====== Raspberry Pi ======

===== install raspbian =====
https://www.raspberrypi.org/documentation/installation/installing-images/linux.md
  df -h
  sudo umount /dev/sdb1
  sudo dd bs=4M if=2015-11-21-raspbian-jessie.img of=/dev/sdb
  sudo dd bs=4M if=/dev/sdb of=from-sd-card.img
  truncate --reference 2015-11-21-raspbian-jessie.img from-sd-card.img
  diff -s from-sd-card.img 2015-11-21-raspbian-jessie.img
  sync


===== initial setup =====
  sudo raspi-config

user: ''pi''\\
pass: ''raspberry''

===== static ip =====
''/etc/dhcpcd.conf'':
  interface eth0
  static ip_address=192.168.2.210/24
  static routers=192.168.2.1
  static domain_name_servers=192.168.2.1

[[https://pi-hole.net/faq/how-do-i-set-a-static-ip-address-in-raspbian-jessie-using-etcdhcpcd-conf/|src]]
  



===== xserver start/stop =====
  sudo startx
  sudo /etc/init.d/lightdm stop

 
===== keyboard =====
''/etc/default/keyboard'':
  XKBLAYOUT="us"
  

===== temperature =====
<code bash>
#!/bin/bash
cpuTemp0=$(cat /sys/class/thermal/thermal_zone0/temp)
cpuTemp1=$(($cpuTemp0/1000))
cpuTemp2=$(($cpuTemp0/100))
cpuTempM=$(($cpuTemp2 % $cpuTemp1))

echo CPU temp"="$cpuTemp1"."$cpuTempM"'C"
echo GPU $(/opt/vc/bin/vcgencmd measure_temp)
</code>

===== wifi =====
  sudo iwlist wlan0 scan|more
''sudo nano /etc/network/interfaces''
  allow-hotplug wlan0
  iface wlan0 inet dhcp
  wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
  iface default inet dhcp

''sudo nano /etc/wpa_supplicant/wpa_supplicant.conf''
  ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
  update_config=1
  network={
    ssid="YOURSSID"
    psk="YOURPASSWORD"
  }

  sudo ifdown wlan0
  sudo ifup wlan0

===== jdk =====
http://www.rpiblog.com/2014/03/installing-oracle-jdk-8-on-raspberry-pi.html

http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

download ''jdk-8-linux-arm-vfp-hflt.tar.gz for Linux ARM v6/v7 Hard Float ABI''

  sudo tar zxvf jdk-8-linux-arm-vfp-hflt.tar.gz -C /opt
  sudo update-alternatives --install /usr/bin/javac javac /opt/jdk1.8.0/bin/javac 1
  sudo update-alternatives --install /usr/bin/java java /opt/jdk1.8.0/bin/java 1
  sudo update-alternatives --config javac
  sudo update-alternatives --config java
  java -version
  javac -version


===== rtc ds3231 =====

1. Enable I2C:
  sudo raspi-config
  "Advanced Options" / "A6 I2C"
  
2. Sort out packages:
<code bash>
  sudo apt-get install python-smbus i2c-tools
  sudo apt-get purge fake-hwclock ntp
  sudo apt-get install ntpdate # TODO: not found

  sudo apt-get update
  sudo apt-get upgrade
  sudo apt-get dist-upgrade
</code>
  
3. Check Pi starts I2C automatically in ''/etc/modules'':
  i2c-dev
  
4. Check user has group (change ''pi'' to required):
<code bash>
  sudo adduser pi i2c
</code>

5. Add at the end of ''/boot/config.txt'': 
  dtoverlay=i2c-rtc,ds3231

6. Add the line in ''/etc/rc.local'' (above “exit 0”):
  /sbin/hwclock -s
  
7. Change in ''/etc/init.d/hwclock.sh'':
  HWCLOCKACCESS=no
  
8. reboot

9. Set date/time:
<code bash>
  sudo dpkg-reconfigure tzdata
  sudo date -s "2 SEPTEMBER 2016 10:00:00"
  sudo hwclock -w  
</code>
  


Done!

14. Other info commands:
<code bash>
  sudo i2cdetect -y 1
  sudo dmesg | grep rtc
  sudo cat /proc/driver/rtc
</code>
  
Compiled from: [[https://elementztechblog.wordpress.com/2015/08/08/real-time-clock-rtc-interfacing-with-raspberrypi/|src1]] [[https://trick77.com/adding-ds3231-real-time-clock-raspberry-pi-3/|src2]]



===== shutdown =====

{{:dev:pi:rpi_shutdown_scheme.png|}}

''/home/pi/softshut/softshut.py'':
<code python>
#!/usr/bin/python
import time
from subprocess import call
import RPi.GPIO as gpio

pinBt=19
pinAC=21
pinLed=23

dlyShutdownBt = 5
dlyShutdownAC = 10

dlyLedOk = 1
dlyLedFast = 0.1


def loop():
  hasBt = False
  hasAC = False
  timeBt = 0
  timeAC = 0
  dlyLed = dlyLedOk
  terminated = False

  while gpio.input(pinBt)>0 or gpio.input(pinAC)>0:
    for i in range(0,3):
      gpio.output(pinLed, True)
      time.sleep(dlyLedFast)
      gpio.output(pinLed, False)
      time.sleep(dlyLedFast)
    time.sleep(dlyLedOk)

  while not terminated:

    if gpio.input(pinBt)==0:
      if timeBt > 0:
        print "Bt OK"
        timeBt = 0
    else:
      if timeBt == 0:
        print "Bt failed"
        timeBt = time.time()
      else:
        if time.time() - timeBt > dlyShutdownBt:
          print "Bt shutdown"
          doShutdown()
          terminated = True


    if gpio.input(pinAC)==0:
      if timeAC > 0:
        print "AC OK"
        timeAC = 0
    else:
      if timeAC == 0:
        print "AC failed"
        timeAC = time.time()
      else:
        if time.time() - timeAC > dlyShutdownAC:
          print "AC shutdown"
          doShutdown()
          terminated = True



    if (timeAC > 0  or  timeBt > 0) and dlyLed == dlyLedOk:
      dlyLed = dlyLedFast
    elif timeAC == 0  and  timeBt == 0  and  dlyLed != dlyLedOk:
      dlyLed = dlyLedOk

    gpio.output(pinLed, True)
    time.sleep(dlyLed)
    gpio.output(pinLed, False)
    time.sleep(dlyLed)



def eventButton(pin):
  print "Button shutdown"
  doShutdown()

def doShutdown():
#  call('halt', shell=False)
  print "SHUTDOWN!!!"


gpio.setmode(gpio.BOARD)
gpio.setup(pinBt, gpio.IN)
gpio.setup(pinAC, gpio.IN)
gpio.setwarnings(False)
gpio.setup(pinLed, gpio.OUT)
loop()
gpio.cleanup()
</code>


''/etc/rc.local'':
<code bash>
# add this line before "exit 0"
python /home/pi/softshut/softshut.py &
</code>