Linux and Microcontroller Tips

Electronics and Robotics Developers Choice: Beaglebone Black

2013-05-12T22:07:00.000+05:30

Developers, makers, and hobbyists looking for a better alternative to Raspberry Pi. Now BeagleBoard.org has taken the wraps off a 1 GHz ARM-based board named the BeagleBone Black (BBB). You can use it as a Computer, Media Center, or the controller of your Robotic Project. One of the features that I am crazy about is the presents of ADC, PWM and lot of GPIO. As a Electronics and robotic developer, I like Beaglebone Black and is a wonderful choice!!!!

The 3.4 x 2.1 in (8.6 x 5.3 cm) BeagleBone Black open-source Linux computer comes pre-loaded with the Ångström distro (which will boot in under 10 seconds) and Cloud9 IDE, freeing up the microSD slot for additional storage. It's based on the Sitara 1 GHz ARM Cortex-A8 processor from Texas Instruments, including a 3D graphics accelerator. There's 2 GB of integrated eMMC flash storage and 512 MB of DDR3 RAM. HDMI monitor, Keyboard and mouse is not must for a developer, Straight away you can connect BBB to your PC and start Development ( Now it will act like an Arduino). If you connect a Monitor, keyboard and mouse you can use it as a standalone PC.

http://www.facebook.com/BeagleboneBlack

Cost : $45 (Indian Price Approx. Rs.3200 + Shiping)

Processor: AM335x 1GHz ARM® Cortex-A8

3D graphics accelerator
NEON floating-point accelerator
2x PRU 32-bit microcontrollers

Connectivity

USB client for power & debug
USB host
Ethernet
HDMI
2x 46 pin headers

Software Compatibility

Ångström Linux
Android
Ubuntu
Cloud9 IDE on Node.js w/ BoneScript library
plus much more

Useful Gimp Keyboard Shortcuts for Ubuntu/Debian Linux

2013-04-29T20:31:00.001+05:30

Use Keyboard Shortcuts to Speed up your GIMP Work flow

Zoom Tool

    Press the + key to zoom in in increments.
    Press the - key to zoom out in increments
    Press the 1 key to zoom in to 100%, ie one pixel in your image matches one
     pixel on your monitor
    Press Shift+Ctrl+E to fit the image to the window

Deselect

Once you've finished working with a selection, you'll want to deselect it.
    Menu Select--> None

     Keyboard Short Cut   - Shift+Ctrl+A

Fill

    Press Ctrl+, to fill with the foreground color
    Press Ctrl+. to fill with the background color
Press Ctrl+: to Fill with Pattern

Reset Foreground and Background colour to Default

Press D

Others

Undo   Ctrl+Z
Redo   Ctrl+Y

Crop and Resize   Shift+C

Bucket Fill   Shift+B

Eraser   Shift+E
Toggle rulers   Shift+Ctrl+R
Toggle guides   Shift+Ctrl+T

Merge visible layers   Ctrl+M
Anchar layer   Ctrl+H

Record your Desktop and Make Teaching Materials with KAZAM in Ubuntu/Debian linux

2013-04-10T17:12:00.003+05:30

A simple tool Kazam will capture the content of your screen and record a video file that can be played by any popular video players.. It also records audio from any sound input device. Kazam provides a simple and clean user interface, I have tested more screen recorders, but kazam is the best.

This will help you to make video tutorials. This will support FOUR modes, Fullscreen, All Screens, Window and Area. you can change frame rate by default it is 15.

Now How to install kazam in ubuntu 12.04
Open a terminal and run the following commands.

sudo apt-get install kazam

If any problem do the following

sudo add-apt-repository ppa:kazam-team/stable-series

sudo apt-get update

sudo apt-get install kazam

Speed up Ubuntu Linux with Swap Fine Tuning

2013-02-22T20:00:00.000+05:30

Swapping is designed for Low memory systems. Now a days plenty of RAM space available. RAM is much faster than HDD. Swap uses Hard disk space as virtual RAM. If you reduce the usage of HDD and increase the usage of RAM will boot the performance of your system.

The parameter named swappiness controls the tendency of the kernel to move processes out of physical memory and onto the swap disk.

swappiness can have a value of between 0 and 100
swappiness=0 tells the kernel to avoid swapping processes out of physical memory for as long as possible
swappiness=100 tells the kernel to aggressively swap processes out of physical memory and move them to swap cache

The default value of swappiness in Ubuntu is swappiness=60.
Reducing the default value of swappiness will probably improve overall performance for a typical Ubuntu desktop installation.
For Desktop users A value of swappiness=10 is recommended.
For Server , it is better to use swappiness=60

How to Check swappiness value
Open a terminal and type the following command
$ cat /proc/sys/vm/swappiness

How to temporarily change the swappiness value
$ sudo sysctl vm.swappiness=10

How to permanently change the swappiness value

$ gksudo gedit /etc/sysctl.conf

change the value of
vm.swappiness = 10

No rebooting required

How to Test the reliability and Speed of your DNS in Ubuntu / Debian Linux

2013-02-21T20:00:00.000+05:30

This post will help you to find the reliability and speed of DNS servers .
You need a simple utility traceroute.

how to install traceroute

$ sudo apt-get install traceroute

Now Run the following Command for testing google dns 8.8.8.8

$ sudo traceroute -n -w 2 -q 2 -m 30 8.8.8.8

output

shibu@keralalinux:~$ sudo traceroute -n -w 2 -q 2 -m 30 8.8.8.8
traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets
1 192.168.1.1 1.656 ms 2.233 ms
2 137.199.0.1 25.909 ms 28.264 ms
3 228.248.170.102 30.771 ms 33.141 ms
4 115.114.130.85 79.373 ms 81.546 ms
5 121.240.1.46 78.806 ms 81.854 ms
6 209.85.241.21 89.617 ms 92.429 ms
7 8.8.8.8 88.498 ms 91.208 ms

If the last line of the output does not list 8.8.8.8 as the final hop, or if there are significant timeouts, there may be a network problem preventing you from contacting DNS servers.

The following command can also use for testing the DNS

$ dig @8.8.8.8 www.google.com.

output

shibu@keralalinux:~$ dig @8.8.8.8 www.depika.com

; <<>> DiG 9.8.1-P1 <<>> @8.8.8.8 www.depika.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- 31859="" br="" id:="" noerror="" opcode:="" query="" status:="">;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.depika.com.        IN    A

;; ANSWER SECTION:
www.deepika.com.    812    IN    CNAME    depika.com.
depika.com.        3352    IN    A    72.167.142.113

;; Query time: 63 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Thu Feb 21 00:20:51 2013
;; MSG SIZE rcvd: 63

How to setup Fast and Reliable Public DNS for Ubuntu Linux

2013-02-20T23:59:00.001+05:30

Fast and Free Public DNS Servers are available. It will increase the browsing speed.

The Google Public DNS IP addresses (IPv4) are as follows:

8.8.8.8
8.8.4.4

Open DNS Ip Addresses(IPV4) are as follows

208.67.222.222

208.67.220.220

Edit /etc/resolv.conf:
$ sudo vi /etc/resolv.conf
```
 
```
Replace the nameserver lines with, or add, the following lines: For IPv4:
```
nameserver 8.8.8.8
nameserver 8.8.4.4
```
Save and exit.

How to unzip a .bz2 file with tar command in Ubuntu Linux

2013-02-12T12:27:00.002+05:30

How to unzip a .bz2 file with tar command in Ubuntu Linux

You can easily unzip .tar.bz2 files using command line

tar -xvjpf filename.tar.bz2

Or

You can use bunzip2 for unziping and usr normal tar command

This command will only work if you have already bunzip2 installed.

bunzip2 filename.bz2

Default Password of Raspberry Pi

2012-11-27T06:52:00.001+05:30

Default password for Raspberry pi

Debian Wheezy

Username : pi Password : raspberry

Arch Linux ARM

Username : root Password : root

How to Install Google drive Client Insync in Ubuntu / Debian Linux

2012-10-25T23:11:00.000+05:30

Google Drive is everywhere you are—on the web, in your home, at the office and on the go. So wherever you are, your stuff is just...there. Ready to go, ready to share. Get started with 5 GB free.

Official clints are not available for linux.

Insync is an unofficial Google Drive client for Linux, is now available in a repository for Ubuntu and Debian user.

Debian-based distributions

Add Insync as a source

Edit /etc/apt/sources.list and add deb http://apt.insynchq.com/[DISTRIBUTION] [CODENAME] non-free
Replace [DISTRIBUTION] with your Linux distro: ubuntu, debian
Replace [CODENAME] with your Linux distro codename: for example Ubuntu 12.04 is precise eg:
```
deb http://apt.insynchq.com/ubuntu precise non-free
```

Run this in a terminal:

$ wget -O - https://d2t3ff60b2tol4.cloudfront.net/services@insynchq.com.gpg.key \
  | sudo apt-key add -
$ sudo apt-get update

Ubuntu with Unity (the default desktop)

$ sudo apt-get install insync-beta-ubuntu

Gnome Shell

$ sudo apt-get install insync-beta-gnome

How to recover windows control buttons in Gnome (no maximize, minimize, close buttons) Ubuntu

2012-10-03T21:07:00.000+05:30

How to recover windows control buttons in Gnome (no maximize, minimize, close buttons) Ubuntu

Metacity is the window manager for Gnome Classic. Compiz is another window manager. If you are using compiz try the following.

Open a terminal

then type

$ ps -ef | grep -e metacity -e compiz

if window manager is compiz

type the following

$ metacity --replace

If you want to add it permanently

Go to System -> Preferences -> Startup Applications
click Add

metacity --replace

How to Change the Baudrate of Raspberry Pi USART

2012-10-02T22:21:00.000+05:30

Default boudrate of Raspberry Pi USART available in GPIO is 115200. To use this serial port for communicating with Slow microcontrollers Like Arduino and PIC you need some modifications. For example if you want to change Raspberry Pi USART Boudrate to 9600:

Fist You change the console baudrate:
To change the console baudrate, edit /boot/cmdline.txt to look like this (this is all in single line):

dwc_otg.lpm_enable=0 console=ttyAMA0,9600 kgdboc=ttyAMA0,9600 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait

Then edit /etc/inittab to change the baudrate of the getty (you should find a line with baudrate of 115200, change that number to 9600):

2:23:respawn:/sbin/getty -L ttyAMA0 9600 vt100

Restart the system.

How to Change Grub2 Default Timeout in Ubuntu / Debian Linux

2012-09-27T22:05:00.002+05:30

To make any changes in GRUB 2 you need to edit the main GRUB 2 configuration file located in /etc/default/ folder, you can edit it by running the following command from terminal:
sudo gedit /etc/default/grub you can see the contents like

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
# info -f grub -n 'Simple configuration'

GRUB_DEFAULT=0
#GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

To change the default timeout option in GRUB 2, just change the GRUB_TIMEOUT parameter.

The value of this parameter is in sec, change this value as per your requirement.

How to Find MAC Address in Ubuntu / Debian Linux

2012-09-18T22:44:00.000+05:30

MAC address is the unique serial number of your Network Card. It is SIX TWO-Digit HEX Numbers Separated by Column(:). By using MAC number You can Identify your Network Card Manufacturer. By using the simple command ifconfig you can find your MAC Address.

Open a terminal and type ifconfig , you will get a text output. In the first line you can see like HWaddr: 00:BA:13:67:78:76.

Gimp Command Reference ( keyboard Shortcuts) for Ubuntu / Debian Linux

2012-09-18T22:16:00.000+05:30

GIMP (GNU Image Manipulation Program) is a free image editing and manipulation tool editor which is often tagged as a free Photoshop alternative. It can handle essential image editing tasks like image resizing, editing, cropping, photomontages, and converting images between different image file formats. GIMP is freely available for most popular operating systems including Microsoft Windows, Apple Mac OS X, and Linux. Also with this free cheat sheet you will receive daily updates on new cool websites and programs in your email for free, courtesy of MakeUseOf. Click Here

Raspberry pi Trouble Shooting: RED Power LED is Blinking

2012-09-13T11:25:00.001+05:30

Raspberry pi Trouble Shooting: RED Power LED is Blinking

The Red Power LED is directly connected to 3.3V Power supply rail od Raspberry Pi. So it should never Blink. If it is blinking , it means the 5V is dropping out. So change the power supply.

Solution: Change Power Supply with rating 5V,1A (5V, 700ma As per specs)

Check the voltage between Tp1 and Tp2 ( Two points you can see in the board component side.

How to set Password in Raspberry Pi (Raspbian)

2012-09-10T10:39:00.002+05:30

The Default Password of Raspberry Pi image of Debian Squeeze, Wheezy is

   username: pi
           password: raspberry

Now How to Change your password :

Type

pi@raspberrypi: ~$ passwd

(current) UNIX password: raspberry # default (Current) Password

Enter new UNIX password: newpassword # Your New Password Type here

Retype new UNIX password: newpasssword #Repeat Your New Password.

How to install Ubuntu / Debian Games : Super Tux

2012-08-31T18:03:00.000+05:30

Mario is now Tux. Super Tux is a replica of our good old Super Mario game, except for the "Tux". There is an similar alternative called Secret Maryo Chronicles which you might want to take a look. If you are an Ubuntu user, click here to install Super Tux.
In debian
Open a terminal and type

$ sudo apt-get install supertux

How to Select Linux Compatible Wireless Network Cards

2012-08-28T11:00:00.000+05:30

How to Select Linux Compatible Wireless netwrok cards

If you are buying a new computer, it is best to select one with a wireless component that is designed for free software like Linux. A card designed for free software gives you improved support. Free software compatible devices also work out of the box.

To determine what wireless card/chipset you have, first determine whether it is a separate device plugged into the computer or not. If it is a separate USB device, open up a terminal and type the following:

$ lsusb

and look for words like "wireless" to find your card type.

For chips that are not USB but included in the computer, type:

$ lspci -v

List of Linux Compatible network adapters available here

Time saving automation of Ubuntu with cuttlefish

2012-08-20T22:34:00.000+05:30

CuttleFish is an Interesting application for ubuntu users , if you want to set a trigger and automate tasks based on the result of a prior action.

Cuttlefish is an app for Ubuntu that allows you to create a series of tasks that can be triggered based on the result of a prior action.

example: you could set up a reflex to deactivate Bluetooth and WiFi when the screen locks; or have Firefox open when you connect to Wifi. You can even set up your wallpaper to change when you plug in a USB device.

How to install Cuttlefish

Open a terminal

sudo add-apt-repository ppa:noneed4anick/cuttlefish 

sudo apt-get update
 

sudo apt-get install cuttlefish

View 40 different Filetype like 3gp / Avi / Jpeg / pdf / ttf in Ubuntu Linux with Gloobus

2012-08-17T20:22:00.000+05:30

By using a Nice utility Gloobus you can view almost all file type. Gloobus is a free application for GNU / Linux . Gloobus-Preview is an extension for the Gnome Desktop designed to enable a full screen preview of any kind of file. It allows instant access to a variety of file types without the need of opening their default application.

You can access the preview mode from several ways, right click on the file you want to preview and choose “Preview” o simply hit the Space key on your keyboard.

Gloobus can currently preview over 40 file formats and its family is still growing:

Images: jpeg / png / icns / bmp / svg / gif / psd / xcf
Documents: pdf / cbr / cbz / doc / xls / odf / ods / odp / ppt
Source: c++ / c# / java / javascript / php / xml / log / sh / python
Audio: mp3 / ogg / midi / 3gp / wav
Video: mpg /avi / ogg / 3gp / mkv / flv
Other: folders / ttf / srt / plain-text

How to Install In Ubuntu 12.04

$ sudo add-apt-repository ppa:gloobus-dev/gloobus-preview

$ sudo apt-get update

$ sudo apt-get install gloobus-preview

$ sudo apt-get upgrade (To upgrade to the patched nautilus)

Finally, restart nautilus

$ nautilus -q

$ nautilus

Free eBook - Linux from Scratch

2012-08-17T09:30:00.002+05:30

Linux from Scratch describes the process of creating your own Linux system from scratch from an already installed Linux distribution, using nothing but the source code of software that you need.

This 318 page eBook provides readers with the background and instruction to design and build custom Linux systems. This eBook highlights the Linux from Scratch project and the benefits of using this system.

Users can dictate all aspects of their system, including directory layout, script setup, and security. The resulting system will be compiled completely from the source code, and the user will be able to specify where, why, and how programs are installed.

This eBook allows readers to fully customize Linux systems to their own needs and allows users more control over their system.

Click Here

How to check disk drive for errors and badblocks in Ubuntu / Debian Linux

2012-08-16T19:24:00.000+05:30

badblocks is a Free software to check for bad sectors on a disk drive. It creates a list of these sectors that can be used with other programs, like mkfs, so that they are not used in the future and thus do not cause corruption of data. It is part of the e2fsprogs project.

It will help you to check your drive periodically for bad blocks. It will list out all bad blocks. This list can be fed to fsck to be recorded in the filesystem data structures so that the operating system won’t try to use the bad blocks for storing data. The following example will show how this could be done.

Open a terminal, type following command:

$ sudo badblocks -v /dev/hda1 > bad-blocks

The above command will generate the file bad-blocks in the current directory from where you are running this command.

Now, you can pass this file to the fsck command to record these bad blocks

$ sudo fsck -t ext4 -l bad-blocks /dev/hda1

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Check reference counts.

Pass 5: Checking group summary information.

/dev/hda1: ***** FILE SYSTEM WAS MODIFIED *****

/dev/hda1: 25/360 files, 44/1440 blocks

If you have already used badblocks , e2fsck will try to move the block to another place. If the block was really bad, not just marginal, the contents of the file may be corrupted.

Looks at badblocks man pages for more command line options.

45 Gram Linux Based Computer Raspberry Pi - Overview

2012-08-14T14:34:00.002+05:30

45 Gram Personal Computer Raspberry Pi - Overview

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What is Raspberry Pi?

Raspberry Pi is a USD $35.00(Approx.Rs.2500/-) credit card sized single board computer with 256 MB RAM, 2 USB Ports, One HDMI Port, 3.5mm Audio Jack, Composit Video out for Connecting TV as Display Device, SD Card Slot, Ethernet Port and GPIO port for Electronics and Robotics Projects. It’s a capable little PC which can be used for many of the things that your desktop PC does, like spreadsheets, word-processing and games. It also plays high-definition video. The Raspberry Pi measures 8.5cm x 5.4cm, It weighs 45g.

What Peripherals Are Required for the Raspberry Pi SBC?

+5V/700ma cell phone battery charger with micro‐USB cable
SD‐Memory Card (2GB minimum) with a Linux OS Image installed
USB Keyboard & USB Mouse
HDMI cable or RCA Video Cable
Display with either an HDMI, DVI, or Composite Video input
Ethernet LAN Cable with RJ‐45 Connectors

Supporting Operating Systems

Debian 6 Linux

Arch Linux

Fedora 14 Remix

Android

How to change Ubuntu Look and Feel with Zorin Splash Screen Manager

2012-08-13T20:39:00.001+05:30

Zorin Splash Manager is a simple application help you to change the theme of Ubuntu desktop. The screen shot of the GUI is given below.

It is basically designed for Zorin OS, an Ubuntu based Linux Distribution

How to install Zorin Splash Screen Manager

Download Package from following Link

Download Zorin Splash Screen Manager DEB Package

Double click on downloaded debian package.

OR You can use
$sudo dpkg -i

How to fix Apache – "Could not reliably determine the server’s fully qualified domain name, using 127.0.1.1 for ServerName" Error on Ubuntu

2012-07-19T20:53:00.001+05:30

How to fix Apache – "Could not reliably determine the server’s fully qualified domain name, using 127.0.1.1 for ServerName" Error on Ubuntu

Just Edit the file /etc/apache2/httpd.conf

$sudo gedit /etc/apache2/httpd.conf

By Default it is blank

add the following to httpd.conf

ServerName localhost

now you can restart apache

$/etc/init.d/apache2 restart

Linux and Microcontroller Tips

Electronics and Robotics Developers Choice: Beaglebone Black

Processor: AM335x 1GHz ARM® Cortex-A8

Connectivity

Software Compatibility

Useful Gimp Keyboard Shortcuts for Ubuntu/Debian Linux

Record your Desktop and Make Teaching Materials with KAZAM in Ubuntu/Debian linux

Speed up Ubuntu Linux with Swap Fine Tuning

How to Test the reliability and Speed of your DNS in Ubuntu / Debian Linux

How to setup Fast and Reliable Public DNS for Ubuntu Linux

$ sudo vi /etc/resolv.conf

How to unzip a .bz2 file with tar command in Ubuntu Linux

Default Password of Raspberry Pi

How to Install Google drive Client Insync in Ubuntu / Debian Linux

Debian-based distributions

Add Insync as a source

Ubuntu with Unity (the default desktop)

Gnome Shell

How to recover windows control buttons in Gnome (no maximize, minimize, close buttons) Ubuntu

How to Change the Baudrate of Raspberry Pi USART

How to Change Grub2 Default Timeout in Ubuntu / Debian Linux

How to Find MAC Address in Ubuntu / Debian Linux

Gimp Command Reference ( keyboard Shortcuts) for Ubuntu / Debian Linux

Raspberry pi Trouble Shooting: RED Power LED is Blinking

How to set Password in Raspberry Pi (Raspbian)

How to install Ubuntu / Debian Games : Super Tux

How to Select Linux Compatible Wireless Network Cards

Time saving automation of Ubuntu with cuttlefish

View 40 different Filetype like 3gp / Avi / Jpeg / pdf / ttf in Ubuntu Linux with Gloobus

Free eBook - Linux from Scratch

How to check disk drive for errors and badblocks in Ubuntu / Debian Linux

45 Gram Linux Based Computer Raspberry Pi - Overview

How to change Ubuntu Look and Feel with Zorin Splash Screen Manager

How to fix Apache – "Could not reliably determine the server’s fully qualified domain name, using 127.0.1.1 for ServerName" Error on Ubuntu

How to fix Apache – "Could not reliably determine the server’s fully qualified domain name, using 127.0.1.1 for ServerName" Error on Ubuntu

Just Edit the file /etc/apache2/httpd.conf

$sudo gedit /etc/apache2/httpd.conf

By Default it is blank

add the following to httpd.conf

ServerName localhost

now you can restart apache

$/etc/init.d/apache2 restart