12 KiB
- Issues to solve
- day-1: Introduction to the beagle-boards and basic applications
- day-2: Control versions and interfacing electronics
- day-3: The internet of things
- day-4: The project
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.