• RaspberryPi

RaspberryPi

• https://www.raspberrypi.org/

• https://en.wikipedia.org/wiki/Raspberry_Pi

• Kit in https://www.chiptec.net/pcs-e-mobilidade/computadores/raspberrypi/kit-raspberry-pi-3-modelo-b-noobs-caixa-carregador-preto.html (Kit Raspberry Pi 3 Modelo B+(NOOBS+Caixa+Carregador) Preto)

Processador     
  Broadcom BCM2837B0, Cortex-A53 (ARMv8) 64-bit SoC @ 1.4GHz
Memória RAM     
  1GB LPDDR2 SDRAM
Armazenamento   
  Cartão MicroSD 32GB com NOOBS
Wi-Fi e Bluetooth       
  2.4GHz e 5GHz IEEE 802.11.b/g/n/ac wireless LAN, Bluetooth 4.2, BLE
LAN     
  Gigabit Ethernet em USB 2.0 (saída máxima 300 Mbps)
Expansão        
  Extended 40-pin GPIO header
  CSI camera port
  DSI display port
  4-pole stereo output e composite video port
Portas  
  HDMI 
  USB 2.0 (4) 
  Micro-SD
Alimentação     
  Entrada 5V/2.5A DC
Prazo de Garantia       
  2 Anos

• Access GPIO https://elinux.org/RPi_GPIO_Code_Samples#C

• https://elinux.org/RPi_GPIO_Code_Samples#sysfs

• https://projects.raspberrypi.org/en/projects/raspberry-pi-setting-up

• https://projects.raspberrypi.org/en/projects/raspberry-pi-setting-up/print

BCM2835

• Timers
• Interrupt controller
• GPIO
• USB
• PCM / I2S
• DMA controller
• I2C master
• I2C / SPI slave
• SPI0, SPI1, SPI2
• PWM
• UART0, UART1

Install and configure screensaver and lock screen

• sudo apt-get install xscreensaver
• Preferences, Screen saver
• Auto lock after 2 minutes
• Create new menu item (Preferences, Main menu editor)
  • Menu item name Lock
  • Command: xscreensaver-comand -lock
  • Icon: /usr/share/lxpanel/images/ns-lock.png

Info

$ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 9.4 (stretch)
Release:        9.4
Codename:       stretch

$ uname -a
Linux raspberrypi 4.14.71-v7+ #1145 SMP Fri Sep 21 15:38:35 BST 2018 armv7l GNU/Linux

Install eclipse

• apt-get install eclipse-platform

Blink led port 26

• https://www.raspberrypi.org/documentation/usage/gpio/python/README.md

• https://gpiozero.readthedocs.io/en/stable/

• python drive_gpio26.py

   1 # drive_gpio26.py
   2 from gpiozero import LED
   3 from time import sleep
   4 
   5 led = LED(26)
   6 
   7 while True:
   8     led.on()
   9     sleep(1)
  10     led.off()
  11     sleep(1)

Install python 3.8.5 in raspberry py

• tar xvzf Python-3.8.5.tgz
• cd Python-3.8.5/
• ./configure
• make clean
• make
• make install
• sudo make install
• /usr/local/bin/python3.8 -v
• /usr/local/bin/pip3.8 install cherrypy
• pip3.8 install jinja2

Enable X11 forwarding

   1 # Raspberry pi side
   2 sudo nano /etc/ssh/sshd_config
   3 # add line X11Forwarding yes
   4 service ssh restart
   5 # client side
   6 ssh -X -Y userx@192.168.2.3
   7 echo $DISPLAY
   8 leafpad & # text editor
   9 pcmanfm & # file explorer
  10 

Blink led service

Starts automatically after boot.

/home/pi/Documents/drive_gpio26.py

   1 from gpiozero import LED
   2 from time import sleep
   3 import os
   4 
   5 f = open('/tmp/drive_gpio26.pid','wb')
   6 f.write(str(os.getpid()))
   7 f.close()
   8 
   9 led = LED(26)
  10 
  11 while True:
  12     led.on()
  13     sleep(1)
  14     led.off()
  15     sleep(1)

/etc/init.d/drive_gpio26

   1 #! /bin/sh
   2 ### BEGIN INIT INFO
   3 # Provides:          drive_gpio26
   4 # Default-Start:     2 3 4 5
   5 # Default-Stop:
   6 # Short-Description: Blinks a led
   7 # Description:       Blinks a led
   8 ### END INIT INFO
   9 touch /var/lock/drive_gpio26
  10 # Carry out specific functions when asked to by the system
  11 case "$1" in
  12   start)
  13     echo "Starting script drive_gpio26 "
  14     su pi -c "nohup /usr/bin/python /home/pi/Documents/drive_gpio26.py >> /tmp/drive_gpio26.log 2>&1  &"
  15     ;;
  16   stop)
  17     echo "Stopping script drive_gpio26"
  18     kill $(cat  /tmp/drive_gpio26.pid)
  19     ;;
  20   *)
  21     echo "Usage: /etc/init.d/drive_gpio26 {start|stop}"
  22     exit 1
  23     ;;
  24 esac
  25 
  26 exit 0

• update-rc.d drive_gpio26 defaults # insert links in /etc/rc*d
• update-rc.d drive_gpio26 defaults 20 80
• update-rc.d drive_gpio26 enable
• service drive_gpio26 status
• reboot

Install MariaDB raspbian

   1 sudo bash
   2 apt install mariadb-server
   3 mysql_secure_installation
   4 # define root pass
   5 mysql
   6 GRANT ALL ON *.* TO 'admin'@'localhost' IDENTIFIED BY '????????' WITH GRANT OPTION;
   7 FLUSH PRIVILEGES;
   8 create database testdb;
   9 show databases;
  10 use testdb
  11 CREATE TABLE locations ( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, lat VARCHAR(30) NOT NULL, lon VARCHAR(30) NOT NULL);
  12 exit
  13 mysql -u admin -p
  14 sudo pip3.8 install mysql-connector-python
  15 #
  16 python 3.8
  17 import mysql.connector
  18 mysql.connector.connect(host='localhost',database='testdb',user='admin',password='xxxxxxxx')

test_mariadb.py

   1 import mysql.connector
   2 conn = mysql.connector.connect(
   3   host='localhost',
   4   database='testdb',
   5   user='admin',
   6   password='xxxxxxxx'
   7 )
   8 cursor=conn.cursor()
   9 cursor.execute("Insert into locations (lat,lon) values(%s,%s)" , ("aaa","bbb") )
  10 conn.commit()
  11 print(cursor.rowcount, "record inserted.")