TRIG to HC-SR04 TRIG

P19 ECHO to ECHO TRIG

BBBmini HC-SR04 wiring

Check / configure BBBmini

Plug USB telemetry radio into your host PC. I recommend to use
APM Planner
ground control station for beginners. Advanced user can use
MAVProxy
ground control station.

Step 1:

Start APM Planner

Step 2:

Change serial port to USB telemetry radio serial port

Set baudrate to 57600

Press connect button, wait for connection established

Wait some seconds to load parameters from BBBmini

APM Planner port settings

Step 3:

Move BBBmini and check that Primary Flight Display is moving too

APM Planner IMU check

Step 4:

Switch to
INITIAL SETUP

APM Planner initial setup

Step 5:

Switch to
COMPASS

Hit button
Live Calibration

Move BBBmini in all axis until calibration is completed

APM Planner compass

Step 6:

Switch to
Accel Calibration

Hit button
Calibrate
and follow instructions 

APM Planner Accel Calibration

Step 7:

Switch to
Radio Calibration

Hit button
Calibration
and follow intructions

APM Planner Radio Calibration

Step 8:

Switch to
Flight Modes

Setup that you are able to switch between
Stabilize
,
Loiter
and
RTL

APM Planner Flight Modes

First Flight / Drive

Be sure all test are successful. Read and follow the
safety instructions
.

Because I did a lot of contributions to the
ArduPilot
project, BBBmini is full supported by
ArduPilot
software. Check
ArduPilot website
for instruction how to setup and use an
ArduPilot
autopilot. The
ArduPilot
website will provide you with all necessary information about how to build and fly (drive) vehicles with your BBBmini.

Links:

Quadcopter, Hexacopter, …









Planes, VTOL



Rover (Boats)

Support

If you have questions about you BBBmini you can join the BBBmini user group on
diydrones.com
or ask for support at the gitter BBBmini support chat.

Links:

BBBmini user group



BBBmini support chat

Dual IMU (optional)

You can connect a second GY-9250 IMU to the BBBmini.

Setup 5GHz WiFi (optional)

Using USB WiFi with Linux can be complicated because of missing support of the WiFi chip by the Linux Kernel. It is very important to select  a well supported WiFi USB stick. One of these are Ralink RT5572 based WiFi USB sticks.  They can transmit at 2,4GHz or 5GHz. It is not necessary to compile a driver, it is supported by the Linux Kernel out of the box. With the Debian we use for the BBBmini you only have to install the firmware and some tools for the RT5572 chip with: 






sudo apt-get install firmware-ralink crda wpasupplicant wireless-tools

Here is a list with RT5572 based WiFi USB sticks.

You have to configure your location because the restrictions of the frequency usage depends of the country where you use the WiFi stick. For me it is DE for Germany. Replace
DE
to your country code.







 

sudo sed -i "s/REGDOMAIN=/REGDOMAIN=DE/g" /etc/default/crda

Edit your WiFi configuration:  

sudo nano /etc/network/interfaces




auto wlan0

iface wlan0 inet dhcp

wpa-ssid "essid"

wpa-psk "password"

Save and exit with Strg + O and Strg + X

You can use WiFi to control your BeagleBone Green Linux, telemetry link or / and Live video transmission.

Live video transmission with BeagleBone Green and BBBmini (optional)

What additional components you need for live video transmission:

  • USB HUB
  • USB camera with hardware H264 support 
  • USB WiFi dongle

I use this H264 
camera
with success with my BeagleBone Green (
Link
).

Install required software: 

sudo apt-get install gstreamer1.0-tools gstreamer1.0-plugins-good gstreamer1.0-plugins-bad

Start video transmission: 

gst-launch-1.0 v4l2src device=/dev/video1 ! video/x-h264,width=640,height=360 ! h264parse config-interval=1 ! rtph264pay ! udpsink host=192.168.178.25 port=5000

Change
192.168.178.25
to our host computer IP address.

Performance:

With ArduPilot running and video streaming the BeagleBone Green has a CPU load of about 25%.






Receive video transmission on Linux host computer: 

gst-launch-1.0 udpsrc port=5000 ! application/x-rtp, encoding-name=H264,payload=96 ! rtph264depay ! h264parse ! avdec_h264 ! autovideosink

Safety

Always follow this safety instructions.

License

License

BBBmini by Mirko Denecke is licensed under a
Creative Commons Attribution-ShareAlike 4.0 International License
.

UNLESS OTHERWISE MUTUALLY AGREED TO BY THE PARTIES IN WRITING, LICENSOR OFFERS THE WORK AS-IS AND MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND CONCERNING THE WORK, EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, INCLUDING, WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NONINFRINGEMENT, OR THE ABSENCE OF LATENT OR OTHER DEFECTS, ACCURACY, OR THE PRESENCE OF ABSENCE OF ERRORS, WHETHER OR NOT DISCOVERABLE. SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES, SO SUCH EXCLUSION MAY NOT APPLY TO YOU. EXCEPT TO THE EXTENT REQUIRED BY APPLICABLE LAW, IN NO EVENT WILL LICENSOR BE LIABLE TO YOU ON ANY LEGAL THEORY FOR ANY SPECIAL, INCIDENTAL, CONSEQUENTIAL, PUNITIVE OR EXEMPLARY DAMAGES ARISING OUT OF THIS LICENSE OR THE USE OF THE WORK, EVEN IF LICENSOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

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