sqlite>.help
output all comands
sqlite>.open database_name.db
open or cretae database.
sqlite>.tables
show tables of active database.
sqlite>.schema table_name show SQL create table fields command.
To show 20 rows of table_name with MySQL look:
sqlite>.header onsqlite>SELECT * FROM table_name LIMIT 20;
Describe table in MySQL look:
sqlite> pragma table_info('table_name');
For this project I used 2 DHT22 sensors modules that include the resistor.
Sensor has 3 wires to connect to GPio: Data, GND and VCC (+5V or 3.3V).
Can be use 5V or 3.3V to provide power to sensor.
With 3.3V sometimes DHT22 sensor did no respond or lost the connection (?), in my case using 5V solve the problem.
Script are coded in Python3, let's install previously the libraries.
1) The Python script:
#!/usr/bin/python3
####################################################
# (C)by MisNotasLinux 2021
# DHT22_01: data wire to gpio 23
# DHT22_02: data wire to gpio 24
# Conect VCC of DHTs to 5V or 3.3V rpi gpio pin.
# Conect GND of DHTs to GND rpi gpio pin.
####################################################
import Adafruit_DHT
import time
import datetime
DHT_SENSOR = Adafruit_DHT.DHT22
DHT_01 = 23 # data rpi gpio pin for dht sensor 01
DHT_02 = 24 # data rpi gpio pin for dht sensor 02
t = 10 # time for repeat measurement
while True:
print(datetime.datetime.now())
print("----------------------------------------------")
h01, t01 = Adafruit_DHT.read_retry(DHT_SENSOR, DHT_01)
if h01 is not None and t01 is not None:
print("Temp_01={0:0.1f}*C Humidity_01={1:0.1f}%".format(t01, h01))
else:
print("Failed to retrieve data from humidity sensor 01")
h02, t02 = Adafruit_DHT.read_retry(DHT_SENSOR, DHT_02)
if h02 is not None and t02 is not None:
print("Temp_02={0:0.1f}*C Humidity_02={1:0.1f}%".format(t02, h02))
else:
print("Failed to retrieve data from humidity sensor 02")
print("Sleeping " + str(t) + " sec ...")
print("----------------------------------------------")
2) References:
http://misnotaslinux.blogspot.com/2020/06/linux-mint-193-tricia-y-window10-con.html
De modo que no puedo aplicar la solución indicada en:
http://misnotaslinux.blogspot.com/2010/10/menulst-de-grub2.html
tampoco me permite cambiar el sistema operativo por edefecto usando BootReapair (???)
http://misnotaslinux.blogspot.com/2012/06/arreglar-el-mbr-con-boot-repair.html
-
Finalmente he podido cambiar el sistema operativo que arraca por defecto al iniciar el ordenador con grub2 del siguiente modo:
# grub-set-default 0
# update-grub
Siendo "0" el primer sistema operativo que aparece en el menu de arranque de grub2.
Ref.: https://askubuntu.com/questions/148662/how-to-get-grub2-to-remember-last-choice
Protocol:
1) Detect my RPi CPU:
$ cat /proc/cpuinfo
processor : 0
model name : ARMv6-compatible processor rev 7 (v6l)
BogoMIPS : 697.95 38.40
..
So my RPi B+ ARMv6 cpu.
2) Download Grafana for ARMv6
from https://grafana.com/grafana/download?platform=arm
Choose the version corresponding with the cpu, copy and execute commans in your RPi console.
Ubuntu and Debian(ARMv6)
$ sudo apt-get install -y adduser libfontconfig1
$ wget https://dl.grafana.com/oss/release/grafana_7.3.6_armhf.deb
$ sudo dpkg -i grafana_7.3.6_armhf.deb
...
### NOT starting on installation, please execute the following statements to configure grafana to start automatically using systemd
sudo /bin/systemctl daemon-reload
sudo /bin/systemctl enable grafana-server
### You can start grafana-server by executing
sudo /bin/systemctl start grafana-server
Execute the indicated command if you want start Grafana at boot.
3) Start Grafana server:
$ sudo service grafana-server start 4) Web Access to Grafana:
Using web browser in address [Grafana host IP]:3000
5) First login to Grafana:
Default user: admin
Default password: admin
Change your password and enter into Grafana:
7) Create new source of data from MariaDB
If you have your database in different host, allow remote access in database server: http://misnotaslinux.blogspot.com/2021/10/allow-access-to-mysqlmariadb-from.html
Add new data source:
Select MySQL:
Fulfill database access data:
... Save&Test
8) Make a Grafana panel
Start to design graph, tables, etc.
Links:
https://websiteforstudents.com/allow-remote-access-to-mariadb-database-server-on-ubuntu-18-04/
https://phoenixnap.com/kb/how-to-backup-restore-a-mysql-database
En resumen:
Backup:
sudo mysqldump -u [user] -p [database_name] > [filename].sql
Restore:
mysql -u root -e "CREATE DATABASE database_name"mysql -u [user] -p [database_name] < [filename].sql
Edit mariadb.conf:
# nano /etc/mysql/mariadb.conf.d/50-server.cnf
change: bind-address = 127.0.0.1
for: bind-address = 0.0.0.0
# service mariadb restart
This allow access from all universe IPs, it can dangerous, is better limit access to localnet.
For example:
bind-address = 192.168.1.0
Grant access from remote host:
with all privileges:
GRANT ALL ON database_name.* TO 'database_user@localhost' IDENTIFIED BY 'database_user_password';
Only read data (select): GRANT SELECT ON *.* TO 'user'@'localhost' IDENTIFIED BY 'password'; and FLUSH PRIVILEGES; Protocol:
Ok, now you can access by Remote Desktop Connection tool from windows computer over net.
Bibliography:
https://www.e2enetworks.com/help/knowledge-base/how-to-install-remote-desktop-xrdp-on-ubuntu-18-04
echo -e "\e[31mRed"
echo -e "\e[32mGreen"
echo -e "\e[33mYellow"
echo -e "\e[34mBlue"
echo -e "\e[35mMagenta"
echo -e "\e[36mCyan"
echo -e "\e[39mDefault"
exit 0
Una forma un poco mas humanizada de colorear el texto en bash:
#!/bin/bash
echo -e $R'Mis '$G'Notas '$B'L'$Y'i'$M'n'$C'u'$D'x'
exit 0
Probando la opcion gratuita de ProtonVPN.
1) Registrarse en ProtonVPN.
https://account.protonvpn.com/signup/account
2) Instalacion en linux mint
https://protonvpn.com/support/linux-vpn-setup/
# aptitude install openvpn
# aptitude install network-manager-openvpn-gnome
Option B: VPN setup for Linux using the Terminal (CLI)
# sudo wget "https://raw.githubusercontent.com/ProtonVPN/scripts/master/update-resolv-conf.sh" -O "/etc/openvpn/update-resolv-conf"
# chmod +x "/etc/openvpn/update-resolv-conf"
Download desde tu web de ProtonVPN el fichero de configuracion de un servidor vpn: por ejemplo este de Japón:
jp-free-01.protonvpn.com.tcp.ovpn
# openvpn jp-free-01.protonvpn.com.tcp.ovpn
Enter Auth Username:
Enter Auth Password:
Este usuario y passwor esta en tu cuenta ProtonVPN en
https://account.protonvpn.com/account
en Nombre de usuario de OpenVPN / IKEv2
...
...
Tue Apr 27 23:56:36 2021 Initialization Sequence Completed
Ok estas conectado a la vpn !!!
Verifica tu ip:en https://ipleak.net/
Ok, esta IP no parece que sea de movistar !!!
Para deconectarte control+c en la consola linux.
Links:
Not free but cheap: https://airvpn.org/
https://protonvpn.com/support/linux-vpn-setup/