RASPBERRY PI 外设学习资源

http://www.raspberrypi.org/

Status LED Indicator 
OK  (Green) - SDCard Access       (D5 via GPIO16)
PWR (Red)   - 3.3 V Power         (D6           )
FDX (Green) - Full Duplex   (LAN) (D7 Model B   )
LNK (Green) - Link/Activity (LAN) (D8 Model B   )
10M (Yellow)- 10/100Mbit    (LAN) (D9 Model B   )

Click here for Raspberry Pi Schematic

Download this quick start up guide to help you install your Linux OS on your Raspberry Pi.

Get yourself a 4GB SD card, which is enough for use in many application.

NOTE: Not all SD cards work with the Raspberry Pi. High speed cards can be too fast for the Raspberry Pi bus. Check out which SD card is suitable for your Raspberry Pi. It has a lists of cards that have and have not worked for Raspberry Pi users. http://elinux.org/RPi_SD_cardsYou may also like to check out the various peripherals that are compatiable to Raspberry Pi.
http://elinux.org/RPi_VerifiedPeripherals

Format your SD card with SD Formatter 4.0 for SD/SDHC/SDXC 
SDFormatter4exe.zip (5.99MB)

You can download the image version New Out Of Box Software (NOOBS), extract all the files and copy into your SD card.

Insert this SD card into your Raspberry Pi, and power on it. Follow the instruction on your screen display to complete the installation process.

You will be ask to select an Linux OS to install on your Raspberry Pi.

Choose the recommended "Raspian", which is also the Raspbian "wheezy".

The installation process will proceed.

Proceed to step 10.

As of 02 Nov 2013, Raspbian now supports and pre-installed with Java.

Note: For those who want to run Java SDK on Raspberry Pi.

Raspbian “wheezy” is the recommended Linux OS for Raspberry Pi. This version is optimized to be run by Raspberry Pi which is using RP‘s ARM processor supporting ‘hard-float‘. However Java SDK only support ‘soft-float‘ at this point in time (Jul 2013).

This call for another Debian Linux version which is known asSoft-float Debian “wheezy” (It is same as Raspbian "wheezy", except that it will be slower. Use this version if you need to run Java JDK Linux ARM)

Download and run the Win32DiskImager on your Windows Operating System.
 win32diskimager-v0.8-binary.zip (5.67MB)

You can download the latest version at this website,
http://sourceforge.net/projects/win32diskimager/

Unzip the Debian Linux version Soft-float Debian “wheezy”, which is a "2013-05-29-wheezy-armel.img" file.

Run the program Win32 Disk Imager.
a) Select the Image File "2013-05-29-wheezy-armel.img"
b) Select the Device, which is your storage drive for your SD card.
c) Click on the <Write> button to write the raw image onto your SD card.

Note: You can also use Win32 Disk Imager software to backup (clone)your existing SD card image, by click on the <Read> button, and choosing a *.img file name.

Insert the SD card into your Raspberry Pi and power it up.

On the first boot, the "raspi-config" menu will pop up.

Note: If you are at the command shell prompt. You can key in"sudo raspi-config" to access to this menu.

This is because the Raspberry Pi‘s default locale code is set as UK. You will need to set the locale code to US, for a US keyboard layout.

Key in the following command,
"sudo dpkg-reconfigure keyboard-configuration"

Alternative method to configure you keyboard layout.
a) key in "sudo nano /etc/default/keyboard"
b) look for the line containing "XKBLAYOUT="gb"".
c) change "gb" to "us" for US keyboard layout.
d) save and exit.
e) reboot or key in the following "invoke-rc.d keyboard-setup start", to reload the keymap.

Select <1> and press enter to Expand Filesystem.

If you are connected to the network, select <8 Advanced Options> and press enter.

<A2 Hostname> to change the hostname default "raspberrypi".

<A3 Memory Split> to configure the amount of ram allocation for GPU (graphic processing).

<A4 SSH> to enable or disable SSH (remote command access); it is enable by default.

<A5 Update> and then press enter to upgrade to the latest version of this tool. Try to perform this update.

"raspi-config" menu 8-A

<I1 Change Locale>, with the following options,
Default Locale : None

<I2 Time Zone >, with the following options,
Geographic area: Asia
Time Zone      : Singapore

<I3>, with the following options, 
Keyboard model : "Generic 105-key (Intl) PC"
Keyboard layout: "Others" -> "English (US)"
AltGr as       : "The default for the keyboard layout"
Compose Key    : "No compose key"
Ctrl+Alt+Backsp: "No", (don‘t use it to terminate Xserver)

You can also configure to allow the system to boot directly straight into the GUI desktop, using this raspi-config.

Select <Finish> then press enter to proceed to the system command shell.

You can always come back to this raspi-config menu again by executing the command "sudo raspi-config" from the shell command.

If you have encounter any error during the Linux operating system boot up, be sure to check the voltage level being supplied to your Raspberry Pi. It is a very common problem faced, if you have tried to power up your Raspberry Pi using any power adaptor that you have picked up.

Always check if your power adaptor is suitable by measuring the voltage supplied to your Raspberry Pi. If you deploy your Raspberry Pi for yoru project without ensuring that your power adaptor is ok, you may face random system error freeze/hang/halt. Problem can occur out of the norm. Be sure to check. Click here to find out how you can ensure that you are using the correct power adaptor and cable for your Raspberry Pi.

My LED indicator wiring is as follows,
LED0 - GPIO_17 (Pin11)
LED1 - GPIO_18 (Pin12)
LED2 - GPIO_27 (Pin13)
LED3 - GPIO_22 (Pin15)
LED4 - GPIO_23 (Pin16)
LED5 - GPIO_24 (Pin18)
LED6 - GPIO_29 (Pin22)

UART (serial communication) wiring,
Gnd -         (Pin06) 
TXD - GPIO_14 (Pin08)
RXD - GPIO_15 (Pin10)

SPI (serial communication) wiring,
MOSI - GPIO_10 (Pin19)
MISO - GPIO_09 (Pin21)
SCLK - GPIO_11 (Pin23)
CE0  - GPIO_08 (Pin24)
CE1  - GPIO_07 (Pin26)

I2C (serial communication) wiring,
SDA0 - GPIO_02 (Pin03)
SCL0 - GPIO_03 (Pin05)

Information taken from
http://www.mosaic-industries.com/embedded-systems/

[email protected] ~ $

A directory folder will be created. "/sys/class/gpio/gpio17/"

More things to learn...

Notes regarding digital I/O pins,https://www.kernel.org/doc/Documentation/gpio.txt

The UART port is actually pin8 (TxD) and pin10 (RxD) on the Raspberry Pi connectors. The UART signal is 3.3V.You can use RS232/RS422/RS485 communication to talk to the UART, but a level shifter (for example MAX3232) required. RS232 uses about +/- 7 to 13V, while UART uses digital voltage (1.8V, 3.3V or 5V). For our Raspberry Pi UART, it is 3.3V. More information about making your own level shifter, you can visit this page. There are also standard USB to UART products for interfacing to your Raspberry Pi.The Raspberry Pi default operating system uses this UART port as its diagnostic port. This port has the following default UART settings,
- Baudrate   : 115200bps
- Data       : 8 bits
- Parity     : None
- Handshaking: NoneThis default port act as another Linux shell terminal screen, as you would have seen on the screen through the Raspberry Pi‘s HDMI or video output.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
[email protected]:~$

In order to use this UART, I need to disable the diagnostic features from the operating system‘s boot up. This means that I do not want the system to setup the UART pins as diagnotic port, when the system boots up.

A summary of the vi editor‘s command is summeries as follows,http://osr600doc.sco.com/en/FD_create/vi_summary.html

Press ‘:q‘ to exit the vi program.

Enter the command "sudo apt-get install minicom"

There are also alternative GUI based serial communication program, cutecom.

Reading package lists... Done
Building dependency tree
Reading state information... Done
...
Need to get 420 kB of archives.
After this operation, 1,189 kB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://mirrordirector.raspbian.org/raspbian/ wheezy/main lrzsz armhf 0.12.21-5 [106 kB]
Get:2 http://mirrordirector.raspbian.org/raspbian/ wheezy/main minicom armhf 2.6.1-1 [314 kB]
Fetched 420 kB in 13s (30.2 kB/s)
...
Unpacking minicom (from .../minicom_2.6.1-1_armhf.deb) ...
Processing triggers for man-db ...
Processing triggers for menu ...
Setting up lrzsz (0.12.21-5) ...
Setting up minicom (2.6.1-1) ...
Processing triggers for menu ...

To run the minicom terminal program. Key in the following command "sudo minicom -b 9600 -o -D /dev/ttyAMA0".

-o              (skip initialisation)
-D /dev/ttyAMA0 (specify the serial port)

Key in command "man minicom" to find out the other options that you can set with the minicom program.

Configuration Settings: 
Baudrate : 9600bps 
Data bit : 8    (default)
Stop bits: 1    (default)
Parity   : None (default)

Apply the configuration settings to serial port "ttyAMA0". The label tty (known as teletype) denotes all serial communication that the linux operating system is handling. In Raspberry Pi, ttyAMA0 refers to the pin8 (TxD) and pin10 (RxD).

When you type a char on your keyboard, an ascii char code is actually sent out of the Raspberry Pi ‘s pin8 (TxD). You will not be able to see it on the screen. What you will see on your screen will be those serial data that the Raspberry Pi received through pin10, which is the RxD.

In order to see what we have transmitted out from TxD, we can short the pin8 (TxD) and pin10 (RxD) together. This means that what you send will be receive and display on the display. The serial port configuration for the TxD and RxD is the same, so the serial data that is received will be exactly what you have transmitted.

The following text "Hello World!!! " were typed on the keyboard after shorting the RxD and Txd pin. The text will be displayed, indicating that the UART is working properly.

Now that you know that the UART on your Raspberry Pi is ready for use, you can use it to communicate with many other peripheral.

Press <Ctrl + ‘A‘>, followed by <‘X‘>, then key in enter for "Yes" to quit the minicom program.

-------------------------------------------
Welcome to minicom 2.6.1OPTIONS: I18n
Compiled on Apr 28 2012, 19:24:31.
Port /dev/ttyAMA0Press CTRL-A Z for help on special keysHello World!!!

CTRL-A Z for help | 9600 8N1 | NOR | Minicom 2.6.1 | VT102 | Offline
-------------------------------------------

- "dmesg | grep tty" checking up the UART available on the system.

SPI

The SPI port onboard the Raspberry is disable by default. The first thing to do is to enable the SPI port.

Edit the file "/etc/modprobe.d/raspi-blacklist.conf"

Comment off the line "blacklist spi-bcm2708" with a # in front.

Key in Ctrl+‘X‘ to exit, then ‘Y‘ yes to save the change to the file, and finally ‘Enter‘. This will brings you back to the command prompt.

GNU nano 2.2.6 File: /etc/modprobe.d/raspi-blacklist.conf Modified

# blacklist spi and i2c by default (many users don‘t need them)

#blacklist spi-bcm2708
blacklist i2c-bcm27088

You should see "/dev/spidev0.0 /dev/spidev0.1" created.

0.0 means SPI0 CS0 (CS is the chip select)
0.1 means SPI0 CS1

download this SPI loopback test code written in ‘C‘ programming language.

spidev_test.c

Compile the *.c file using gcc command,then run the compiled program.

You should see the following hex dump data, indicating all 0x00.

This means that the SPI is receiving nothing, no data.

00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
00 00
[email protected] ~ $

From this test, we will be able to know if SPI hardware for sending and receving is working ok. Whatever that is sent out, the data should be properly received.

Run the compiled program again.

You should see the following hex dump data. This means that your SPI peripheral is working fine.

spi mode: 0
bits per word: 8
max speed: 500000 Hz (500 KHz)

FF FF FF FF FF FF
40 00 00 00 00 95
FF FF FF FF FF FF
FF FF FF FF FF FF
FF FF FF FF FF FF
DE AD BE EF BA AD
F0 0D
[email protected] ~ $

The SPI port onboard the Raspberry is disable by default. The first thing to do is to enable the SPI port.

Edit the file "/etc/modprobe.d/raspi-blacklist.conf"

Comment off the line "blacklist i2c-bcm2708" with a # in front.

Key in Ctrl+‘X‘ to exit, then ‘Y‘ yes to save the change to the file, and finally ‘Enter‘. This will brings you back to the command prompt.

GNU nano 2.2.6 File: /etc/modprobe.d/raspi-blacklist.conf Modified

# blacklist spi and i2c by default (many users don‘t need them)

blacklist spi-bcm2708
#blacklist i2c-bcm27088

Add in "i2c-dev" to the end of the file.

Key in Ctrl+‘X‘ to exit, then ‘Y‘ yes to save the change to the file, and finally ‘Enter‘. This will brings you back to the command prompt.

# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.
# Parameters can be specified after the module name.

snd-bcm2835
i2c-dev

This allow configuration of the software.

You should see "/dev/i2c-0 /dev/i2c-1" created.

You will see that there is a total of 0x77 or 119 blanks "--". This indicates that no I2C devices is detected on the bus.

--- 192.168.1.1 ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 1.171/1.399/1.988/0.340 ms

--- yahoo.com.sg ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 16.996/20.762/28.140/4.441 ms

Other command:
- ifconfig eth0 (display the first ethernet adaptor) 
- ifconfig -a (show all network interface, active or inactive) 
- traceroute

Ensure that the network cable (internet enabled) is plugged onto the Raspberry Pi before powering on the board. Enter the following command to install samba software. The process will fetch the installation from the internet.

Alternate command "ifconfig" to check the IP address of my Raspberry Pi, which IP address is "192.168.1.99"

[email protected] ~ $  ifconfig
eth0  Link encap:Ethernet  HWaddr b8:27:eb:dc:ee:af
      inet addr:192.168.1.99  Bcast:192.168.1.255  Mask:255.255.255.0
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:337 errors:0 dropped:0 overruns:0 frame:0
      TX packets:198 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000
      RX bytes:30734 (30.0 Kib)  TX bytes:20136 (19.6 Kib)

auto lo

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

iface lo inet loopback

#wired connection (using static IP address, instead of DHCP to auto allocate IP) 
#iface eth0 inet dhcp
iface eth0 inet static
address 192.168.1.201
netmask 255.255.255.0
gateway 192.168.1.1

#wireless connection (using static IP address, instead of DHCP to auto allocate IP) 
allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
#iface wlan0 inet dhcp
iface wlan0 inet static
address 192.168.1.202
netmask 255.255.255.0
gateway 192.168.1.1
#iface default inet dhcp

Go to window‘s to map a network drive. The network folder path is "//192.168.1.99". Check box for "Reconnect at logon" & "Connect using different credentials"

From the list, it can be seen that UDP port 6324 is currently being used by process ID PID 2361/java program.

The method above requires you to plugged a monitor display to your Raspberry Pi in order to obtain its IP address. The following method allows you to obtain raspberry pi address through thr

You can also check the IP address of your Raspberry Pi that is plugged into a dynamic network through the router webserver. Typical router‘s IP address for a local network is 192.168.1.1. You will need your user name and password to log into the router‘s webserver. From the webserver, you should be able to locate the device name "raspberrypi" (or known as hostname) and its allocated dynamic IP address and its MAC address.

Alternative, you can use this software "Advance Port Scanner" to scan for your Raspberry Device on the network.

Your new hostname will appear on the raspberry prompt, after the device reboot.

[email protected] ~ $ sudo nano /etc/hosts

[email protected] ~ $ sudo reboot

[email protected] ~ $

Alternative, you can also use this program call Putty.
http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

Alternative, you can also use this program call Filezilla
https://filezilla-project.org/ (for Microsoft Windows OS).
or (for Linux OS) "sudo apt-get install filezilla"

These program allow SSH connection logging in to your Raspberry Pi. You will be able to see what you would see with the display monitor and keyboard connected to your Raspberry Pi

Key in the Login user name "pi", then press enter, and 
standard password "raspberry" then press enter key.

You will see the following display as on the right.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Mon Jul 22 13:47:57 2013
[email protected] ~ $

You may need to reboot the Linux in order for the change to take effect "sudo reboot".

It should solve the problem. For more information regarding this issue, you can visit the following website,
http://www.geekride.com/ssh-warning-remote-host-identification-has-changed/

When finish typing in the source code text, press CTRL+X to save this file "main.c", press ‘Y‘ to confirm. Press enter key to finish the process.

int main()
{
   printf("Hello World!!!");
   return(0);
}

Type the script >>> print "Hello World!!!"

You will see the "Hellow World!!!" text echo back.

Press <Ctrl+‘z‘> to terminate the Python program.

Create a folder "python_tutorial" to hold the files for this tutorial

Key in the following hello world source code into the nano editor.

When finish typing in the source code text, press CTRL+X to save this file "hello.py", press ‘Y‘ to confirm. Press enter key to finish the process.

print "Hello World!!!"nt "Boon, you‘re awesome"
else : 
print "Hello", name

1) import RPi.GPIO
2) setup I/O direction, as output port. 
3) set digital I/O port to logic ‘1‘, high
4) set digital I/O port to logic ‘0‘, low

You should see the LED lights up and switched off, if wired an indicator to pin 12.

import sys
import time
import serial

#print title 
print("start python program.")#print out the arg passed from command line 
for arg in sys.argv:
  print arg#delay 0.1sec 
time.sleep(0.1)
#delay 1.0sec 
time.sleep(1) #setup serial port 
port = serial.Serial("/dev/ttyAMA0", baudrate=115200, timeout=3.0)#get user input
name = raw_input(‘what is your name? ‘)#conditional statement
if name == ‘Boon‘ :
  print "Boon, you‘re awesome"
else : 
  print "Hello", name

#while loop
while True: 
  port.write("\r\nSay something:")
  rcv = port.read(10)
  port.write("\r\nYou sent:" + repr(rcv))

import time
import RPi.GPIO as GPIO

GPIO.setup(11, GPIO.IN)
while True:
  mybutton = GPIO.input(11)
  if mybutton == False:
    print "giggle"
  time.sleep(.2)

Installing Java to your Raspberry Pi

First, we will need to download and instal the Java JDK onto the Raspberry Pi.Do take note that the JDK version that we will be downloading is meant for Linux ARM processor "Linux ARM v6/v7 Soft Float ABI".
(28 July 2013)
JDK for Linux ARM, "jdk-21-linux-arm-sfp.tar.gz (65.12MB)"

You can download the lastest version of this file from thisJava website,
http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html

Remember to accept the Oracle Binary Code License Agreement for Java SE.

Note: If the following error is encountered when the command "java -version" is executed. 
java: error while load­ing shared libraries: libjli.so: can­not open shared object file: No such file or directory

It is propably that you have installed the incorrect version of Debian Linux. At this point in time, Java SDK for Linux ARM has yet to support.

Please refer to the previous section, for the installtion of the correct Debian Linux version for use with Java SDK Linux ARM.

Check out PI4J website for more information.

Check if PI4J is installed correctly.
Go to PI4J directory.
Compile the example "WiringPiGpioExample.java".
Run the compile java program "WiringPiGpioExample".

I am able to see my rows of LED lighting up in a wave sequence, up and down non-stop.

Key in "nano hello.java".
This will open a text editor for us to key in the java source code for our hello world example.

Key in the following java source code.

Press ‘Ctrl+X‘ to exit, then ‘Y‘ to save, then press ‘Enter‘.

class hello
{
   public static void main(String args[])
   {
      System.out.println("Hello World!");
   }
}

You should be able to see the printed text "Hello World!" after execution.

Taking a look at the java code using pi4j wiringPi.

- WiringPiGpioExample.java

Gpio.digitalWrite(l, s);
            
            if (Gpio.digitalRead(7) == 1) // Pressed as our switch shorts to ground
                Gpio.delay(d * 10); // Faster!
            else
                Gpio.delay(d * 100);
        }
    }
}

Run the java program.

You may notice "wiringPiSetup: Unable to open /dev/mem". This means that you do not have access to the hardware.

Run the java program with the "sudo" in front as follows.

You should see the LED light running from left to right.

<--Pi4J--> GPIO test program
wiringPiSetup: Unable to open /dev/mem: Permission denied
==>> GPIO SETUP FAILED

[email protected] ~ $ sudo java -classpath .:classes:/opt/pi4j/lib/‘*‘ WiringPiGpioExample

<--Pi4J--> GPIO test program

- SerialExample.java

// create and register the serial data listener
        serial.addListener(new SerialDataListener() {
            @Override
            public void dataReceived(SerialDataEvent event) {
                // print out the data received to the console
                System.out.print(event.getData());
            }
        });
                
        try {
            // open the default serial port provided on the GPIO header
            serial.open(Serial.DEFAULT_COM_PORT, 38400);
            
            // continuous loop to keep the program running until the user terminates the program
            for (;;) {
                try {
                    // write a formatted string to the serial transmit buffer
                    serial.write("CURRENT TIME: %s", new Date().toString());
    
                    // write a individual bytes to the serial transmit buffer
                    serial.write((byte) 13);
                    serial.write((byte) 10);
    
                    // write a simple string to the serial transmit buffer
                    serial.write("Second Line");
    
                    // write a individual characters to the serial transmit buffer
                    serial.write(‘\r‘);
                    serial.write(‘\n‘);
    
                    // write a string terminating with CR+LF to the serial transmit buffer
                    serial.writeln("Third Line");
                }
                catch(IllegalStateException ex){
                    ex.printStackTrace();
                }
                
                // wait 1 second before continuing
                Thread.sleep(1000);
            }
            
        }
        catch(SerialPortException ex) {
            System.out.println(" ==>> SERIAL SETUP FAILED : " + ex.getMessage());
            return;
        }
    }
}

Run the "SerialExample.java"

If you encounter error when opening the serial port, do check out the eariler posting to ensure that the serial port is properly configured.

If the RX pin received data from other serial devices, the data can be seen on the console as well.

CURRENT TIME: Mon Nov 04 12:23:23 SGT 2013
Second Line
Third Line
CURRENT TIME: Mon Nov 04 12:23:24 SGT 2013
Second Line
Third Line
CURRENT TIME: Mon Nov 04 12:23:25 SGT 2013
Second Line
Third Line

- WiringPiGpioExample.java
- ControlGpioExample.java
- ListenGpioExample.java
- ShutdownGpioExample.java
- TriggerGpioExample.java
- SerialExample.java
- SystemInfoExample.java

The following is an example of the script,
"run.sh"

Key in ". run.sh" to run the script in Linux command prompt.
Note: remember to make this file "run.sh" executable. (see examples in this website.)

[email protected] ~ $ . run.sh

Add in the following to the file,

cd /home/pi/smartHomeSensor
echo "Run script for SmartHomeSensor Java program"
SCRIPT="/home/pi/smartHomeSensor/run.sh"
echo "run script \"-> $SCRIPT\""
sudo $SCRIPT &

The add command set the current directory to the project folder. During the boot process, it cannot be assume that you are in the user directory. Reference to the root directory to be safe.

Use sudo to run the script, and make the script run in the background.

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
   printf "My IP address is %s\n" "$_IP"
fi

cd /home/pi/smartHomeSensor
echo "Run script for SmartHomeSensor Java program"ensor Java program"
SCRIPT="/home/pi/smartHomeSensor/run.sh"
echo "run script \"-> $SCRIPT\""
sudo $SCRIPT &

exit 0

The result shows that the java program is running with PID 2242 (process ID). Remember this number, for you may need to use it to kill the process.

This is generated before the Java program is launch. Remember this PID no. You may need this number to kill the same java program.

2233 ? S 0:00 sudo /home/pi/smartHomeSensor/run.sh
2241 ? S 0:00 /bin/bash /home/pi/smartHomeSensor/run.sh
2481 pts/0 S+ 0:00 grep --color=auto run.sh

Example to display Linux OS information, key in "cat /etc/lsb-release"

Hardware : BCM2708
Revision : 000e
Serial : 000000005fdceeaf

Command "ps" is a useful troubleshooting tools. Other related command is "top".

Other useful troubleshooting commands are,
- "strace", "ltrace"
- "mtrace"

These are the bash session started by various user session 0, 1, 2, etc... ,

3477 pts/0 T 0:00 -bash
347? pts/1 T 0:00 -bash
347? pts/2 T 0:00 -bash

This is a bash session started for the main hardware,

2121 tty1 S+ 0:01 -bash

To list only the PID for a particular program, you can use with grep.

[email protected] ~ $ ps ax | grep java
3478 pts/0 Tl 0:03 java -classpath .:bin:lib/log4j-1.2.14.jar:lib/commons-logging

Putting an option -9 will force the process to be killed.

The process PID can be kill from another user session, even if the PID is not listed in its session.

or

[email protected] ~ $ kill -9 ####

You can actually name the file whatever you like, but it is good to keep the *.sh file extension as under some GUI Linux OS, double clicking the file will automatic launch the correct application which runs the file.

To run the "bash_script.sh" without the command bash, set the file as executable and run the file.

Note: You may encounter with the following 
./test.sh: /bin/bash^M: bad interpreter: No such file or directory.

There is a ‘^M‘ char detected at the end of the first line. Ensure that the script is not written on a Microsoft Window OS. Window‘s environment will append ‘^M‘ for enter key.

Use vi editor to view the file.
Type in command "vi bash_script.sh".
You will see the ‘^M‘ char in blue.
Delete those char.

Press ‘:w‘ save the text file.
Press ‘:q‘ to exit the vi program.

Try again, it should work fine now.

or
[email protected] ~ $ sudo chmod u+x bash_script.sh
[email protected] ~ $ ./bash_script.sh
Hello World!!!

To check the permission for the files in the current directory use "ls -l".

To check permission for a particular file, type out the file name behind "ls -l filname"

File permissiondrwxrwxrwx 2 pi pi

d - represent the name as a directory.
    - - Regular file or program.
    l - file/dir is a symbolic link.
    s - setuid/setgid permissions. 
    t - sticky bit permissions.
    b - driver for storage medium.
    c - driver for communication hardware.

rwx - ‘r‘ refers to the read permission
      ‘w‘ refers to the write permission
      ‘x‘ refers to the permission to execute

1st "rwx" -> owner (‘u‘) 
2nd "rwx" -> group (‘g‘) 
3rd "rwx" -> all users (‘o‘ or ‘a‘) 
2 - referes to the number of hardlinks to the file.
pi pi -> Owner:Group

To change the file permission, use the following command,

"chmod a+x filename"
This will add all (‘a‘) with executable (‘x‘) permission.

"chmod a-x filename"
This will remove all (‘a‘) with executable (‘x‘) permission.You can also set file permission using binary references (set to _rwxr-----),
command "chmod 740 filename"To change file‘s owner and group,
command "chown newuser:newgroup filename"

[email protected] ~ $ ls -l Desktop 
drwxr-xr-x 2 pi pi 4096 May 30 04:07 Desktop

[email protected] ~ $ chmod a+x ocr_pi.png
[email protected] ~ $ ls -l
drwxr-xr-x 2 pi pi 4096 May 30 04:07 Desktop
-rwxr-xr-x 1 pi pi 5781 Feb  3  2013 ocr_pi.png
drwxrwxr-x 2 pi pi 4096 Mar 10 18:20 python_games

[email protected] ~ $ chmod a-x ocr_pi.png
[email protected] ~ $ ls -l
drwxr-xr-x 2 pi pi 4096 May 30 04:07 Desktop
-rw-r--r-- 1 pi pi 5781 Feb  3  2013 ocr_pi.png
drwxrwxr-x 2 pi pi 4096 Mar 10 18:20 python_games

Comment away the following line by inserting a ‘#‘ in front of the statement.
"#1:2345:respawn:/sbin/getty 115200 tty1"
and insert the following line below it.
"1:2345:respawn:/bin/login -f pi tty1 </dev/tty1 >/dev/tty1 2>&1"

Reboot the system and you should be able to power up and go striaght into the command prompt without being prompt for user ID and password.

#1:2345:respawn:/sbin/getty 38400 tty1
1:2345:respawn:/bin/login -f pi tty1 </dev/tty1 >/dev/tty1 2>&1

"script1.sh" will run after the user has been sucessfully login. Local or remote user will get to auto execute "script1.sh" after login.

NOTE!!!
Please ensure to set the file as executable and run the file.

1) Create a script "script2.sh" in the folder /etc/init.d/script2.sh.
"sudo nano /etc/init.d/script2.sh"

2) Make the script executable.
"sudo chmod 755 /etc/init.d/script2.sh"

3) Test the script (service start).
"sudo /etc/init.d/script2.sh start"

4) Test the script (service stop).
"sudo /etc/init.d/script2.sh stop"

5) Register the script to be run at start-up (with default priorities).
"sudo update-rc.d script2.sh defaults"

update-rc.d is a program which mananged the start-up and shutdown using the file /etc/rcX.d (where rcX.d means rc0.d to rc6.d, rcS.d)
You can key in the following command to view the link to your script. 
"ls -l /etc/rc?.d/"

6) To remove the script from start-up,
"sudo update-rc.d -f script2.sh remove"
‘-f‘ is to force the removal of the symlinks even if the script is still under the /etc/init.d folder. Remember to delete away your script away from the folder /etc/init.d 
Note: The command above will only disable the service until the next time the service is upgraded. To enable the service will not be re-enabled upon upgrade, type the following command, "update-rc.d script2.sh stop 80 0 1 2 3 4 5 6"

7) You can also register the services with custom priorities. (you can visit this website)

exit 0

--- Booting process --------
    before user login

- Script registered with update-rc.d
- /etc/rc.local

--- User login prompt-------
    after user login

- /etc/profile
- /home/pi/.bashrc

--- End of start-up process -----
    command prompt

Name your image file to "splash.png" and copy to the directory /etc

****encounter problem copying file to /etc directory.***
If the error above is encountered, copy the image file to the user directory instead. Then use "sudo mv" (move file command) to move it to the etc directory.

Edit a new text file "sudo nano".
Cut and paste the followings,

#! /bin/sh### BEGIN INIT INFO# Provides:          asplashscreen# Required-Start:# Required-Stop:# Should-Start:# Default-Start:     S# Default-Stop:# Short-Description: Show custom splashscreen# Description:       Show custom splashscreen### END INIT INFO      do_start () {        /usr/bin/fbi -T 1 -noverbose -a /etc/splash.png          exit 0  }    case "$1" in    start|"")      do_start      ;;    restart|reload|force-reload)      echo "Error: argument ‘$1‘ not supported" >&2      exit 3      ;;    stop)      # No-op      ;;    status)      exit 0      ;;    *)      echo "Usage: asplashscreen [start|stop]" >&2      exit 3      ;;  esac   

:

save the file as /etc/init.d/asplashscreen

make the script executable and install it for init mode:

"sudo chmod a+x /etc/init.d/asplashscreen"

"sudo insserv /etc/init.d/asplashscreen"

Reboot

"sudo reboot "

The custom logo is displayed near the end of the booting process, not at the beginning.

This is followed by a blank screen.
Press <Ctrl + Alt + F2> to return to the command prompt.

[email protected] ~ $ sudo mv splash.png /etc

[email protected] ~ $ sudo nano

cut and paste, save file as

/etc/init.d/asplashscreen

[email protected] ~ $ sudo chmod a+x /etc/init.d/asplashscreen

[email protected] ~ $ sudo insserv /etc/init.d/asplashscreen

[email protected] ~ $ sudo reboot

Root access

Some users believe that the root account has a password that they are not aware of. This is not the case. For security reasons, Raspbmc has been hardened by disabling the root account. There is no need to enable the root account in Raspbmc, and doing so increases the likelihood of you causing damage to the system. Instead, the following options are recommended:

• Prefixing the command requiring root privileges with sudowill allow you to run the command as root.
• Alternatively, you can temporarily have root privileges with the command sudo -s

If you truly wish to enable root access so that you can login as root. You can do so as follows:sudo passwd rootYou have now set a root password you can login with.To disable the root account again:

sudo passwd -l root

Follow the following procedure,

Adding user `newUserName‘ ...
Adding new group `newUserName‘ (1004) ...
Adding new user `newUserName‘ (1001) with group `newUserName‘ ...
Creating home directory `/home/newUserName‘ ...
Copying files from `/etc/skel‘ ...
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
Changing the user information for newUserName
Enter the new value, or press ENTER for the default
     Full Name []:
     Room Number []:
     Work Phone []:
     Home Phone []:
     Other []:
Is the information correct? [Y/n] y

After you have finished, key in Ctrl+‘x‘ then ‘Y‘, followed by enter key.

pi ALL=(ALL) NOPASSWD: ALL
newUserName ALL=(ALL) NOPASSWD: ALL

[email protected] ~ $ login

Enter your newUserName and passsword.

Delete the line containing the "pi" user, if it is no longer required.
After you have finished, key in Ctrl+‘x‘ then ‘Y‘, followed by enter key.

The process of changing the Raspberry Pi user name and password is completed.
Reboot the Raspberry Pi for the new user name to take effect. Old user name can no longer be in use.

(method do not work so well. still able login using pi as the user name.)

BLANK_TIME=0
BLANK_DPMS=off
POWERDOWN_TIME=0

I have created an overview directory maps of my Raspberry Pi directory map to assist me in understanding the files modification that I will be dealing with.

Learning how things are being organised in a Linux platform.

Linux Files and Directory Structure Reference

-/??? -> Directory related to the Linux operating system that needs careful attention in handling.

Linux Command Reference
- linux_quickref.pdf
- linuxcard.pdf

WiFi dongle keyword
- Edimax EW-7811Un 
- Dynamode WL-700N-RXS

http://elinux.org/RPi_USB_Wi-Fi_Adapters

In this example, D-Link DWA-123, H/W Ver.: B1, P/N IWA123EU.....B1G

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
auto wlan0
iface wlan0 inet manualdhcp
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
iface wlan0 inet manual
address 192.168.0.100
netmask 255.255.255.0
gateway 192.168.0.1
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp