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12 KiB

Issues to solve

which version of beagles to buy

  • I prefer to use the beaglebone black wi-fi, if it is possible to connect them to Jade's internet

  • Otherwise the ethernet version is preferred to use with usb-internet sharing

  • Install in computer the PuTTY software and some bash option to use.

day-1: Introduction to the beagle-boards and basic applications

Introduction to the beagle boards.

Connection

  • Basic USB connection

  • Connect to a IP address

  • SSH connection

ssh -X debian@192.168.7.2 debian:temppwd

Error connection

When getting the error:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@       WARNING: POSSIBLE DNS SPOOFING DETECTED!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
The ECDSA host key for beaglebone.local has changed,
and the key for the corresponding IP address 2806:103e:5:50f4:3ad2:69ff:fef9:46b4

you have to edit the '.ssh/known_hosts' file, and delete the lien that contains the offending key and the corresponding IP address given the warning.

Sharing the internet through usb

Wi-Fi

To connect to your Wireless network type the following command in the terminal window:

$sudo connmanctl
connmanctl> enable wifi
Enabled wifi
connmanctl> scan wifi
Scan completed for wifi
connmanctl> services
wifi_506583d4fc5e_544e434150413937414239_managed_psk
connmanctl> agent on
Agent registered
connmanctl> connect wifi_506583d4fc5e_544e434150413937414239_managed_psk
Passphrase? xxxxxxxxxxx
connected wifi_506583d4fc5e_544e434150413937414239_managed_psk
connmanctl> quit
$ping www.google.com

Beagle software

Basic File System Commands

Name Command options example
List files ls -a shows all ls -la
-l long format
-R recursive
Current directory pwd -P prints the physical location pwd
Change cd .. takes you up a level cd /home/gmarx
directory ~ takes you to home directory cd ~
Make mkdir -p make parent directories as needed mkdir -p test/example
directory -v print a message for each directory mkdir -p /test/example
*first example creates
folders inside the
current folder, other one
creates folder in root directory
Delete a rm -r recursive (use for directories) rm sample.txt
file or directory -d remove empty directory rm -r test
Copy a file cp -r recursivec copy cp a.txt b.txt
or directory -u copy only if the source is newer cp test-a test-b
-v verbose (show output)
Move a file or mv -i prompts before overwrite mv a.txt c.txt
directory No -r; Moving into the same directory mv test example
performs a renaming
touch
more
cal

Terminal

Command Description
CTRL-c Stop current command
CTRL-z Sleep program
CTRL-a Go to start of line
CTRL-e Go to end of line
CTRL-u Cut from start of line
CTRL-k Cut to end of line
CTRL-r Search history
!! Repeat last command
Tab key Autocompletes

Package management

Command Debian
Install a package sudo apt install vim
Upgrade the package in your system sudo apt upgrade

Basic file editing with VIM

Expanding the file system

with 'lsblk':

debian@beaglebone:~$ lsblk
NAME         MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
mmcblk0      179:0    0 28.9G  0 disk 
`-mmcblk0p1  179:1    0  3.5G  0 part /
mmcblk1      179:8    0  3.6G  0 disk 
`-mmcblk1p1  179:9    0  3.6G  0 part 
mmcblk1boot0 179:16   0    2M  1 disk 
mmcblk1boot1 179:24   0    2M  1 disk 
mmcblk1rpmb  179:32   0  512K  0 disk 
debian@beaglebone:~$

then df -k:

debian@beaglebone:~$ df -k
Filesystem     1K-blocks    Used Available Use% Mounted on
udev              220088       0    220088   0% /dev
tmpfs              49496    5628     43868  12% /run
/dev/mmcblk0p1   3558936 2233396   1125044  67% /
tmpfs             247468       0    247468   0% /dev/shm
tmpfs               5120       4      5116   1% /run/lock
tmpfs             247468       0    247468   0% /sys/fs/cgroup
tmpfs              49492       0     49492   0% /run/user/1000

we have to use some tools at 'opt/scripts/tools'

debian@beaglebone:/opt/scripts/tools$ sudo ./grow_partition.sh 
[sudo] password for debian: 
Media: [/dev/mmcblk0]
sfdisk: 2.26.x or greater
Disk /dev/mmcblk0: 28.9 GiB, 31016878080 bytes, 60579840 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xbecca426
...

sudo reboot

Now is sure to update packages or kernel with 'sudo apt upgrade', and 'uname -a'.

Developing applications

On-Board LEDs

first go to:

cd /sys/class/leds/

then, follow the next commands for the beaglebone:green:usr3:

debian@beaglebone:/sys/class/leds$ ls
beaglebone:green:usr0  beaglebone:green:usr2  wl18xx_bt_en
beaglebone:green:usr1  beaglebone:green:usr3
debian@beaglebone:/sys/class/leds$ cd beaglebone\:green\:usr3
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$ ls
brightness  device  max_brightness  power  subsystem  trigger  uevent
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$ cat trigger 
none rc-feedback rfkill-any kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock usb-gadget usb-host mmc0 [mmc1] mmc2 timer oneshot disk-activity ide-disk mtd nand-disk heartbeat backlight gpio cpu cpu0 activity default-on panic netdev bluetooth-power hci0-power rfkill0 rfkill1 phy0rx phy0tx phy0assoc phy0radio 
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$ echo none > trigger 
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$ echo 1 > brightness 
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$ echo 0 > brightness 
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$

In this case, cat trigger results in a [mmc1], and it is necessary to change its state, first to none, then we are able to modify its brightness by echoing 1 or 0 to this sysfs virtual file system.

Delay example:

echo timer > trigger 
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$ cat trigger 
none rc-feedback rfkill-any kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock usb-gadget usb-host mmc0 mmc1 mmc2 [timer] oneshot disk-activity ide-disk mtd nand-disk heartbeat backlight gpio cpu cpu0 activity default-on panic netdev bluetooth-power hci0-power rfkill0 rfkill1 phy0rx phy0tx phy0assoc phy0radio 
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$ ls
brightness  delay_on  max_brightness  subsystem  uevent
delay_off   device    power	      trigger
debian@beaglebone:/sys/class/leds/beaglebone:green:usr3$ cat delay_on 
500

Shutdown

>sudo shutdown -h now
>sudo shutdown -h +5
>sudo reboot

Node.js, Cloud9, and BoneSccript

The BeagleBoard.org Linux distribution comes complete with a set of technologies that you can use to quickly get started with developing software and hardware applications on the boards. These are called Node.js, Cloud9, and BoneScript. Node.js is a programming language, Cloud9 is an online software integrated development environment (IDE) in which you can write Node.js code, and BoneScript is a library of code for Node.js that allows you to interact with Beagle board hardware[Molloy@2019].

Node.js

Node.js is a platform for building network applications that uses the same JavaScript engine as the Google Chrome web browser. JavaScript is the programming language that is often used to create interactive interfaces within web pages.

debian@beaglebone:~$ cd es-jade/
debian@beaglebone:~/es-jade$ mkdir node-test
debian@beaglebone:~/es-jade$ cd node-test/
debian@beaglebone:~/es-jade$ vi hello-jade.js

In the file add the next line of code:

console.log("Hello World!");

Then, run the script by using the node command:

debian@beaglebone:~/es-jade/node-test$ node hello-jade.js 
Hello Jade-HS and world

The call to the node command works because the Node.js runtime environment is preinstalled on the BeagleBoard.org Linux image.

Now lets try a more complex script; a web server.

The linux file system and commands

day-2: Control versions and interfacing electronics

git for control version2

C and C++

GPIO interfacing

4. Bone scripts

UART communication

day-3: The internet of things

A beagle board IoT sensor

Sensor web server

Linux cron scheduler

QT rich user interface

day-4: The project

project development