OpenTechLab

PyQt: power of Python, beauty of Qt

2011-09-03T06:00:00.000-07:00

Qt is very powerful tool for GUI programming. But programming using Qt C++ is not always easy because of unavailability of libraries and difficulty in coding. But Python is powerful and has abundant list of libraries related to virtually anything. Some operations in Python is very easy to use. But the problem of Python is that, it has no GUI its own as handy. PyGTK (Python and GTK) and PyQt (Python and Qt) are the remedy. Here I am explaining how to start with PyQt.
PyQt has no support from QtCreator yet, but the features of QtDesigner can also be used for the PyQt coding. This tutorial explains how to start PyQt programming if you are already aware of Qt C++ programming. This is not just a 'hello world' program, but the code will do something and make you capable of coding your own programs.
In this example, we are building a simple GUI with three LineEdit bars and a single button. When the button is clicked, the numbers entered in the LineEdit a and b are added and the sum is shown in the third LineEdit.

First of all, make GUI widget in Qt Designer and rename the objects a, b, sum and pushButton as shown in screen-shot below. Also make a custom slot named calc_sum(). Save and quit the Designer program.

Now you can see the user interface file named 'widget.ui' (the filename may vary if you changed the widget name while creating your project. Anyway, the filename with .ui as extension is the file we need). We need to create the curresponding python file for user interface. In C++, it is done using uic(User Interface Compiler). In our case, in python, we use a utility named 'pyuic4'. If 'pyuic4' will be automatically installed while you install PyQt. If not, especially in Linux, install it from the repository. Then make the user interface file 'calc_ui.py' (or any name you wish. But for the first time use this name to avoid ambiguity) file using the command:

pyuic4 widget.ui > calc_ui.py

This command will generate a new file named 'cal_ui.py'. This is the user interface file only. We are going to make another file 'calc.py' which will handle the core program. Use a text editor and copy the code below:

import sys
from PyQt4 import QtCore, QtGui

from calc_ui import Ui_Widget

class MyForm(QtGui.QMainWindow):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)
        self.ui = Ui_Widget()
        self.ui.setupUi(self)
    def calc_sum(Widget):
   value1=Widget.ui.a.text();
   value2=Widget.ui.b.text();
   result=float(value1)+float(value2);
   str_result=str(result)
   Widget.ui.sum.setText(str_result);

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    myapp = MyForm()
    myapp.show()
    sys.exit(app.exec_())

Save the file. Then run the file:

pyhon calc.py

I am not so good in explaining the code. I think you got the idea of how to make a custom slot and to make a standalone program. If any reader need clarification or more explanation, I will try to explain further.

Qt Programming in Malayalam Part-2

2011-08-06T02:07:00.000-07:00

Before reading this tutorial, read my previous post "Qt programming in Malayalam" if you have not read it yet.
Have you ever wonder about easy switching from English to other languages such as French, Spanish etc. in software applications? Even though Malayalam switching is rare, translation is possible in Malayalam as well like any other language. Qt provides an easy way of language switching by means of Qt linguist. This tutorial describe how to build a Malayalam switchable application in Qt. An easy to start tutorial is packaged with Qt Help itself. Here is a quick tutorial of how to build a Malayalam application if you have the source code of the English version. Before we start, I assume:
1) You have Qt installed in your PC.
2) You have a very basic knowledge of Qt programming. How to compile, build and all.
If the above is not qualified, sorry, it is better to pause here and read this and resume. Suppose you have a Qt application in English (If you have not your own, a lot of examples are there in qtdir/qt/examples. (qtdir is the directory where you installed Qt). For better understanding, I prefer an application named 'QMusicPlayer' from examples(qtdir/qt/examples/phonon/qmusicplayer). You can take other examples as well. Open qmusicplayer.pro using Qt, then build and run it. You will get a minimal musicplayer in English. Now our aim is to make the malayalam version of the same application.

Now we need to edit two files 'main.cpp' and 'qmusicplayer.pro' as follows:

main.cpp

#include

#include "mainwindow.h"
#include

//![1]
int main(int argv, char **args)
{
    QApplication app(argv, args);
    QTranslator translator;
    translator.load("malayalam");
    app.installTranslator(&translator);
    app.setApplicationName("Music Player");
    app.setQuitOnLastWindowClosed(true);

    MainWindow window;
    window.show();

    return app.exec();
}

qmusicplayer.pro

QT        += phonon

HEADERS   += mainwindow.h
SOURCES   += main.cpp \
             mainwindow.cpp
TRANSLATIONS = malayalam.ts

# install
target.path = $$[QT_INSTALL_EXAMPLES]/phonon/qmusicplayer
sources.files = $$SOURCES $$HEADERS $$FORMS $$RESOURCES *.pro *.png images
sources.path = $$[QT_INSTALL_EXAMPLES]/phonon/qmusicplayer
INSTALLS += target sources

wince*{
DEPLOYMENT_PLUGIN += phonon_ds9 phonon_waveout
}

symbian:TARGET.UID3 = 0xA000CF6A

Changes made in the code are highlighted. The changes in code simply add a Translator feature to your application. While running, your application will seek a file named 'malayalam.qm' which contains one to one translation of all English words used in program to Malayalam. 'malayalam.qm' is a binary file and is to be generated from a file named 'malayalam.ts'. This file is automatically generated using the command in terminal:

lupdate -verbose qmusicplayer.pro

Then the newly generated file - 'malayalam.ts' can be seen in the project directory. But it is an empty file and we need to update that file with all one to one translations. To do so, open the file with Qt linguist:

linguist malayalam.ts

If you couldn't find any command like 'lupdate' or 'linguist', most probably, you have not added the qt directory to the PATH. To do this use the following command Linux,

PATH=$PATH:qtdir/qt/bin/

directory may be different and must change it as your needs. Then use 'lupdate' and 'linguist'. If you are still stucked, check whether you completely installed Qt SDK. In Windows, if you are using Qt enabled prompt, I hope there will be no any problem.

Now I assume you opened 'malayalam.ts' successfully in Qt Linguist. It shows all english words which translation is enabled. (Refer fig). Click on each english word in 'Source Text' list and add curresponding Malayalam translation in the 'English Translation' edit box at the bottom (highlighted on figure). Repeat the process for all words and save. Then File->Release. It will generate the binary file 'malayalam.qm' in the same directory.
Now run the qmusicplayer application with file 'malayalam.qm' is placed in the same directory of the executable. Now you can see the malayalam version of 'qmusicplayer'.

In the absense of the file 'malayalam.qm', there will be no run time error in the program, it simply shows the english version. Similarly you can build a multi-lingual swithable version.

How to heal? Some keyboard keys are not working

2011-07-19T06:01:00.000-07:00

It is a common problem that failing some keys in PC keyboard. But it become cumbersome while you type anything seriously. Replacing or repairing keyboard is not always easy, especially you are using a laptop. The seriousness of the problem depend on the failed key operation. If ENTER, DELETE, SPACE, SHIFT, CTRL, ALT etc are failed, your keyboard is almost at the worst state. Here I am trying share how to dilute this key failure effect.

Method 1 - On screen keyboard(Quickest way)
If you are doing something seriously, and don't have enough time to dismantle keyboard and clean, best method is to use virtual keyboard. On MS Windows, it is built in. You can access it by,
Start - All Programs - Accessories - Accessibility - On-Screen Keyboard
The fundamental advantage is that it is independent on how much keys in your keyboard are failed. Also you can access and use this utility completely using your mouse. In Linux, there is a similar utility named 'onboard' (use command 'onboard' to open it) and most probably it is built in. But it considerably lowers the typing speed.

Method 2 - Key mapper (Quicker enough)
SharpKeys from RandyRants is a good utility (for windows) to assign function of one key to another key. It can be done using a registry hack, but using Sharpkeys is a handy method. A good number of keys are there in your keyboard which are rarely or not used at all. Function keys F1, F2 ..., Win Key, Home, End, Print Screen, Pause/Break. If you use only left or right CTRL key is using other can be contributed for other function, because right and left CTRL keys are considered different. The same is applicable to SHIFT and ALT. Although this method slightly lowers your typing speed, you can still do everything.

Method 3 - Cleaning
Open it, clean well. If you are lucky, it will give life to your keyboard (I am unlucky).

Method 4 - Repair or Purchase
This is the last way. Of course, result will be positive.

LED Matrix pattern designer

2011-07-16T08:16:00.000-07:00

LEDmatrix pattern designer is a tool used to generate matrix(2D) patterns in hex numbers for displaying LED matrix using a micro controller.

It is based on Qt framework and hence cross platform. It supports up to 16x16 matrix size. You can increase it by making minor changes in the sourcecode, but 16x16 is enough for most cases. This is done from the same pace of my previous project - ChaserDesigner. Only you need to do is that, specify the 2D pattern either manually or using the enhancing tools provided by the software. Then you can generate it's hex equivalent by a single click. A 2D pattern can be scanned either horizontally or vertically. The scanning mode can be switched in the software while making frames.

I think most of the features of the software are self explanatory. If you have any doubts, please comment. All files associated with this project are free to download.
Project source(Linux, Windows)
Windows executable
Required dlls for Windows executable

How to make bitmaps for graphic LCD (glcd)?

2011-07-06T05:04:00.000-07:00

Making bitmaps for graphic LCD is pretty easy. There is a lot of free tools available over Internet, but I think there is no need to download them if you have already installed an image editing software in your PC. Also it is interesting to know what's actually they do. In this quick tutorial, an example using GIMP - a free image manipulation program is described. This is a general tutorial and can be applicable for almost all type of graphical LCDs.

Step1: Know the pixel size of your graphic LCD. For KS0108 (a general purpose glcd), it is 128x64.
Step2: Choose an image(any image) to be embedded on LCD.
Step3: Scale the image to 128x64. In GIMP, (menu)Image -> Scale Image. Change height to 64 and width to 128.
If your image is not an exact multiple of 128x64 and if you want to keep the aspect ratio, you need to do any of the following:
a) Crop the image to 128x64.From toolBox(dock in the left hand side most probably), choose Rectangle Select Tool and spcify the size to 128x64 in the bottom of toolbox and select a portion you want and crop it. (menu)Image -> Crop to Selection.
b) Resize the image to less than or equal to 128x64. Then start a new image by (menu)File -> New. Then from the dialog box choose size as 128x64. Copy the previous image to the new image.
c) If you want to just check and image is not matter, image search on Google specifying the size 128x64 ;-)
Step4: Before going to this step, I assume you have an image of the same size of your LCD. In this example, 128x64. Next is the conversion of your color image to monochrome image. For that, choose, (menu)Colors -> Threshold. Using the dialog box, you can change the threshold in realtime.
Step5: Change mode.(menu)Image -> Mode -> Indexed.From the dialog box, choose 'Use Black and White (1bit) palette'. Click 'Convert'
Step6: Save the image.(menu)File -> Save as. Choose extension .bmp (bitmap).

Now your image is ready for embedding to your LCD. For some programs like MikroC for PIC, there is a built in tool to convert the bitmap into array. If you don't have such advanced tools, don't worry, let's do it using open source tools.
Using Octave/Matlab for KS0108
Now you have a monochrome bitmap of only zeros and ones. Now it should be grouped and formatted to a format supported by glcd. I did the conversion using octave. The script shown below accepts the bitmap name as argument and convert it to the glcd compatible form. make appropriate changes to run the script in MATLAB. Also change yourself the program if your lcd size is different.

#This code input a monochrome bitmap of size 128x64 and convert it to a form compatible to ks0108 graphic lcd(glcd)
arg_list=argv();
x=imread(arg_list{1}); #accept argument
num=0;
printf("Controller 1 (left)\n\n");
page=0;
for offset = [1:8:64]
    printf("Page %d:\n",page);
    page+=1;
    for j=1:64
        for i=[offset:offset+7]
            num=num+x(i,j)*(2^(i-offset));
        endfor
        printf("%d ",255-num);
        num=0;
    endfor
    printf("\n\n");
endfor
printf("Controller 2 (right)\n\n");
page=0;
for offset = [1:8:64]
    printf("Page %d:\n",page);
    page+=1;
    for j=65:128
        for i=[offset:offset+7]
            num=num+x(i,j)*(2^(i-offset));
        endfor
        printf("%d ",255-num);
        num=0;
    endfor
    printf("\n\n");
endfor

The output of above script when mickey2.bmp as the argument is given below:
Controller 1 (left)

Page 0:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 128 192 224 240 240 248 248 252 252 252 252 252 252 252 252 252 248 248 240 224 224 128 0 0 0 0 0 0 0 0 0 0 0 0

Page 1:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 240 252 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 254 240 0 128 128 128 192 192 192 192 192 192

Page 2:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15 63 127 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 127 31 15 199 35 33 49 1 3 7 15 31 127

Page 3:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3 3 7 7 15 15 15 15 15 15 15 15 143 255 255 255 255 255 15 0 0 0 0 1 0 128 112 8 8 8 16 224 0

Page 4:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 255 255 255 255 255 255 240 192 0 0 0 0 0 127 128 240 248 248 248 241 24

Page 5:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 195 255 255 15 207 103 119 247 151 4 0 0 0 0 9 119 255 251 255 239 231

Page 6:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 15 31 56 112 96 192 193 131 134 140 140 24 48 240 240 240 240 225 225 225

Page 7:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 3 3 7 6 14 29 59 54 108 108 109

Controller 2 (right)

Page 0:
0 0 0 0 0 0 0 0 0 0 0 128 224 240 248 252 252 254 254 254 254 254 254 254 254 254 254 252 252 248 248 240 224 192 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Page 1:
192 192 192 192 192 192 192 128 128 128 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 252 96 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Page 2:
127 15 7 7 3 1 49 49 99 195 7 15 63 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 127 31 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Page 3:
0 128 224 48 8 8 8 112 224 0 0 0 0 0 15 255 255 255 255 255 255 199 7 7 7 7 7 7 3 3 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Page 4:
0 63 255 248 248 248 240 96 63 0 0 0 0 128 240 255 255 255 255 255 255 255 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Page 5:
239 231 239 255 255 255 127 4 8 0 0 0 2 219 251 115 115 99 7 159 255 255 64 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Page 6:
225 225 225 225 224 240 240 240 240 56 140 142 195 129 192 224 112 120 28 31 7 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Page 7:
105 105 108 108 127 55 27 29 14 7 7 3 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Now your image is ready to send to your glcd. Almost all microcontroller and embedded tools have an inbuilt function to write the image when the form above is given. Since it is a general tutorial, I just don't go to any specific one.If your software tools have changes, do appropriate changes in the format also. This tutorial aims to make your hands dirty even though full fledged software tools available(sometimes for free). But I recommend to work out this at least once to understand the internals of the image conversion.

ChaserDesigner - A professional approach for fancy light design

2011-07-04T08:42:00.000-07:00

This project is published in July 2011 th issue of Electronics For You (EFY) magazine (Page no: 94 to 98) titled:"Microcontroller-Based Light Chaser". Thanks to EFY for publishing this. You can read full article from EFYmagonline or purchase one.

ChaserDesigner is a useful project for fancy light designer professionals as well as enthusiast who want to make their own LED patterns while decorating home during festivals. It's hardware part is simple one which uses 8051(or any variants of 8051) and a handy software part based on Qt. In the GUI, you need to specify how the pattern appear on LEDs(or connected higher loads) and it will automatically generate the source code for 8051(in assembly language). Only you need to do is that, burn the program in to the micro and put it on the circuit. Then the LEDs start to glow in the designed pattern. This is very handy and there are some tools provided to easily make your own patterns. The software works in Linux, Windows, or MAC and hardware components chosen are almost ubiquitous. In case, if any component found unavailable, please comment, I will try to recommend any alternative if any. I have put source code,circuit diagram and all other associated diagrams free for download.

1. contents.zip - Article before published, circuit diagram, images etc.
http://www.4shared.com/file/MolWxWP_/content.html

2. chaserdesigner_src.zip - Software source code.http://www.4shared.com/file/zY9fz6LF/chaserDesigner_src.html

3.chaserdesigner1.0.zip - Windows XP executable file
http://www.4shared.com/file/3WmVxoaF/ChaserDesiner10.html

4.videos.zip - videos describing, how to operate the software and hardware.
http://www.4shared.com/file/EagoltHS/videos.html

Note: Since it is published by EFY, it is better to read this article in EFY to get more pretty article with PCB layout also.

One day PyBrain came to power....

2011-06-11T06:58:00.000-07:00

Recently, I went straight away to PyBrain and found it is useful to AI researchers and enthusiasts. Python rocks once again. PyBrain is a modular library for python. As far as PyBrain developers is concerned, it is Python Based Reinforcement Learning, Artificial Intelligence and Neural Network Library. PyBrain is opensource and it is licensed under BSD software license.
PyBrain simulates neural networks inside our brain in a computer. Once you created the neural networks, you need to train it for a particular task. Sometimes training of more than thousand times is required to properly get done it's job. Sometimes, training will be frustrating especially when you didn't give proper degree of freedom to the neural network structure. However, I found pyBrain interesting.
It is good idea to start with pyBrain documentation. In the beginning of the tutorial, they provide a simple example of training for an X-OR gate. But it will take a lot of training steps to work properly. But for the same neural network structure, if you are trying to simulate an AND gate or an OR gate, you probably get everything done.

Story of a 'spinning lady'

2011-03-09T06:06:00.000-08:00

Did you notice the figure above? To see the spinning lady, click this link and return back. Is it a spinning lady? In which direction, you feel the lady is spinning? clockwise or counter-clockwise? One can feel the spinning of the lady in either clockwise or counterclockwise. But once you feel lady spin in one direction, your brain continues in that state and insist to be in that state. If you feel that the lady is spinning in clockwise, it is too difficult to see the motion in counter-clockwise direction. But sometimes our brain switches from one state to other state automatically, but changing the state of feeling of brain is difficult to achieve manually.
This is a beautiful eye illusion. Do you know how that beautiful lady, cheated your brains?
Answer is, the lady didn't cheat you, but the cheater is her shadow. Actually, the image shows the shadow of a spinning lady. In this, a 'shadow' plays in important role in cheating you. The pure shadow of an image will not provide the entire information about an object to the brain. From a shadow, we can't predict whether the front side or backside of the object we are viewing. If you didn't understand what I just said, please go through an example.
Look at the picture below.
The middle picture is photo-shot of the spinning lady. Concentrate on the picture and tell what you are viewing- the frontside or backside? It may be both. Look at the left picture. It is the modified version of middle one by adding eyes in her face. Now you feel that you are viewing the front side of the lady. At the same time, you see the backside of the lady in the right picture, but that also a modified version of middle picture with marking of a hair bud. This is important to be noted. While you are viewing the middle picture only, your brain fall in to the mess of finding whether the shadow is of the front side or backside. Then your brain 'randomly' choose one possibility (not actually). But in other pictures, your brain has powerful proof that indicates the state of the lady's body.
Now the problem associated with the spin direction of the lady is not vague. If your brain 'assumed' a side of the lady's body you are viewing, this will determine which direction, she is spinning.

Make yourself a Qt Hacker

2011-02-14T21:51:00.000-08:00

A presentation of Qt for beginners was held in Jyothi Engineering College for ISTE students. It was taken by me and I have just put the presentation and the associated files here and think it may be useful for those people who have attended. For any doubts, feel free to ask me.
Download files here

Just bought an Arduino, What's next?

2010-11-27T09:49:00.000-08:00

This article briefly explain what is to be done just after purchasing an Arduino board. Even though the prerequisites of Arduino is less compared to other development boards, I think this article will be useful because Arduino is being popular among beginners. This article deals with the latest version of Arduino at the time of writing - it is Arduino UNO.
Setting up drivers
Connect Arduino to your computer via USB cable. It will power up from USB power. Now start Arduino IDE. If you have not Arduino IDE download from here. No need to install the software. Just extract using your favourite decompressing utility (my favourite is 7zip) and run the executable named 'Arduino'. Now you have to set up your IDE to work with your Arduino UNO. First select your hardware from Tools -> Board -> Arduino UNO (or your exact hardware name. If it is not listed, try to download the latest version). Next, select your serial port from Tools -> Serial Port. Selecting serial port is in different way different OS.
Linux
If the 'Serial Port' menu is not active, probably, your device is not connected properly. Try to reconnect. If more than one serial ports are shown in the menu, we need to find out which is the correct one. To do that, disconnect your arduino first. Then you probably need to restart the IDE. Then look at the 'Serial Port' menu and note down the listed COM ports. Then reconnect your device and track the newcomer. This is the easy way. Select it.
One of the problem I suffered while playing with arduino in my Ubuntu 10.04 LTS was that, the compilation of the program was a failure. It was a dependancy problem. So what I did is that, installed Arduino IDE as described here. But it was an older version and my device UNO is not listed in it. Then downloaded the newer version from the downloads page. That was really a tricky step!
MS Windows
In Windows, just after connecting your device to the PC, a device driver wizard appears and try to find the appropriate device driver for the device. It will take a while and at the end of the fight, it fails to find an appropriate driver. Close the wizard and go to 'Device Manger' (Either via Control Panel or by right clicking 'My Computer' then 'Manage'). Then you can find Aduino UNO as the unknown device. Right click on that and choose the option to manually install the driver. Then locate the directory where you have installed Arduino IDE. Then the system install the appropriate driver and now you can see your device on the list named 'Ports' in the Device Manger. In parenthesis, there will be the curresponding COM port number (eg: COM 4) . Then choose that COM port in the Arduino IDE.
Starting with 'Hello World'
The commonly accepted 'Hello World' in embedded devices is LED blinking. There is an example in the IDE itself. Open the file from File -> Examples -> Basics -> Blink
Look at the program. For an average C programmer, the program seems self-explanatory. To compile your program, choose Sketch -> verify/compile. Then to upload the executable to your device, choose,File -> upload to I/O board. If everything you have done is correct, you will get your Arduino programmed and starts working just after burning the program using the USB power. Disconnect it from USB and use in your standalone applications.
Read more..
Arduino Lanugage reference
Arduino Playground

SMS email alert in mobile phone

2010-11-14T07:47:00.000-08:00

One of the major disadvantage while handling e-mail services is that we need to check mails by intervals. Most people checks their account more than once a day. Some people start up their computer to only check the e-mail and finds that 'No e-mail today' and continue their frustrating work after a couple of hours. This type of services are 'pull-email' type services. Conversely, there's a 'push e-mail' service which will send the mail to your mobile devices. But this service is not available in all mobile phones or services. So here is a method which can be used virtually in any mobile phone. This service will alert you whenever you get a new mail with some information about the sender. The alert is done by sending an SMS. Unfortunately, this method can only be applied in INDIA. Sometimes, all mails receiving in your mailbox including spam may not be important to alert. So by setting up your gmail, you can select which type of mails should be alerted.
I assume you have a gmail account. If not, either you can make a new gmail account or a similar approach will work on your other accounts also- explore it. Moreover, you need to have an account in way2sms.com . Register on way2sms (The service of way2sms is currently limited to India only). You will get your own free email address in way2sms domain.
Setup in gmail account
Go Settings->Filters
Click 'Create a new filter'. Then a box will appear which shows that which type of mails are to be forwarded to way2sms.com. For example, if you type user@gmail.com in the 'from line-box', all mails from user@gmail.com will be filtered. There are several other options also. You can test your filter by clicking 'Test Search'.
Click 'Next Step' button. Then a new box will appear. Check 'Forward it to' option and enter your way2sms email address.
Click 'Create Filter'.
Now onwards, all your filtered mails will be sent to your way2sms email.
Set up in way2sms account
Log in to your way2sms account.
Click 'Mail Alerts' link in the top right corner of the page. Here you can activate mail alerts for 14 days. After 14days, it will be automatically deactivated. So it is needed to activate the alerts in every two weeks. You can deactivate it at any time.
Done. Now you will get an alert SMS whenever you receive a new e-mail.

Set up Toshiba L650 laptops after ubuntu installation

2010-11-07T17:36:00.000-08:00

This article explains how to set up device drivers after installing Ubuntu in Toshiba laptops. Most probably Ubuntu will not support LAN, WiFi, Bluetooth and in some systems, anomaly in working of fan, battery are reported. Some of my problems like LAN setup, WiFi and Bluetooth have overridden and my battery is still showing some problems. I hope these instructions will be helpful for Toshiba Laptop users. Note that this article is a "how I did" type article rather than a "how to".
Some models of Toshiba Satellite are preloaded with Windows and some are not. In pre-installed models, try to make the system dual boot. There are a lot of tutorials for that and in Ubuntu, this is pretty easy compared to other distros. Anyway, I assume you have Toshiba system with a fresh Ubuntu installed. I used Ubuntu 10.04 LTS on by Toshiba L650-i5310.
Setting up Ethernet
My ethernet card was from Atheros Communications. A driver for Atheros is available from http://linuxwireless.org/download/compat-wireless-2.6 . Download and unzip the file. Then in terminal, cd into that folder. Then type the following code:

scripts/driver-select atheros
make
sudo make install

Then reboot the system.
Setting up Wireless
My Wireless LAN card was from Broadcom Corporation. The driver is readily available from ubuntu repository.

sudo apt-get install bcmwl-kernel-source
echo wl | sudo tee -a /etc/modules

Reboot the system.
Setting up Bluetooth
In bluetooth, I did nothing in Ubuntu and I installed a bluetooth driver from Toshiba in Windows 7. After that incident, my Ubuntu also start detecting bluetooth adapter and don't know how this happened.

How to run custom scripts at Linux startup?

2010-09-18T07:35:00.000-07:00

It is a good idea to make your own scripts at the Linux start up. Here I am explaining the things with a simple example. I want to make a directory in desktop named 'folder' in each start up. If it is deleted, a new 'folder' is created in the same place in the next start up. Here is what I did.
first make a new script- here 'my_own_script'. Open the file in gedit and add the following:

#! /bin/bash
# chkconfig: 345 40 60
mkdir /home/tom/Desktop/folder

You need to change to the correct path in 3rd line. Here 345 means different run levels and 40 and 60 are the order for start and stop. save the file in /etc/init.d .
Then open terminal and execute this command:

chkconfig --level 345 my_own_script on

Then restart you computer and you can see a directory named 'folder' on your desktop in each start up. For more details, use:

man chkconfig

The mkdir command can be replaced by your own custom scripts. This worked on my PC powered with fedora 12. I found in linux forums that, it will work on Redhat/CentOS/Mandriva.
Start up programs are sometimes irritating and delay start up. So if you want to turn off your script from next start up, use command:

chkconfig --level 345 my_own_script off

Indian languages support and software tools

2010-09-09T23:27:00.000-07:00

Indian Govt. have an official website for Indian language support. You can download language support and software tools from this website or order for a free CD. The major tools are:

True type fonts with keyboard driver
Multifont keyborad engine for the true type fonts
Unicode complient fonts
BHARATEEYA Open Source
Language OCR
Language spell checker
Bilingual dictionary
Font design tool
Transliteration tool
Language text editor
Tutor package
Text to speech system
Database sorting tool
Number to word tool
Typing tutor
Language suppoted microsoft excel
Type assistant

The CD is released by Ministry of Communications and Information Technology, Government of India. Contibuters are, C-DAC, Cyber space multimedia Ltd.,C K Technologies, Cadgraf Digitals System Ltd., Cyber Thomson, IMRC.
Click here to visit Technology Development for Indian Languages(TDIL).

Reveal Them! A Qt entertainment

2010-08-30T05:30:00.000-07:00

I do some Qt exercise when I get leisure time. RevealThem is just the after effect but I hope source code will be useful for somebody. While I was over consuming my vacation in front of TV, found a nice program like RevealThem. Hiding a celebrity behind a brick wall, and player can remove bricks one at a time so that, a part of the face is visible. People get higher points if they identify the celebrity with minimum number of picks. I found it was interesting to realize in Qt.
How to use the software?
Step1: Download the program(Go to end of this post)
Step2: Download some pictures of celebrities in .jpg format and save it in images/ directory in the directory where the program is installed.
Step3: Open the executable and click 'Load Image'. then you can pick bricks by clicking on it and select correct answer from the list and click 'Check' button. For each pick you, lose your 10 points.
Step4: This program is just for fun only.

Download source code (Tested in both Linux and Windows - 3.27KB)
Download Windows binary (5.03MB)

Qt Programming in Malayalam Part-1

2010-08-28T05:21:00.000-07:00

Qt Programming in Malayalam is quite easy. Most of the strings used in Qt is of type QString. QString support all kind of unicode standards. So one can include mathematica and technical symbols, and non-English characters. Malayalam characters are also included in unicode. So usage of Malayalam in Qt is possible almost anywhere in Qt software designing. There are three major standards for unicode- UTF8-8bit, UTF-16-16bit, UTF-32-32bit. QString supports all standards and there's a bunch of translating functions to and fro for transforming QString to other types such as const char*.

You can transform simple programs in Qt to Malayalam with a little care. But still there may be problems while playing with non-English languages. Like other GUI's Qt is also limited in support to non-English languages, but still it is translatable.
Download this example (Windows binary - 4.76MB)
Download the source code (Tested in both Linux and Windows - 3.27KB)

Also read Qt Programming in Malayalam Part-2

Malayalam for Windows

2010-08-27T17:52:00.000-07:00

*Note: The above information is adapted from the resources of http://malayalam.web4all.in
The information in this post is specific to Malayalam users in Kerala, India. Other readers may not find anything useful in this post
"I need to do some work in Malayalam in Windows XP. What should I need to do?''
My post here tries to find the answer for the above question. Malayalam implementation can be done in two ways.
1)In-script keyboard - Each corrector in Malayalam is assigned to the key layout in the US keyboard. It become easier only after some practice2)Transliteration - This is easier method for beginners. In this method, you just type a word similar to the Malayalam word. (For example അമ്മ in Malayalam can be printed on screen by typing 'amma' in English.

Setting up Windows XP for In-script keyboard
Step1: Go to Control Panel->Regional and Language Options
Click on 'Language' tab
Step2: Check whether the check-box corresponding to "Install files for complex script and right to left languages(including Thai).
If not check it. If it is already checked, go to Step5.Step3: Then Computer ask your Windows CD for further installation of fonts. Then put your CD on the drive and click OK. Wait until complete installation. Then reboot your system after closing all dialog boxes.
Step4: Again do Step1 and this time the check-box will be checked.
Step5: Click 'Details' button. Then click 'Add' on the new dialog box. Choose Malayalam(India) and click OK.
Step6: Close all dialog boxes. In your task bar, you can see the current layout as 'EN" by default. Click on it and choose Malayalam from the list. Then 'EN' is changed to 'MY'. Now Malayalam keyboard is activated. and you can start type in Malayalam.
Open Wordpad (or any other text editor) from Start menu and start typing in Malayalam.

Setting up Windows XP for Transliteration
Step1: Download Mozhi Keyman from this link. Install it.
Step2: Just after installation, Mozhi Keyman icon will be visible on your task bar. Click on it and choose 'Mozhi Keymap' from the following list and you are done.
Open a text editor- I recommend Wordpad and type 'amma' and press enter. You can see the difference now.

You will get more information and support from
http://smc.org.in
http://malayalam.web4all.in

mcu8051 IDE for Windows

2010-07-04T11:58:00.001-07:00

mcu8051IDE can now be used in Microsoft Windows also. If you are not aware of mcu8051IDE, read my previous post: Introduction to mcu8051IDE

Download the following:

First install ActiveTcl and SDCC and then mcu8051IDE.
Then you have just completed mcu8051IDE installation in windows.
If you want to report bug, go here.

How to activate BSNL 3G in iPhone?

2010-07-04T11:37:00.000-07:00

Maintaining iPhone features in India is not easy because almost all mobile phone users are belong to Nokia or Sony Ericsson. So support for Apple iPhone is less. To use BSNL 3G features, you require a 3G supported mobile phone and BSNL 3G USIM. Normally to get activated in BSNL 3G, you need to send {your mobile model} to 58355:

example: NOKIA E65
to 58355

It worked for my Nokia E65. But for iPhone it is currently not possible because, they are not having the settings for Apple iPhone. I activated 3G successfully and I did what follows.

Step1: Go Settings->General->Network->Cellular Data Network
Step2: Edit under the tab - Cellular Data
APN => bsnlnet
Usename => {Left blank}
Password => {Left blank}
Step3: Go Settings->General->Network
Step4: Switch 'Enable 3G' to ON. Also switch 'Cellular Data' to ON if not.

*Note: 3G will work if you are in a 3G coverage. Else you can get connected and use internet with 2G or 2.5G. If you are not in a 3G coverage area, it is better to turn off 3G. This will save a lot of battery. If you are in a 3G coverage, and you turned on 3G on your iPhone, a '3G' symbol will be displayed on top left corner of your iPhone screen. If you are in 2G, a 'E' symbol is displayed to remind that you are in EDGE network.

Step5: You are done. Use 'Safari' to browse internet.

If you are having any problem please report. If you found any other methods, please comment about it.

Qt - Ping Pong Example

2010-04-11T03:37:00.000-07:00

This is a simple ping pong (not game) play area example in Qt. You can modify this program to make your own arkanoid/ping pong games. I think it is useful for somebody. All files associated with the program with source can be downloaded. If you are Qt beginner like me, this example will help you how to use QTimer class and time interrupts.

Download ArkanoidArea

FEL: Qucs tutorial for beginners Part1

2010-03-27T22:15:00.000-07:00

Qucs- Quite Universal Circuit Simulator - is now as the name suggests, quite universal. Pspice, Tina Pro etc give a very fine experience for circuit designers. But as far as a student is concerned, buying them seems difficult. Even though SPICE and its open source derivatives were free to download, their user interface was diffcult to be handled by a beginner. In such cases, people go for a demo version. But some people need freedom to do anything and Qucs is intended for such people.
Qucs is opensource an run on both Linux and Windows platforms. Most probably, you can find the binary in your OS repo while a readily installable file is available for Windows users.
After successful installation, launch qucs from menu or entering command 'qucs' and hitting enter. A window similar to figure shown will appear with a plane work space. Click components and add std. compnents to workspace by drag and drop. You can change the component parameter by double clicking on the component. A label should be added to the workspace to indicate that which simulation you are doing. For a beginner, it is easy to learn simulation in Qucs after watching this video: Qucs.ogv

Download Qucs video tutorial : Qucs.ogv

Download Qucs sources.

Download Qucs for Windows
Note: You need FreeHDL to be installed along with Qucs in order to simulate digital circuits properly. It will be installed automatically if you install it from repo. If not, you should manually download and install and reinstall Qucs if necessary.

FEL: Introduction to MCU8051IDE

2010-03-22T07:19:00.000-07:00

There is a lot of free and propitiatory IDEs for micro controllers. Here I like to write about MCU 8051 IDE - An open source project packaged under FEL (Fedora Electronic Lab). Intel 8051 is a standard micro controller and that's why it is essential in engineering syllabus even though some good stuffs are there in newer micro controllers from Microchip, Atmel etc. Simulating 8051 is pretty easy if you own a good 8051 IDE. There is a lot of IDEs available for 8051 simulation and emulation. But it is not a good idea to spent your valuable money for that, if such good free and open source IDEs are available. I am just coming to my point. It is about MCU 8051 IDE. It is packaged with fedora electronic lab. If you intend to stick with other OS, you need to compile the source code. Currently it supports more than 79 MCUs. Know more and how much powerful it is. I have uploaded a screencast of MCU 8051 IDE and I think it is enough to start with for a beginner who knows assembly level programming in 8051. Of course, one can write and simulate the program in C also.
Download video tutorial mcu8051.ogv.

You can view the screencast with VLC media player or any other ogv supported media player.

mcu8051IDE for Windows

Inside the Mosquito killer

2010-03-13T09:26:00.000-08:00

Nowadays, people widely uses mosquito killer bats because of their easy usage. The product is imported from China for very cheap price. There's some electronics inside it. If you understand the working principle of that circuit and if you are an owner of soldering iron, you can easily troubleshoot the problems and can use the product for a long time.
The power source of old products was dry cells, while now it is rechargable battery of 2.4V. There is bridge rectifier and a capacitor is used to get enough power to charge the battery. Transistor become ON, when switch is closed and the sudden change in current in the primary coil in the transformer forms a higher voltage. The voltage is coupled to the secondary coil. transformer winding is so that peak voltage will be about 2000V. The diode network only pass a fraction of the output voltage to the metal net.

Slider game using Qt

2010-03-12T17:42:00.000-08:00

It is better to do simple things first in Qt before making hands dirty with complex programs. Now I just prepared a slider game using Qt.Hope all of you know how to play slider game. My code is simple and having a slider panel of 3x3 matrix. I know the code is not much pretty. But I just put my source code to download. It may be helpful for beginners. Of course, you can modify the code to satisfy your needs.
Enjoy!

Download slider.zip
Note: You need to recompile the code before using. I successfully compiled the code in Linux. Of course, you can compile it in other platforms without modification of code.

Welcome note on Puppy Linux boot up screen

2010-03-01T02:39:00.000-08:00

Is it fun to display a welcome note with your name while booting up Puppy linux? If you think so, you can continue reading. Here I am telling how to set up your Puppy Linux to display "Welcome, {your name}" at boot up. Probably you can do this in other Linux based OS with slight or no modifications. But nowadays bulky operating system intentionally hide the boot up screen with a splash image.
First of all, navigate to /etc/rc.d
Then open 'rc.sysinit' . You should have root privileges in order to edit this file. Read carefully the 'Read me' file before going to do anything. If you are not going to take a risk, back up the file into any other externally accessible directory.
After you open the file in your favourite text editor, just go through the file, you will notice that, this script is automatically executed at every boot up. Go to the end of the file and append the following script.

##########CUSTOM SCRIPT##############
echo -n "

" >/dev/console
/bin/echo -e "\\033[10G\\033[1;34mWelcome, {Your name}\\033[0;39m" >/dev/console
echo -n "

" >/dev/console
sleep 2
###################################

Edit the script with your name instead of '{Your name}'. The script is nothing but an echo statement to the console. It is possible to change the display properties by changing the parameters along with the text. First test it in terminal and then write script is recommended. Now save the file and reboot.
Done.
If you avoid 'sleep 2' statement, you may not see the text at boot up. One best way is remove the line 'sleep 2' and set a login password for Puppy as I did. Then Puppy gives a cool welcome to you and then ask password.

Free anonymous email now for security

2010-02-20T01:43:00.000-08:00

If you want to register in a website which is untrusted and you are not intend to reveal your identity to them, but the website need your email ID and it is mandatory. What do you do? In such cases it is good idea is to have a temporary email which lives only for few days or months and will expire. But for some instant access, it is necessary. You are allowed to read incoming mails till the account expires.
Go here.
You just need to make your account by entering your user name. password is optional. you also need to specify the date which the account expires. Nothing more and you have done.

Yo Frankie: Open Game Project from Blender

2010-02-14T09:52:00.000-08:00

Do you remember Big Buck Bunny?

'Big Buck Bunny'(Code-named Peach)is a classical animated short film entirely from Blender platform which is open source. The video reveals the power of Blender of course, and also contains a neat story with full of fun. If you didn't see this short film yet, you are too late, but here is the chance to download. The hero in this film is a big Buck. Other characters are some naughty animals named Frank, Rinky and Gamera. I personally like Frank's acting than others. I think many people realize that secret, that is why the rise of new open game named Yofrankie (Code-named Apricot). The name came from Frank's name and hero is Mr. Frank. You need to download the game (~120MB) which will run on a Blender engine or Crystal space. Another good side of YoFrankie is that you can develop it in your way wince it is open source. A number of good tutorials are there published in the official website. Both Big Buck Bunny film and YoFrankie are released under Creative Commons Attribution License. Watch a video of Yofrankie below:

Let's have fun during festivals!

2010-02-10T09:35:00.000-08:00

Festivals are not only for entertainment. You can do some cool things. I have just made a fire powered car using commonly available things during festivals. See how:

The things you required:Now, make the things done.
Unfortunately, I can't capture pictures and videos of running the car, because, my mobile phone did something wrong while capturing. Sorry. I don't have another sample to do once again. I will try it next year!

Car after launching.I got everything fine. Even though you think this type of stuffs are gibberish, people like me find entertainment by doing so.

Warning: use a metal or card board plate above toy car in order to avoid over burning. Don't do it in you room. Do it away from your home as well as from inflammable things. Don't launch while you stand behind the car.

Kolibri : Just 3MB size for this OS!

2010-02-05T07:44:00.000-08:00

I am a fan of small operating systems, because, I really suffered the problems of bulky operating systems. I used puppy Linux (It's something great), Damn small Linux etc. Damn small Linux is only 50MB in size and works much fine. Some floppy Linux comes in 1.44MB but it has no GUI at all. A normal user need GUI with some office applications, media player, internet browser, email client, need some programming, and games. But all of the listed above is not included in the floppy linux at all, but almost all are covered by Puppy Linux and DSL. Average of 50MB is happy for me, but for some users, it is too high!. This is what the reason of development of ultra small OS with a size of only 3MB.
The 3MB sized OS is named 'Kolibri' which means humming bird- world's smallest bird. Kolibri is moderately fare OS for eyes with very high performance. In order to increase efficiency of code, OS itself is written is assembly language. I installed Kolibri in my pen drive. The boot up time is less than 3 seconds. I really shocked while seeing the stuff included in just a 3MB. About 30 classic games, text editor, image viewer, text based internet browser, hex editor, assembler,music player, of course a shell and many more. kolibri argues that, it is not windows, linux or anything. It's shell which can accept only 20 commands. But I found all are linux/unix cmmands. There is a bunch of 3D demoes which are excellent.
Go to Kolibri official wesite.
How to install?
You can download iso image and write it to a CD. But I felt ashamed to write 3MB sized iso image to CD. So I opted my pen drive. Installed it using windows XP. It can be installed using linux also. Download image for floppy/hardware first and unzip it. You probably need 7zip for that. Then copy Kolibri.img into thumb drive. Before copy, you need to fromat your thumb drive/pen drive to FAT32. After copying, go to HD_load->USB_Boot directory and run inst.exe then, run setmbr.exe. You need to reboot now and boot from usb. If you don't know how to boot from usb port, you need to read my old post: Booting from CR-ROM or USB devices
Sometimes, you need bulk operating systems to get your job properly done. But this type of efforts of developers seems really appreciable.

Swathanthra Malayalm Computing

2010-01-16T10:15:00.001-08:00

Note:- Malayalam is the mother tongue of Kerala (India). I don't know people other than keralites interested in it.

I will be a little verbose, if I am telling about my childhood and my mother tongue - Malayalam. It intrude in my words, however I try to hide that. Everything I first heared in Malayalam - stories, poems everything and of course, I first read the Holy Bible in Malayalam. Now what about Malayalm computing?? Now the Open source community offers "Swathanthra Malayalam Computing" for Linux Systems. Just see the Ubuntu malayalam desktop below(this picture is not captured by me. Thanks to http://arunmvishnu.com/).Visit official website of SMC.
You can turn your desktop into full fledged Malyalam desktop if you follow the instructions in the official page. I am not intended to copy the same instructions in the official page.But the following links will be useful:

If you can't read anything from SMC, your browser probably haven't the malayalam font installed. I purposefully doesn't added any malayalam words in this post in order to clearly read those who haven't their firefox installed with malayalam plug in. Today onwards, you can easily read any malayalm websites on your firefox. Here is the solution.
Mozhi:You can write malyalam articles of your own using Varamozhi. I personally felt a little difficulty in writing malayalam in Mozhi compared to blogger. But Mozhi offers a unique english character bunch to represent a malayalam letter.
A guide for malayalam in computer.
Download Debian Lenny in malayalam.
Have a look at Wikipedia in malayalam.

Some malayalm blogs:
http://berlytharangal.com/
http://karinkallu.blogspot.com/
http://workersforum.blogspot.com/
http://vellezhuthth.blogspot.com/
http://rajvengara.blogspot.com/
http://marjaaran.blogspot.com/
This is a small list and you can see several hundreds of Malayalam blogs by searching with a keyword something like 'malayalam blogs list' or in this link.

Here comes Octave Online

2010-01-12T05:27:00.000-08:00

Before going to read more check whether you know about Octave.

From the inspiration of my last post about the online Python, I searched internet for the online octave. Luckily, it was a success. All scripting languages or tools are feasible to convert to its online version, even though it doesn't exist for the most. Come back to Octave online. I don't know whether it can be called as octave online, but they calls it Math calculator which supports octave. I was successful in executing simple matrix calculations in the Octave online. Anyway, it is the time to dive into Octave online. You just need to click here.
The parent website http://www.online-utility.org/ offers other free online utilities. Search and explore more.

Online Python

2010-01-12T04:52:00.000-08:00

My friends always complaint that they don't have an environment for learning python. They have internet connectivity in the college, but not having the permission to install python interpreter on those machines. So they satisfied by just reading the tutorial only and not by doing python. But here is the solution. Online Python Interpreter is an online python terminal and you can enter python commands as like in your shell. The virtual browser shell is a little bit slower and and again slower for slower internet connections. The speed is entirely depend upon your internet connection and no way to increase because entire python engine is on the server side. But I am sure it will be a boon for the beginners and net-book users. Current limitations are:

Can't define functions or classes.
Can't run a script

Click to enter online python interpreter
Click to view the ubuntu forum discussion about online python interpreter

Let's make our hands dirty with PIC

2010-01-06T07:30:00.000-08:00

This is my first cook book on beginner level PIC programing. This book is useful for the very beginners who don't know how to develop in PIC programming. I included a screen cast video to learn the entire tutorial within minutes. The book format is available in both pdf and doc format. Of course, everything is free and distributed under Creative Common's License. All codes under GPL. I am thankful if you suggest any improvement and point out any errors. Nothing more to say.

Download Introduction to PIC Micro (9MB)

View the tutorial video: (It is included in the download package)

How to hack passwords in windows XP?

2010-01-02T11:18:00.000-08:00

Warning!
Things here explained can be used in extremely nasty things. They are not recommended by Opentechlab. Use everything in your own risk. Also Opentechlab suggest some tips to avoid password hacking.

Here I am going to say something cumbersome to somebody. Here is a guide to hack the login passwords in windows XP. Also given how to avoid such hacking and keep your PC maximum protected from crackers. Opentechlab does not crack, it will hack only!

Password hacking using Backtrack
You first download the following file

Backtrack 3 Final (BT4 is also available, but I suggest BT3)

BT3 is an opensource Linux OS. BT3 consists of just a slax and the hacking and network security software. Since Slax uses lzm module mechanism, it is easy to install and remove the modules we need to. You ca download it as a bootable iso image or as USB pen drive installation file. I downloaded iso and write it to a CD and everything going perfect. Once you installed BT3, you just need to boot up from CD-ROM. Within minutes, linux kernel loads and backtrack desktop appears. Now you need to do the following things:

bkhive /mnt/hda1/WINDOWS/system32/config/SYSTEM key

(result is the boot key)

samdump2 /mnt/hda1/WINDOWS/system32/config/SAM key
samdump2 /mnt/hda1/WINDOWS/system32/config/SAM key >~/Desktop/password.txt
john ~/Desktop/password.txt -users=Administrator

now the hashed password will be showing below

Here, it is assumed that hda1 is C: drive (where MS windows XP is intalled). If not, that should be repaced with the actual one. The password.txt is file which contain passwords of all users, but they are no readable, they are hashed. To remove hash, you need to call a program called john.
john ~/Desktop/password.txt -users=Administrator
only gives the password of Administrator. If you want to know the password of another user, type:
john ~/Desktop/password.txt -users=username
You can simply do this:
john ~/Desktop/password.txt
to get passwords of all users, but it is time consuming. Knowing what you want is ponentially advantageus than knowing everything. And it will not eat much of your time. Somethimes if the password to be hacked is much complex, you get a leisure time to drink a cup of coffee!

How to use rainbow tables in backtrack?
You can use rainbow tables while hacking passwords. You can download lot of rainbow tables from freerainbowtables. I think downloading all rainbow tables in your hard disk is frustrainting (more than 1000GB!). Download some simple tables to experiment with. To use rainbow tables, BT3 provides a program called 'rainbowcrack'. It can be accessed from:

Main menu -> Backtrack -> privilege escalation ->All -> Rainbow crack

But rainbow crack only supports tables of type *.rt. But rainbow tables with type *.rti is abundant over internet to free download. Solution is to download *.rti tables and conver it to *.rt using rti2rto.exe. Here you are able to use rainbow crack instead of john. All other steps are same.

Using Ophcrack
Ophcrack is also opensource and is also useful. I personally didn't tried that, however many of my friends work successfully with that.

Download Ophcrack
You need to download rainbow tables also.
Read more about rainbow tables

How to prevent password hacking?
Here again, prevention is better than cure. If you care about how much your data secure to be, you should keep your passwords be secure first. First of all, you do not store your passwords anywhere other than your brain. Every time you enter your passwords at login, is boring, but you should aware of the consequences. I said it generally, but here this is not possible. Use more than 10 characters for your password. For each addition of a new character, you can see that how much extra time BT3 takes to find out the password. Add symbolic characters and numbers. Finding a password with symbolic characters and numbers are very frustrating, and a cracker work hard for hours on such computer until he get a message 'Failed to find password'. Don't enter a password with meaningful words. If your password is a sentence such as 'Mary had a little lamb' and others password is 'asdfiuerh', then it is very easy to find out the former even though it is lengthy in character. Use different passwords for diffenrnt internet accounts. If you feel difficulty to memorise all passwords, you requre a good password manager (I recommend Keepass). Change your passwords periodically. It will save you a lot. If you have a top secret information, and is not to be revealed to the world for any reason, I have a good idea but is not guaranteed. Just copy the thing to any portable device and put it in a Bank locker and through your computer to fire and keep watching until it get into ashes.

PYRO : Python in hand with Robotics

2010-01-01T10:24:00.000-08:00

Python developers all over the world are searching for fields that are not involved python. I recently found a good job by them - a boon for robotics enthusiasts - that is Python Robotics or simply Pyro.

Go to pyro project page

Download Pyro live CD

Many built-in python scripts are there to define the robotic brain and paths. Of course, you can write your own scripts. Anyway, pyro is a wonderful experience.

I encountered a problem while booting from pyro live CD. It seems to be mother board and chipset specific. My problem was, no x start up. It hangs up when displays "Probing/Loading AGP Modules...". I used several knoppix cheat codes to enter into kde desktop. It was successful. Thanks to knoppix developers forum. The boot time cheat code i entered is:

knoppix noagp

If you encounter any such problem, try to search for knoppix boot problems and not for pyro boot problems.

A lady who travelled faster than light....

2009-12-30T05:24:00.000-08:00

I recently read and much inspired by this old poem:

Once there lived a lady
She could travel faster than light
She left out of home today
And returned back yesterday!

Sometimes the real things are stranger and mysterious.....

Gui front end for parallel port controller in Linux

2009-12-29T09:55:00.000-08:00

A graphical front end for the parallel port controller in Linux was my dream and I just satisfied it in my Xmas vacation. I used Qt framework from Nokia. I just put here everything I did. Of course you are allowed to download and use it under GPL (GNU General Public License). You are appreciated to modify source code according to your needs.
Now the program supports only on Linux platforms even though qt frame work is independent of platform. The reason is that, parallel port controlling is directly depend upon the OS you are used. You can easily control your parallel port in MS DOS environment, but things become worse when you try in Windows XP. Since the program calls the ioperm() function, you should have root privileges. Otherwise an abrupt exiting of the program occur. You only need to do the following things:

Be root, and start the program by ./parport2. Try to open it from terminal at least for the first time in order to track bugs.
Click 'Initialize' to call ioperm(). If you are not root, then the program abruptly exits while you click it.
Nothing will be happened at outside while you click in 'Initialize'.
You can use 8 switches to turn on or off the output data ports.
The current output value in decimal is displayed on lineEdit.

Most probably the executable version will not work in your system unless your system configuration matches with mine. So it is recommended to compile entire program using qt. You need to have qmake installed in your system (qt-dev-tools). The compiling instructions for qt program is beyond the scope of this post.

Download parport.tar.gz (1.4MB)

I tested it in my PC and worked without any problem.
Warning: Take care while you play with parallel port. Very rarely, the after effect may fatal.
Note:- This program is intended for educational purposes only. May not be updated until anyone report a bug or a request to modify.

PHET science simulations for students

2009-12-26T22:04:00.000-08:00

PhET interactive simulations - Fun, interactive, research-based simulations of physical phenomena from the PhET project at the University of Colorado.

I found those simulations were good in today's eduction- thanks for university of Colorado. Most of them are intended for Upper and High school students and pre- graduate students. However, if you just spend your time in experimenting with it, I am sure you get something new. Phet interactive simulations create a virtual lab environment. It's just a feeling that to enter into a physics or chemistry lab in a college. You can do anything in your own lab. Nothing to fear. No more comments from teachers...
One more advantage is that, you only need a java powered web browser. You can browse through different lab environments. If you like PhET virtual lab, you can download it for offline usage. Linux(80MB), Windows(97MB) and Mac OS(85MB) installation supported.

Browse phet simulations
Download phet for offline usage.

Parallel port programming using C/C++

2009-12-23T07:23:00.000-08:00

Parallel port programming is easy with C or C++. Even other languages integrate C/C++ codes to their codes in order to program parallel ports. If you are a beginner in parallel port programming and know nothing about it, just go through this intro page. Nevertheless the efficiency of code, the code may be different for different platforms and need to be compiled with some change in the code.Here we see how to program parallel port(printer port or LPT) in both GNU/Linux and MS Windows platform.
Parallel port programming in GNU/Linux
I am not intended to make a wide description. I am directly give an example and this is what you want. If you are experienced the taste of C, you can easily catch what the program code mean.(We use LEDs to check whether our program run. You can see a simple circuit in the intro page). Connect the circuit described in intro page. to the parallel port properly. Then make new file parport.c and edit the file as shown:

#include stdio.h
#include stdlib.h
#include asm/io.h
#include unistd.h

#define base 0x378           /* printer port base address */
#define value 255            /* numeric value to send to printer port */

main(int argc, char **argv)
{
if (ioperm(base,1,1))
fprintf(stderr, "Couldn't get the port at %x\n", base), exit(1);

outb(value, base);
}

The above program is copied from epanorama. You should compile the program as su (super user) since ioperm() function needs root access. But in my system the above program didn't work. Many of my friends got error while compiling. The solution is to change the 4th line
#include asm/io.h
to
#include sys/io.h

You change the line and recompile only if you get a linking error. Sometimes you get an error like "Couldn't get the port at 378". But this is not a problem due to the port address. You probably may not be su.

Parallel port programming in MS windows
Converse the subtitle suggests, this program is not working in the windows environment, but in the MS DOS environment. I think you have basic knowledge of how to compile a C program.

#include stdio.h
#include conio.h
#include dos.h

/********************************************/
/*This program set the parallel port outputs*/
/********************************************/

void main (void)
{
clrscr();             /* clear screen */
outportb(0x378,0xff); /* output the data to parallel port */
getch();              /* wait for keypress before exiting */
}

The above program is also from epanorama. If you try to compare those programs, you can see a very little difference between those codes. Parallel port is a hardware and surely it is depended upon the OS you are using. So you can't write a cross-platform code for the parallel/printer port control. Please note that you can read inputs as well as write as output however, the example only shows the output control. Sometimes your port address may be different, however in most cases it will be 0x378. If it fails try 0x278 and 0x3BC. Read more here.
You can check your program by simply inserting an LED connected in serial with 1K ohm resistor.

Read my post on parallel port control on python

How do we think? A brief introduction

2009-12-23T04:58:00.000-08:00

Thinking about how we think is difficult, because thoughts of thoughts are limited by thoughts itself. But learning of how we think is essential in computing as well as AI powered robots. The basic reason of our thinking ability is a special type of cells in brain - neurons. A neuron is not perfectly known to human yet, but many similar models are proposed. The power of neurons is in its networking ability. Neurons are connected to each other and these complex networks may called as neural networks. I am not describing much about neurons because it is beyond our task. It's well enough if you just get an overview from Wikipedia. As I said, many convenient models are there to explain the behaviour of a neuron (Of course, a networked neuron is complex than a single one), but I am just touching simplest one named Perceptron. I will also mention back propagation during the example. I have pasted one figure from Wikipedia because you need it.The area in the shaded square can be considered as a neuron. x1,x2,......x7 are the inputs and w1,w2.......w7 are the corresponding weights (I will tell you what it is). and f is simply a function and outputs y. If the weighted sum of the inputs exceeds a particular threshold (which is previously be set), output y fires out. In actual neurons, y depends on other parameters such as input frequency. Since whole process in actual neurons are chemical, the explanation become rather complicated. But in all models we consider input as well as output signals are electrical in nature.I am explaining once again: first find

x1*w1+x2*w2+.........+x7*w7

If the resultant value is greater than a threshold (Typically 0), y=1; otherwise y=0.
I hope you understand something. But I know most of you are not satisfied because, you don't know what is really going on! Right?
Let me tell an example. This is a story. Here is you, Heroin is you.
Consider you have three friends and you(your brain) thinks that they are:

Albert - Your best friend. You have a confidence level of 0.7 on him. You trust him and ask his opinion before every important attempt
Deepika - Your classmate. Confidence level 0.3. Good personality.
Tom(me) - Confidence level of -0.55. Always say lie. Cheating personality.

These prejudice are taken by your brain from your experience. May be true or may not be.
The problem starts here. You are getting ready to go to your office/college. There are two ways to go. One is short path (easy way). Other is long. But short way has a problem is that sometimes it will be blocked. If you take the long path, you may reach the destination late. But if you choose the short path and in any case if blocked, you can't reach the destination on that day.
Then you come to know that today short way will be blocked. Then you consult your friends. Check their opinion:

Albert - Short road is not blocked. Damn sure.
Deepika - Someone told me about it. Short way may not be blocked. But I am not sure.
Tom - Hey man, road is blocked.

Can I go straight away through the short path?
Let's look how your brain solve the problem. Albert surely says that road is not blocked. Put a value of +0.95 for his opinion. The positive sign indicates that he is opposing. If Albert says sure that road blocked, the value may be -0.95. You don't know much about Deepika. But she may be right. Put a value of +0.1. Tom says it is blocked. So put -0.8.
Here threshold value is 0. If weighted sum is greater than 0. road is blocked. It is good to choose the long way. I not, road is not blocked, choose the short path.

Weighted sum is:
signal strength of Albert * confidence level+ signal strength of Deepika * confidence level+ signal strength of Tom * confidence level
=0.95*0.7 + 0.1*o.3 + (-0.8)*(-0.55)
=0.66+0.03+0.44
=1.13 which is greater than 0.

The brain successfully derived a decision for you. It is almost sure that road blocked with a confidence level of 1.13. Did you notice the analysis of Mr.Tom's opinion. You think tom is cheat. So the opposite of what he tells will be right. If you didn't understand the meaning of previous sentence just read one more time because some interesting things hidden in that sentence.

Ok, let's continue our story. Then you started going straight away through short path. You started journey in your own car but Alas! road is blocked. You couldn't just believe your eyes. but suddenly you realize the fact that you can't reach your destination today - you trapped in a huge road block.
Here, your brain attempts to rewire the entire circuitry inside it. Your thoughts were entirely wrong. Both Albert and Deepika was wrong, but Tom was right. You change the congedence level as,

Albert - 0.4 - I can't blive he cheated me.
Deepika - 0.1 - no coments.
Tom - 0.2 - oh, sorry Tom.

The actual working principle of neural networks is far deviated from the above story, but the fundamental thing in both is same. Actual neurons has a lot of diifernces and complexities than the neuron models

Go on with pyS60

2009-12-08T19:04:00.000-08:00

I got a very good feedback from my previous post: "How to simulate PyS60 in your PC". As the request of opentechlab readers, I am attempting to write a brief beginner level tutorial on pyS60 emulator.

Once you are successful in installing and setting up the environment (If you didn't set up yet, click here), it is the time to go on.

Start the emulator program from:

Start->All programs -> S60 Developer tools -> 3rd edition FP2 SDK -> v1.1 -> Emulator

You probably need to wait for a couple of seconds to load it if your system is slow. Then a medium sized window with a full fledged mobile phone appears on the screen.

Now you need to open python. Just do as in your mobile phone. it's in Menu -> Installations -> python.

Now it's ready and do what you want.

Hacking python script

Select options -> Run script ->ball.py

You can move the ball anwhere in the screen. It's a physics simulation example in python. You can see the actual python script by opening ball.py file using any editor (notepad is not recommended. programmers notepad is good). The file is stored in :

C:\S60\devices\S60_3rd_FP2_SDK_v1.1\epoc32\winscw\c\python

Search for the word 'blobsize'. Then you can find a line like:

blobsize = 16

Change the value of blobsize into 25 and save it. Then open ball.py in emulator. Did you notice any change? Similarly you can change acceleration, gravity (what about changing gravity into -0.01 ?) etc.

Developing your own programs

I am just starting with a hello world. Here is the program.

1)Simple hello world

print "Hello World!"

2)Say, hello world

from audio import*

say("Hello World!")

3)graphical hello world!

import appuifw
appuifw.note(u"Hello World!", "info")

It is good practice to make a short cut of python on the mobile desktop by changing options in settings.

How to simulate PyS60 in your PC

2009-12-07T01:21:00.000-08:00

You can do your experiments in PyS60 without touching your mobile phone. The experimentation is easy while you set up everything in your PC. Here I am explaining how to set up the PyS60 environment in WinXP platform. I didn't try this attempt on my Linux yet. I will surely post about it if I get some good mobile stuff on Linux. This will be a boon for python developers in Nokia S60 mobile phones. But rarely it can be seen that some python scripts works neatly on simulator may cause strange responses on your real world system. I would like to here about it if you get any funny experience on your S60 device.
Download the required things:

1)Download S60_3rd_Edition_SDK_Feature_Pack_2_v1_1_en.zipfrom the following link:
http://www.forum.nokia.com/info/sw.nokia.com/id/807ec36d-0a8e-4bda-8e10-4d5e5bb4764a/S60_3rd_Edition_SDK_Feature_Pack_2_v1_1_en.zip.html

2)You can find ActivePerl 5.6.1 build 635 here:

http://downloads.activestate.com/Act...SWin32-x86.msi

3)Download PythonForS60 _1_4_5_SDK_3rdEdFP1.zip from http://sourceforge.net/projects/pys60/files/

First install ActivePerl because S60 SDK requires it.
Then install S60 SDK. Please note to install it in C:\ drive to avoid confusion.
Extract PythonForS60_1_4_5_SDK_3rdEdFP1.zip. Then you get another archived file sdk_files.zip.
Extract it again and you get a directory named 'epoc32'.
Copy this directory into "C:\S60\devices\S60_3rd_FP2_SDK_v1.1"
Then probably Windows XP asks to replace the already existing folder 'epoc32'. Click yes.
You have done. Cheers!

Don't believe your eyes!

2009-12-06T05:00:00.000-08:00

Don't believe your eyes, because everything you see, touch and feel is just a feeling only. Consider you are traveling in a space ship. No way to look outside. Space ship is traveling with higher velocity. If there is an obstacle present in front of the spaceship, sensors feel the presence of obstacle and it is reported on your computer. Then you turn the spaceship left or right. Then sensors feels that obstacle is removed (not obstacle, you!) and computer indicates that you can go straight way.
The above explained is a successful turning. But here I go in a something different way. The sensors are intelligent enough to send a fake signal that "there is some sort of obstacle" on the monitor. Actually, there is nothing in front of it. But your computer shows some obstacle. So you put a signal to turn right. Then the sensors shows that "now obstacle is removed. Go straight". You feel that you done well, but the sensor and the computer system really cheated you. Sometimes it was not a cheating, because ,there will be a possibility of thinking that there is an obstacle.
Our brain is not much different or error free in similar cases. If you are think that you know the universe, I think it is actually bad. Things you feeling from the surroundings may be different from reality. Your eyes are similar to the spaceship sensors. Not only your eyes, every sensors just see one phase of the reality. That really implies that knowing reality is too difficult.
I am not going too inside. I am not a philosopher. So let's have a fun. just go thruogh this link. A number of good eye illusions are included. Here I give a puzzle from eyetricks.com - Find which is longer?

Why there is so many constants in equations?

2009-12-06T04:45:00.000-08:00

I will tell you the secret of constants in mathematical equations. They are not intruded or the error or nothing, but it is essential part of the equation. I will tell you some facts while going on your story. I will exemplify what you want in this story.
Consider you are a young scientist. You close your room's door and start experimenting on something when you get leisure time on Sundays. You are doing something seriously on your table, with an electrical circuit. Your aim is to find the dependence of a node voltage X (ie, a voltage in a part of the circuit). You came to know that X depend upon the supply voltage V. You start experimenting and plot graph of X for different values of V. Then you
got a graph like this:
It is perfectly linear. So you write,
X is directly proportional to V
To be more specific, X increases for an equivalent increase in V. You repeated your experiment and plot another characteristics with time. This time, your supply voltage kept constant. Plot X with time t.

From the plot, it easy to find that dependence is,

X is directly proportional to e^(-t)

Then from the above town experiments, you can write that,

X is directly proportional to V*e^(-t)
ie, X = K*V*e^(-t) where a K is the proportionality constant.

You can find K from single experiment. Once you got the value X when for a particular V and t,

K = X/(V*e^(-t)

But I want to tell you that your experiment as well as your mathematical expression is not perfectly true. A true dependence of X on it's environment will be very complex and tedious to express in mathematical form. Your X may depend on the atmospheric pressure, temperature, material properties,...raining in New Delhi,.....war on Iraq and so so.
After several years, you repeated your experiment and find that X depending on temperature also. Temperature has a direct linear relationship (like V) on X. But last time, you didn't got it. What's the reason? You were not aware of that, you did the experiment in room temperature itself. But this time you get different answers in day and chilled night. Now you modify your equation as,

X is directly proportional to V*T*e^(-t) where T is the temperature
X = L*V*T*e^(-t) where L is the proportionality constant.

Here I want a point to stress. Do you think your previous equation was wrong? Not at all. It is correct in an isothermal environment. But it become wrong in a temperature varying environment. A single measurement depending upon many things in the surroundings. But many of them can be ignored, because, they have less relationship with X. Something can't be ignored, but they may not be measurable (such as number of electron collision per second).In such cases, just put a constant for that, as long as they are constants. To be more clear, if your experiment depends upon the radius of earth, just put it as a constant in your equation. But when you do the experiment in moon, your experiment may troubled, unless you replaced the radius of earth with moon. I meant that variables can be considered as a constant or variable according to the environment.

Puppy Linux : Give life to your Thumb drive

2009-11-28T20:34:00.000-08:00

If you didn't tried Puppy Linux - one of the smallest Linux, core's yet-remember, you have only one life, try Puppy today itself. Puppy Linux - the name is not much inspiring for geeks, but I found it is the most stable and useful OS in the pocket Linux category.
It has the following advantages over other less-sized Linux operating systems.

Small sized. Ranges between 80MB to 150MB
Install anywhere - HDD, USB Pen drive, biz. card sized CDs. (You can use ordinary CDs, DVDs, Blu-ray discs - but it is too big for puppy.)
Easy to use.
Official website offers boot time of less than 1 minute. But it is typically less than 15s in my Intel P4 with 2GB RAM.
Puppy is beautiful than any other pocket OS.
Smart and crash free. I used more than 10 Linux flavors. Everything crashed, but I haven't experienced Puppy's crash.
Puppy sessions are saved in *.sfs file. It can be placed everywhere. Puppy search for it at boot time to recover the previous session. There are a number of fundamental advantages for that. I found many of my friend's computers not supporting USB boot. Of course they can boot from a CD-RW but it is not writable. Puppy offers several ways to overcome it. One is that, it can write previous sessions in CD as a multi session write. But it can be used until CD size limits. Another way is to write *.sfs file in HDD (for home usage) or USB pendrive ( for portability) and puppy kernel file in a a CD. So CD can be booted easily and can save sessions.
You can resize puppy save session file while running.
Comes with almost all drivers.
A wide variety of Puppy flavors are officially and unofficially available. These flavors are called 'Pupplets'. Pupplets are intended for a particular task - ie, it supports a task greatly. There are pupplets for painters, gamers, processionals, children, students and so on.
Brief and understanding tutorials, quick replying forums, community etc.

Once you downloaded Puppy, you have a lot of questions about installation, usage etc. Most of them answered in the official website and associated forums. Otherwise just google for that.

How to prevent virus from USB pendrive

2009-11-18T06:40:00.000-08:00

Sometimes attacks of virus through USB pen drives are a real headache. Even though most of them are trivial, anti virus programs may not catch them. Use this following techniques in order to prevent them.

Make a raw file in the name same of a virus file. Most probably, these these files will be hidden. To view this, a good way is open the pen drive in Linux OS. you can see some names such as "virus.exe" on the root folder of pen drive. If it exists, open it using a text editor program and delete all the characters and if you want, include some raw characters and save. If you don't have any such files, but want to prevent them, you first of all need to find the name of that virus file and make a raw file in any text editor and save it in the same extension of the virus file. I successfully prevented a most common virus named "autorun.inf". Warning : This method not always work.
Use a good anti virus on your PC as well as in your pen drive. Some good links are http://www.usbantivirus.net/ and http://www.zbshareware.com/download.html
Format your pen drive well, if your head ache is cumbersome. Some virus programs can override quick format in windows. So use GParted.Prevention is better than cure. Formatting is the last chance.

Let's do a simple hack!

2009-10-17T04:02:00.000-07:00

If you are not aware of the difference between the words 'Hack' and 'Crack', I recommend you to hear what wikipedia says. Anything you want to do in a propitiatory program like MS Windows which is prohibited by license or it is not intended to do so may be called as crack. But the word 'hacking' has a great meaning which is different from 'cracking'. You can do anything on your open source program. If you are trying to crack your Linux OS which is open source, it may be called as 'hacking'. What is I want to say is that, an open source program can't be cracked because, they provide source code and hacking (cracking!) is allowed by license. If you are trying to beat an open source program, surely it will become a part of development. So an open source program can't be beaten. Hacking is intended for fun, especially by applying intellectual skills on something and and allowed by law. If anything you find violating the law, please call it as 'crack' not 'hack'.
If you are a beginner in Linux, like me, this simple hack will really attract you. This hack is done in my pocket slax 6.1.2 which is installed on my USB pen drive. But you can do this in any linux based distro which has a boot splash screen or login screen. The only thing you need to do is,
Navigate to /boot directory. In pocket slax, it is situated in the following path:
system:/media/sda1/boot
Then you can see one or more image files with .png extension. In slax, it is 'slax.png'. Edit this picture with a suitable image editor and change as you like it. For example, type "Hacked by ". It is interesting that you see your name at every boot up. If you are interested, you can put your photograph. But it is recommended that, you should not change the size of the image. Also, you should not change the name of the image. Of course, you should copy the original image.png file to any other directory in order to undo everything you have done.

Mouse gestures for Mozilla Firefox

2009-10-10T22:27:00.000-07:00

Mozilla Firefox one of the leading power of internet browsers, shows its real power and beauty only when the appropriate add on-s are installed. You can download and use them from Firefox add on page. There are a plenty of add-ons available and no need to specify which is good because it greatly depend upon your tastes. Recently I installed an add-on named All-in-one gestures and I feel it very interesting. You can install by clicking 'add to Firefox' button as you usually do while installing add-on. There provision to change the gesture pattern in the 'preferences' mode. Mouse gesture means that, some operations you done in Firefox such as 'back', 'forward', 'refresh' etc can be done simply by moving your mouse. I experienced no problem with both Windows and Linux platforms. There are tons of interesting add-ons like this. It is really fun to experiment with Firefox add-ons.

Booting from CD ROM or USB devices

2009-10-02T06:57:00.000-07:00

Booting from resources other than HDD is very simple, but the way in which configure your system for boot from a particular task may differ. First of all, you should know that, the boot configuration appearing on your monitor is independent of the OS, or any other peripherals connected to your system and it is occupied in your BIOS and it may vary for various type of mother boards. Nowadays, many people use liveCDs or liveUSB loaded with their favorite Linux OS for the sake of portability. So I think this tutorial will be useful to you.

After you power on your PC properly, a splash image will appear within few seconds on your monitor probably mentioning about your motherboard vendor or vendor logo. Some keys and their function may be mentioned on the screen.
For example: F9 : Boot menu F2 : Setup
The keys used for boot setup and boot menu will greatly varied. But the major problem is that this splash screen appears for less than a second in some systems so that you can't even recognize what is written on the screen. Here you should do is that press 'Pause/Break' key in your keyboard (It is positioned in between alphabetic keypad and numeric keypad). Then the screen pauses. Then you can configure as you like it. If you now want to boot system normally, press 'Enter'. Each of the operation will be explained while you are attempting to change this. This will not be explained here because this is different for different systems. But in most systems, if you think that you did something and don't know what is the consequence press 'Esc' continuously and probably one dialog box asks you to save changes. Press n/N for No or y/Y for Yes if you want to save changes.

If you want to just boot from CD ROM or like external devices, good option is that select one resource form the boot menu. The way how to navigate to the boot menu will be specified on the splash screen. If not, try F8 because, many systems having F8 as the boot menu key may not be explicitly shown. In boot menu, you can see several sources. 1.FLOPPY 2.HDD 3. CD-ROM 4.USB HDD .Select one which you want to and press 'Enter'. The system try to boot from the source. If fails, system may try a normal boot or a restart. Sometimes some devices for example USB HDD will not be listed until you inserted your memory stick or pen drive to the system before power up. In this case you should insert the USB device and try a restart and do the same procedure. Similarly, you should insert CD ROM to your drive before selecting boot device. One more thing is that if you are attempting to boot from a pend drive (or memory stick or thumb drive), you should select USB HDD. Some other options like USB FDD, USB ZIP may also be listed. One more problem associated with USB boot is that if you didn't enable USB boot in the boot setup (the key for boot setup will be displayed on splash screen), USB boot will be failure. In some systems you have options to enable/disable USB 2.0. All you need to do is that if a USB boot failure occurs, you should navigate through the boot setup menu and do as your need. In this case, the boot selection will not be saved and need to do the same procedure every time you boot time. Otherwise a normal boot will occur.

To permanently setup a boot configuration, you navigate to the boot setup menu and change the 'boot priority'. In normal case, first boot device will be HDD. You can change it to CD- ROM or USB HDD. One thing be noted is that you should give a priority to HDD as second or third device. Hence, if a boot error occur on the first device, system try on the second device (here HDD), so a normal boot will occur. Change the boot priority to CD-ROM as the first device and second device as HDD is a good practice in order to debug your OS, in case of permanent system crash. Here the system ask to save changes. Press y/Y to say Yes, and this configuration is saved on BIOS for future.

If you do the configuration permanently, every time system checks for first priority device and may feel time consuming if you are waiting for a normal boot. If you are doing it in temporary, every time you need to select boot device. It is recommended that you permanently change boot setup in your Home PC while temporarily do in office PCs.

In the worst case, your motherboard will be entirely different thing and you need o read motherboard users manual. If you didn't got any manual on purchase, you can freely download it from the vendor's website. Probably you need to search by the part number. The part number of your mother board can be found on the top side of your motherboard (Hmmm..Best chance to hack your PC).USB boot is not allowed in some old PCs. But all general purpose motherboards not older than 3 or 4 years can have USB boot capabilities.

Battle Game - The computer thinks!

2009-09-14T23:23:00.000-07:00

Recently I built a game and named 'Battle' as a consequence of my studies in the field of artificial intelligence. As a first step, I built a mathematical model instead of more flexible neural network model. The work on neural model is on the way and the work is very slow. The mathematical model also not much efficient but I took care to make the program 'act' as intelligent (I know intelligence is needed to act!). Rarely the program may crash. I not interested to make this game for commercial use and I am givin it under GPL. The program is not much pretty both in efficiency and it's intelligence. Since I am not a proffessional programmer, the rules for a good program may not be satisfied. I compiled it in C++, but the entire structure is like C.
The game is like ordinary 'Tic Tac Toe'. but has a little difference that maximum number of players is limited to 3 and If you placed your all three players, you can move them to adjacent places to align the players in a line. For the simplicity of learning the game I have put a video of how to play the game.

I have built a Qt (which is cross platform) GUI for my game for beginners but have put also the CUI mode game for code diggers. Even though this game is not intended for entertainment surely it provide some entertainment if you read the code. I need you comments to speed up the development of neural model of the game. I did all the work in win32 platform and linux users also can compile the code because, Qt is cross platform. But you need to install Qt on your distro.
Here's the download links:
GUI BattleGame (Recommended)
CUI version 1a.0
CUI version 1b.0

Hackthissite.org A hacker's university!

2009-09-14T04:33:00.000-07:00

Hackthissite.org seems like a hacker's university. This website provides a good stuffs useful for hackers (crackers also). The hackers community is really powerful and active. Only you have to do is facing different types of hacking problems and find a quick and easy way to solve it. If you are a perl programmer or a javascript hacker, it is a plus. Innovative php users get the points more. A deep knowledge in html is not needed. Above all, the most important thing is your common sense. The problem phase is broadly classified in to:
personally I felt basic and javascript is good for beginners, but advanced problems like programming missions are needed to eat more points. Earning points is not for just earning points, but it will give you some reputation. You are ranked by your points:

Pentitioner-0 Points
Script Kiddie-700 points
Apprentice-1700 points
Wiseman-3200 points
Master-5400 points
Hacker-7000 points
Elite-8400 points
Sage-10000 points

W3schools help you a lot in learning web programming. Navigate to hackthissite.org and show who you are.

Make your own animations using Gimp

2009-09-11T01:08:00.001-07:00

Hey Gimpers,
Gimp is not only an 'image manipulation' program. You can build your own animations using Gimp. It is very very easy. Just try it. There are plenty of tutorials available on the Gimp official website.
Click here for a nice and intuitive video tutorial.

Bhuvan, still have a lot of void

2009-09-02T10:35:00.000-07:00

ISRO(Indian Space Research Organization), launched Bhuvan , a Google earth for India (But more than Google earth) after the successful launching of Chandrayan-1. In the first sight, it is like Google earth, but tons of information is there and covering almost all over India. Bhuvan is a strong rival for Google earth, and seems better view than Google earth and have some good features, and is more informative. Currently, Bhuvan works only on Win32 platform. You need a program (about 15MB) and a need a good broad band internet. Bhuvan works fairly well in my system with 2GB RAM. All you need to play with Bhuvan is included in their website.
Bhuvan has enough tools to find exact area, length and other terrestrial info. Bhuvan works well even though you have low bandwidth network because it is designed such a way that it covers almost Indians. I personally don't know Bhuvan supports current GPS systems.

Bluetooth interactive console using pyS60

2009-08-31T06:05:00.000-07:00

Nowadays, text messages via mobile phones are shortening to small, but difficult to understand language. I don't think whether the major reason behind this shortening is economic, but most people feel tedious to type text through a 4*3 panel. Typing a program like, C or python in correct syntax is again a tedious work. You can use bluetooth console, in order to avoid this problem effectively. Here I describe how to setup bluetooth consloe communcation in your MS Windows XP platform. For beginners, this procedure may feel ambigous. So I tried my maximum to describe it with screenshots.

If you are not aware of pyS60 please read this.

You can find some other tutorials here:
s60python
nokia wiki
pys60 Library Referance
Yet another tutorial
Lecture

The above links were extremely useful to me. The procedure is repeated here, but I tried to describe it in rather simple way. If you feel any difficulties, please inform me.

Setting up bluetooth interactive console in winXP

step1: Plug your bluetooth device into your PC (any USB port). Then Run your bluetooth driver program which you installed from the CD/DVD when you buy your bluetooth dongle.
Then automatically a serial port is assigned for it. In my PC, it is COM6. You can do step 5 in case you don't know the COM port your PC supported.

step2: Run command 'hypertrm' in your run window. Run window can be opened by clicking Run option from the start menu.

step3:You will get hyperterminal opened like this:

Enter any valid name for your connection and select a suitable icon and forward.

step4:Then you will get another box like this:

Type any 3 digit area code and phone number.Your country or region may be automatically filled. If not, do it manually. Select COM6 from 'connection using' lineEdit tab. It may be changed. You will get which COM port your computer assigned (If you didn't get it, notice first screenshot)

step5:Take your symbian smart phone with pys60 installed. Turn your bluetooth ON and open pys60 application. From 'options' menu, select 'bluetooth console'. Your application then searches for blutooth device. You can optionally select it as your default connection.

step6 (Error Debugging): You are now probably connected successfully. Not yet? Check your connections. Check whether you run your bluetooth driver.If your bluetooth driver is running, a symbol of bluetooth will appear on the panel (see screenshot 1). I used Enter blutooth dongle (part number:E-UBTV) from entermultimedia. and it's driver(BlueSoleil). The driver is downloadable in case you lost the CD/DVD with your dongle. If you can type anythong on the white blank screen of hyperterminal, you are probably done everything. Else, you should check the whole procedure.
In any case, you should plug out the dongle and replug.
Didn't connected yet? Some mysterious powers are playing around you ;-)
I am happy to help if you can't find any way to connect.

step7: If you are successful in connecting your mobile, you are done.

step8:You can do anythong with python. Try these

step9: While you close application, you get a dialogue box and click yes.

You can save hyperterminal settings for the future use. Then when you run 'hypertrm' command, you will get a window like screenshot 2. simply close the box named 'Connection Description' and then you can open the saved file (here, pybluetooth.ht). Again there is an option to save the connection in your mobile and make it as default connection.

Slax- A brief review

2009-08-28T02:32:00.000-07:00

Yesterday, I found some good stuff on the official website of Slax (It is a simple but very beautiful distro. Yes, it's build up of KDE). Website itself is very cute and everything is simple as like SUSE or Mandriva. I know some real geeks may not like the entire structure of slax, but it will be stunning those who were allured with Microsoft Windows OSs. The simplicity makes everything easy.
One more advantage is that they give a free 30MB online memory which can be easily be used like ordinary disk drives. The memory of 30MB is free for slax users for unlimited period even if you didn't use it for a long time (The info is from the official blog, the unlimited period may be varied. But they didn't commented about it yet). You can use the online memory from any machines that supports slax, or any other OS, even Windows. A 200MB iso file or tar file is to be downloaded in order to make a liveCD or USB. I installed latest version of slax (slax6.1.2) to my SanDisk Cruizer 4GB pendrive and it works fine. A live CD can easily be created, but to do USB installation, you need to work for 2 minutes.
The whole procedure can be done in your windows platform itself. Try this link.
Another fantastic feature I've seen in their website is to run an application without actually installing on our system known as 'activat'ion. Almost all general purpose applications are available as .lzm binary format which is ready for the installation without any dependencies. You can select which software you want to use from modules page. There are three options - first to download (normal download for later installation), secondly 'add to build' which helps to customize your distro before download. If you want to check whether the software listed is good, just do the third method -activate. Then you can use the software as you have installed it in your system, but actually not.

The major advantage is that it is pocket linux (handy) and can be used everywhere. But personally I felt that it has less hardware support compared to Puppy Linux. But I stil like slax because of it's greenish beauty!

Happy slaxing!

Linux Demo? What's the hell?

2009-08-26T06:55:00.000-07:00

One of the reason why I love linux a lot is that it has no barriers at all. Many programs usually comes as a demo version which will not not be as much handy as a proffessional or full version. Demo versions seems sometimes nasty, and is too dry to wet out appetite. So I hate the word 'Demo' itself.
But what's going on there is the arrival of "Demo Linux". I just wondered for a while and navigated to the official website.
But I found there is nothing to afraid and found some good stuff. How many of you felt boring while repeatedly installing and formating to find a suitable distro. Live CD's reduces this problem to a great extend. But now this problem is greatly dealt by Pendrives (Memory stick). Demo Linux is specially built linux distro to be alive!. That means there is no need of a hard disk at all. A 32MB of RAM is enough to work with it. Hope it will be useful for those people who loves to be small.
Also read about Puppy Linux Slax and Kolibri

Resize images in Gimp

2009-08-13T06:55:00.000-07:00

Resizing pictures is quite easy and there are several free programs available for this purpose. Resizing images by mouse is quite easy, but here is how to resize images in a professional way. It is quite easy.

Here is two images, one is the resized form of the other. To know the actual size difference, please download these images.

step1: Open GIMP
Applications->Graphics->GIMP in Linux (you can enter command 'gimp' in your terminal window as geeks do)
start->programs->GIMP in Windows

step2: Open image in Gimp

step3: Rigt click on the image and select image->scale image..
step4: Change width and height. If you change any one of them, the other will automatically be changed.

step5: Click 'scale' button

step6: Save yoiur image

Try Ruby on your browser!

2009-08-08T07:17:00.000-07:00

If you are ready to spent a 15 minutes of free time, it's enough to learn ruby. Ruby is Japanese brain and quite easy also. It is famous in its simplicity. You need not install ruby to try it, you can do it in your browser- Not joke!
Just navigate to the official website of ruby.

On the sidebar, you have a wonderful tutorial "Ruby in twenty minutes" to start with. Put a click on "Try ruby on browser" -circled in the above screenshot. Then you will get a command prompt like screen on your browser. Then now ruby is ready to what you want!
If you are beginner, type 'help' on the prompt and hit enter. Then the 'virtual' ruby navigate you through an interactive tutorial which is very useful for beginners. The tutorial takes only about 15minutes.

World's Smallest "Hello World" program

2009-08-08T06:55:00.000-07:00

It's quite formal way to start with a "hello world!" program while introducing a new programming language. It is convinient by starting from "hello world" because the program may run properly and is helpful in gaining the confedence. Also it gives a proper output - Prints "hello world!" on the monitor. The programmer becomes happy while seeing this output. Here is a simple "hello world!" program in C.

#include
main()
{
printf("hello world!");
}
//output is
//hello world!

Quite simple?
But I think it is not at all simple. The special characters present in the program really offer some disturbances for the beginner, however a C program is not redundant and it is extreamly powerful.

In Python, I found a much more convenient way.

print "hello world!"

Simple?
It seems good but there is still void to shrink.

Take a look at Ruby,

"hello world"

That's it. I didn't found any void to shrink here. Just put the string you want to print in quotes (" ") and it is pretty easy. But this is not the standard way of printing a string on the monitor, as far as the offcial website of Ruby is concerned. They recommends,

puts ("hello world!)

Then the output will be,

Hello World

=> nil

nil stands for there is nothing to return.

Introduction to parallel port (LPT) interfacing

2009-08-01T08:22:00.000-07:00

Warning!:Usage of parallel port without care may cause serious impact on your PC.

Nowadays programing parallel ports (also known as printer port LPT (DB25 female on the back of IBM type PC) are prone to disappear from newer PC's. But, as far as computer based control engineering is concerned, parallel port is the easy way. So many people stick on parallel port. There are a plenty of programming languages offers convinent control over parallel port by high leve l of abstraction.In order to control things through your parallel port,you need a simple hardware also. Don't need to buy, just build one in your home. Before you dig into parallel port, just know what is a parallel port. If you are confedent that you have some knowledge of parallel port, just skip the links below.

Assuming you acquired basic operation of parallel port. Now let's begin to dig. Here I tried to describe maximum of how to work with parallel port in different systems and different platforms. You can read all of them in posts tagged in Parallel Port.

Read my post on parallel port control using python
Read my post on parallel port control using C/C++

A programming language in my name!

2009-07-30T06:43:00.000-07:00

While googling in a sleepless night, I found something intersting (interesting for me and all other Toms!). A good looking programming language named "Tom" which is my name. I just went through the official website and found it was cool. I liked some of its specialities available, and also it's license.-Yes, it's under GPL (GNU General Public License). Some of the pecularities are: (I just copied it from the official site)

TOM sports extensibility of objects: a class is not just defined by its main definition: classes can be adjusted, even at run time. A prime example of this is to modify in your program a class offered by a shared library, just to make it suit your program better.
TOM methods employ default argument values and multi-valued returns;
TOM has multiple inheritance - with semantics much simpler than in C++ or Eiffel and obviating the need for interfaces (Java) or protocols (Objective-C);
TOM offers reflectivity on objects, their classes, member variables, and methods;
TOM discerns classes and a few basic types - like Java and Objective-C;
TOM has conditions modeled after CLOS conditions;
TOM, as compiled by Tesla, the first TOM compiler written in TOM, adds blocks to the language;
The TOM standard libraries offers time-constrained garbage collection, multi-threading, distributed objects.

In their FAQ, I found a question "What does the name "Tom" mean?
The answer given was like this: "The name TOM is a name. Names don't need to have a meaning. :)"
Well, here is simple "Hello Tom" program in TOM which resembles C and Java.

int
main Array arguments
{
[[[stdio out] print "hello, Tom!"] nl];
}


Currently Tom is available for Linux,BSD platforms. An unsupported version of win32 platform also
Visit official TOM website

What's the value of 0/0 ?

2009-07-27T06:07:00.000-07:00

Do you know what's the value of 0/0 ?
Most books just don't care about it. Also many teachers are not interested to touch anything like this. Students are fearing to see this, especially while they are doing some calculations on the exam paper!
Anyway, it is good to be aware of 0/0. I continue this article assuming you know basic addition, multiplication etc.
One question: What's the value of 10/2 ?
It's 10/2 = 5. Is it?
We got the answer as 5. Is that mean 5*2 =10 ?. For example, if you have money Rs.10 and distributed to your two friends equally. Then your friends get 10/2 = Rs.5 each.
From the above example, we can generalize that if a fraction exist in the form x/y=z , then z*y =x.
please note the above line. I will tell you more about that line!
Then the question is if you divide your Rs.x to y people equally, each will get Rs.z. Then what is z?
The answer z is a number which satisfies z*y=x. In the above example, you put different values for z such that, z*2 =10. Then z is the amount in your each friend's hand. Here 5, the only 5 satisfies the equation when it put to z. Thus each of your friend get exactly Rs.5.
Then consider the case of 0/0 . Like the previous example, if 0 is divided to 0 people, how many rupees each of your friend get? If the answer of this question is z, we can write z*0 = 0. Put some values for z in order to satisfy the equation. All values of z which satisfies the above equation are the solution. We know that multiplication of any value with 0 is 0. So z can take any values to satisfy the equation.
If the solution of z is written in a page, your page may not be sufficient to include all solutions of the equation because solution is 'any value'. More mathematically,
z = -infinity.......................0.......................+infinity
So, 0/0 = any value
It seems very interesting on the first sight. You have nothing, and you are dividing that to nobody. Then the amount in the nobody's hands may be millions, trillions or anything. If you think, this is like a magic to generate millions from nothing, you are absolutely wrong. Think about it.
Let's go for an example to describe what's actually I am trying express. To understand this example, you should aware of a great law named Ohm's law in Electricity (The circuit shown below is stolen from Wikipedia). If you don't know anything about Ohm's low, you must make yourself aware of that before going to continue.

According to Ohms law (refer picture), R is V/I.

R=V/I

If V=10V and I=2A, then R = 10/2 = 5 ohm. In the above picture, if Voltage V=0, Current I will also be zero (without voltage there will no current). Then R = V/I =0/0.
According to our previous result 0/0 can be 'any value'. So R = 0/0 simply means R can take any value. R can be anything.
R*0 =0 can be treated like this: R is the values that exists when V=0 and I=0.
If you put a resistor in your pocket, the applied voltage V = 0 and hence current I = 0. So you can put Resistances of any value in your pocket. Think about the world of 0/0 = a fixed value. For example, take the fixed value 0/0 = 100. Then Resistance R =100ohm is the only value that can put into your pocket and others can't!
Seems funny? but it is fact.

Parallel port programming using python

2009-07-26T07:24:00.001-07:00

Setup parallel port in linux (Debian/Ubuntu)
You should have installed python on your distro. You must have the previlages of 'su' to do the following installation

# apt-get install python-parallel
# rmmod lp
# modprobe ppdev
# python

>>> import parallel
>>> p = parallel.Parallel()
>>> p.setData(0xFF)

Assuming you have some basic python knowledge. If you didn't install pyhton -parallel, you can't import parallel. Now p.setData(oxFF) sets every outputs of parallel port to ON. Try different values instead of 0xFF. (To do this you require basic knowledge of hexadecimal representation of binary numbers). Try this chaser program.

x=[1,2,4,8,16,32,64,128]
while(1):
for i in x:
p.setData(0xFF)
time.sleep(2) #Good night for 2 seconds

The program will work until you force to quite python or an unexpected UPS failure. That may be funny ;-) But Intentionally did that for the program simplicity.

No Linux? Windows only? :-( Just try it out

There is nothing to do in windows. Download latest python first. Install it. Then download pyparallel for windows fron sourceforge. Install it Now everything OK. Open python either by command or open IDLE (It will be installed with python core in windows). Then type the following:

>>> import parallel
>>> p = parallel.Parallel()
>>> p.setData(0xFF)

The example chaser program is also applicable for windows platform.

Read my post on parallel port programming in C/C++

Teach your computer how to speak!

2009-07-22T09:55:00.001-07:00

It is good idea to teach computer to speak!. There a number of programs available for winXP paltform, but here is a unique program "espeak" for your linux. Just enter the command in terminal,

$espeak "Boss, I can speak now"

will work fine. It is useful for some scripts in linux to remind some status of computer to the user like a personal assistant. espeak is not an internal bash command and need to be installed. I simply installed in my Debian from repository.

#apt-get install espeak

The command above will work well with ubuntu systems also. If you are using any other distro, you need to download and install it manually. Click here to know more.

Here is a simple python program which uses espeak as system command. To use it you require python and espeak installed.

#! /usr/bin/python
# File: speak.py

import os
from Tkinter import *

class App:

def __init__(self, master):

frame = Frame(master)
frame.pack()
self.button = Button(frame, text="Click", command=self.activate)
self.button.pack(side=LEFT)

def activate(self):
os.system('espeak "Boss, I can speak now"')
print "Boss, I can speak now"

root = Tk()

app = App(root)

root.mainloop()

Just copy the above program into a new file named speak.py and 'cd' into the directory and enter,

python speak.py

You are free to use this program anywhere since espeak is under GPL.

About our knowledge

2009-07-17T06:44:00.000-07:00

We dig everything from the centre. Every experimentation of any branch of science starts learning our world neither from the beginning nor from the ending,but from in between. We don't know the beginning and the ending. But we dig to above and below from the middle, but never reaching anywhere.
For example, a man start to learn about the world. He first learn about the present things -trees, birds, humans etc. He digs to the past and also digs to the future. Here time is the base. When size becomes the base, that man start to learn back to molecules, atoms, sub atomic particles, quarks....And when going up, sun, Milkyway...Here again we don't know the ending. It seems that, man's knowledge is isolated in every axis didn't touch the starting or ending yet. Yes, it's really floating!

Physical Interpretation of DeMorgan's law

2009-07-09T07:17:00.000-07:00

I am asking you what is De Morgan's law. This may be the answer.
If A and B are two events,

(A+B)' = A' . B' and (A.B)' = A' + B'

(Here the operator ' represents the compliment of the operand. That is If A is 'yes' then A' is 'no' and if A is 1 then A' is 0 and vice versa). I assume you have basic knowledge of Boolean algebra. Now I am giving a physical interpretation of the law which is very useful in analising the law.

Consider first law,

(A+B)' = A' . B'

Here '+' is OR operator. That is A or B. Let Y be an event of shutting down your computer. You can do it in two ways and B.

A=>shutdown manually by pressing the power button of CPU.
B=>click 'shtdown' using your mouse.

Then,
Y=A + B ie, Y= A OR B

Another iterpretation is that, you can turn off your computer by either clicking 'sht down' or by pressing power button. If any one event occured, the computer turns off. ie, Y become true.

One day, your friend came to your home and want to learn about computer. He did something in your computer in order to turn off.Unfortunately, the computer didn't turn off. He reported you in the other room. Then you think in this way, what may be the reason why the computer didn't shut down. The output occured is Y'. ie, computer didn't turned off.

Then from the previous equation,

Y' = (A+B)'
Applying De Morgan's law,
Y' = A' . B'

Here the interpretation is that, The event A is false and event B is false. ie, he neither clicked 'shutdown' nor pressed power button.

Take De Morgan's second law (A . B)' = A' + B'
Consider two dependent events. For example,
let A and B be two dependent events. If your friend dont know how to call someone using a coinbox telephone. The procedure written on the side of the machine is first put the coin and then dial the number. They are dependent events.
A => Put the coin.
B => Dial the number.

Here the output Y is to call somone successfully. ie Y = A.B
(Here A.B is not equal to B.A which is another boolean theorm. Here just don't think about it.It will be explained later)
Unfortunately, your friend could not call the other. He asked for help. Then you analise the problem why he didn't call.

Y' = (A . B)'
By, De Morgan's law,
Y' = A' + B'

ie, he either didn't put the coin or dial the number properly. The above example is conditional events.

Google maps works without GPS

2009-06-20T08:14:00.000-07:00

A GPS phone with Google maps is really amazing. But unfortunately, my Nokia E65 has not any GPS support, but navigator programs are included in Symbian. A bluetooth GPS device can be used along with many phones without any GPS module in-built. But it costs around Rs.5000 India. But Google maps is useful even if you have any GPS support because it works well using GPRS network to find current position, not much accurate because it will show the nearest mobile radio transmitting tower. But it becomes handy and have only 1.3MB to download and useful in navigation. Recently, Nokia also provided "nokia maps", but I am not commenting about it because, now I decided to stick with Google!
You can download Google maps directly to your mobile phone from m.google.co.in/maps
or vist www.google.co.in/mobile from your PC.

Open electronics - Philosophy

2009-06-13T20:35:00.000-07:00

Electronics is nowadays being a part of modern human life. Computer, Television, PDAs, Mobile phones, ,Vehicle Engines, and every field of communication, Medical science, Military requirements and everywhere….A similar boom was taken place years ago in the software field. The necessity of software with less cost and freedom opened the windows of open source software foundations like GNU. Thanks to GNU/Linux.

But the case is different in the case of electronics. Here the real source is the circuit schematic and logic. Here the source is more valuable than software distributed under GPL License. But as development goes on, the nomenclature of “opensource” is becoming relevant in electronics also. In modern digital control, the logic is not only the part of hardware and is shared by the software also. That means, hardware is likely to be same in all devices, but the complexity of logic completely depend upon the program itself. That is what is I want to emphasize “opensource” is being relevant in the filed of electronics also.

In older age, it was easy to 'hack' the circuit by the method known as 'Screw Driver Engineering'. But as micro electronics development goes on, a single chip can hide most of the important logic to the end user. The arrival of microcontrollers again increase the complexity of hacking. These technology is extremely useful where security is required. The same security issues exists in software field also. But a programmer can hide important parts of program from the user. This is considered to be severe from the perspective of openness. The similarity in the electronic field and the computer software field gives us a way for a new revolution - open source electronics.

Read more about the open electronics philosophy here.
Another good website concerning open circuits.

Portable programs for your pen drive

2009-06-13T04:01:00.000-07:00

Nowadays, there is no need of an introduction to portable applications, but I am starting from introduction before going to some useful portable application links.

Most of the computer application programs are to be installed in your system. It is not a problem in Windows platform just click next->next->.......finish. Quite complicated but amazingly interesting way in Linux. There are several Java programs which is intended for direct work instead of initial installation setups. The problem arises in installable applications comes to play if you are working in your office, college in computer. The computer administrator may prohibit to install your favorite Firefox in the office computer. These problems can be avoided by using some portable versions of your favorite applications. Just download an unzip it in into your pen drive and use it every where. Currently, most applications support portability in MS Windows OS. If you are a Linux user, Linux OS itself become portable to follow you!

Some good links for MS windows:

http://portableapps.com/

http://www.pendriveapps.com/

Here follows a junk of pen drive Linux:

http://www.pendrivelinux.com/

Python for Symbian s60

2009-06-13T03:30:00.000-07:00

Python is very convinient language compared to any other and constantly increasing it's popularity. It is listed in the top 10 programming languages also. It can be used in MS Windows, Linux and everywhere. It's a best hacker's choice also. Many varieties are emerging from python. Portable python- which need not be installed but paste the file in your Thumb drive or any other portable devices and you can use it everywhere. Really Nice. Now the pyhton coming to conquer the mobile phone world!. Yes, you can do what is you go for in a PC.

Just donwlad the pyhton instllalble file. Install it
Open python for s60
Options->Interactive Console
Do what you want
You can see some example *.py files in Options->Run Script

simplest example:

print "hello World!"

#Note: Wherever you want to press enter in PC version of linux, in mobile, you use 'scroll key', not 'enter' character in the list of special characters. You can run python scripts also bu require one text editor. One good text editor is JtextLite.

Happy Programming!

Play with "cdrom" in Linux

2009-06-12T22:17:00.000-07:00

Linux comand shell "bash" is powerful as we know. Here is a fun with bash. You can control your cdrom using 'eject command'. Here is only a simple description. For nore details, you should look at it's man pages.

This is not a project or something serious. just for fun. You can control your cdrom by using this code. This will only work on Linux platform. I did it in fedora core 9. But it will work other disro's also.

!!!!!!!WARNING!!!!!!!!
1)Some procedure described in this article is not a recommended or the hardware devices are intended to work like it. Do it in your own risk.
2)Don't interrupt the way the hardware working (the movement of CD ROM tray by your hand).

Open your 'cdrom' tray under software control
Try this command

$eject cdrom

It will try to open your cdrom tray. if you have two or more cdrom drives, try

$eject cdrom0

If you havn't any cdrom device, bash will return an error message:

$eject cdrom2
eject: unable to find or open device for: `cdrom2'

You can find your device name ( "cdrom0', 'cdrom1' etc.) from "/media"

Close your 'cdrom' tray under software control
Try this command

$eject -t cdrom

Other useful parameters are there in 'eject'. You can read about it:

$man eject

Writing a bash script
Just entering the command at a time is not convenient. You can write some commands together and execute it when you want.
Open a new file using gedit editor (or any other you want)

$gedit cdromplay

A winow will appear and type what you want. For example, if you want to open and close your cdrom continously three times just print like this:

eject cdrom
eject -t cdrom
eject cdrom
eject -t cdrom
eject cdrom
eject -t cdrom

save it and close.
Then to resolve permission,

$chmode +x cdromplay

Then execute cdromplay

./cdromplay

You can see what I said before.

Do it in your real applications
As you know, we did some rubbish things before. There is no need to do so. But this is useful in some applications like CDburner - It will automatically eject tray after writing a CD ROM or you can control convineiently in a CD ROM player. We can use python to do a GUI application.

# File: cdromplay.py

import os
from Tkinter import *

class App:

def __init__(self, master):

frame = Frame(master)
frame.pack()
self.button = Button(frame, text="Quit", command=frame.quit)
self.button.pack(side=LEFT)

self.hi_there = Button(frame, text="Eject", command=self.say_hi)
self.hi_there.pack(side=LEFT)

def say_hi(self):
os.system("eject cdrom1 -T")
print "boss, cdrom activated"

root = Tk()

app = App(root)

root.mainloop()

As you can see, the above program is the altered version of "Hello World!" program of one famous python tutorial. Don't get upset or confused by the defnition names. The confusion in program code will not affect the real program.Copy and save it or download it from here. You require python to do this. 'cd' to the appropriate directory and run,

$python cdromplay.py

Now you will see a simple widget with a button.

Press button and observe what's happen.

Download cdromplay for python
Download cdromplay bashscript

Watch the video how cdrom is ejected:

Good Luck!

Increase Battery life of your Nokia!

2009-06-12T06:44:00.000-07:00

There are several ways to increase the battery life of your Nokia mobile (not only nokia ;-) ). One good advice read from this link. I am now describinf how to turn off dual mode of your mobile to GSM in Nokia E65. Other mobile phones (probably using symbian OS) have the same step to do so.

Navigate to
Main Menu->Tools->Settings->Network

Change network mode to 'GSM'

It will ask to restart. Press 'Yes'.

Another good link here.

Industrial Training in All India Radio

2009-05-31T20:46:00.000-07:00

In this vacation, we(me and Anil CS, my class mate) planned to go to All India Radio for the Industrial Training. It was a 5 day program. I am not attempting to publish a technical report on this because I am too lazy to do so and AIR(All India Radio) technical details cannot be revealed much without the permission by the Government of India. Also restrictions are there in capturing photoes of inner side macines and electrical connections. So we got only the picture of the main gate Akashavani and the Transmitting station residing at avanoor. You can see the 122m long MW antenna (630Hz) on the picture of Avanoor Transmitting station. It is propagating a power of 100kW. An old 20kW antenna is there in Akashavani, but it is not using now. Most of the technical details are kept secret because of the security reasons. But they tried to explain maximum technical details to us. They opened old 20kW propagation station for us, but they were fully build up of large triodes, tetrodes, etc. Some of the valves were very costly, but I didn't like it much because, I usually play with transistors and integrated chips. They were not working for 10 or more years and were dusty. Next day, we went to Avanoor 100KW transmitting station. It was much more sophisticated.
I am not trying to describe a lot about AIR, but here I give an overview. The programs are recorded and live programs are set up and edited at Akashavani, Ramavarmapuram. Since there is no active antenna, the program is transmitted through FM. It is short range, but enough to receive the signal at Avanoor. They said that probably we can hear programs in 103MHz FM also from near Avanoor. I tried it in my home, but failed. They also provide microwave (Micrwave is default medium, FM is used if microwave transmission failed.) transmission in addition with FM.

About random numbers

2009-05-31T20:34:00.000-07:00

Nothing is random in this world. But something feels to be random if we do not consider some of the associated parameters. If we consider all parameters (ideally), and can feel things in every perspective, it becomes a definite process. The lack of determining the parameters associated with a process is the reason why some process likely to be random.
For example, consider a coin is tossed, it appears a random process to get an outcome of 'head' or 'tail'. But if we simulate the whole process in a computer oriented mechanics simulation program, the process definitely depend upon the orientation of the coin while tossing and air friction, gravity, and so many other things. It is clear that one can say definitely what will be the outcome of the toss. Then why are you saying that it is random? All called random process definite in the other kind. Nothing is random. Nothing should be random.

Software install problem in Nokia E65

2009-05-30T08:58:00.000-07:00

My nokia E65 is cute and smart, but had some problem while installing softwares inside it. It uses symbian OS. I googled about this problem and searched several forums and found that, only some mobile phones in this series has this problem. While installing a software (.jar , .jad or .sis, .sisx files), a progress bar appears and an error "Unable to install" appears while the progress bar becomes almost complete.
The solution is to upgrade the firmware inside your E65 and restart your mobile. Now my E65 is really smart!!!
Steps to upgrade your mobile phone firmware(This is applicable to almost all nokia phones)
1) Download Nokia updater software from nokia website. Here is the download link:
http://europe.nokia.com/get-support-and-software/download-software/device-software-update/download
2)Install nokia updater in your OS.
3)Back up your data in mobile phone using backup utility in the Nokia PCsuit. No need to back up the data in the memory card.
4)Check your mobile phone is fully charged in order to ensure that, it will not switched off during update process
5)Start Updater.It will detect your phone while connected to PC via cable and automatically download and install firmaware.
6) Do not unplugg PC cable during the installation process.It will cause severe damage.
7)Copy the data from backup after successful installation

8)Try install software now, it will surely be installed.
Good Luck!

Learning something from exams!!!

2009-05-05T21:22:00.000-07:00

Last week, I have electronics lab exams. I went as usual and got a simple experiment to form a wave form as shown in figure using clipping, clamping and rectifier circuits from a sine wave. The frequency of input sine wave was not given so that we can choose a convenient frequency. I drew appropriate circuit which I was studied earlier and got "proceed" command from the external examiner to do it.

I quickly build circuit on bread board and double checked it. Then input is taken from signal generator and output is fed to CRO. I gave all power supplies and swtched on Vcc to circuit, CRO and signal generator. Alas! signal is different. I rechecked my circuit again and again but no use. I got a signal like this.

But the required signal is different.. First half cycle is Ok. But second halfcycle is clipped off. I couldn't understand what's the reason. Wasted a lot of time by rearranging the circuit components and adjusting the knobs of signal generator and CRO.The actual signal required is also given.Chances were going to be worse. Started to troubleshoot it from one corner, I realised that the bridge rectifier circuit using four 1N4007 diodes is the problem centre. I rechecked all the diodes using multimeter, but no use. At last, I replaced some new diodes, no use.. I passed a simple sinewave through the circuit, again second half cycle is clipped off. All diodes are correct. There is only 10 minutes to complete exam. Dresses become wet even under the fan in full speed. Nothing to do more than return the components. But I prayed GOD, what a destiny. Then I got an idea to replace the signal generator by a transformer directly from power supply since the frequency os oscilation was not given. I just replaced it, but got the correct answer. Really- but had some noise, its not a probelm. I comleted exam within 5 minutes and showed correct output.
Actually what may be the reason? May be some evils playing inside the signal generator. But I think some strong reasons are there. In the case of signal generator, there is no negetive voltage exists to forward bias the dioes in the bridge rectifier even when we 'feel' some negetive effect on CRO. No use by adjusting 'offset' knob in the signal generator. That effect only occur in the CRO display, but not in physical.

How to activate GPRS on E65 with vodafone prepaid

2009-04-30T22:19:00.000-07:00

I got one great mobile Nokia E65, and I am starting to dig it. First of all I am going to activate GPRS to get full power of E65. I am using a lifelong Vodafone sim card. To activate GPRS we should do the following:

1)To activate GPRS on simcard
2)Download and save settings on your mobile phone.

To activate GPRS on simcard, send a message
ACT VL to 144

Automatically settings will be sent as SMS. Save it. But I didn't get any settings at all. So I set up it manually. To do it manually,

Go to menu->Tools->Settings->Connection->Accesspoints

Here shows available accesspoints. Probably you should make a new one named 'Vodafone live!'.To make new one,

options->New access point

Enter into new access point,then configure as shown.

Connection name : Vodafone live!
Data bearer : packet data
Access point name : portalnmms
User name : None
Prompt password : No
Password : (No change)
Authentication : Normal
Homepage : http://live.vodafone.in

Then do,

options->Advanced settings

Network type : IPv4
Phone IP address : Automatic
DNS address : Automatic
Proxy server address : 10.10.1.100
Proxy port number : 9401

To access GPRS,

menu->Web

Yes, you have done!

Note: I am residing at Kerala,India. So people residing outside Kerala, should take appropriate changes. Call 111 for any help from vodafone.

My Life: A turning point...

2008-12-29T06:22:00.000-08:00

Sometimes, our way will be very different from the expected. Here, I am just sharing how I became inetersted in Electronics from a flare of nothing. I recognized my way when I was 13 – from a low cost book from a footpath. The book included fundamentals of electronics as well as some simple example projects. I really attracted by one project-a musical bell using a single IC UM66 and a single stage amplifier. Major attraction was it's low cost. Next morning, I went to purchase all components. I saw transistors and other components for the first time. I started assembling my first project. I had not even soldering iron or bread board to assemble. I just connected all components with some waste copper wires with bare hand. Practically the process was extremely complex for my age I think. If one wire is joined together, the other will be disconnected. A small change in the positioning was capable for the system does not work. After completing my work I verified all connections. The circuit was not much pretty – a heap of wires only. I had no any great expectations because I knew that connections were not proper. Took a silent pray and connected to a cell directly without a switch.
............The result was amazing!! . It did work. Hearing a strange music all in our home came in to my room with a pleasant smile. Even though the circuit was a simple one, that incident was a milestone in my life. If that circuit hadn’t work, the destiny may be rewritten.