Robotics for you !!

How to hack facebook ? - An implementation tutorial !

2012-01-30T22:43:00.007+05:30

Hi guys,
I haven't made a post in a long time. I guess its time for me to bounce back in the blogging arena. The latest gadget I have built is a device to hack Facebook users who connect to some random un secure internet. This device has some serious limitations but none the less cool and works on carefully social engineered situations. This type of attack is called "Pharming" . Its different from Phishing since the user is not tricked into clicking a bogus URL. The video below demonstrates the mock attack that we carried out at my home !

Pharming (pronounced “farming”) defined by Symantec Inc is “A form of online fraud, very similar to its cousin phishing. Pharmers rely upon the same bogus Web sites and theft of confidential information to perpetrate online scams, but are more difficult to detect in many ways because they are not reliant upon the victim accepting a “bait” message. Instead of relying completely on users clicking on an enticing link in fake email messages, pharming instead re-directs victims to the bogus Web site even if they type the right Web address of their bank or other online service into their Web browser.”

The hardware platform I used is from OpenPicus and I made use of their Flyport module with a USB nest.
Below are the links to presentation and source code. I will explain more in the next post.

Project Presentation

Source Code

Disclaimer: This post is to expose the serious vulnerability of the systems in place and for educational purpose only, I can't be held liable for any damage or losses caused to persons who are using this type of attack based on my design and idea.

Adding Security Certificate to JVM to handle SecurityCertificateError

2010-04-13T10:57:00.004+05:30

Handling SecurityCertificateError exception in JAVA by adding security certificate using Keytools

To add the security certificate for https URL the following steps needs to be followed

Take a backup of cacerts file in the following directory (This can be your default JRE directory also) C:\Program Files\IBM\SDP70\runtimes\base_v6\java\jre\lib\security\
Save the security certificate in some location for ex c:\certificate.cer
Go to Run type cmd
Execute CD C:\Program Files\IBM\SDP70\runtimes\base_v6\java\jre\bin (This is the location of the JRE WebSphere uses, in other environments please navigate to the JRE BIN the application uses)
Then execute the following command

(SYNTAX Keytool –keystore – import – file -alias<> )

Command
keytool -keystore "C:\Program Files\IBM\SDP70\runtimes\base_v6\java\jre \lib\security\cacerts" -import -file c:\certificate.cer -alias https://your-url.net

It will ask for a password , enter changeit
The security certificate will be added for the JRE

Now you can access the URL or access the webservice in the URL.

Fire bug - An invaluble tool for debugging

2010-04-02T00:52:00.004+05:30

If you have been into web programming, you will know its hard to develop front screens than to write the backend business classes. Also debugging Java Script is also a head headache. Fire Bug is a plugin for firefox that saves valuble time in web application development. It has nice features like inspecting the html elements, it shows the CSS applied. You can also see the Java Script.

You can also view POST headers that are sent to the server. One more interesting feature is you can edit the HTML in the browser and see it work.

The above picture is a snap shot of the Firebug tool. You cant use it in IE , one close too that is a substitue for it in IE is Fiddler , but it no where comes close to Firebug in terms of the richness of features.

Setting JAVA HOME through Command Line in Windows

2010-04-02T00:33:00.004+05:30

Hi all,
If you are working on some old windows machines and want to set JAVA_HOME and PATH environment variables follow the steps.

Start --> Run-->CMD .. In the command prompt first type

echo %JAVA_HOME% , if the JAVA_HOME variable is already set the path will be printed.
eg: c:/Program Files/java1.6

else %JAVA_HOME% will be printed.

You can set JAVA_HOME by typing

SET JAVA_HOME = c:/Program Files/Java (The path where your JRE or JDK is installed)

Then you can set the bin path by typing

SET PATH = %PATH%;%JAVA_HOME%\bin what you are doing here is appending the existing set PATH's with JAVA_HOME/bin.

You can also directly set the path to the JAVA Bin directory instead of the above steps like
SET PATH = %PATH%;c:/Program Files/JAVA/bin

Then if you want to view the set path you can type echo %PATH% ..

Beachfront Vacation Living for Non-Millionaires

2010-03-31T00:15:00.003+05:30

Fractional ownership is gaining popularity these days . The National News Today has covered the scenario. They have discussed the knick knacks of this type of ownership. The three main rules that they emphasize is

A) Understand the rules of occupancy and the usage schedule-
B) Review the rules for selling your fractional sale-
C) Understand how the property is to be managed-

Though Emerald Isle, NC is not a place for an ideal Beachfront vacation home. If Water Everywhere, Plentiful Beaches, Family Atmosphere and affordability are important to you, this is your kind of place. Most vacation destinations along the East Coast are very commercial.

The Emerald Island vacation home is ideally suited for people to buy vacation homes with fractional ownership without ever having to take the risk for investing the whole lot of your hard earned money. The fractional ownership real estate is really a boon for the middle class people to fulfill the dream of owning a vacation home in the beachside. Considering all the points and a great place like NC its a good deal overall.

There is one more thing you should consider. The Green Revolution is here, whether we like it or not. Yes, we all know deep down that we need to do our part to make the planet a better place and to make sure that future generations have the same opportunities as we have had. So which is better for our planet………. 10 vacation houses that are built and sit empty for 47 weeks a year, or 1 perfect vacation house that is used for 50 weeks a year?

LoudLaunch - Compensating bloggers for their unbiased opinions, reviews, and analysis.

Everything you need to know about organic apples

2010-03-31T00:13:00.002+05:30

The coming fall its apple harvest season . These days agriculture is taken over by artificial fertilizers, insecticides and pesticides. The National News Today has featured a farmer who does organic farming using natural methods.The farm direct organic apples are sold by them in person in Seattle. They give away free samples of their farm grown harvest. The farmer Paul Madden is obviously a lover of apples. This is evident from this article organic fruit of the month. He cares so much about them he says "I just want you to understand how much I care about the apples I feed to my children and your children."

He has a large 50 acre farm where he produces Washington organic apples . Washington takes advantage of the arid climate and plentiful sunshine needed for the best organic apples. The arid climate results in fewer insect and disease issues. They are on the banks of the Columbia River and the cool, clear water of the mid-Columbia is used for the irrigation of my orchard. His orchard has been organic since 1990 and has been in my family for 99 years. So he obviously produces the best apples in USA .

LoudLaunch - Compensating bloggers for their unbiased opinions, reviews, and analysis.

New Adventures and Favorite Destinations

2010-03-30T00:49:00.003+05:30

Breezes Resorts is one of the exclusive resorts in Jamaica . Perhaps its the best place to enjoy the warm summer weather. If you have been frozen by last years harsh winter and looking for a nice package to get some sun tan and warm yourself, you should consider all inclusive vacation packages given by them.

The Runaway Bay Jamaica conveniently located just about an hour away from the city of Montego Bay, Breezes Runaway Bay Resort & Golf Club is one of the world’s truly great escapes. You can go for a Carmaran ride in the crystal blue Caribbean sea. They also have video assisted golf and tennis court where you can enhance your skills

The Negril Jamaica is located between rugged mountains and sun drenched beaches, emrald jungles and blue Caribbean waters, the island of Jamaica is both a study in contrasts and a living lesson in geography. You should definitely take a vacation here to chill off from your hectic schedule this summer.

This is really the finest place to enjoy your honeymoon. The beaches are creating more romantic mood to you and your partner. Breezes.com offers all inclusive vacation packages for you. So you can enjoy a lot in lowest cost. These all inclusive vacation packages from breezes.com included deluxe accommodations, all meals & snacks, unlimited premium beverages, land & water sports and many more. These are available in your budget. You can enjoy and play at Runaway Bay Jamaica. Surely you will get more entertaining moment in Breezes Resorts. Everything from Breezes.com is fantastic a fabulous. If you looking for wedding in Breezes resort, they can arrange everything for you. You will get new experience in breezes resorts. So simply book the breezes resorts for your vacation in Negril Jamaica. And enjoy a lot.

LoudLaunch - Compensating bloggers for their unbiased opinions, reviews, and analysis.

Online Disclosure Policy

2010-03-30T00:05:00.000+05:30

This blog is a personal blog written and edited by me without bias or influence from others. While this blog accepts forms of cash advertising, sponsorship, paid insertions or other forms of compensation, it does not publish in a way that is contrary to my personal integrity. The compensation received will never influence the content, topics or posts made in this blog. I am free to reject posts that I do not agree with or approve. My writing represents the truth and I do not write about items that I do not personally support. This blog does not contain any content that might present a conflict of interest but it does follow international ethical guidelines and best practices for the internet and online advertising.

JAVA Jokes - The fun side of JAVA

2010-02-28T18:23:00.000+05:30

Too much of JAVA technical stuff , now here is a collection of some JAVA jokes that caught my eye..

---------
9:00 AM
Project manager: ” Where is Joe?”
Java programmer A: ” You know he is always lazy loadded.”

1:00 PM:
Project manager: ” Where is Joe??”
Java programmer B: ” He is in passive mode.”

5:30 PM:
Project manager: ” Could I see Joe in rest of my life ?????”
Java programmer C: “Never, he has been garbage collected.”

————

Why did the Integer drown?
Cos he couldn’t Float!

————

Q: Why did the Java Chicken cross the road?
A: He didn’t, he was just referred to on the other side.

————

yo mama’s so fat… she get an ArrayOutOfBoundException!
yo mama’s so poor… she does garbage collection for a living!
yo mama’s so ugly… her java.lang.reflect took down the mirror site!

————

Two ints and a Float in a bar. They spot an attractive Double on her own. The first int walks up to her. “Hey, baby”, he says, “my VM or yours”. She slaps him and he walks back dejected.

The second int walks over. “Hey, cute-stuff, can I cook you Beans for breakfast”. After a quick slapping, he too walks back.

The Float then ambles over casually. “Were those two primitive types bothering you?”, he remarks.

“Yes. I’m so glad you’re here”, she says. “They just had no Class!”

Buy and Sell Ipod to become richer!!

2010-02-15T17:31:00.000+05:30

Australia’s Commonwealth bank uses the comparative price of iPod Nano’s, as an index, to compare global currencies and purchasing power across countries. In the results of their latest survey, Brazil is the costliest place to buy an iPod and India comes second. The cheapest iPod can be bought in Canada followed by Hong-Kong.

Suddenly, iPod arbitrage sounds like a good business plan. Buy them in Hong-Kong and sell them in Brazil

YAHOO Pipes

2010-02-02T16:53:00.001+05:30

Yahoo has come up with yet another Web 2.0 gizmo. This one is called Yahoo Pipes. Its like Unix pipes applied to the web!

It goes like this .. anybody with a Yahoo ID can define a “pipe”. A pipe at its most basic form, picks data from “X” source and applies “Y” transform over it and finally provides “Z” output. Here, X could be anything ranging from an RSS/ATOM feed, any URL emiting JSON or XML content (even plain HTML works, I think ..), or it could be user input. Y implies a transform like applying a filter on the data, searching on Yahoo, Google or Flickr etc and Z is the final output you get. The best part is you can do all this “piping” using Yahoo’s web-visual editor (see the pic below), without knowing a thing about XML,HTML,RSS,whatever …

I created a Pipe just for kicks .. its at href="http://pipes.yahoo.com/pipes/pipe.info?_id=jnZ0iPYa3BGXuH3I6kjTQA"

This pipe consumes the RSS feed from digg.com’s technology section and extracts all posts that have the keyword “Google” in it. Simple, but cute !

Accessing Webservices from PHP

2010-01-28T16:48:00.001+05:30

Normally, most of the current windows products provides webservice for many of its functionalities. Particularly the sharepoint 2007 server, has lot of webservice that external applications can use it.

Again, accessing those webservices through .NET is pretty easy with its built in function. But, to access it through languages like PHP, requires some analysis, particularly for those who are doing it for first time.
The nusoap.php is a populat choice to access the webservice via Php.

It can be downloaded from the following sourceforge URL.

href="http://sourceforge.net/project/showfiles.php?group_id=57663

Here is the code snippet to access it

require_once( '/nusoap.php');

$client = new soapclient('http://ctsgvcchannel1/_vti_bin/SearchWebService.asmx',false,$proxyhost, $proxyport, $proxyusername, $proxypassword);

$client->setcredentials($username,$password);

$err = $client->getError();

if ($err) {

echo '

Constructor error

' . $err . '

';

}

// Doc/lit parameters get wrapped

$param = array('strKeyWord' => 'java','pageLength'=>(int)'5');

$result = $client->call('SimpleSearch', $param, '', 'http://tempuri.org/SimpleSearch', false, true);

// Check for a fault

if ($client->fault) {

echo '

Fault

';

print_r($result);

echo '

';

} else {

// Check for errors

$err = $client->getError();

if ($err) {

// Display the error

echo '

Error

' . $err . '

';

} else {

// Display the result

echo '

Result

';

print_r($result);

echo '

';

}

}

echo '

Request

' . htmlspecialchars($client->request, ENT_QUOTES) . '

';

echo '

Response

' . htmlspecialchars($client->response, ENT_QUOTES) . '

Web Services - How does it work and where to use ?

2010-01-23T16:26:00.001+05:30

Web Service has been the new buzz word in the past few years. In this post we will explore the basic elements of it and where it can be applied.

Consider this scenario a JAVA application running in a server and has an access to a stock price data base, where the recent stock prices are updated and you have a stand alone .NET stand alone application running in your computer from which you want to access the stock prices and display it in your computer. Remember you cannot be provided access to their database. So what is the solution ???

You face 2 problems

You dont have access to their database
The application that has access to the database is totally a different platform

How do you overcome such a situation? .. The answer is webservice.
If the a JAVA method that could fetch the data is exposed to the outside world that listens to the incoming requests and sends back the requested data that would be perfect isn't it?..

WebService uses HTTP protocol to send the request and response in SOAP (Simple Object Access Protocol) format.

There should be a contract to access the webservice this is provided by WSDL -Web Services Definition Language, it is also a XML file containing the method names and their return types and lot more. To learn more about webservice visit this page.

Know the core libraries in Java

2010-01-15T00:32:00.000+05:30

Java differs from other languages in that the number of classes and interfaces in its standard libraries is very large.Beginners to Java should take note that very many common tasks have already been implemented in the libraries. The most widely used packages are probably java.lang, java.util, java.sql, and java.io.

As well, the libraries

* are built by experts
* generally improve their performance over time
* are widely used, and form defacto standards

Implementing something which already exists in the libraries is probably wasted effort.Significant changes and additions to the standard libraries occur in each major release, and it pays to keep current. For example, the 1.4 release of the JDK includes regular expressions, assertions, logging services, and more, in its list of new features. The Java 5 release has several major new features, including generics, an enhanced for loop, enums, autoboxing, and metdata. The Java 6 release has no new language features, and is not as dramatic as the 1.5, but it still has some interesting new features, such as scripting, the JConsole monitoring tool, and various Swing improvements.

2010-01-10T00:20:00.000+05:30

You can compare String objects in a variety of ways, and the results are often different. The correctness of your result depends largely on what type of comparison you need. Common comparison techniques include the following:

Compare with the == operator.
Compare with a String object’s equals method.
Compare with a String object’s compareTo method.
Compare with a Collator object.
Comparing with the == Operator

The == operator works on String object references. If two String variables point to the same object in memory, the comparison returns a true result. Otherwise, the comparison returns false, regardless whether the text has the same character values. The == operator does not compare actual char data. Without this clarification, you might be surprised that the following code snippet prints The strings are unequal.

String name1 = “Michèle”;
String name2 = new String(”Michèle”);
if (name1 == name2) {
System.out.println(”The strings are equal.”);
} else {
System.out.println(”The strings are unequal.”);
}

The Java platform creates an internal pool for string literals and constants. String literals and constants that have the exact same char values and length will exist exactly once in the pool. Comparisons of String literals and constants with the same char values will always be equal.

Comparing with the equals Method
The equals method compares the actual char content of two strings. This method returns true when two String objects hold char data with the same values. This code sample prints The strings are equal.

String name1 = “Michèle”;
String name2 = new String(”Michèle”);
if (name1.equals(name2) {
System.out.println(”The strings are equal.”);
} else {
System.out.println(”The strings are unequal.”);
}

Comparing with the compareTo Method
The compareTo method compares char values similarly to the equals method. Additionally, the method returns a negative integer if its own String object precedes the argument string. It returns zero if the strings are equal. It returns a positive integer if the object follows the argument string. The compareTo, method says that cat precedes hat. The most important information to understand about this comparison is that the method compares the char values literally. It determines that the value of ‘c’ in cat has a numeric value less than the ‘h’ in hat.
String w1 = “cat”;
String w2 = “hat”;
int comparison = w1.compareTo(w2);

How to get time information in java.sql.Date?

2010-01-05T00:19:00.001+05:30

The answser is you cannot.
java.sql.Date does not store/retrieve any information related to time.

So, how do you solve the problem of saving the date with time in your database?

Simple… use java.sql.Timestamp. There are methods in java.sql.PreparedStatement and java.sql.Statement to set the timestamp.

PIC Microcontroller Programming Tutorials - Part 1

2010-01-03T00:15:00.002+05:30

See the basics of using MikroC compiler and Oshonsoft PIC simulator.

Proceed to the next part >>

PIC Microcontroller Programming Tutorials - Part 2

2010-01-02T23:56:00.004+05:30

Learn how to simulate the code..

Previous Tutorial

Next Tutorial

PIC Microcontroller Programming Tutorials - Part 3

2010-01-02T23:55:00.001+05:30

Learn how to read an input from the pin and use it to control LED

Previous Tutorial

Next Tutorial

PIC Microcontroller Programming Tutorials - Part 4

2010-01-01T00:02:00.001+05:30

How to use for loop in MikroC compiler

Previous Tutorial

Disclosure Policy

2009-12-10T01:31:00.000+05:30

This blog is a personal blog written and edited by me. This blog accepts forms of cash advertising, sponsorship, paid insertions or other forms of compensation.

This blog abides by word of mouth marketing standards. We believe in honesty of relationship, opinion and identity. The compensation received may influence the advertising content, topics or posts made in this blog. That content, advertising space or post will be clearly identified as paid or sponsored content.

The owner(s) of this blog is compensated to provide opinion on products, services, websites and various other topics. Even though the owner(s) of this blog receives compensation for our posts or advertisements, we always give our honest opinions, findings, beliefs, or experiences on those topics or products. The views and opinions expressed on this blog are purely the bloggers' own. Any product claim, statistic, quote or other representation about a product or service should be verified with the manufacturer, provider or party in question.

This blog does not contain any content which might present a conflict of interest.

The ruling attendant steams before the infinite disguise.

2009-03-30T01:40:00.001+05:30

The ruling attendant steams before the infinite disguise.

All LED Blinking Program RA4 not Blinking solution .

2009-01-15T00:30:00.003+05:30

Previous Tutorial

If you execute the previous program it will work fine except that RA4 wont blink .A quick search showed me that I need to make some extra register configurations with ADCON1 and COMCON registers .

ADCON1 = 0x06 makes all the pins of PORTA as Digital .
COMCON=0x07 disables the comparators

So the rectified program is below .
void main (){

ADCON1 =0x06 ; // Changes PORTA to digital
CMCON = 0x07 ; // Disable analog comparators
PORTA = 0x00 ;
PORTB = 0X00 ;
PORTC = 0X00 ;
PORTD = 0X00 ;
PORTE = 0X00 ;
TRISA = 0x00 ; // Configure PORTA as output
TRISB = 0X00 ;
TRISC = 0X00 ;
TRISD = 0X00 ;
TRISE = 0X00 ;

while(1){
PORTA = 0XFF ;
PORTB = 0XFF ;
PORTC = 0XFF ;
PORTD = 0XFF ;
PORTE = 0Xff ;
Delay_ms(500) ;
PORTA = 0X00 ;
PORTB = 0X00 ;
PORTC = 0X00 ;
PORTD = 0X00 ;
PORTE = 0X00 ;
Delay_ms(500) ;
}
}
Now all this is rectified .The LED's should blink fine .If you think so you are fooled for the second time .Even this program wont make RA4 blink .You need to pull RA4 high in order to make it blink .I am sure you will run into this problem if you are using PORTA .Hope my post helped you .Please leave your valuable comments if you like my blog and a link back if you find it worthy .

PIC16F877 All Led Blinking Program

2009-01-15T00:11:00.008+05:30

Have you ever tried the Hello World of Embedded programming ,well I am talking about the LED Blinking program .Well if you have worked with PIC microcontrollers most probably it must have been your first program . My guess is you must have tried it in any 1 one of the pins .(I am talking all this assuming that you are either using PIC16F877,PIC16F877A or PIC16F874A they are all pretty much the same ) .

Only today when I was testing the PIC16f877/877A/874A Development board that I developed I was stuck up with a peculiar problem .I was trying LED blinking program in all the ports simultaneously .And everything worked fine except for RA4 .The LED connected to it didnt blink .It is the 6th pin and remember it iis an ADC outcast :P .Well being in PORTA where the rest of the pins have a inbuilt ADC this pin doesnt have one so I consider it as so .But it serves as a Vref to the comparator .

I wrote this simple program to make all the led's blink in My dev board .

void main (){
PORTA = 0; // Initialize PORTA
PORTB = 0X00 ;
PORTC = 0X00 ;
PORTD = 0X00 ;
PORTE = 0X00 ;
TRISA = 0x00; // Configure PORTA as output
TRISB = 0X00 ;
TRISC = 0X00 ;
TRISD = 0X00 ;
TRISE = 0X00 ;

while(1){
PORTA = 0XFF ;
PORTB = 0XFF ;
PORTC = 0XFF ;
PORTD = 0XFF ;
PORTE = 0Xff ;
Delay_ms(500) ;
PORTA = 0X00 ;
PORTB = 0X00 ;
PORTC = 0X00 ;
PORTD = 0X00 ;
PORTE = 0X00 ;
Delay_ms(500) ;
}
}

If you think this will work , you are in for a surprise .Check out the next post for the answer .

Next Tutorial>>

My Transition From C to JAVA

2009-01-14T10:48:00.004+05:30

Hello Readers

When I was in college and underwent a course in OOPS c++ and JAVA ,I wondered why do we need this horrible OOPS when easily solve most of the problems using C . And ofcourse the lecturer who handled OOPS was no good .It made my learning experience worse .

But only after I entered my company and took up the JAVA course I found how easy JAVA is and moreover Eclipse makes programming feel like a cool breeze . The ctrl+space code auto generation feature is awesome which programmers will love .But there are some downsides in JAVA as well .Which I found out after some programming experience .You can't play with the memory in JAVA ie there is no such thing as pointers in JAVA .So when it comes to applications where you have to play with the memory you face a down side .But you have something called as Native Method support in JAVA , where you can write a method implementation in some other programming for a JAVA interface .

So explore JAVA and build applications with ease .

MIT Chrompets Annual Techfest -Asymptote

2009-01-02T19:43:00.000+05:30

MIT Chrompet for the first time is conducting a Intercollegeite techfest in a big level .

ASYMPTOTE -- (Jan 9 - 11)

It doesn't contain any robotics event as such .But there are lots of technical and management events .

One of my all time favorite event is the Soap Box Derby Car competition its conducted under the name Drag Race .Where in you have to build a model car without any propulsion system .It has to race down the slope under the influence of gravity and reach the finish line .The one that reaches the finish line fastest is the winner .

I remember my days in the 2 nd year of college when I participated in this event .This is one event where you can get hands on experience in mechanical Engineering .So do participate in it and enjoy building the car .

MikroC Code for reading and writing data into EEPROM

2009-01-02T16:55:00.000+05:30

<---Previous Tutorial

Here is an example program showing how to read and write into EEPROM ,This program first writes 0x80 into the address 0x00 and the reads and displays it in portb .

unsigned short data = 0x80,address=0x00;

void main() {
PORTB = 0x00;
TRISB = 0x00;

EEprom_Write(address,data); //writes 0x80 into the location 0x00
Delay_ms(20); //insert 20 ms delay between every read and write cycle
PORTB = Eeprom_Read(address); //reads the data from 0x00 and send it to portb
Delay_ms(500);
}

Kurukshetra CEG's Annual TechFest (21 st - 24 th january)

2008-12-28T18:48:00.004+05:30

Kurukshetra is an Annual Tech Fest of College Of Engineering Guindy (CEG) ..Its a part of Anna University Chennai .Its one of the premier institutes in India .The best part there are prizes worth 10 million waiting to be bagged .

Kurukshetra (21 st - 24 th january)

Designer's Quest
The Road Not Taken
Robotics - Line Follower
Robo Soccer

These are the four robotics event in kurukshetra 09 .

Robo Soccer is the easiest among these events and perfect for newbies .
Robotics - Line Follower lies in the intermediate category .
The Road Not Taken is based on image processing .Which is somewhat advanced .

There is also a special event for showing your creativity "Designer's Quest" . Where imagination is the limit .So participate in kurukshetra and win grand prizes .

Creating simple image using INTEL'S OPENCV

2008-12-28T10:16:00.001+05:30

Hi Everyone
In future there are going to be no robots without a vision system .Computer vision is going to be a main and integral part of future robots .Even at present there are lots of robots using image processing to navigate and identify objects .

Now to explore this science MATLAB is a very good tool .But for real time applications and applications that are fast MATLAB is no good .MATLAB consumes a lot of your computers resources .

Now here I found a neat blog for tutorials on openCV . myopencv has tutorials at beginner levels .
Here I have tweaked one of his code to create an image with black and white striped pattern .Do look at the site for more information .Here is the source code for generating black and white striped pattern .

#include "cv.h"
#include "highgui.h"
#include "stdio.h"
int main()
{
/*Creates an image size 600 by 600 ,IPL_DEPTH _8U
means each data Element has a pixel depth 8 bits
1 means one channel*/
IplImage *img = cvCreateImage(cvSize(600, 600), IPL_DEPTH_8U, 1);

int i, j,k,l;
uchar *data;
data = (uchar *) img->imageData;//pointer to the Image data
/*consider a 2d array here, we go to the first horizontal line
process it and then we go to the next horizontal line.
The above for loop goes to the next line after a line is processed*/
for (i = 0; i < (img->width); i++)
{/*This for goes length wise(means it works horizontally on the Image.*/
for (j = 0; j < (img->height); j++)
{
for(k=0;k<5;k++){ one="255”" style="color: rgb(255, 0, 0);">data[i * (img->widthStep) + j * (img->nChannels)] = 255;
j++ ;
}
/*else assign zero, image should not contain garbage values it
is always good to force assignment*/
for(k=0;k<5;k++){ style="color: rgb(255, 102, 102);"> data[i * (img->widthStep) + j * (img->nChannels)] = 0;
j++ ;

}
}
}
/*This function creates an image with name ‘image’*/
cvNamedWindow("image", CV_WINDOW_AUTOSIZE);
//showing the image
cvShowImage("image", img);
/*saving the image parameters name with Extension*/
cvSaveImage("testimg for_prog.jpg", img);
//wait for any key and Exit
cvWaitKey(0);
//release img
cvReleaseImage(&img);
//destroy the window
cvDestroyWindow("image");
return (0);
}
The important lines ,I have highlighted in red .

PIC16F877A EEPROM Tutorials

2008-12-14T15:51:00.000+05:30

There is a inbuilt EEPROM in most of the PIC microcontroller series .PIC16F877A has 256 bytes of EEPROM inside it .So you can use it to store data that you might need on a permanent basis and you can read it back from it .The picture below shows the representation of the memory in the EEPROM .

For instance in the above picture I have entered 0x01 in the location 0x88 .
0x01 is the data and 0x88 is the address where the data is stored .I guess you
got the system .

Now let is look at the mikroc specifics of the EEPROM library .There are two functions in this library to accomplish the task

Eeprom_Read
Eeprom_Write

Eeprom_Read function returns an integer and takes a parameter of the address from which the data has to be fetched .The following is the syntax .

unsigned short Eeprom_Read(unsigned int address);

Eeprom_Write takes two parameters the first one is the address and the second one is the data .The syntax is given below .

void Eeprom_Write(unsigned int address, unsigned short data);

You can use these two functions to read and write data from the pic EEPROM .I will show you the actual working code in the next post .

Next Post ---->

mikroc program pulse width modulation

2008-12-13T12:28:00.002+05:30

<---Previous Tutorial

Now lets see how to write a code using the mikroc compiler to control the pwm module .
For your convenience MikroC provides PWM library and there are 4 functions present in

Pwm_Init
Pwm_Change_Duty
Pwm_Start
Pwm_Stop

The pwm_init takes a arguement of frequency in hertz

To Initialize a PWM module at 5KHz do this :Pwm_Init(5000);

Pwm_Start and Pwm_Stop are self explanatory I guess .These functions doesnt take any arguements .

Pwm_Change_Duty Changes PWM duty ratio. Parameter duty takes values from 0 to 255, where 0 is 0%, 127 is 50%, and 255 is 100% duty ratio. Other specific values for duty ratio can be calculated as (Percent*255)/100.

Take a look at the following simple program

void main (){
portb = 0x00 ; //clear portb
TRISB = 0xFF ; //Set PortB as input
PORTC = 0x00; // clear PORTC
TRISC = 0; // PORTC is output
Pwm1_Init(5000); // Initialize PWM modulen set frequency as 5000
Pwm1_Start(); //Start the pwm module
while(1){
if (portb==0x80) //if rc7 is high
Pwm_Change_Duty(127); //set the duty cycle as 50%

}
}

This program creates a pwm on pin17 of PIC16F877A .

Hope you found this tutorial useful .If you have any doubts about the program .Leave a comment .

CCP Module in PIC16F877A -- Tutorial

2008-12-12T11:10:00.006+05:30

<--Previous Tutorial Next Tutorial--->

In this post I will cover about the PWM module present in the pic microcontroller .I will cover it using PIC16F877A but it can be applied to any pic with a CCP module .

What's CCP module ?

CCP-- Capture Compare Pulse Width Module

Capture - The contents of the 16 bit timer,upon detecting an n th rising or falling edge, is
written to internal registers .
Compare - Generate an interrupt, or change on output pin, when Timer 1 matches a pre-set
comparison value .
PWM - Create a re-configurable steady duty cycle square wave output at a user set frequency.

For more information see this MicroChip pdf .

For now I am not going to cover the capture and compare modules .Lets see about the pwm module . You have 2 channels in PIC16F877A to accomplish the task .
Its present in pins

16 --- RC1 ---- CCP2
17 --- RC2 ---- CCP1
As you notice there are two channels present in the pic .This is ideal for robots with two wheel differential drive .You can achieve smooth turns acceleration if you use these two pins intelligently .Now let us see how to program the pwm using mikroc in the next tutorial .

<--Previous Tutorial Next Tutorial--->

pwm pulse width modulation tutorials

2008-12-11T10:33:00.004+05:30

There are a number of occasions where you might need Pulse Width Modulation for regulating power to a number of devices .It could be your Motor or even a lighting device .Let me explain
PWM first .

It is the variation of duty cycle from 0 to 100 % .To put it in a smiple way

"Pulse width modulation is the process of switching the power to a device on and off at a given frequency, with varying on and off times."

The following picture will give you a clear idea about it

It shows three different PWM's of 10% , 50% and 90% .
Notice: 100 % would become constant DC .

For instance take 10% duty cycle .You switch on the power for 10% of the time and switch it off for the remaining 90 % of the time .

Let me give you a practical example .Take a wave of frequency 1KHZ =1000 HZ .The time period of one wave as you know is 1millisecond .So a wave of 10% duty cycle will remain switched on for .1 millisecond
50% for .5 ms and so on .

You could achieve PWM by simple circuits like using a 555 timer .But the best part is you have built in pwm modules in PIC16f877A .Using which you can modulate the wave .For applications like motor control you can acheive smooth acceleration using these pwm modules present in the PIC .I will tell you about the coding and pic specifics in the next post .

next Tutorial -->

Lead Acid battery Choosing For Final Year Project

2008-12-09T18:03:00.000+05:30

Batteries are an integral part of robot design, as important as the frame, motor, and electronic brain. Batteries come in all sizes and shapes .So, an appropriate choice has to be made depending on the application .If the application demands high current and longer period of operation lead acid battery is a good choice. Although Lithium ion battery would be a ideal choice for our project it is very costly when compared with lead acid battery .Since our design can carry heavy weights we decided to use lead acid battery for its cheap availability even though it is heavy.

Lead acid Battery Types Usage

2008-12-09T17:59:00.000+05:30

LEAD-ACID BATTERY

Lead Acid batteries were developed in the late 1800s, and were the first commercially practical batteries. They remain popular because they are easy and inexpensive to manufacture. Rechargeable lead-acid batteries have been available since the 1950s and have become the most widely used type of batteries today.

There are three main types of lead acid batteries.

Wet Cell (flooded)

Gel Cell,Absorbed

Glass Mat (AGM).

The Gel Cell and the AGM batteries are specialty batteries that typically cost twice as much as a premium wet cell. However they store very well and do not tend to sulphate or degrade as easily or as easily as wet cell. There is little chance of a hydrogen gas explosion or corrosion when using these batteries. Gel Cell batteries, which are best used in very deep cycle applications, still are being sold but AGM batteries are typically better. In most cases AGM batteries will give greater life span and greater cycle life than a wet cell battery.Why I choose Lead Acid for my project ,I've written in my next post .

Tracked Robot Fabrication tutorials

2008-11-28T16:39:00.000+05:30

The following parts were fabricated for the constructions of the robot .They are explained one by one below.

WHEELS

The wheels used in the construction of robot were machine moulded plastic wheels with hollow space inside. The diameter of the wheel is 61 mm and the width of the wheel is 20 mm.

BELTS

The belts that we have used are reinforced rubber belts .Some of the remarkable characteristics are wearing resistant, high strength, waterproof, heat resistance, crack resistance, aging resistance and longer use life.

The ball bearings that support the rear wheels need to be housed in a housing that could support the ball bearings and it also provides adjustable facility so that the slack that occurs in the belt over a period of time can be adjusted .It also facilitates the easy removal of the belt are loosening it.

REAR WHEEL SHAFT

The shaft shown freely inside the ball bearing providing smooth motion .One end is threaded to connect the encoder wheel and the other end is connected to the wheel.

BALL BEARING HOUSING

PROVISION FOR SLACK adjustment

As the rubber belt slacks due to temperature variation and ageing a slot was milled in the robot’s body for slack adjustment which ensures that the belt stays taut at all times.

Final Year Project Robot design

2008-11-27T12:43:00.000+05:30

Final Year Tracked Robot Sketch Up Drawing

Google sketch up is a very useful tool for drawing fine and detailed drawings of your robots .Its easy to use as well Below is the 3d view of my final year project .

Isometric View

Side View

The real picture of my robot ..

The body frame was made of aluminium sheet and the wheels are plastic and the belts are rubber belts .I've written about the construction in the following posts .

Internet Controlled Telerobot Using Flat File System

2008-11-26T11:58:00.000+05:30

Hi Readers

I've worked on a project "INTERNET CONTROLLED TELE- ROBOT USING FLAT FILE SYSTEM"

while in college and published my research work as a paper .I've deceided to give my paper to you people so that you could use it in your work and benefit from it .

My project is still online and you can login here and see the working .How ever the robot isnot connected to the computer .You can just get to know the layout and working code .

TELE ROBOT LOGIN

UserName:demo

Password:demo

Heres the word document of my paper .You can modify it as you like .

I am willing to give you the code on special request .

The Abstract and Introduction are given below .

Abstract - Our method aims at using the web browser for transferring the commands from the remote client operator to the robot’s control desk through a server which eliminates the need for costly equipments, complicated software’s and also consumes only a low bandwidth which is an added advantage .And moreover it provides security and eliminates the tedious process of IP address identification and verification used in the conventional methods of teleoperation through the internet. The main improvement that we would like to highlight is eliminating the need for installing client side software’s since the whole process can be done using the web browser ,through which the operator has real-time access to the robot .

INTRODUCTION

Today many robotic applications demand teleoperation. The current methods are mainly developed around wireless protocols which involve high cost equipments and can transmit only through a limited distance or by using complex software’s in the client end which consumes a large chunk of the bandwidth. The security concern of the process also becomes a huge question mark in these methods.

So in order to eliminate the installation of software in the client end and to avoid the direct connection of the clients we need a server in between as some sort a meeting and a communicating point from where the operator and the robot can put and get the data .An php server was used for the purpose because of the ease of scripting and also its open source .And using this scripting a login interface was added as a first security measure.

Robot Locomotion Mechanisms And Natural Movements

2008-11-25T11:33:00.000+05:30

Locomotion Mechanisms

Hello everyone ,It has been very long since I posted in this blog .I have been busy with my new job and training .

I am going to write about different locomotion mechanisms.So far I've worked mainly with wheeled robots and a few legged robots.There are other types of motions like (Given below )

Flow in a Channel
Crawl
Sliding
Running
Jumping
Walking

Click one the image for an enlarged view

One interesting locomotion that I found is the human walking.It is approximately equivalent to rolling polygon.with sides equal in length to the span of the step.You can see a detailed picture below .

The side of the polygon equals the span of the step.

Sex with robots ....IS it possible ?

2008-11-10T16:32:00.000+05:30

Ever Imagined marrying a robot in the future ?
Levy the artificial-intelligence researcher thinks that legal marriages between homo and Robo is possible by mid century .It was pretty shocking to me when I first read it .But Levy says that with the advances in computing, the day may not be too far away .

So Who know we may be having ROBOT Girl friends in the next 50 years .

Read these two articles from Scientific American

Not Tonight, Dear, I Have to Reboot
Humans Marrying Robots? A Q&A with David Levy

Who won ROBOCON 2008 ?

2008-11-10T16:28:00.000+05:30

Nirma Wins ROBOCON 2008

Nirma Institute Of Technology, Ahmedabad has won Robocon India 2008 after beating MIT, Pune in the finals!

SEMI FINALISTS

Indian Institute of Technology, Delhi.

Nirma Institute Of Technology, Ahmedabad.

Maharashtra Institute Of Technology, Pune.

Vishwakarma Institute of Technology, Pune.

FINALISTS

Nirma Institute Of Technology, Ahmedabad.

Maharashtra Institute Of Technology, Pune.

And the winner was: Nirma Institute Of Technology, Ahmedabad.

read more ............

Sensor types Analog and Digital Sensors

2008-11-09T17:42:00.001+05:30

TYPES OF Electrical SENSORS:

There are two types of sensors

· Digital sensors provide simple on/off or true/false results or the stepped binary results. A switch is a good example of a digital sensor: either the switch is open or it’s closed. An ultrasonic ranger, which returns a binary value, with each bit indicating a specific distance, is also a digital sensor.

· Analogue sensors provide a range of values, usually a voltage. In many cases, the sensor itself provides a varying resistance or current, which is then converted by an external circuit into a voltage. For example, when exposed to light the resistances of a CdS (cadmium sulfide) cell changes dramatically. Built in a simple voltage divider, the voltage output varies with the light striking the CDS cell.

How to Program a PIC Microcontroller ?

2008-11-07T03:43:00.000+05:30

How to program PIC Video tutorial ?
This is a cool video that I found in Youtube .It shows you 4 different ways to program a PIC microcontroller .

ICSP
JDM Programmer
Microchip USB Programmer(ICD)
USB Programmer (Not exactly a clone of ICD)

Watch this video and get started with PIC Programming

Getting started with pic16f877a interrupt programming .

2008-11-06T22:18:00.000+05:30

What is an interrupt and why do we need an interrupt in PIC16F877A ?

NEXT TUTORIAL >>>>

This is the second tutorial in the series of "Mastering PIC16f877A programming " .

Without interrupts you would have to do loops in order to check if one or another event occurred. This routine checking is called as polling .Polling has disadvantages like consuming valuable microcontroller resources and time . These resources may be used for other data processing tasks. This is why microcontroller comes with built in interrupt support. Instead of checking events microcontroller has ability to interrupt normal program flow on event and jump to interrupt service subroutine(ISR) .

Imagine the ISR as a function in the program and the interrupt source as a event that calls the function .

During interrupt microcontroller stops the task at current point, saves necessary information to stack and gives resources to interrupt subroutine. When interrupt subroutine finishes, and then normal program flow continues .And more over priorities can be set in the interrupts and it can be masked according to your needs .

Here is the famous telephone conversation example for interrupts .

Suppose you are sitting at home, chatting to someone. Suddenly the telephone rings. You stop chatting, and pick up the telephone to speak to the caller. When you have finished your telephone conversation, you go back to chatting to the person before the telephone rang. You can think of the main routine as you chatting to someone, the telephone ringing causes you to interrupt your chatting, and the interrupt routine is the process of talking on the telephone. When the telephone conversation has ended, you then go back to your main routine of chatting.
(read more) .

Before Moving on lets see some interrupt constraints .

INTERRUPT CONSTRAINTS
Usually when an interrupt source is ready it sends a signal to microcontroller saying that it is ready to be serviced.But this signal which is sent by the source must occur in a timely manner or else it may cause malfunction.Usually interrupt source must be initialized considering two important parameters:

1.Minimum time interval between interrupts from the source .ie(The next interrupt should not occur before the interrupt service routine is processed for the previous)
2.Maximum time it takes the microcontroller to execute interrupt service subroutine .

So lets see how to configure the registers in the next tutorial .And another information for those who are wondering what registers are ? .
Registers are something like memories that are built inside a PIC by means of which you tell the microcontroller how it should set the pins or interrupts or timers or anyother peripherals .Its what you use to make the initial settings .

Lets move on to the next tutorial about the register configuration .
There are totally 5 registers so I've broken the tutorials into 4 parts for easy reading .You can follow to the next tutorial by clicking the link below .

NEXT TUTORIAL >>>>

Robonics - My Robotics Start Up

2008-03-29T15:35:00.001+05:30

Heyy People
It has been a while since I wrote something here. I have been busy all these days.. Busy with what ???? ..
Well I have been working hard to launch my own company. What does the company deal with ?
What other than robotics (my passion). Presently I am have developed and manufactured some development board, programmers and a few mechanical parts. I hope to extend my catalog to lots of other parts.

Company Name
I have named my company ROBONICS.
etymology: Robo from Robotics and nics from electronics constitute ROBONICS.This name was suggested by my friend gopi.. I liked it and so named it.Some of my friends accused me for the name not being jazzy ... I should have added an X or Z. Well I like to keep it clean and simple .. I am happy with this name.

Why I started this company ?

One major reason being there arent any robotics company in Chennai , Hyd , Cochin that manufactures and sells kits. Of course there are many players in North India.
Second reason being, all the kits that you get online are costly which are sold at a huge margin.So I wanted to provide kits for students that is cheap as well as easy to use .(Budget is always a problem for we robotists)

Wish me good luck for my business to succeed guys and gals .. For I need you to for this business to succeed.

Shop
There is an online shopping cart that you can use to shop for products. Some of the very useful products that I would like to recommend is

Please do check out the website guys ..and wish me luck again.

Knowing pic16f877 Interrupt Registers

2008-03-02T20:55:00.004+05:30

<<<Previous Tutorial

Next Tutorial>>>

INTERRUPTS IN 16F877A

The interrupt sources in PIC can be broadly classified into .
1.External interrupt
2.Internal interrupts .

There are totally 14 sources of interrupts in PIC16F877A .

Timer0 overflow interrupt
Timer 1 interrupt
Timer 2 interrupt
Capture compare interrupt ccp1.
Capture compare interrupt ccp2.
Comparator Interrupt
USART Transmitter interrupt
USART Receiver Interrupt
Synchronous Serial Port interrupt
EEPROM Write Interrupt
Analog to Digital Converter interrupt
Parallel slave port read write interrupt
Bus collision interrupt
External interrupt (RB0/INT0)

Starting with the registers .
The global register for the interrrupt is INTCON .The following tables show you the individual bits .

GIE

PEIE

TOIE

INTE

RBIE

TOIF

INTF

RBIF

The description of the individual bits are given below .The status of different interrupts when set as o and 1 .

BIT	NAME	WHEN SET 1	WHEN SET O
GIE	Global interrupt bit	Enable all	Disable all
PEIE	Peripheral interrupt enable bit	Enable all unmaskable peripheral interrupts	Disable all peripheral interrupts
TOIE	Timer 0 overflow interrupt enable bit	Enable	Disable
INTE	RB0/INT external interrupt enable bit	Enable	Disable
RBIE	RB port change interrupt enable bit	Enable	Disable
TOIF	Timer 0 overflow interrupt flag	TMR0 reg overflows
INTF	RB0/INT external interrupt flag	External interrupt occurs	No interrupt
RBIF	RB port change interrupt flag bit	One line changes its state from RB7 to RB4	No line changes

The first five bits are configuration bits and the next 3 lower bits are FLAGS .That will be set as 1 when the corresponding interrupt occours .It is the programmers responsiblity to clear those bits .It wont be cleared automatically .Its for the reson because if another interrupt occours while processing the previous interrupt it will lead to chaos .So the task is given to the programmer to clear the bits .

In addition to INTCON reg peripheral interrupt also has 4 more reg PIE1 , PIE2 corresponding to PIEX and PIR1 and PIR2 coressponding to PIRX.Let us see these registers in the next tutorials .

<<<Previous Tutorial

Next Tutorial>>>

pic16f877a interrupt register config

2008-03-02T19:55:00.004+05:30

<<<Previous Tutorial

Next Tutorial>>>

PIE1 REGISTER
The Table for PIE1 configuration is given below .

PSPIE

ADIE

RCIE

TXIE

SSPIE

CCPIE1IE

TMR2IE

TMRA11E

Please take a look at the table to configure it according to your needs .For example PIE.6 corresponds to ADIE and setting it as 1 enables the A2D converter interrupt.

PIE.6 = 1 ;

PSPIE

SSPIE

CCPIE1IE

BIT	NAME	ENABLE	DISABLE
Parallel slave port read/write interrupt enable bit	1	0
ADIE	AD conveter interrupt enable bit	1	0
RCIE	USART receive interrupt enable bit	1	0
TXIE	USART transmit interrupt enable bit	1	0
Synchrous serial port interrupt enable bit	1	0
CCP1 interrupt enable bit	1	0
TMR2IE	TMR2 to PR2 match interrupt enable bit	1	0
TMRA11E	TMR! overflow interrupt enable bit	1	0

PIE2 REGISTER

---

EEIE

BCLIE

---

CCP2IE

	NAME	ENABLE	DISABLE
EEIE	EEPROM write operation interrupt enable bit	1	0
BCLIE	Bus collision interrupt enable bit	1	0
CCP2IE	CCP2 interrupt enable bit	1	0

EEPROM Bus collision and CCP2 interrupt enable bit are available in PIE2 register .All other bits are
kept clear in this register

<<<Previous Tutorial

Next Tutorial>>>

PIC16f877a PIR1 and PIR2 Configuration .

2008-03-02T06:55:00.001+05:30

<<<Previous Tutorial

Next Tutorial>>>

PIR1 REGISTER

The bits are listed below .

PSPIF

ADIF

RCIF

TXIF

SSPIF

CCPIE1IF

TMR2IF

TMRA11F

BIT	NAME	ENABLE	DISABLE
PSPIF	Parallel slave port read/write interrupt flag	1	0
ADIF	AD conveter interrupt flag	1	0
RCIF	USART receive interrupt flag	1	0
TXIF	USART transmit interrupt flag	1	0
SSPIF	Synchrous serial port interrupt flag	1	0
CCPIE1IF	CCP1 interrupt flag	1	0
TMR2IF	TMR2 to PR2 match Interrupt flag	1	0
TMRA11F	TMR! overflow interrupt Flag	1	0

PIR2 REGISTER

The Configuration bits are listed below .Take a look at it to understand .

---

EEIF

BCLIE

---

CCP2IE

BIT	NAME	ENABLE	DISABLE
EEIF	EEPROM write operation interrupt flag	1	0
BCLIF	Bus collision interrupt flag	1	0
CCP2IF	CCP2 interrupt flag	1	0

<<<Previous Tutorial

Next Tutorial>>>

PIC C Programming Video Tutorial (ADC)

2008-02-22T23:42:00.007+05:30

< << PREVIOUS TUTORIAL

Now we shall Jump into PIC ADC Programming using C .As I told you in the previous post we are gonna use MIKROC and The simulator that we will be using is OSHONSOFT PIC Simulator(download link ) .

Watch this video tutorial to get started with PIC16F877A programming and set up using the MikroC compiler and Oshonsoft PIC Simulator .

PIC C programming is just like normal C programming that you do for you computer .The differences being you have to declare the ports set the registers and there is no printf and scanf of course .

Here is the small program that I teach you in the video .It simply reads the value from the 2 nd ADC channel and outputs it to the PORTB .And also I've configured the ADC ports as 8 bits and all analog inputs .If you not sure about the register settings read my previous tutorial .
So look at the table that I've given in my previous tutorial and configure ADCON1 .

unsigned short adc_val ;
void main ()
{
ADCON1 = 0x00;
TRISA = 0xff ;
TRISB = 0x00 ;
while (1)
{
adc_val = adc_read(2) ;
portb =adc_val ;
}
}

After setting ADCON1 .The TRIS registers have to be set .The TRIS registers configures the port as either input or output .Just suffix the TRIS register with the PORT name .
TRISA is the register for PORTA ,TRISB is the register for PORTB .Here we are going to use PORTA so I've to set the TRISA register as inputs .So how do we do this ?
I am going to use hexadecimal to configure the registers and ports .You can also use binary to configure the ports which is good and easy for beginners .
So to use hexadecimal you've to add the suffix 0x (0xFF) and to use the binary you've to use the suffix ob (0b11111111) . Looking at my program I've used

TRISA = 0xFF which can also be written as
TRISA = 0b11111111 in biinary .

The next thing is setting the port as input and outputs .Let us take PORTB as example .
TRISB = 0x00 ;
TRISB = 0b00000000 ; configures the port b as outputs .

So I guess you must have learnt how to set a port as input or output by now .
TRISX = 0x00 makes the port as inputs and TRISX = 0xff makes the port as inputs .
(Substitute the port name in the place of X ) A combination of input and output can also be done .
for ex

TRISB = 0xF0
TRISB=0x11110000

sets half of the upper ports as input and the other half as outputs .
After setting the ports we shall get into the main program .
You must have noticed an unsatisfied while loop .Yes there must be at least one unsatisfied loop inside your program ,because your microcontroller doesn't have a operating system there has to be atleast one unsatisfied loop inside the program to make it run continuously.

MikroC has lots of inbuilt libraries . For reading the analog inputs
adc_read(unsigned int channel number ) is used .

Getting back to my program what I do is I get the input from the channel and output it to the PORT B .

So I hope this tutorial has helped you .
Please leave your comments if you have any suggestions .

Getting Started :PIC 16f877A Analog to Digital conversion tutorial

2008-02-21T01:25:00.005+05:30

What is Analog to digital conversion ?

NEXT TUTORIAL>>>>>>

My first post in the series of "Mastering PIC microcontroller Programming " is gonna be about ADC(Analog to Digital Converter).
Well what is A2D first of all ?
We all have done analog to digital conversion (A2D) .You dont beleive me ? .Remember the 5th grade science experiment of finding the boiling point of water .We take down the readings of the thermometer every 30 seconds until it reaches a contant .Although the temperature varies continously we only note the reading between specified time interval ie You are sampling the continuous data into a sampled data and reconstructing the continuous curve based on the data we have .So we all have done the basis of A2D in our lives .

PIC Microcontrollers have 10 BIT ADC's .That means the range is from 0-1023 or 0-(2^10 - 1).If we set the reference voltage at 5 volts then 0 - 5 volts can be represented as 0 - 1023 in the digital format .ie 5 v would represent 1023 2.5 v would represent 512(rounded).That is the microcontroller would understand 2.5 v as 50% of 2.5 .
The formula to calculate the digital value is

x= (Vin/Vfullscale )(2^n-1)

following this formula

x=(2.5/5)*1023 =511.5 (512 approx)

Then the next question arises about the a2d resolution .To put it simply what is the minimum voltage that the microcontroller would be sensitive .The resolution of 10 bit microcontroller with 5 v as reference is

5/1023 =4.88 mv .

The microcontroller would measure a minimum change of 4.8 mv below which it will be insensitive .
The general formula for resolution would be

V res = V Fullscale /2^n-1

Vfullscake = What you set as reference
n= No of bits (10 bit in PIC16F877A)

I assume that you might have understood the basics of A2D and move on to the next step .
The next tutorial is gonna be about the A2D Registers in PIC16F877A . NEXT TUTORIAL>>>>>>

PIC Analog to digital conversion registers

2008-02-21T01:22:00.008+05:30

<<<Previous tutorial
Next Tutorial >>>
There are totally four registers for A2d conversion in PIC16f877 and PIC16f877A .They are the following .
(NOTE : Almost all the PIC series of IC's have this same register configuration .So knowing this is enough to program all the PIC series IC's )

registers for analogue inputs.
Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
ADRESH	A2D Result Register - High Byte
ADRESL	A2D Result Register - Low Byte
ADCON0	ADCS1	ADCS0	CHS2	CHS1	CHS0	GO/DONE	-	ADON
ADCON1	ADFM	-	-	-	PCFG3	PCFG2	PCFG1	PCFG0

ADCON0 Configuration

Since PIC has 10 bit A2D and its a 8 bit microcontroller it needs an extra register to store the extra 2 bits resulting in the A2D conversion .Thats the job the first two registers ADRESH and ADRESL name itself is self explanatory .
ADRESH:Stores the higher 8 bits .
ADRESL:Stores the lower 8 bits .
So now we are done with the first two registers .

The next register that we are gonna see in PIC16F877A is ADCONO .
The first two bits ADCS1 and ADCS0 is required to select the A2D clock .The table for clock selection is given below .If I am using 5 MHZ I will select 01 thats fosc/8 .

ADCS1	ADCS0	A/D Conversion Clock Select bits.	Max. Clock Freq.
0	0	Fosc/2	1.25MHz
0	1	Fosc/8	5MHz
1	0	FOsc/32	20MHz
1	1	Frc (Internal A2D RC Osc.)	Typ. 4uS

The next set of bits are channel select .YOu can select the appropriate channels by selecting the appropriate bits .So now I am using 5 MHZ and selecting RA2 for example , now bit selection will be 01010xxx .The bits that are named as X are still to be selected .

The next bit is GO/DONE .Setting this bit high starts A2D conversion and it is automatically cleared when it is complete .So monitoring the status of this bit can tell us about the status of Analog to digital conversion .So we have to set it high to start conversion .So now our bit configuration will be 010101xx .

If you look at the first table you will see bit1 is useless .So put a zero there .So now our bit configuration becomes 0101010x .
The last bit is ADON .When the bit is set it turns on the A2D when cleared it turns off .So we are setting 1 there .Now it becomes
01010101 .This is the bit configuration to select 5 MHZ clock channel AN2 .The next three bits are useless .

CHS2	CHS1	CHS0	Channel	Pin
0	0	0	Channel0	RA0/AN0
0	0	1	Channel1	RA1/AN1
0	1	0	Channel2	RA2/AN2
0	1	1	Channel3	RA3/AN3
1	0	0	Channel4	RA5/AN4
1	0	1	Channel5	RE0/AN5
1	1	0	Channel6	RE1/AN6
1	1	1	Channel7	RE2/AN7

ADCON1 Configuration

The next channel is ADCON1 . The bit7 ADFM(Analog to digital conversion format ) is used to select the format .Setting this bit high makes it 10 bit converter .And clearing it makes it 8 bit ie the result only appears in ADRESH and ADRESL is ignored .
Now we are entering thre most complicated part of the register selection .Please look at the following table to select the configuration you need .

Visit WINPIC PROG to learn more in detail about the register selection .

PCFG3: PCFG0	AN7 RE2	AN6 RE1	AN5 RE0	AN4 RA5	AN3 RA3	AN2 RA2	AN1 RA1	AN0 RA0	Vref+	Vref-
0000	A	A	A	A	A	A	A	A	Vdd	Vss
0001	A	A	A	A	Vref+	A	A	A	RA3	Vss
0010	D	D	D	A	A	A	A	A	Vdd	Vss
0011	D	D	D	A	Vref+	A	A	A	RA3	Vss
0100	D	D	D	D	A	D	A	A	Vdd	Vss
0101	D	D	D	D	Vref+	D	A	A	RA3	Vss
0110	D	D	D	D	D	D	D	D	Vdd	Vss
0111	D	D	D	D	D	D	D	D	Vdd	Vss
1000	A	A	A	A	Vref+	Vref-	A	A	RA3	RA2
1001	D	D	A	A	A	A	A	A	Vdd	Vss
1010	D	D	A	A	Vref+	A	A	A	RA3	Vss
1011	D	D	A	A	Vref+	Vref-	A	A	RA3	RA2
1100	D	D	D	A	Vref+	Vref-	A	A	RA3	RA2
1101	D	D	D	D	Vref+	Vref-	A	A	RA3	RA2
1110	D	D	D	D	D	D	D	A	Vdd	Vss
1111	D	D	D	D	Vref+	Vref-	D	A	RA3	RA2

in the next tutorial we are going to kick start with PIC16F877A programming in C .I am gonna use mikroc compiler .

Previous

Mastering PIC16f877A programming .

2008-02-19T18:36:00.007+05:30

I bunked college today to do a lot of work that was left to do but ended up seeing cricket match instead .But I did a small portion of the shopping cart for the site that I am building .And my 2nd review is also nearing .But I'vent finished any considerable amount of work except for fabricating a few parts for my robot .

So what am I gonna do now ?.
I am going to dedicate this week for "Mastering PIC16F877A Programming " .
Although I've programmed a lot of robots using C .I always had difficulty with programming .And moreover I always used simple techniques .In fact I've never used TIMERS and Interrupts which has many functionalities.So I am planning to learn all the pheriperals of the PIC like

TIMERS
INTERRUPTS
USART
CCP Modules .

And I also dont know assembly language which I consider as a huge drawback .Although PIC is based on RISC architecture and has only 35 instructions I never managed(not even tried)to learn it .And I am gonna post a new tutorial every day about programming the PIC .So lets see what happens this week .

* Tutorial 1 Programing ADC's
* Tutorial 1 Programming Interrupts

How to Post HTML Tables in Blogger without the big gap ?

2008-02-18T18:12:00.000+05:30

Have you ever tried posting tables in blogger ?

If you have done so ,you will see a huge gap in between the table and the text above it .Heres an example .

Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
ADRESH	A2D Result Register - High Byte
ADRESL	A2D Result Register - Low Byte
ADCON0	ADCS1	ADCS0	CHS2	CHS1	CHS0	GO/DONE	-	ADON
ADCON1	ADFM	-	-	-	PCFG3	PCFG2	PCFG1	PCFG0

So how do you get rid of the space between ?
First let me tell you why there is a huge gap when you post a table on blogger.Blogger inserts a line break tag tag every time you hit enter that is why you see a huge gap .
To get rid of this you will have to insert a small piece of CSS code which will solve the problem .


<style type="text/css">.nobrtable br { display: none }</style>


Paste this on the top of your post and use the div tag to reference it


<div class="nobrtable">

Post your table here -------------------

</div>

Heres the table after inserting the code .

**registers for analogue inputs.**
Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
ADRESH	A2D Result Register - High Byte
ADRESL	A2D Result Register - Low Byte
ADCON0	ADCS1	ADCS0	CHS2	CHS1	CHS0	GO/DONE	-	ADON
ADCON1	ADFM	-	-	-	PCFG3	PCFG2	PCFG1	PCFG0

YOu can see the table is correctly formatted .

Robotic Contests and Techfests in India

2008-02-15T22:18:00.004+05:30

There are lots of Robotic competitions going on in India .Almost every big college has an annual techfest .IIT's lead the race followed by other big universities .The following are the links to the major techfests .

COLLEGE
NAME
MONTH

* IIT Bombay TECHFEST January
* IIT Delhi TRYST March
* IIT Guwahati TECHNICHESeptember
* IIT Kanpur TECHKRITIFebruary
* IIT Kharagpur ROBOTIX February
* IIT Madras SHAASTRAOctober
* NIT Warangal TECHNOZION january >
* NIT Surat MINDBLEND March
* NIT Calicut THATVA September
* NIT Calicut THATVA September
* NIT Bhopal AUTOFESToctober
* NIT Rourkela NITRKLjanuary
* NIT Tiruchirappalli PRAGYAN march
* NIT Durgapur MUKTHImarch
*KIIT kritansh

DCOE TRIOKA
Anna Univ Kurukshetra Anna Univ
NIRMA PREVOYANCEMarch
JIIT JIVE
COEPMind SpaekOctober
SNIST RobovedaAugust
NIST ORISSASANKALP
ECBS SHAKSAMAOctober
IIIT IIT Robotics club

If I had missed out anyother important techfests please bring it to my notice by commenting .

PCB designing Video Tutorial and Ebooks

2008-02-14T19:08:00.003+05:30

Easy to use PCB designing Tutorial

PCB designing is no more a hard core designer’s job , even cons like us can design the PCB using this brilliant software “PCB WIZARD”. You need not be a wizard when you Have PCB wizard in hand.

Unlike most of the PCB designing software’s PCB WIZARD is very user friendly.
(I am telling this keeping in mind that I‘ve tried many other designing software’s).
.The coolest thing that I found in this software is you don’t have to design the PCB at all. It makes PCB for you. How cool is that?

You’ve to just draw the circuit (schematic diagram)

then select the option convert
“Design to Printed circuit board”

The software makes the PCB for you .This is done by auto routing .They even provide manual design mode for advanced users.

Autorouting in action watch the video .

No more you have to be a master knowing each and every spec of the electronic components the pins diameter the size of drill bit .Nothing nothing this software does it for you.

COMPONENT LIBRARY

But there are a few draw backs as well .When you choose the automatic conversion option It lets you down on the aesthetics part .But I don’t mind as far as it is done at the hobby level and if I can design PCB so easily why care about aesthetics.
And the component library is also not adequate .Especially L298 is missing .It also lacks SMD library.

They even have tutorials about etching PCB‘s .And more importantly they don’t have restriction on the size of the PCB.

Download it from here
If you are looking for Ebooks about designing here is the link .

Ebook-Tutorial-1
Ebook-Tutorial-2
Ebook-Tutorial-3
Ebook-Tutorial-4

Final designed PCB

You can select different view modes like prototype,solderside layout ,component side layout and silk screen layout .If you want to design a PCB to replace all your annoying soldered circuits boards which gives you head ache "PCB WIZARD " is the software for you .

How to remove the blogger bar on the top ?

2008-02-13T20:03:00.001+05:30

REMOVE BLOGGER BAR ON THE TOP
I personally don't like the blogger bar at the top of blogger templates .Its good as well as bad .Its good because it provides a search box to search my blog .And bad because it gives an option to flag my blog for objectionable content which I guess you wont like if you blog about some "objectionable content" ;) .But Moreover who needs their search bar when you get cool google search box to search your site .

So how do you remove it ? .Heres a small piece of CSS code which will do the job .Go to
Layout
Edit HTML
Before doing any changes always copy the html code and save it in a text file in your PC .So that
if you mess up something you can always copy paste the code and get back your original template .Or you can download the templete in XML format as a backup .
Paste the following code inside the head tag inbetween the outer-wrapper and header-wrapper definitions

#b-navbar
{
height: 0px;
visibility: hidden;
display: none;}

#navbar-iframe
{
height: 0px;
visibility: hidden;
display: none;
}

<>

#outer-wrapper {
font: $bodyFont;
}
/* Header
----------------------------------------------- */
copy paste the above code exactly here
here goes the code
#b-navbar
{
height: 0px;
visibility: hidden;
display: none;}

#navbar-iframe
{
height: 0px;
visibility: hidden;
display: none;
}

#header-wrapper {
margin:0;
padding: 0;

< / head>
Preview to see if the bar has disappeared and then save the template and view your blog the blogger bar must have disappeared .

How to couple a robot's wheel with motor ?

2008-02-05T19:17:00.002+05:30

COUPLING MOTORS AND WHEELS

When you have motors and wheels the question arises how do I couple them ?.As far as I've experienced they never fit together .So you have to make a coupler to couple both so that it can be removed and used later in any other robot and for easy dismantling .I've written the steps for fabricating it elaborately .You can use either ms(Mild steel ) or Brass for fabricating it .

STEPS OF FABRICATION

First measure the diameter of the motor shaft.
Then measure the internal diameter of the axis the wheel.
If both match then you can fix it directly.
Otherwise choose a rod that is at least 4 mm greater in diameter than the motor shaft.(so that you can use a miimum size of 2mm screw to secure it)
Step turn one side of the rod slightly larger than the internal diameter of the axis of wheel to give a tight fit.
Then on the other side drill a hole with a drill bit that is little larger than diameter of the motor shaft in the rod along its axis .This side is given a loose fit since motor can be reused .(Note this is a drill to insert the motor)
Drill until a depth that is little shorter than the height of the motor shaft.
Then grind the motor shaft with grinding machine to make a flat surface along the axis if your motors shaft is cylindrical. Some motors shaft will be like half cylindrical .This step is not needed if the motor is of this type.
Then drill a hole perpendicular to the axis of the coupling shaft matching the place where you ground the motors shaft, then tap the hole to form thread and use a bolt to tightly secure the coupling shaft with motor.
Before doing the above step don’t forget to fix the wheel.

Wheels fitted to the motors with the coupler .

MOTORS AND SPEED CALCULATION

2008-02-05T18:45:00.001+05:30

MOTORS AND SPEED CALCULATION

When you start designing wheeled robots start from the motors .
Decide the type of motor you are going to use .

According to gear arrangement DC motors can be broadly classified into

1. Motors with Internal gear's
2. Notors with External gear's

For beginners I would recommend using motors with internal gear box motor ,since they are easy to use(they eliminate the whole process of designing and fabricating the gear box ) .Internal gear box are available from a range of anywhere between 5 to 5000 RPM .And their speed can be varied either by

1.Varying the supply voltage or
2.Pulse width modulation (PWM )

After you choose the motor you can calculate the speed of the robot to get a rough idea about how fast your robot will go .(Never forget to do this while designing a robot ,otherwise you will end with a robot that is either too slow or too fast) .
The speed calculation doesn't involve big mathematical formulas .
Measure the diameter of the wheel (in meters) that you are going to use .Then multiply it with PI(pi = 3.14159265) .This gives you the circumference of the wheel .So you get a rough idea about how far the robot moves on one rotation of the wheel .

Circumference = Diameter X PI

Most cheap motors availabe never work to the specifics .The best way to find the RPM is trial and error .Apply the required voltage(remember to connect the wheel before applying the voltage) and start a stop watch for (say) 10 seconds and see how many time it rotates and then multiply it with 6 .This gives u the approx speed of your motor in RPM .And also mark a position on the wheel to make it easier to track it visually .
After getting the RPM of your motor multiply it with the circumference of your wheel .This gives u the approx speed of your robot in meters per minute.

Speed of your robot = RPM of motor x Circumference of your wheel (meters/min)

My Final Year Project

2008-02-03T14:03:00.001+05:30

Hi Everyone very long time since I blogged ...
I guess I will blog regularly in blogger .

From now on I will post about my final year project .Which I am doing in CVRDE .Its a R & D center for Ministry of defence India .

My project title is
"AUTONOMOUS NAVIGATION OF A SURVEILLANCE ROBOT IN STRUCTURED ENVIRONMENT AND TELEOPERATION THROUGH INTERNET"

I am planning to build a tracked robot (click here for my tracked robot tutorial)which has basically two modes of operation .

a.Manual teleoperated mode through the internet .
b.Autonomous mapping mode .

Here is the basic block diagram of how the robot operates .

SCOPE OF WORK
Design and fabrication of tracked robot .
Setting up wireless communication between the remote computer and the robot
Dynamic mapping of the given area.
Obstacle avoidance using triangulation principle.
Setting up of the image acquisition device to relay back the images to the remote location.

This is what I am trying to accomplish .Hope I finish it with in time .

Starting off for SHAASTRA 2007

2008-02-03T13:52:00.001+05:30

Its pretty interesting that I overcame my laziness for another post here .I promised to myself that I will post regularly (see my previous post) .I was also inspired my Ganesh my friend and also my school mate who has renewed his old blog (meet him here) to give it a new look .And I also grew a little jealous by the fact that he was getting about 30 hits a day :D .Inspired by all these factors I am back here again .

I am starting off for shaastra 2007 . I am planning to compete in all the three robotics event .
This time I am pairing up with Prassana my class mate and his cousin and his friend Siddarth for the mission mars event.

Mission Mars
We are planning to start building the robot for mission ma Post Options rs event .The task of the robot is to autonomously navigate a surface similar to mars .We had long discussions regarding the design of the robot .
Finally we made the following conclusions about the design
1.Track drive for the robot .
Since this the best available simple method to navigate a rugged terrain and also we have the belts ,sprockets and boggie wheels for construction which they used for their staircase climber in shaastra 2006.

2.Distance measurement sensors
We planned to implement a real time distance measurement and comparison algorithm to navigate the terrain .Sharp IR sensors seemed to be a good choice .But calibrating them is
surely gonna be a challenge .As the ADC pin give a o/p ranging from - 0.3 to 0.3 volts .I have
to Google and learn a lot to do that .

3.Image processing
Since Siddarth had previously worked in Image Processing .We have also planned to implement
this with image processing method with a TMS32054x Processor .But I guess the problem here lies with connecting the camera to the chip .We have to figure out a way to do that .

Because I have CAT this week .Oh well please don't think CAT that I have mentioned as the common aptitude test for Gods sake ,I am not a MBA freak.This CAT is called as Continuous Assessment Test the great method my college uses to find out how a student
is performing and award him marks accordingly which is accompanied with partiality and grudge . Well I guess I am deviating off topic .Getting back ......I wont be working on it until Saturday .

wish me good luck .I want to win this event .

Some things that I want to remind myself to do it this week
Finish eeemaniacs .(The site that I am building for my class mates.)
Get the 3.2 CC engine running .For the hovercraft event.
And study something for CAT exams .

PODWORKS Beach house party at Tidel Park .

2007-11-07T07:08:00.002+05:30

Hi people
Pod works was held in Tidel park on June 9 th and 10 th .On saturday night they arranged for
a beach house party .This was made by me and this is about the beach house party .

Watch and enjoy .

Robocon Pick N Place Robot !

2007-05-02T09:24:00.001+05:30

This is the video of the pick and place robot that me and my team mate madan made for
ROBOCON 2007 .I am the one controlling it and madan is the one shouting from behind :P .

Watch this video in the testing phase

This is our robot in action in ROBOCON .It looks drunken and slow because we forgot to recharge the battery ...shit we lost the match ......

WORKING
Here is the picture of the pick and place mechanism that I came up with .
The working is pretty straight forward. It has a moving and a fixed arm .
I use the nut bolt arrangement to close and open the arm .And it has a center spring
which provides the force to automatically open the arm .And I used a motor fixed
with a pipe in the shaft to rotate the nut .
Heres the diagram of it .

How to build a tracked robot ?

2007-01-19T12:10:00.001+05:30

If there is a design that combines speed ,power ,maneuverability,control thats track drive.You must have seen this design in a battle tank ,bull dozer and lots of off road vehicles .
Click on this picture to enlarge

Basically this kind of drive can be imagined as a vehicle that lays a track for itself as it moves.
And don't get tensed we are not going to build anything this complicated.
PRESSURE STUFF
So what this basically does is spreads out the weight evenly,as a result more traxion.Consider this example For instance, the ground pressure of a car which may weigh a tonne is equal to the pressure of the air in the tires, perhaps 30 psi (207 kPa), whereas the seventy-tonne M1 Abrams tank has a ground pressure of just over 15 psi (103 kPa).(amazing isn't it ).So as the ground pressure is less the vehicle rarely gets stuck when it goes off road .Well how are we going to build a robot like this ......Lets see.
LETS BUILD
First consider the size of your robot and choose a rubber belt according to the size of your robot.The belts come in varying shapes and sizes.Small like this one

If you want to make a bigger bot you can go for industrial belts with custom made sprockets and boogie wheels .I know a place in Chennai where you get those belts .I'll put the address in a few days.This is the industrial belt available.

MACHINING SPROCKETS AND BOGIE WHEELS
Sprockets can be machined from poly carbonate rods available commercially .And the machining process is normal like machining a metal and the same tools can be used .
BUILDING THE CHASSIS
The chassis can be built by conventional methods by using a plywood ,sheet metal or u can build your own chassis by welding metal pipes or flat rods.
STEERING
The tank uses a differential steering mechanism.
These are the pictures of bots which have used the same materials that I mentioned .Take a look at it.

The first one had used a plywood base and second one a sheet metal..
So start building good luck:) !!!!!!!

How to build a sumo robot ?

2007-01-03T08:15:00.001+05:30

How to build a sumo robot ?
Sumo wrestling is an interesting and thrilling event and it has a history and tradition behind it.Basically it may be held as an autonomous or wireless controlled event.So lets see the basics of building a SUMO robot.
CHOOSING A MOTOR
First deceide the motor you are going to use.Speed is inversely proportional to torque.So go for a slow speed motor that gives good torque.And then start building the chassis click here ---> > for more mechanical designs and ideas.
STEERING MECHANISM
Then build your chassis .And deceide the steering mechanism that you are going to use.Always go for differential steering than ackerman steering mechanism.Differential steering provides more manuverablity and easy control which is crucial.Incase you dont know what differential steering mechanism is I will explain you with the following diagram .

I'll explain you the steering mechanism

Both motors forward bot moves forward . If left motor is switched off or reversed bot and right motor is forwarded turns towards left ..and the other way for the right turn.This is very basic and most people know it.
INTERFACING RADIO CONTROL
Then you have to choose a radio control kit.it is always better to have two kits to avoid frequency interference.You can use RC kits stripped from old cars .Then you will have to use the signal from the receiver and drive your motors.If your are using big motors do not use the receicer to drive the motor directly .you might fry it.So you have to make a driver to drive the motor.A H bridge is usually used to drive the motor, relays can also be used.If you use relays you need not worry about voltage and current ratings of motor.
VERY VERSATILE H BRIDGE

Click on the image to see clearly .

This is a very versatile H bridge circuit.And D88O is a power transistor having a max current range of 3 A and voltage range more than 50 v and more amazing is is that it costs only 4 rupees in my backyard.So what happens is when D1 and D3 are switched on motor runs in forward direction and when D2 and D0 is switched on motor reverses its direction.
TIP
If you look at the RC kit you will find 4 controls forward ,reverse,left and right.So the easiest way to drive the robot is use the forward and reverse channel to control one and left and right to control another.Of course can make better controls by decoding the output but this is the easy way.
LOOKS CRAPPY BUT DAMN EASY!!!!

click on the image to see clearly .
RELAY BASIC IDEA
This is the circuit to drive the motors using relays.A relay has 5 pins 2 for the energising coil and 3 for contacts .There is one movable contact and two fixed contacts .And the movable contact is in contact with a default pin when the relay is not switched on .For more tutorials on how relay works> click here .
HOW THE ABOVE CIRCUIT WORKS
So here when when one transistor is switched on the movable contact moves and comes in contact with the +ve supply and since the other end is grounded the motor runs in one direction .And the viceversa happens when the direction is reversed .(Those protection diode is not needed this transistor can withstand much abuse)
AND AT LAST PS
PS:THIS CIRCUIT MAY LOOK COMPLICATED BUT ITS VERY EASY I'VE USED THIS CIRCUIT A LOT OF TIMES .YOU CAN USE 12 V OR 6 V SUPPLY.AND YOU CAN EVEN USE A 6 V RELAY IN CASE YOU ARE USING 12 V SUPPLY(its so versatile), AND NOTHING HAPPENS WHEN 6 V RELAY IS CONNECTED TO 12 V SUPPLY (thanks to back emf)...

My staircase climbing robot @ Shaastra 2006

2006-12-02T07:28:00.001+05:30

This is my staircase climber that I made for shaastra 2006 which did decently well in the contest .It clocked about one and a half minute in the contest.The cool thing my robot is it's extreme simplicity and it was finished in a night ,and only half of the designed mechanism climbed the stairs .I started constructing it only on 5 th october 2 pm(and competition was on 6 th Oct11 am ) as I was concentrating in gold rush (which messed up in last minute).

Watch my bot climbing

This is a very well designed bot built by Anand mugilkar from Mumbai .Their bot used servo motors 3 kg.This is just a 10 second video.

Contact me

2006-01-06T19:47:00.000+05:30

Contact me at

arunvijaykg [at] gmail [.com]