es-2022-p1/es.org

* 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:

#+begin_src 
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@       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
#+end_src

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:
#+begin_src
$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
#+end_src
** 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':

#+begin_src 
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:~$ 
#+end_src
 
then df -k:
#+begin_src 
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
#+end_src

we have to use some tools at '/opt/scripts/tools/'
#+begin_src 
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
#+end_src


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

** Developing applications
*** On-Board LEDs
 first go to:

 #+begin_src 
 cd /sys/class/leds/
 #+end_src

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

#+begin_src 
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$ 
#+end_src

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:

#+begin_src 
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

#+end_src
*** Shutdown
#+begin_src 
>sudo shutdown -h now
>sudo shutdown -h +5
>sudo reboot
#+end_src
*** 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.

#+begin_src 
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
#+end_src

In the file add the next line of code:
#+begin_src 
console.log("Hello World!");
#+end_src

Then, run the script by using the ~node~ command:

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

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