Darsh Shah's Blog

Indian Censorship on Internet

2012-02-04T18:34:00.001+05:30

Past one month has been a mixed bag for Internet as in USA, the SOPA(Stop Online Piracy Act ) and PIPA (Protect of IP Act) were pulled off after a strong resistance from the internet community. But there is a loss in Indian context as the Government is intervening in free speech as it has asked the giant internet companies to censor content.

But as the whole online community went against the US Govt. to stop SOPA and PIPA, who will act in India ? We can't allow the Govt. to deprive our basic right of Free Speech. Recently, the Govt. of India asked 21 companies to censor data. But Google has strongly rejected it. Similarly, other firms will also reject it. We want a nation in which free speech is valued.

May be one of the reasons why govt. wants to censor data is to prevent what happened during Anna Hazare movement. People got connected via Facebook and Twitter to organize protest and the internet played a major role in involving people and especially the youth.

There is a lot of debate against censorship and I hope the govt. understands the basic right of people and values it instead depriving the nation of it.

Startup experience

2012-01-11T18:16:00.000+05:30

First of all Happy New Year to all and hope you keep your new year resolutions intact over the coming year.

One of the good news which I wanted to share is that I recently joined a start-up company based in Gandhinagar, India. The name of the company is Playpower Labs and is an educational gaming company. It has been stated by my dear friend Kishan Patel and I hopped on as an intern in the team to understand the craze behind the startups and help him out. And I must admit, i m having an awesome time till now.

Currently, I am wearing many hats in the company but one of my major role is as a developer to make games using ActionScript. ActionScript is an awesome language and I love coding in it. Among other duties, I sometimes fill water to say the least :P

But really you can learn loads if you work in a startup. The whole process of establishing yourself as a company, secure funding, making contacts in industry, launching products, managing people, and working very hard while having fun are some parts which happen in a company.

So, its gonna be some exciting time ahead with this new startup and hopefully Playpower Labs will be the best among all the other gaming companies in future.

And btw if you are planning to start your own startup, do read this: http://paulgraham.com/start.html

Optical Cense update

2011-12-22T14:00:00.000+05:30

During research internship in summer, I and Vedang testedMCP2120 which improved the IR communication speed between the nodes. Aftersummer, we became Research Assistants and continued working on this project.

So this is the latest update of the project: We have madethe circuit and the layout and our PCB is ready. We made the pcb smaller andnow its size is just 6 cm x 6 cm. We are currently testing various sensors andwill now start working on the protocol part soon.

The images of he new PCB are below:

Front View

Top View

Bottom View

My first Field Testing experience

2011-12-21T03:42:00.001+05:30

Today I went for my first field test with my senior who isdoing is Phd. I tested stuff sitting in lab but to go out and sweat it out is atotally crazy experience.

We were testing a multi-hop protocol using Xbee on the nodesfor communication. The specified range for Xbee is about 1 Km but we don’t havethat much open space. So we kept the nodes at some hidden places to have someobstruction and so to test the multihop capability.

Node having Xbee

One node acted as a receiver and was connected to the laptopand was constantly giving out the received values on the ts.erminal. Theintermediate node was a router which router traffic to the receiver. Thetransmitter node broadcasted “hello” and flooded the network. More explanationabout the setup in given in the video below.

There is one more video which I will upload soon. The first field test experience was awesome and I hope I canenjoy some more of these in coming month.

AVR Dragon and STK500

2011-12-08T11:30:00.000+05:30

Just came to know that I had taken a video on how to use AVR Dragon to program STK500. But the video is on youtube and so in continuation with last post, the video from youtube is posted here.

Debugging AVR Dragon

2011-12-07T15:30:00.000+05:30

AVR Dragon is one of those rare commodities which everyonewants to have. Rare as in that the dragon is one of the best resource used forprogramming/debugging the atmel chips via JTAG or ISP.

AVR Dragon

I think I had a post about using AVR Dragon for programmingSTK500 but this post is about a peculiar experiment which I did which saved myresearch group some good amount of money. While browsing the inventory, I founda box containing around 12 dragons which were labeled as faulty. On inquiring Igot to know that the guys who tested these devices used Windows and so some software update did some weird thing to the dragon. So, Iembarked on a mission to find the working dragons from this stack.

Setup

So here is the procedure:

Connect the AVR Dragon to any one of the nodes which youwant to program. Now type the following code in the terminal:

avrdude –v –P usb –c dragon_jtag – p atmega1281

I had a board which had atmega1281 and used jtag forprogramming.

If the dragon is alive i.e. working properly, it will outputthe fuses of the controller.

Fuses are read if it works correctly

Out of 12 , I found 3 in a perfect working condition andsaved 3 x 6000 = 18,000 INR J

Animations !!

2011-11-26T11:30:00.000+05:30

The most interesting thing which I did this semester was totake up a course in animation. Though I suck in designing, I thought I canlearn some animation and make some short movies for fun.

But the real fun started when we were given various assignmentsduring the lab sessions. Firstly, it took some time to familiarize myself with AdobeCS5.5 and then started making some short clips like jumping, punching, walking, etc.

The video below shows my final project. It is a bitamateurish but at the end, I learnt something new J

Btw, below are the link of other animations which I made:

NI sbRIO + LabView

2011-11-14T21:30:00.000+05:30

In my robotics course, we got achance to play with National Instruments sbRIO robotic starter kit. It is anawesome piece of hardware having a controller and an FPGA along with heavywheels. The image is shown below. The eyes are the ultrasonic sensor whichmeasures the distance from the object.

Front View

The best thing about the robot isthat it is coded in LabView graphical coding language and is programmed viaEthernet. LabView

is amazing in a sense that it allows to easily run a complexcode without writing a single line of code. The power of visualization which itprovides is one of the best I have even seen. There are lot of inbuilt moduleswhich represent functionality of various components like motors, encodes,sensors, etc. So just place them and connect them and voila, the code is ready.

Chassis

This post is just an overview of the hardware and software which I have been using and will write a separate post on LabView coding soon.

I have done a project on controlling this robot using IR and will share it soon.

Top View

Line Follower Robot v2 + Obstacle detector

2011-11-02T19:30:00.000+05:30

The robotic course was offered for the first time at myinstitute and it was a great learning experience for both the students as wellas the professor. As always the first project of any robotics course is tobuild a line follower robot.

LFR is like a 101 project of robotics. I had made a lfr 2years ago but it was for fun and was very easy. This time, we made a robotusing prebuilt components and it was a project worth doing.

We were given a chassis with 4 wheels and 2 motors. We had amicrocontroller board with us. We had a line detecting sensor which was builtusing IR. An obstacle detector sensor was a Sharp distance sensor. So we had all the components ready. But the real task was how toassemble it properly. It took around a week to gel all those things togetherand come up with a working prototype but the time was worth investing.

I learnt about many important issues like power consumptionsand sourcing which are often neglected. How to counteract the slip of thewheels, how to make motors move slowing or faster and lots of other smallsthings which are very important for the proper working of the robot.

Bit untidy but it works :)

RF Controlled Robot

2011-10-27T02:31:00.000+05:30

During my robotics course this semester, my team was given atask to build a Radio Frequency (RF) controlled robot. Many may call it aremote controlled robot. But it is one and the same thing.

So what we did: We took up a chassis with 4 wheels and 2motors and hooked up a microcontroller board on it. We bought a 315MHz RF transmitter andreceiver module from a hobby shop. The receiver was connected to a decoder chipcalled HT12D and the output was HT12D was given to the microcontroller.

The remote had 4 push button switches which were connectedto the HT12E Encoder chip. The encoder chip can encode up to 256 differentmessages. We had just 4. So the 4 push button switches were 4 logic levels andthe Data out of the encoder was connected to the 315MHz transmitter module. Soif none of the switches are pressed, the data out was 0000. If 2^ndswitch was pressed, then 0100 and so on. Hence these messages were decoded andthe robot moved according to the pattern transmitted.

Both the receiver and transmitter modules had antennas andthe system worked perfectly without any lag.

Got the Job :D

2011-10-10T20:53:00.000+05:30

Finally after a hectic schedule, time to update something..

Recently, a well known company called Qualcomm came to my university for campus placements. I have heard that campus placements are a rarity in Europe but in India, almost all well known engineering institutes have a campus placement system.

So luckily, I sat for Qualcomm. Qualcomm is one of the best technology company currently and is well known for CDMA technology. When Qualcomm came to campus for placement, we had only around 50 eligible people sitting for the interviews. I qualified for second round after passing the aptitude and technical test in the first round.

The interviews were fun altogether. I went through two rigorous rounds of interviews which lasted for 2 hours combined. The interviewer had a tremendous amount of knowledge and were grilling in on all the topics irrespective of whether it was listed on my resume or not.

So at the end of the day, 6 people qualified for the HR interview. HR interviews are pretty notorious as the kind of questions fired at you are uneasy to answer. We were told that the interviews will happen within few days. And then waiting, the days became week and finally I received the 'call'.

The interview was smooth and the next day when the results were declared, I was very elated as I got selected for the company. 'I have a job' and this feeling was very difficult to subside for some coming days.

But truly, it was a lifetime of experience to give 3 tests and 3 interviews and getting selected for one of the best companies in the world.

I am looking forward to join and waiting for that day to begin a new experience of my life :)

PS: Really thankful to my family and friends who stood by me during the whole process and gave me encouragement throughout it.

TinyOS and Meshbean

2011-10-02T02:00:00.000+05:30

In one of my courses taken up this semester, I have to work on TinyOS and Meshbean platform. These can be considered as a part of Sensor Networks.

The Meshbean node is from Meshnetics which is now taken over by Atmel

The kit which I experimented on was given to me by my professor. The picture of one of the node is below.

One of the Meshbean nodes

The whole package which I have is

MeshBean development board is based on the 2.4 GHz ZigBit OEM Module with dual chip antenna. The board supports standard extension connectors and includes temperature, light sensors and other peripheral devices.

The ZigBit module featuring ultra small size and superior rf performance enables the board’s wireless connectivity and makes it function as a node in the ZigBee network. The MeshBean board can be configured to operate as a network coordinator or a router either by DIP-switch settings or via AT-commands. Powered by two AA batteries, the MeshBean development board comes preset with 2 frequently used sensors – temperature and illumination. The board features PCB antenna, three Status LEDs, power on/off button and two programmable buttons. (Courtesy: Internet)

So, to use these nodes for wireless communication, I needed a OS to burn into it. I chose TinyOS as it is one of the leading OS used by researchers around the world. (Another major OS is Contiki)

To learn more about TinyOS, visit http://www.tinyos.net/. It has all the latest information and an active community of developers.

Finally, I had the hardware and the OS. Now, we require a program which will help in burning the OS into the hardware. To solve this purpose, I used Meshprog. I downloaded Meshprog from here.

So with all the components ready, I successfully ran a demo application in TinyOS on Meshbean Node.

I made a small video explaining the steps to be followed and a made a working demo and uploaded it on Youtube.

After this demo, I also configured two nodes and sent data packets at 2.4 GHz. Now, I am learning NesC, a programming language for TinyOS. With this knowledge, I can built better programs and use the nodes for various new things with an aim to create 'Internet of Things'.

On the final note, it was amazing to play with new hardware and learn something new :)

Network Simulator 2 (NS 2)

2011-09-24T19:30:00.000+05:30

As I am doing my research in Wireless Sensor Networks, it was like a prerequisite for me to opt for a course on Network Protocols when it was offered this semester. Though the sensor nodes are easy to make and configure, the standalone nodes make no sense. It is a necessity for them to talk and this talk is controlled by some protocol. The object of a network protocol is to make these nodes efficiently talk within themselves and to the outside world.

Networks is not all about theory. And so there exists a powerful simulator to simulate protocols. This simulator is called 'Network Simulator 2'. It is one of the most used simulator among researchers in the world.

To start with NS-2, the only suitable source according to me is to read Marc Greis tutorials. (http://www.isi.edu/nsnam/ns/tutorial/). It is an excellent source of information and has helped me to understand the simulator over past few weeks. I am using NS 2.4 but the latest version NS-3.12.1 has arrived. You can download it from here.

A snapshot of the simulator is given below. The example is taken from Marc Greis tutorial.

Now to install NS in your system, use the following commands (I am using Ubuntu 10.10 and NS 2.4)
Please note that these commands are run inside the ns folder.

./configure
make
make install

The NS-2 is an interesting tool and it has many other functionality. So to understand the power of NS-2, make sure to read Marc's tutorial.

I am working on a project in this domain and will simulate my new protocol using NS-2. When I am successful in doing that, I will share it with you guys !

Optical Cense Post Summer Update

2011-09-06T01:26:00.000+05:30

The project on which I was working on in my summer vacation as a research internship was optical cense. I remember that I had written a post about the same at the starting of summer when this was done as a course project. I and Vedang continued this project in summer and also working on it now. We have been assigned as Research Assistants for this project.

Work progress

Previously, we tested the IrDA chip which worked at 115.2 kbps. We tested the nodes for different parameters like angular displacement, distance between nodes, vertical displacement and other parameters. Over the summer, we have improved the speed of transmission from 115.2 kbps to 312.5 kbps. The MCP2120 transmit data at 312.5 kbps. We made a circuit on a general purpose PCB to test it. We made a transmitter and receiver and tested for the same parameters while using the new chip. The image of our transmitter and receiver is below.

Transmitter node

What took us long time is ordering and receiving of the ICs. We took a week to design the new circuit and then ordered the ICs. The IC took 15 days to arrive. Then we soldered on a PCB. One thing I learned properly through my RI is how to solder properly. I also tried my hands at SMD soldering. After soldering the circuits, we tested them. As everyone knows, an electronic circuit doesn’t work at the first time. Same happened with us. Then we debugged the circuit and finally we made it working. During the summer, we also took some detours and did fun things apart from this project.

Receiver node

Overall significant work was done as the speed was doubled. Now, we are in process of making a PCB and writing a protocol for communication between multiple nodes. More updates as the work progresses.

IELTS Experience

2011-08-31T00:08:00.000+05:30

International English Language Testing System (http://ielts.org/) is an exam required for admission in U.K., Germany, Canada and Australia. Some US universities also accept IELTS score. I also gave my IELTS exam recently. The scoring is pretty simple. You get a band score out of 9. Nine means you are expert user. IELTS is paper based test and is administered by British Council and IDP.

I gave my exam from the IDP center (www.ieltsidpindia.com). Personally I felts that IELTS is simpler than TOEFL. I prepared for IELTS for only 1 week. Exam takes around 3 hours.

Exam Format

1. Listening
2. Reading
3. Writing
4. Speaking (On a different day)

Listening is easy and the recording is played for 30 min. You get time to read the questions and hence you know what to listen in the recording. Also, the answers can be written on a paper and then additional time of 10 min is given to transfer the answers to the answer sheet. Listening is quite simple but concentration is needed. If you get stuck at one answer, then skip. Utilize the time given for reading the questions judiciously. Note down what the answer requires and search for the answer when the recording plays. 10 mins are enough for transferring the answers, so don’t waste time to transfer answers during the 30 min period. Be careful about the tense, plural/singular, etc while answering. Also use a/the wherever required i.e. answer whatever is spoken. Recording will not be played again, so write when you listen.

Reading is similar to TOEFL reading. 3 passages and 60 min are given. Practice for accuracy. Different question types are there and so practice sample examples for mastering them. Take your time and answer. As it is a paper based test, you can move back and forward. Also, you can underline the passage and so it is helpful in reading. Summarizing and paraphrasing are important questions and you should practice them more.

Writing has 2 tasks. One independent where we have to write on topic and other task is to summarize a chart/graph or some given statistics. You should practice the latter one as they are a bit tricky. Also minimum words are required in each task. The former has minimum 250 words and latter has minimum 150 words. So keep the word limit in mind while writing. Total 1 hour is provided, so you can balance accordingly. One thing to note is that we have to write it on a paper. So your writing should be legible. Also, use a pencil so that you can erase when you find a typo mistake. Practice this section for getting a good score.

Speaking is done with an interviewer on a separate day. It is a 15 min task. The interviewer will ask you questions and will give you a topic to speak on. To crack this section, you should speak confidently. You should have a good vocab. Accent doesn’t matter but the pronunciation does. So, speak clearly without fumbling and repeating the same ideas/lines. The topics are easy so you don’t need a huge IQ. Common general knowledge will suffice. Keep a good body language. Speak while looking at the person in front of you. Don’t talk unless asked. Practice in front of mirror or with your friends to get a good score.

My IELTS was exactly a week after my TOEFL and so, I didn’t prepare rigorously for IELTS as I had prepared well for TOEFL. I just gave 5 practice tests and did speaking practice with my sister.

The above is my experience for IELTS and hope it helps you. All the best !!

TOEFL: Tips and Tricks

2011-08-26T23:31:00.000+05:30

As I am aiming for my masters in USA in the coming year, I gave my TOEFL (http://www.ets.org/toefl) which is compulsory for admission in US universities. TOEFL stands for Test Of English as a Foreign Language. It is an easy exam and one can prepare for it in 15 days (if GRE already given). I gave my exam recently and wanted to share my experience with you.

Test Format

TOEFL is generally around 4 hour’s exam. The test has 4 sections.

1. Reading

2. Listening

3. Speaking

4. Writing

30 marks for each section. Hence total exam is out of 120 marks.

I am going to explain the sections in detail below along with how to prepare and some tips.

Reading section is relatively easy one. If you have aced your GRE Verbal part, then Reading section is easy to deal with. But beware about the questions types. They are different varieties and you need to practice examples to get familiar with it. Reading section gets over very fast, but I feel that you should utilize all your time and aim for accuracy instead of speed. Normally you will encounter 3-5 passages.

Listening section is a bit difficult according to some people. There are 6 listening passages which have different scenarios related to academic setting. The important thing to remember is to write notes as the recording will not be played again. I first tried to memorize the conversation but then after listening to 4-5, I got mentally tired and hence note making is an important technique according to me. Don’t write each and every word. Just scribble the gist of the sentence. Don’t be so focused on writing that you miss the recording.

Speaking section is the difficult task according to me. I am not as fluent as I thought and I found out that while I was preparing for the exam. For effective speaking, try to speak on some topics daily as a practice. Take care that you don’t repeat the same lines, fumble with words, and mispronounce them as marks are deducted for it. Also long pauses are bad. How quick you can think on the given topic in 15 seconds is the key. So practice, practice and practice. Be confident in your speech. One approach which I took was to just speak about 2 points on a given topic. So I quickly thought of an introduction, then 2 topics' justification with examples and then a conclusion. Take care to complete in the given time or marks will be deducted. I think practice is the only key to crack this section.

Writing section is the simple for those who got a good score in their AWAs. You have to write on two topics, one integrated task and other independent task. Practicing how to write will help on the exam day. Independent writing is easy as you must have written these kinds of things in school or college. But, you should practice integrated task as it is quite difficult.

Important points (My opinion)

1. Take full time to complete each section.

2. Mugging words like GRE is not necessary but having a good vocab is always a boon.

3. Utilize the 10 min break given after listening section to relax.

4. Choose the test center properly and in advance. My test room was congested and I could hear what other candidates spoke.

5. Many people complete their reading and listening sections fast. So they start their speaking section early. Because of this, multiple people will be speaking at the same time. So to avoid this, be patient and take full time to complete each and every section. By the time you start your speaking test, there will be silence as most of other candidates would have completed their speaking section.

6. Another advantage is that during the 10 min break, you can overhear people speaking and can get some hints for your own task.

7. Some candidates tend to keep their headphone volumes too loud and you can hear what your neighboring candidate is hearing. This was the case with me. So concentration and focus is important.

8. At last, practice. I took up Cambridge book and gave all the 7 tests. Giving test helps to boost confidence.

Whenever you take up a date, try to plan out as people (including me) procrastinate and start the test prep just few days/weeks before the exam. Once your date is fixed, try hard to achieve your intended score and start preparing well in advance. Also speak in English with your friends as it will ultimately help you in your TOEFL test.

The World Wide Web is flooded with articles on TOEFL and this post is just my experience of the test. Hope this helps !!

Back with a bang !!

2011-08-20T05:08:00.000+05:30

Finally back :D

Its been a long break since June when I wrote my last post. Many things have changed and many things have occurred since that time. So expect a lot updates soon.

I miss writing and so I have promised myself to publish at least one post per month.

Below is the list of activities happened during this period:

Research Internship successfully completed. (till July end. Really busy completing the report and remaining work. Wrote a post but didn't publish it. (lazy?))

Successfully started my last year in hope that I pass out soon. (August 1st week)

Got a job :D (2nd week of August. Worked hard for getting a placement)

Temp Teaching Assistant for Embedded Hardware Design Course (mid August: 2 weeks)

Hunting for internships (please help !!!) (Currently)

Also I am learning 2 new tools: Network Simulator 2 (NS2) and TinyOS 2.1.1 + Meshbean.

NS2 is used for simulating a wired/wireless network. So, if someone makes a protocol, then NS2 will help in simulating the protocol and it helps in visualizing it. TinyOS is a operating system made for Wireless Sensor Networks. It has networking part in it. Meshbean is a kit from Meshnetics on which TinyOS can be ported.

So currently doing experiments while learning about the two new tools.

Also one exciting news is that this time I have taken a course called Robotics Lab and we are making all sorts of robots :) So more pictures and code in coming semester !!

Btw I am a super duper soccer fan and support Man City in EPL. So this post is dedicated to their awesome team and a glorious start to the season.

Adios

Using Modela MDX-20 PCB Milling Machine

2011-06-22T02:39:00.000+05:30

Roland Modela MDX-20 PCB milling machine is an awesome piece of hardware. This machine can be found in any FabLab around the world. It can be used for scanning 3D objects, making 3D shapes and finally making Printed Circuit Boards (PCB). This machine was recently purchased by our professor Dr. Prabhat Ranjan. As we wanted to use this machine in one of our projects, we had been given the task to run the machine. I had once used this machine in COEP FabLab, but had never used it on my own.So heres how to do that.

Modela MDX-20 in the Lab

Searching for ‘Modela PCB’ gives numerous results and I too found out 4 different methods to do the same, One of the method was to use a .png image and generate a dxf and send it to the printer. Other method used the cad.py script to visually set the parameters and send the file to modela. It used Python Imaging Library.

I used Marc Boon’s method for sending the files to modela and it worked perfectly. The same method is described in http://mlab.taik.fi/paja/?p=1874

Links:

Marc Boon method: http://fablab.marcboon.com/pcb/index.html

Manchester Fablab: http://www.fablabmanchester.org/p66/Eagle-To-Modela-Program.html

MIT method: http://fab.cba.mit.edu/content/processes/PCB/modela.html

Today finally we tested and made a demo board using the above said method. I was happy as this will definitely

help us in our project.

Few important things to be kept in mind:

1. Give offsets correctly. The circuit is mirrored and so don’t mess up the PCB.

2. Set the Z point manually. i.e. Touch the tip of the drill bit on the PCB and then tighten the screw.

3. Each drill size has different Design Rules (.dru) files. So, be sure of the drill bit. Also use proper bits.

4. Always use a sacrificial board beneath the PCB.

5. A particular problem we faced was that the buffer capacity of the machine was less. We were using USB to Serial converter(FTDI chip) and hence the whole file was not completely read. Hence, we had to send the data in small files.

More tips and tricks will be posted soon after we make our real project PCB.

Website up !

2011-06-18T03:03:00.000+05:30

Today finally I bought my domain. I had initially some confusion on what to select, but finally settled for '.org'.

So, my website is at: darshshah.org

Blog: blog.darshshah.org

Email: darsh@darshshah.org

Blogger has a nice feature where we can provide our custom domain as the URL.

How to configure and start using GitHub in 10 mins

2011-06-17T12:57:00.000+05:30

Version control systems are awesome piece of software and are really helpful in maintaining huge codes. I wanted to use such systems and even tried before, but never got any hang on it. Tortoise SVN, BitBucket, Bazaar and GitHub are some of the systems which I installed in my computer but never really used.

I recently came across an instance where I was in a desperate need to use GitHub. I had made account long ago but had never set up a repo before. This time it was essential to make a repo and push some files as I wanted to host my website on GitHub pages. GitHub has an awesome help and support pages to get started. But the main problem is that SSH is blocked in my college because I am behind NAT (Network Address Translator). So, one of the way out was to use HTTPS for pushing to the GitHub.

Since, I was a beginner, I saw some youtube videos and googled crazily for the same but I didn’t get any accurate results and step by step technique to start with. So this is my step wise list to start using GitHub and making pushes within 10 mins. I want to thank @viranch _mehta for helping me out.These steps are for Windows but I think it will equally work for Linux.

Right click and select Git Bash

1. You probably must have made an account on GitHub and if not, make one!

2. Follow the initial steps after making the account. Download cygwin and exe files for Windows.

3. To make a repo, click on create repo and fill in the details.

4. Now a page of settings would come. For the first timers, configure the global setting part.

Now instead of following the rest of the steps as they are for SSH, do the following:

5. Go to the directory where you want your repo to be kept locally in your computer.

6. Now right click and select “Git Bash”.

7. You will get a cmd prompt window.

8. Now just clone the repository using https by writing:

git clone https://path _of _repo

The path of the repo can be seen on the HTTP tab on the GitHub website.

HTTP address of repo

9. Now a new folder has been created and has the name same as that of the repo in the current folder. To verify, you can see a hidden folder named .git in the repo folder. This means that git has been initialized.

10. Now copy the files which you want to commit and push in the folder created in step 9.

11. Now type the following on git bash

cd name_of_the repo

12. Now, in this step, I have assumed that you have copied the files in the repo folder.

13. Type:

git add name_of_the_files

This will add files locally.

14. Now type:

git commit –m “commit_msg”

Message is required every time you commit something.

15. Now type:

git push origin master

Provide the password. This will push your files to the Github servers and will be online within few seconds.

16. Congratulations! You have successfully pushed files in your repo. You can verify the same by going to Github website.

First time push

Now the above steps are to be followed only during the first time when you clone a repo. Afterwards, just go to the folder (You can see .git hidden folder here) and right click to select “Git Bash”. Then do git add and git commit which you did in step 13 and 14. For pushing, just write “ git push” and it will do the pushing stuff.

For later pushes

Hence this is a quick and simple way to start using GitHub within 10 mins

Summer Saga

2011-06-12T17:17:00.000+05:30

Summers are here. Actually they are about to get over.
I felt like writing something about myself as the blog is pretty dried up. So here's the "non-techno" post for the glorious summers.

Summer vacation provides me with some extra time to learn new things.. but alas, the summer also makes me a lazy person.

Staying in hostel with temp around 42 degree Celsius is some serious problem. Its too hot to do anything here. This is when the laziness creeps in. But altogether, I am having a time of my life. No more early morning lectures, no compulsory labs, and no more assignments. Just working on a project and then enjoying rest of the day. Sleeping late is in vogue for me and also the occasional sports sessions with the batch mates. Playing cards all night and watching an action movie on 2000 W speakers makes me a happy man. Apart from this, eating out daily and consuming non healthy junk food is on rise. But this is summer. Summer to enjoy. It feels that I have studied and worked hard for past 3 years so I am entitled to enjoy a good break in Summers.

Apart from the above mentioned things, I also do my project work. Devoting minimum 2-3 hours a day is a necessity and I am able to keep up with the target.

I am also making a website and so learning HTML/CSS to code it. Site is almost complete but yet to buy a domain name.

This is a small to-do list for the summer and hopefully I may able to achieve this:
1. Complete project
2. Try for a paper
3. Complete website
4. Give TOFEL

Seems nice and easy but lets see how much I will be able to complete in the glorious summers. Lets see how fruitful is my Summer.

Btw I am finally and officially a senior undergrad and feeling imba about it :)

Different Android Apps which communicate with Computer

2011-06-02T03:19:00.001+05:30

As a part of applying for GSoC this year in KomodoOpenLab, I did some research on some of the open source apps or softwares which can be useful in communication between mobile phone and PC/Laptop via Bluetooth and/or WiFi interface.

The data is summarized below. I directly copy pasted the table from my wiki page on the site. (I am a bit lazy)

App	Source / License (important!)	Notes
Gmote	Open Source	(see details below)
RemoteDroid	Free version and Paid version	§ Mouse control via phone. § Works over WiFi network
PRemoteDroid	Open	§ It has features like secure connection, screen capture and mouse and keyboard control on phone. § Works over WiFi and Bluetooth network.
v.:mote	Open Source	§ vmote can be used as a gamepad, mouse or keyboard. § Website not currently accessible. § Works over Bluetooth and WiFi
mkRemoke	Free version and Paid version	§ The website suggests that it can be used for controlling slides. § Mouse and Keyboard control on phone. § Works on WiFi and Bluetooth.
PaDroid	Open Source	§ Cannot find the proper website. § Video of app [Youtube link]. § Works over WiFi.
Free PowerPoint OpenOffice Remote	Open source	§ Control presentations on Openoffice as well as Powerpoint. § Works over WiFi.
GRemote	Free version and Paid version	§ Website mentions that it can control any application on PC. § Demo is available for free on its website. § Works over WiFi, Bluetooth and 3G.
myRemote	Open Source	§ Windows Media Center can be controlled by it. § Special features are Snapshots and Voice Input. § Works over WiFi.
PPT Remote	Open Source	§ Specially for controlling Power point presentations. § Works on Bluetooth and WiFi.
PPT Controller	Open Source GNU gpl v2	§ Works with PowerPoint 2007 only. § Works over Bluetooth and WiFi.
Remote Mouse	Open Source	§ Wireless Mouse/Trackpad and Keyboard. § Works over WiFi and 3G
Unified Remote	Free and Paid version	§ Advanced Slide presenter(PowerPoint) along with other features. § Mouse and keyboard control available. § Works over WiFi
Swiftp	Open Source	§ Not Maintained now. § Basically used for file sharing over FTP.
Google TV		§ Interesting app: makes your android/iphone work as a remote control for the Google TV. § Works over WiFi
Phone Mouse	Open Source	§ You can control only the mouse. § Works over Bluetooth and WiFi.
PcRemote Andvance	Open Source	§ You can control mouse, keyboard and also can control slides. Best feature is that it can map android phone's sensors to the Windows 7 system. § Works over WiFi, Bluetooth and 3G.
i-Clickr PowerPoint Remote	Open Source	§ Slide presenter supporting PowerPoint 2010, OpenOffice on Windows and Office Mac also. § Works over Bluetooth and WiFi.
RemoteSMS	Free version and Paid version	§ Sends and receives text from PC instead of phone. § Works over Bluetooth, WiFi and USB.
android-notifier	Open Source	§ Sends notifications to PC when certain events happen on an Android device § Works over Bluetooth, WiFi and USB(under development).
PrinterShare	Open Source	§ Print documents using phone by printer on nearby WiFi enabled printer or a remote printer via internet. § Works over WiFi and Internet.
androidscreencast	Open Source	§ Desktop app to control an android device remotely using mouse and keyboard. § Works through USB.

I have written some reviews which i will update in the coming posts.

LCD Controller using MICROBLAZE Processor and Spartan 3E Starter Kit Board

2011-05-23T15:31:00.000+05:30

The MicroBlaze is a soft processor core designed for Xilinx FPGAs from Xilinx. As a soft-core processor, MicroBlaze is implemented entirely in the general-purpose memory and logic fabric of Xilinx FPGAs.(Source: Wikipedia)

We had EDK 10.1 (Embedded Development Kit) installed in our lab PC and hence we used the Microblaze to write a LCD GPIO. GPIO means General Purpose Input Output. The Spartan 3E kit has various GPIO’s like Switches, LEDs, RS232, etc. But the LCD attached to FPGA wasn't in the list of recognized GPIO by EDK.

Hence we used an available code and modified it to include LCD as a part of GPIO. We used the OPB bus i.e. On-chip Peripheral Bus. Though we wanted to do more about it, we didn’t have enough time for it as submission deadline was near. Initially we wanted to use the Xilinx LWIP (Light Weight IP) library and make a network communication and to send a packet between the FPGA and PC using Ethernet. But we had some technical difficult and hence we couldn’t do that thing.

This project was small but it taught me how to use an EDK, how to use Microblaze and its architecture and various other aspects of making a hardware project and of course how to do jugaad.

Optical Cense: Wireless Optical Sensor Network Design for a Conducting Chamber

2011-05-17T14:32:00.002+05:30

During the last semester, I and my teammate(Vedang) were given an interesting project to work on. This project is in domain of Embedded Systems, which I love the most. The title is big, the project was bigger. We had to design sensor nodes to put in a conducting camber of a nuclear fusion reactor and the communication between the nodes was done using IR technology instead of RF. The benefit of Infrared communications is that it is Line of sight communication and does not suffer from multi path fading effects.

ENDEC IC on the node

Our task was to test the nodes to cross check its working as specified in the datasheet. Various experiments were done to check the maximum LOS range of the transmitter and receiver. Also, the lateral displacement results were measured. In addition to that, vertical displacement results were taken. The transmitter was kept at 73 cms above the ground. This will help to stop the reflection from the ground. The receiver was kept on a camera tripod which can change height and hence was very helpful in getting the readings. A 15 byte pattern was sent continuously to the receiver and the output was observed on the LEDs. If the correct pattern was displayed for 10 times, then it was assumed that it works correct for that setup.

Receiver on the tripod

The transceivers were tested on 115200 bps baud rate which is maximum data rate in the IrDA SIR standard. Most of the results were found satisfactory and within the specifications of the standards. On the coding side, we coded the transmitter to have all 10 available baud rates. By pressing a switch connected with the external interrupt, we changed the baud rate. Next, when the baud rate is change, a special character is sent to the receiver indicating that from now on, all the communication will take place at the new baud rate. Hence, using this setup, we tested for various baud rates and various distances.

The results were satisfactory and complied to the standards and the datasheet.

Multi Encoder System

2011-05-16T23:19:00.004+05:30

During the semester, I got a chance to work upon a project on Field Programmable Gate Array (FPGA). I was a part of a team of 5 students. As we had only 2 days to implement a project, we selected this one as it was aptly fitted into the problem domain and was doable in 2 days. The FPGA we used was Spartan 3 from Xilinx.

Flow Chart

Encoding/Line code means to wrap data in some format or send it with other redundant data, so that it can be easily recovered at the receiver side even tough noise is present. Various encoding schemes are used keeping in the mind the amount of data to be transferred and the noise in the system/channel. In this project, we implemented 3 encoding schemes in hardware namely Manchester coding, Non Return to Zero Inverse (NRZI) and 4B-5B schemes.

These encoding schemes are conceptually very easy and can be looked up in any book or the internet. We made a system in which all 3 encoding schemes are implemented and the user chooses than by selecting the proper combination of the input switches. The data is given via the 16 switches and the output can be seen on the oscilloscope.

RTL diagram

Implementing the system in Verilog was easy but the demonstration on the real FPGA kit was a bit difficult as the hardware has its own limitations.

The code is given below.

Code:

Manchester Coding output

module top(in,clk,controller,cnt,out,out_s,data);

input [7:0]in;

inputclk,cnt;

outputout_s;

input [1:0]controller;

outputreg out;

outputreg[3:0]data;

psps(in,clk,cnt,out_s);

nrzi n1(clk, out_s, out1);

mnc n2(clk, out_s, out2);

encoding n3(in,clk,data,out3);

always @ (controller or out1 or out2 or out3)

begin

case(controller)

2'b00: out <=out1; //nrzi output

2'b01: out <=out2; //manchester output

2'b10: out <=out3; // 4B-5B

endcase

end

endmodule

4B-5B output

modulemnc(clk, a, out);

inputclk, a;

//reg b;

outputreg out;

always @ (clk or a)

begin

// b <= a;

out = a ^ clk;

end

endmodule

modulenrzi(clk, a, out);

inputclk, a;

outputreg out=0;

always @(posedgeclk)

begin

if (a)

out<= ~out;

else

out<= out;

NRZI output

end

endmodule

moduleps(in,clk,cnt,out);

input [7:0] in;

inputclk,cnt;

outputreg out;

reg [2:0]i=3'b000;

always @(posedgeclk)

begin

if (cnt)

begin

out = in[i];

i= i+1;

end

endmodule

module encoding(in,clk,data,out1);

input in;

inputclk;

wirerst;

reg [4:0]out=5'b00000;

outputreg [3:0]data;

outputreg out1;

reg [1:0]i=2'b11;

reg [3:0]a;

reg b;

reg [2:0]j=3'b100;

wire clk_4;

always @(posedgeclk)

begin

a[i] <= in;

if (i == 2'b11)

begin

data<= a;

end

i <= i-1;

out1 <= out[j];

j <= j-1;

if(j==3'b000)

j <= 3'b100;

end

cnt_4cnt(clk_4,clk,rst);

always @ (posedge clk_4)

case(data)

4'b0000: out <= 5'b11110;

4'b0001: out <= 5'b01001;

4'b0010: out <= 5'b10100;

4'b0011: out <= 5'b10101;

4'b0100: out <= 5'b01010;

4'b0101: out <= 5'b01011;

4'b0110: out <= 5'b01110;

4'b0111: out <= 5'b01111;

4'b1000: out <= 5'b10010;

4'b1001: out <= 5'b10011;

4'b1010: out <= 5'b10110;

4'b1011: out <= 5'b10111;

4'b1100: out <= 5'b11010;

4'b1101: out <= 5'b11011;

4'b1110: out <= 5'b11100;

4'b1111: out <= 5'b11101;

endcase

endmodule

module cnt_4(q,clk,rst);

inputclk,rst;

output q;

reg [1:0]p =2'b00;

always @ (posedgeclk)

begin

p <= p+1;

end

assign q = p[1];

endmodule

Connect2Learn: Interactive Virtual Classroom

2011-05-14T20:12:00.016+05:30

Connect2Learn is an open source interactive virtual classroom which works on low bandwidth. This software was created during our software engineering course. I was the team leader and hence had to take care about every aspect of the work. Though the course was a bit boring, the project turned out to be an awesome one and far better than expected.

I must admit that all people in my group contributed to best of their capabilities and worked hard to make this software. Though our initial problem statement was a bit different, we are happy as we have been able to achieve much better results. In process of 3 months to make this project, we made around 25 documents. These documents, at first seemed waste of time, but later on, we realized their importance. But I strongly felt that if more time would have been given to coding, then the softwares/website developed by various groups may be of much higher quality.

All the above was just the background to show that even though all the points above affected us, we were able to make our software ready. Now about the software:

Website

Connect2Learn is open source software made in JAVA. It requires the Java Media Framework and the Java Runtime Environment to work. We built it on Java as we wanted to make this software platform independent. This software uses a Whiteboard, with drawing tools, to scribble or do doodling on the board at the teacher side. The teacher can use a pen or a mouse to make drawings or write on the board. Then whatever written is compressed and sent on a multicast network. We have used multicast in order to minimize bandwidth. The student can see the board on his side.

Apart from the board, we have a chat box, which is used for asking questions to the professor and for inter-student chats. Also, attendance list is visible to the professor. One of the main features is a one way audio transmission on multicast. The professor speaks in the mic and the students connected to that session can hear it. The audio uses Realtime Transmission Protocol which is the basis of VoIP technology. Hence, minimum lag is assured between the speaker and the listener. Backed with these mentioned features and a user friendly GUI, this software is nearly release ready.

Since the software works on multicast, the prerequisite for using the software is that the routers should be multicast enabled. Another option is to use it on LAN (same subnet), where no multicast is required. To facilitate worldwide usage, we have built a website which gives information about the type of sessions which are going to be conducted, the details of lecture, multicast id on which it is going to work, etc. The professor can register and can book a slot for a lecture. The students can register can view the upcoming lectures and participate in it.

Screenshot of the teacher side of software

Prior to making this software, we did a lengthy background study and found out that most of the softwares which are available in this domain are proprietary. Also, almost all of them use video as a part of teaching. We are trying to give the same classroom experience without the high bandwidth requirements.

The software is licensed under GNU GPLv3 and is hosted on Google Code. The URL is www.code.google.com/p/connect2learn The software is under constant revision and the next version will be released in July with added functionalities.

At last, I would like to thank all my group mates for working very hard to deliver this software within the time bounds. Bhavin, Narra, Shilpi, Shantanu, Muskan, Abhimanyu, Naman, Vivek and Palash... thanks a lot !!

Retrospect --> Future

2011-05-13T22:58:00.002+05:30

This post is a long due one. Finally my semester has ended successfully. I am really lucky that I scrapped through it as this was one of the toughest semesters of my college life. During the past 4 months, I learned new things, developed new interests, made some good projects and all this things were done in concurrence with the hectic semester.

I really wanted to write about things, but as it is evident, I have an unnecessary habit of procrastination. So, whenever I sat down and began to write, I always put it off due to some reason or the other. But now I have free time and hence no problems in coming up with some good new posts.

This semester, I was involved in making a project for my software engineering course. I was the team leader and as expected, I had to work hard to see the project through. We made an iterative virtual classroom based on java which uses low bandwidth. The key part here is that it does not use any video and hence saves a lot of bandwidth. Also, having audio gives an advantage to use local language for teaching. I will give out more details about this project in my next post.The software is called Connect2Learn.

Also, for my mandatory internship in summer, I applied for Google Summer of Code (GSoC). I was one of the competitors’ vying for a spot in KomodoOpenLabs organization. I did a lot of work to get worthy of selection, but alas was rejected due to less exposure to android coding. I had done lot of research on apps which can communicate with PC/Laptop via the phone’s Bluetooth/WiFi. Not getting selected made me more and more eager to learn android coding and now in my vacation time, I am aiming to master this platform and become a developer.

One of the main highlights of this semester was the awakening of a research interest in me. I became aware of the current problems of accessibility and wanted to work in that field. KomodoOpenLabs works in that field and so I applied to that org. Even in my university, I took a course on Human Diversity where my focus was on Assistive Technology for Visually Impaired. This topic arose from the work we did during our MIT Media Lab workshop in Pune, where we made a Braille printer for the visually impaired. Hence, during last 4 months, the accessibility part has caught my fancy but I don’t know whether it is a temporal interest or indeed worthy of an academic career in it.

Finally, one thing I learned from this semester is that life screws, people screw you, but you have to live with gusto and enjoy every moment. Whining about little things or grades is now no more a joy as I learnt to accept things as they are. I didn’t get into GSoC, I applied to Indian Space Research Organization (ISRO) for an intern, but got rejected due to HR issues and hence have to finally settle for a intern in college under a professor. Though, this is a setback for me as I got rejected from 2 great organizations, but I reassured myself that something far more interesting and nice is kept for me in future. (Paulo Coelho effect J ).

So, ending note: this summer, I am working on a topic called Pervasive computing, learning android device, giving my TOFEL and finding out good universities to apply into. Hope, this summer is more fruitful as the previous ones.

"What is this life if, full of care,We have no time to stand and stare"

2011-03-20T02:42:00.000+05:30

The title aptly suggest my plight as my university is sucking all my time to the core. It is a metaphor to say that i don't have time to write a new post as i was busy. But its just a matter of time. Come 1st May and i m free for 2.5 months !!! Did nothing great during past few months to brag here... So the post here is about the things which i m doing.

It has been a long time since I wrote something. Firstly, the MIT-CoEP workshop was awesome and I and my team are planning to continue to build the prototype and make it into an actual product.

This time, in my university, I have a subject named Software Engineering. The name itself suggests the heaviness of the course. We are being taught all the software engineering principles in a span of 4 months. So obviously, it is a huge load on us. The nice thing about it that we are doing a project as a part of the requirement of the subject and we are making a interactive virtual classroom which uses minimal bandwidth. We are making this software open source as lot of virtual classroom softwares are closed source. Doing this specific project, I got an opportunity to learn java (which I was planning to do before but never did) and came to know the importance of documentation. Seriously, we do a lot of documentation for our project.

Also, last month, our univ organized a workshop on android programming and I made my first app from scratch. Having an android phone obviously makes your hands itch to do something with it and write an app. I used AppInventor to make my first app, but to use eclipse and understanding the manifest file,etc is very cool.

The best part is that I have taking a very interesting course on Multi-Cultural Education and Human Diversity and as a part of my project, I am working on assistive technology for the visually impaired. Assistive Technology is quite an unexplored field and lot of research is going on. But the actual implementation is a bit lacking in real life. The penetration of research in actual use is quite less. Making the Braille printer initiated in me a curiosity about the current assistive technology what is needed in future.

The board we used to embed linux via ethernet port

Another interesting thing I am learning is in my embedded systems programming course. I learned RTOS and embedded FreeRTOS in ATMega32. Also used the ARM board and embedded the linux image in it.I complied my own kernel and learnt how to install device driver. I think I have a video. I will put up.

Apart from these things, i and my group went on a sort of unplanned expedition trip and it was the best ever. And we had our annual festival Synapse which filled the campus with colors.

Apart from these mentioned activities, the college life is going very hectic and soon our final exams will start. I had few topics to write but I felt that I must write this one as this is what I am actually doing right now. The irony is that the name of the blog is Robotics Blog, but since a long time, the focus has deviated and now it’s a generalized blog and I write about thinks I love.

The board i used

Also, arduino is an awesome board to use. Though it has Atmega microcontroller at core, the Java wrapping is simply awesome. I learnt its coding in just 30 mins which in contrast with Atmega and GCC is quite good.

Also different in-built libraries and functions and external digital/analog pins are very good. For beginners, i would definitely recommend it if you are trying to do it without any help. The community support is great.

Bye for now and i will return with something nice next time.

Title borrowed from W.H.Davis poem "Leisure"

MIT-CoEP Design Innovation Workshop 2011

2011-02-09T21:02:00.000+05:30

This post has been overdue for more than a week due to my exams. But nonetheless, finally I managed to write this one.

This post is about the awesome time we had at MIT-CoEP Design Innovation Workshop 2011 which was held at CoEP, Pune. Firstly, it was an achievement to get selected in the workshop as I was among the 10% lucky ones who got selected. Secondly, the instructors and the organizers did an awesome job for conducting the workshop. Thirdly, i learnt many new things and meet new people and finally the name MIT itself was such huge motivating factor for me to participate in it and also i got an opportunity to listen to Pranav Mistry.

Me, Nitin, Adwait, Saurabh and Anant with Nadya Peek

College of Engineering, Pune is more than 150 years old and is the 3^rd oldest college in Asia. The campus is huge and spread out and the buildings are like the heritage sites we see in India. The campus also has an underground tunnel to go to other side like IIM, Ahmedabad. The college is on the bank of a river and the college had its own boat club with people rowing and boating as a sport. The college campus was simply awesome. The best thing I liked about it was the large, old tree which was like more than 100 years old.

About the workshop, it was organized under MIT India Initiative. The workshop was spread over 5 days with the activities including field trip, brainstorming session, prototype designing and finally an exhibition to showcase our ideas. More info: MIT-CoEP Desgin Innovation Workshop website

I meet some great people there which included people from all over India from various filed like engineering, science, designing,etc . The participants were all the brainy and talented lot with lot of creativity and enthusiasm. There were 4 tracks and I was selected in Living With Machines track.

Ken Endo

Our instructors were Ken Endo and Nadya Peek from MIT and Dhananjay Gadre from NSIT and Vinayak from Fab Lab Vigyan Ashram.

First day: We had a field trip to see problems around us. Then we had a brainstorming session, which lead to creation of many ideas and we presented them in front of our instructors.

Second day: We were divided into groups of 5 people each with different variety of people in each group. So my group had Saurabh and Adwait, mechanical engineers; Anant from electronics background; Nitin from computer science and I was from ICT. We had a great diversity in our team. So, our task that day was to think of an innovative idea and make a prototype for the same in coming days. We had many ideas but we narrowed it down to braille printer for blind.

Third/Fourth day: We worked day and night to take our idea from imagination stage to design stage to hardware implementation. It was a very enriching experience as i was learning how to do mechanical stuff and operate the machines in the fab lab.

Final day: We had a exhibition which displayed the prototypes and ideas of all the teams which participated in

the workshop. Also heard what research is going in MIT Media Lab and very informative talks from Prof. Josepf Paradiso, Prof. Ramesh Raskar and Pranav Mistry.

Working on our prototype

Along with the tracks, we had an option to attend 3 tutorials. The tutorials included Embedded Systems, FabLab, Image Processing, Arduino, Audio Software, Web Technology, Android, CAD and Photography.(Hope I am not missing any names)

The instructors were very talented and helped the students at every step. The organising team provided us with every facility including any hardware we needed for the prototype bulidling, access to FabLab at any time, awesome and tasty food and guiding us every time when we had a problem to find a place in CoEP. Also, this was my third visit to Pune and the place has really grown. I can strongly say that Pune was very hospitable to me and i also had one of its most chocolaty delicacy called CAD-M. My team was awesome and i thank you guys for doing this project with me. Staying with my daiict pals for 5 days was also very fun. 6 people cramped into a 3 bed room in a lodge and sharing a single bathroom knowing that we have to reach the workshop on time was a challenge. Train journeys were also very eventful.

Final Exhibit: from idea to prototype in 3 days

This experience was very memorable and hope the prototypes which were made on that day may be made into product and help society. I will post about the braille printer, fablab and arduino in coming days. Also description of this workshop came in The Hindu newspaper along with my name :) link: Workshop coverage

Working on Scroll Saw

My first robot: LEGO MINDSTORM NXT

2011-01-01T23:25:00.004+05:30

In summer of 2008, when I was having a lot of free time, I got an opportunity to play with Lego. Not Lego bricks but Lego Mindstorm NXT Robotics kit (http://mindstorms.lego.com/en-us/Default.aspx). I was totally enthralled with the prospects of making robots without even studying electronics or knowing mechanics fully. But the Lego kit provided me with such an awesome experience as it was very innovative way to introduce me to robotics and in making robots without understanding the basics of servo motors or sensors or controllers.

Humanoid

Obstacle avoider

The Lego kit was simply awesome. It had an intelligent brick which was the brain of the robot. The brick had many options. We coded through the brick using its interface and also uploaded our code from the PC to the kit. There was a manual which described step by step instructions to build a robot from scratch. The kit had sensors – tactile sensor, sound sensor, ultrasonic sensor and others. Though we didn’t know how they function at that time, we just were having fun bumping the robot into the wall and taking the feedback of touch sensor to change its direction or to make the robot move forward by just clapping our hands using the sound sensor. It was fun. I learned how to balance things, how motor works, how the gears affect the working and lot of other stuff.

With my humanoid

I and my friend jayam made two robots from the kit – an obstacle avoider and a humanoid robot. The graphical programming language in software was also very easy to understand and very easy to code. The drag and drop feature was just awesome. We played around a lot with it and tried out different tricks on it. Currently I don’t have the kit and so further experimentation on it is not possible.

When you are a budding robot enthusiast, Lego kit is must have. It gives you the feel when you are a starter without the hassles of coding the microcontroller (atmega or audrino or pic), calibrating the motors, building the robot mechanically and making the sensors work correctly. These things you will eventually do if you develop an interest but jumping directly to the harder stuff will make you lose interest. Also the Lego robots developers community is very active and lot of stuff is available on the internet. So, my first robot was made from Lego Mindstorm NXT kit and I had such a great experience with it.

Me and Jayam

The kit by the way was of Dr. Ronak Shodhan and i thank him for letting us play with it.

By the way, Happy New Year and enjoy this year with full fun and happiness.

Meeting Dr. APJ Abdul Kalam @ NIF Ignite Awards 2010, IIM-A and Automatic Mail Detecting Postbox.

2010-12-30T14:45:00.000+05:30

Dr. APJ Abdul Kalam is a hero to many of us and has inspired dozens of people including me. I got a chance to meet him and shake my hands with him during the National Innovation Foundation’s Ignite 2010 awards held at IIM-A. I made a prototype of the idea given by a child named Utkalika Patnaik from Orissa. The idea was to detect mail whenever it drops in the mailbox. People don’t have to constantly check for their important mails – they come to know when the mail arrives (it becomes tedious going down again and again to check the mail when you are living in an apartment with your mail box suited on the ground floor).

How it began

The Postbox

This all began with the Prof. Anil Gupta coming to DA-IICT in ifest 2010 to give a talk on innovation. Things started building up and with efforts of our professors and ieee committee members, we went to IIM-A to interact with him. He gave us some ideas and we decided to make the prototypes for it. These prototypes were going to be displayed at the ignite awards 2010 going to be held at IIM-A. Though we had exams and tight schedule, we were very eager to participate with NIF as the chief guest was none other than Dr. Kalam. This gave us inspiration to make the innovative ideas into working prototypes with our full effort.

Prototype: Automatic Mail Detecting Postbox

The microcontoller board and letters for demo

So, mine topic was Automatic Mail Detecting Postbox. The idea was simple but implementation was tough as i had to take care for each and every aspect of the design and our prototype should also run in worst case scenario. I had several methods of implementation in mind, but on frequent discussions and revisions, the final design came to be pretty neat. I selected to use the IR-Photodiode sensor which is connected to comparator and gives a digital value if the object is in front of it or not. These sensors are very cheap and can be made in around 75 bucks. The first thing was to make the box. Luckily, I found a suitable box and decorated it(with help of my mom) to make it look like an actual postbox. Secondly, I put 3 of these sensor modules – 2 facing upwards and 1 facing forward. The calibration of the sensors took a lot of time as in different light conditions, the sensors behave differently. For the intelligence part of it, I used a Atmega16 microcontroller and used Vedang’s board to run my postbox. The output was displayed on LEDs to the visitors. The output can be connected to a gsm module and a sms can be sent to user mobile whenever a mail arrives. Also by using RF, we can sound a buzzer in the house. It just depends on what the end users want.

Experience on event day

Giving a demo

Explaining to Dr. Kalam

The event day is the most treasured memory of all. First of all, we were given spots to display our prototypes and secondly our poster on the prototype was put up nicely there. People were seeing our models and asking questions and it was nice to see so many school children with such wonderful innovative ideas. Parth, Poojan and Pavas made a navigation system for blind people and along with them, I and vedang guided Dr.Kalam to the exhibition through this system. We walked along with him at the entrance. It was such an honor. Then Dr.Kalam started seeing the exhibits and when he came to see mine, I explained him the working of prototype, gave a demo and also took an autograph on a postcard. He listened intently for the whole time and also appreciated the work. After the exhibition, he gave away the awards and also gave a very inspiring speech. I think NIF’s effort was excellent as students from all across India participated and also came there to display their working ideas. This proves that Indian students have a lot of potential and they can do innovations which can help society in a direct or indirect way. It was a day worth remembering...

Computation of 4 Point DFT using Radix 2 FFT Algorithm on Field Programmable Gate Array

2010-12-21T00:20:00.001+05:30

Our Embedded hardware design course had 2 class projects. The first one which was real time clock emulator (I had written about it in earlier post) was made on microcontroller. The second project was to be done on Field Programmable Logic Array aka FPGA. Our project should implement the parallel processing capabilities of the Hardware Description Language (HDL).

We were given a week’s time for the project. And in the following week after the due date of submission, our final exams were starting. Now, as the end sems were approaching, only some people were genuinely interested in doing the project. Many didn’t care and many didn’t know how to code in HDL. So, we thought we do a sincere attempt for the project as it would be a good experience and also we can write it on our resume and even get a good grade. Now the main thing was the parallel processing usage of HDL. As always, we procrastinated for 2 days thinking about the topic and finally zeroed on the computation of Discrete Fourier Transform (DFT) using Fast Fourier Transform (FFT) algorithm. We had studied the concept in our DSP course and it was easy to implement. We decided to use the Analog to Digital Converter (ADC) to take eight samples from oscilloscope and then compute its DFT and show the result on LCD. We decided to take first eight samples from the oscilloscope and then compute the FFT simultaneously – utilizing the parallel processing power of Verilog and FPGA.

Now 3 main problems came – First the kit was Spartan 3 which used the now obsolete parallel port for programming. So, we needed an old CPU which supported it and also had enough RAM to run Xilinx. Secondly, no one knew how to code for LCD and the internet provided with such vast codes which were like in encrypted language – so difficult to use as we didn’t understand it. Thirdly, Verilog doesn’t support division by 3 and papers were written for handling the fractional part. So we had to write our own code for division.

As 4 days were left, we started doing our assigned tasks of completing the project. The exam was coming near and the interest in doing the project was dwindling hour by hour. No one was ready to devote a large chunk of their time for the project. So, we decided to cut through and simplify the project. First, we did 4 point FFT – hence no need to divide by 3. Secondly, we decided to use 7 segment LEDs for the value to display. Hence, no wastage of time for understanding the LCD code. Thirdly, we took the ADC code which was made by our TA since it was legally allowed by our professor.

Now the ADC code was working fine and was tested on the kit, the 4 point FFT code was fine and the logic worked. We checked it on LEDs instead of 7 segment display as we thought we will do the code for 7 segment later. Now only 2 days were left – we tried to get the code of 7 segment display but it didn’t work out. So the best solution is to leave it and display the output on 16 LEDs. On the night of submission, we integrated the ADC code and FFT code in one file and made a nice looking, full informative documentation and sent it to our professor. We never tested our combined code and hoped that it may perform during the presentation.

So, next day our presentation time was at 5 and we were sitting in a jam packed lab setting up our kit and oscilloscope at 2 o’clock. And when we burned the code – our breaths were on hold and hands in praying position with lord’s name constantly in our mind – but alas, it didn’t work!!! Now we had almost 150 mins to rectify our code and do some magic to make it work, but we were really exhausted. Everyone in the group wanted to get over with it. So, we hard coded the value of samples in the code and displayed the result. We made a mechanism such that the values change when we pressed the switch. And to our shock, we found that we were victim of switch debounce – the phenomenon which had harassed many students like us. But, when we realized this, it was just 15 mins from presentation and there was no quick fix. So, we left everything in god’s hands (btw in my hands as I had to press the switch delicately and show the demo) and when the professor came, he took a small viva and we gave all correct answers. So, he was pleased. Now when he asked us to show the project, we told him everything truthfully and he also understood as we had time constraints for the project. We showed him our half working demo.

I think we got a good grade as the professor was happy because we made something different from others, put up a serious effort and it utilized the parallel processing power of verilog, which many few other groups had done. I think we went wrong with the clock calculation as ADC was working at different clock speed and we were taking samples out of sync. But nonetheless, it was a brave effort from our side. I would sincerely like to thank my group mates – Abhirag, Subodh, Ashwin and Kartik for tolerating with me for 2 projects and helping me to make such good projects. Thank You guys.

The documentation of the project can be seen by clicking on the link below. The code in it may not be too useful but you can use the ADC code and the FFT code separately. The description of the Spartan 3 FPGA kit and FFT calculation is surely awesome.

Documentation

A random essay

2010-12-10T15:58:00.000+05:30

"The media (books, film, music, television, for example) tend to create rather than reflect the values of a society."

The issue which states that the media (books, film, music, television, for example) tend to create rather than reflect the values of a society is a controversial one. On the one hand, the media digresses on the issue of existing values and tend to create new one for its own reasons. On the other hand, the media truely reflects the existing values of society. However, in the final analysis, the media correctly reflects the values of society.

   Firstly, the media is a medium through which the thoughts of people are expressed to the society. So, whenever any problem is to be made known to people, media acts as a correct medium to spread the awareness. The media, particularly films, sometime portrays the lives of very great people to display the values followed by them to the world. For example, the movie Gandhi, based on the life story of Mahatma Gandhi,the father of Indain nation, portrays the values of non violence and truth which were used by gandhiji in freedom struggle. So, these values are an important part of the world today and if people practice these virtues, than future wars may be avoided.

   Secondly, the flaws of the society are generally portrayed by the media to make people aware of the malpractice taking place in society. There is widespread corruption, hostility among people, fear of war, etcetera among the people and these issues are the pith of some type of media particularly the metal genre of music. The themes of metal genre contains, in addition to above stated issues, topic like drugs, slavery, violence, prostitution, etcetera. Hence, media also displays the negative, but prevailing values of society.

   However, there are some works of media which falsely display or tend to create values of a society just in order to get publicity. These works tend to create uproar among people by conjuring some false values so that their sales are boosted. For example, the horror films which shows a psychopath killing and eating human beings, are just suited for the movie theatre. This thing never happens in real life and is not a value prevailing in society. However, such type of media is rare. Hence, the media tend to create rather than reflect the values of a society.

  To conclude, the media acts as a medium to displays the prevailing values of society. Next, media like songs show the malpartices happening in society. However, sometimes the media tend to create values to boost their sales. However, in the final analysis, the media (books, film, music, television, for example) tend to create rather than reflect the values of a society.

GRE: How to prepare and my experience

2010-12-06T17:07:00.000+05:30

What is it

GRE stands for Graduate Record Examination and is conducted by ETS. It is required for getting admission to US universities for doing masters.

The total score is 1600, out of which 800 are for quant and 800 for verbal section. Also there is an analytical writing (AWA) section which includes an issue and argument. The AWA section has total score of 6. So you will be graded like 3 or 5 etc.

More details are there on http://www.ets.org/gre

How to Prepare

The GRE pattern is changing from 1 August, 2011. So, what I am describing now is for the current pattern.

Quant/Math

Math section has problems of difficulty level of 10^th std. They are very easy. You just need to brush up your concepts about algebra, geometry, trigonometry, etc. The important part of math section is DI i.e. Data Interpretation – they provide you with sets of data in form of charts or graphs and then you have to answer based on the data given. This is a new type of question which people may not have come across in their school or college. So, practice is a must to solve this question.

Be careful about the questions on percentage and ratios as they can be bit tricky.

If you confident in math then don’t totally neglect it, practice for half hour each day. There is ample of time for math section – 28 questions in 45 minutes, but when you get stuck at question, then it becomes tough to complete the section in given time. So, speed with accuracy is necessary.

Verbal

The not so good part is verbal. It has 4 types of questions – antonyms, analogies, sentence completion and reading comprehension. Each type has a different strategy to solve it. Barrons book has explained beautifully about it. The main headache about the verbal section is the limited time. 30 questions in 30 minutes. The reading comprehension takes lot of time to solve. They will give you a long multi-paragraph write up on social science, history or from science field and just ask 3-4 questions from it. You should have good reading and reasoning skills to solve it accurately.

The major part of verbal is vocab. If you don’t know the words, it is no good to solve analogies and antonyms.

For vocab, barrons provide comprehensive list of 3500 most probable words. They are divided into 50 wordlist (WL).

AWA

Pool of arguments and issues is given on http://www.ets.org/gre. Questions will come from it. You will have a choice in issue. An issue is like an essay and argument is to give opinion on the authors writing. See the sample in barrons. I suggest you to write many issues and arguments prior to exam day as you will feel shortage of time on exam day.

My approach

For quant, I just solved Barron’s book for math and also 440 questions of some GMAT book. I gave daily half hour for math.

For verbal, solve barrons and when you think you good command our vocab, start solving BigBook papers. There are total of 27 papers, each having 2 sections – so total 54 papers. Math portion is easy, so just do data interpretation sums to get hang of it. Its verbal section has different format, but the quality of the questions are really good. At the starting, do untimed solving and use dictionary to see words, but later when you are confident, start solving with proper exam atmosphere.

For vocab, the best approach to do words is to do 2-3 wordlist/day. I used to read the word, see its meaning in Webster’s online dictionary and writing them down in my book. It took me 1.5 hr per wordlist in beginning and then gradually I could do 1 WL in 1 hr. After completing 3 WL, I revised them and at night before going to sleep I read them once more. So this cycle gave me pretty good strength on words. Sunday was revision day. No new words, just revision of previously learned words. The bigbook words are around 5000 and many overlap with barrons. So, if you have time and completed barrons list fully, then only go for bigbook words. For difficulty words – use roots, prefix and suffix methods to get hang on them. Barrons have given the root words and it makes life simple if you know it, but it is not necessary. Also you can make flash cards for the difficult words and read them regularly when you are free.

People having problem of remembering the words can listen audio wordlist. It is also good way of revising. Still not getting words – then do group words. On website http://www.drrajus.com/ you can find group of words relating to same category, Eg – for happiness, sadness, anger, lies, etc. For beginner – tyro, amateur, novice, etc is used. So remember the link and connect the words.

Still not good – make pictures of the thing you visualize after reading the word. It is used for connection and is quite helpful. Eg- for tyro – I pictured a mechanic who cannot fix a tyre properly: so inexperienced/amateur.

Also you can use - http://www.mnemonicdictionary.com/ and http://www.etymonline.com/ They come handy sometimes.

For AWA, I did around 10 issues and 10 arguments. It is necessary to get good score in AWA. I read random topics from the internet and also did group discussion of the topics with my friends. It helped me to expand my views on certain topics. Remember – plagiarism is not allowed. So you can get the central idea of an issue from the internet and then it write in your own words. As the issues are divided into categories – i thought about the pros and cons of each category and then it became very easy to write down the issue. So by devoting one hour each day, just go through 10 topics of issues and arguments. Get the basic idea. It helps a lot as you are not surprised when a similar topic comes on the exam day and it also boosts up your confidence.

Remember, the issue and argument is to be written in a notepad for practice. The software they use in exam don’t have spell checker. Also Ctrl + C and Ctrl + V shortcuts does not work. You have to select the text, press cut button. Then press paste button after placing the cursor where you want to paste it.

So I have given you all the tricks of trade which I knew or used.

Tips (from my experience and general observation: random order)

·         Planning for GRE - get your passport first and arrange for a credit/debit card.
·         Aim high
·         Commitment is necessary. Once you decide to devote 8 hours a day, then it should be 8 and no less than it.
·         Take the exam seriously. It cost around $190 for exam, which is a huge amount and you will regret if you have to give 2^nd time.
·         Always book the date 2 months in advance. It will give you a goal. I wrote my date on a big poster and it hanged on my study table. So whenever I sat to study, seeing the date gave me inspiration to work a lot harder.
·         Plan properly and follow it. It you couldn’t complete the WL in a day, then squeeze some extra time on next day and complete previous day’s work.
·         Don’t get scared by words. You will feel damn bored when you do them, but it is necessary to get good score.
·         Don’t try to do new books or words (apart from barron). First complete the basics and then move forward.
·         Unexpected words are bound to come in exam as English dictionary contains more words than barrons/bigbook. So don’t be surprised to see a new word and curse it. (It happened with me)
·         If you do the words, learn their spellings also. It will be helpful in issue and argument.
·         When you are nearing your exam, a week before it, start giving mock tests. Give Cambridge test, Kaplan test and finally Power Prep on last two days. This test will gauge your performance. Give it seriously and review your mistakes. Also take the mock test in the same time slot as your actual exam. It will prepare your mind and body for that day.
·         Don’t give your mock test on laptop. Sit on a desktop or use external keyboard with laptop.
·         Your typing speed should be good and use notepad will you practice for issues and arguments.
·         Be confident. The first 15 questions matter the most as it an adaptive exam. So take a lot of time to see that you get the first 15 correct. Also don’t forget to complete the test. Answer wrong but complete the test as it will cost you the marks.
·         Don’t take anything else to exam centre apart from passport, receipt and secondary identity card. Everything else is kept in the locker.
·         If you are unlucky, your exam may start late due to some “technical problems”. So you have to wait there sitting idly – prepare for such scenario. Don’t talk with people around you – they will mess you up.
·         Don’t get upset when you don’t know the answer to question. Make an intelligent guess.
·         Revise Revise Revise and Practice Practice Practice
·         Remember, anything above 1400 is good.
·         Come prepared with details of the 4 universities in which you are going to send your score. Know the name of department, college/university name and the state name where they are located.
·         First 15 minutes are wasted in instructions and GRE search service. If you want to look up the instructions, do it on its website or in powerprep software. If you want to sign up for GRE search service, do it on website. Waiting for 15 minutes after sitting in front of computer really makes you anxious.
·         There will be a research section which you can skip. It will be indicated on the screen.
·         First comes AWA in exam. Then quant or verbal section may appear. No fix order in the latter.
·         There is a break between sections. Use it appropriately to go to washroom or drink water to relax.
·         Reach the centre at least half hour before. Prepare for the worst, Hope for the best.

· What happened with me

I was all prepared. I had got 1450 in my mock and was happy with it. I reached the centre at 8:30 am and my exam was at 9. I registered and showed my documents and kept my things in locker (wrist watch, wallet and a pen). Then started the waiting game. There were around 15 people with me. We were asked to be silent and wait for the exam. A boy hadn’t brought his passport along. He pleaded to let him give the exam, but that boy was sent back ($190 wasted!!!). At 9:10, the administrator said that there was some technical problem and exam will start soon. We people only had passport and a form in our hands. So people starting talking. One girl was so freaked out as she was underprepared and started asking math formulas like what is sin 30, etc. It was so stupid there. Also people were getting bored and said “I aim for 1000. Hope I get it. “. Other guy said “can you tell me briefly what to do in issue and argument. I got to know yesterday only that they are coming in exam “. One girl told to her friend “I did just 20 wordlist from barrons. Can you tell me some important words”. It was such bullshit talk going around and it will lead to distraction.

At 9:30, the admin said, be prepared, we are starting in 15 mins. So now the water-bathroom cycle started. Each person drank 2 glasses of water and then went to the bathroom. I remember, even I did that in the anticipation of the exam. This ritual went till 10:00 and finally we were called in one by one.

I skipped all the tutorials and by mistake entered the GRE search service. It took me 10 mins to complete it. Then I took God’s name and stated.

In my GRE exam, issue and argument were both known to me. So, I did it quickly. I took a bathroom break and drank some water. First came the math section, I did all correct. I was very happy. Now when the first question of verbal section popped up, I was stumped. It was an antonym and I was unfamiliar with the meaning. It was outside from barrons and bigbook. So, I guessed it but alas I knew it was incorrect. My morale took a dip but somehow I managed to complete it and got a decent score of 1440.

Hope you got something good from this article and all the best for your GRE exam.

Comments please!!!

Real Time Clock Emulator Based System Actuator

2010-10-14T02:15:00.000+05:30

Recently, in September, we had a project based used of microcontroller in real world applications. We decided to make a Real Time Clock in software which would do a task based on the time of the day. RTC chips are available in market and are used in almost every application which needs a real time clock.They precisely calculate the time.

We implemented it using Atmega32 controller. We used timer1 at 8MHz frequency and used switches for time input and LCD for output. In our code, we first ask the user to enter the the time at which the system should start, for how much time to be on, after getting over - after what interval should be restart and how many times per day it should run. The current time is fed to the microcontroller using USART, but switches can also be used.

Finally, the data is displayed on the LCD while the user is pressing the switches and manipulating it. The output is connected to motor, which runs when current time=desired time.

We have taken care of many test cases where user gives invalid data. Our code runs fine and we have tested it on STK500. One thing to notice is that using 8MHz freq clock, so even though I am giving interrupt at every 1 sec, an error of approximately 50 seconds per day.
So, we have to add 50 secs to each day. Instead, you can use a external crystal for minimizing the error.

The project report is below:

RTC emulator based system actuator - Report

Examples for the applications of the project

  Handheld Data Loggers
  Security and Surveillance Systems
  Entertainment Systems
  Embedded Systems related to Agriculture
  Automotive Embedded Systems

Though the code works fine but little tweaks may be required if you are not using USART or LCD or your microcontroller is different.

Wordle

2010-10-14T01:34:00.003+05:30

It's been a long time since my last post and i know i have become very lazy to update my blog.

I found a website called wordle.net which shows the maximum used words in the text/blog/website in an artistic way.
So here's the wordle for my blog:

Finally: After a long break

2010-08-24T20:19:00.000+05:30

Hi folks, it's been a long time since my last post but the delay was due to the fact that i had been super busy from last couple of months. Firstly, the good news is that i cleared the GRE ( Graduate Record Examination) exam which is needed in order to pursue higher studies in US. My last 3 months of effort was on getting a good score in GRE which i achieved. I got 1440 / 1600, which is considered to be a pretty good score. Secondly, my internship with Playpower was going and it required much of my time in summer. The project is still going on and i am very hopeful about its future prospects. Also, in summer we had a two and half months of vacation time and like most of the people, i also became quite lazy and lethargic. So, due to all these reasons, i didn't write any post recently.

I devoted my full time in summer for preparing for GRE and doing the Playpower project. So, i didn't get any time to pursue my interest in robotics. Hence, there any no updates on that part. However, i came across Mr Dhananjay V. Gadre, when he visited our college as a speaker on embedded systems workshop. He is a proficient person in the field of embedded systems. His projects are amazing and quite different from others. His website is:
http://dvgadre.blogspot.com/ and http://www.dvgadre.com/
If i am allowed, then i will put up some of the materials and presentations given in the embedded system workshop.

Right now, my new semester has started and i will try to post something regularly.

How To Use the FamiTracker Driver Source to make NSF Music Files

2010-06-24T13:19:00.000+05:30

Firstly sorry for a long break from posting anything new on the blog. I had vacations which means i went into my laziness mode. But i was working also and the new post is as a result of what i learnt something new and useful. I am doing a lot of NES video game coding this summer and a major part of it is to include sound it the video game. So i am writing this tutorial as many people have doubts in about this topic.

How To Use the FamiTracker Driver Source to make NSF Music Files

You have made your own game but without sound, it’s uninteresting. So let’s see how to put some sound in your game at your desired position.

This article contains the method to convert the raw music data to NSF file using ca65 compiler. If you haven’t been introduced to NSF or FamiTracker, go to http://famitracker.shoodot.net/ and download it. YouTube contains many videos regarding how to make music using this software.

Firstly many people are making music in FamiTracker software and are exporting it into .nsf format. This file they include in their code using .incbin to play the music. But there are two main disadvantages – Firstly, the nsf file has 3 important address – LOAD, PLAY and INIT. So by directly exporting as nsf file, we have no control over the these addresses. So if you have some code at the same place as LOAD address of the song, then there is a problem. Secondly, the output file size is large. So if you have limited space, then it’s not the best option.

But we can do in another way. When you make your music in FamiTracker, export it as .bin = Raw Music Data file. Then you have two files with you- 1. music.bin and 2. samples.bin

Now go to ftp://ftp.musoftware.de/pub/uz/cc65/ download the cc65 compiler according to the OS you are using. Then go to http://famitracker.shoodot.net/downloads.php and download the NSF Driver Source. This folder contains 14 files. Now copy the compiler ca65, linker ld65 and necessary files into this folder. Also copy your music.bin and samples.bin files to this folder.

Now open up nsf.cfg file. It may look like this:

MEMORY {

ZP: start = $00, size = $100, type = rw, file = "";

RAM: start = $200, size = $400, type = rw, file = "";

HDR: start = $7F80, size = $80, type = ro, file = %O;

PRG: start = $8000, size = $20000, type = rw, file = %O;

}

SEGMENTS {

ZEROPAGE: load = ZP, type = zp;

BSS: load = RAM, type = bss, define = yes;

HEADER: load = HDR, type = ro;

CODE: load = PRG, type = rw, start = $8000;

MUSIC: load = PRG, type = rw, start = $A000;

DPCM: load = PRG, type = rw, start = $C000;

}

So now you can change the address in the CODE and PRG from $8000 to desired position. The address you put will be the LOAD address. The INIT address is same as LOAD address. The PLAY address is 3 more than INIT address. So PLAY = INIT + 3

So for example, if you locate it at $A000 then init = $A000 and play = $A003

Now we can remove the MUSIC and DPCM lines in the SEGMENTS as we don’t use it. Also if you don’t want the header, then remove HEADER line also. But by doing this, you need not remove the first 128 bytes (header) of your nsf file manually.

Now we make the compiler. Make a compiler.bat file and put the following lines in it:

ca65 driver.s -D INC_MUSIC

ld65 -C nsf.cfg -o music.nsf driver.o

pause

So by these commands, the music.bin file converted and put into driver.o file along with other details. Then the nsf.cfg file determines the addresses and the final resultant file will be music.nsf

You can also use these lines if you don’t remove the HEADER line in nsf.cfg file:

ca65 nsf_wrap.s -D INC_MUSIC

ld65 -C nsf.cfg -o music.nsf nsf_wrap.o

pause

Then by doing this, you have to manually remove the header using any hex editor software (I use xvi32).

Now the first objective is achieved. We now have control over the addresses. For the second part, reducing the file size is a tricky task. When you open driver.s file (it opens in an editor. I use ConText) , you will notice that the code contains many lines which are not useful. So we can remove these lines and can save space.

Firstly, if you are not using any external chip like MMC5 or VRC6, you can remove that part of the code. Also if you are not using any bank switching, remove that part also. Notice the following lines in the code :

.include "init.s"

.include "player.s"

.include "effects.s"

.include "instrument.s"

.include "apu.s"

So to reduce space, you can remove unnecessary code from these files also. For example, if you are not using the effects of Vibrato, you can remove its code. Similarly, if the instrument remains same throughout the song, then instrument.s can be removed also. Please don’t get excited and remove code haphazardly as it might affect your music.nsf file. So it is advisable to check the proper working of the file after every modification. Also if you know which system you use – PAL or NTSC, then you can remove the other one and save the space.

So, the second objective is fulfilled. Though large amount of file size will not be reduced, but nonetheless this is useful if you are tight on space.

Finally, after doing all these things, test you code with sound and enjoy!!!

I would really like to thank jsr and miau for their help. They both cleared my doubts and helped me on this topic. Also a really nice place to learn these things http://famitracker.shoodot.net/ and http://nesdev.parodius.com/

For knowing how to play song in your code, see this open source code for multi-song NSF: http://no-carrier.com/index.php?/vegaplay/

Also the irc channel #nesdev is the best source to interact with these people and involve in NES mania.

Crashing and Juggling OS’s

2010-05-01T02:00:00.000+05:30

Finally my exams are over and i have completed two years of engineering. So after the exam pressure is over, this is the best time to post one of my experience:

This is one tale to tell. I am basically known as a format guy among my friends as my change of OS rate is very high. But last month was the most amazing one. Not only did i waste my 3 days but also came to know why my laptop is good enough to sustain my changing habit.

I had a linux partition in my laptop but when i installed Windows 7 from Vista, the grubloader vanished. So now i was in a fix. I knew a software which could fix my grub, but none the less, i am not good at grub scripting. So on advice on my senior, who is a linux guy, he told me to format that partition from windows and install a new OS. So now which linux to use ? I used fedora, open suse and ubuntu. So as I am a great amarok fan, i decided to go for Kubuntu. That’s mixture of Kde + Ubuntu = Kubuntu !!! So installed the new kubuntu in partition, but the main problem was I didn’t had any packages. I thing to clarify = My coll net SUCKS. We are not given enough bandwidth to satisfy our needs. Hence the best way to get packages was to use apton cd, a cd of a packages from a super geek’s computer. Hence i installed it but alas, they needed upgrade. So when i had so much fetish of using amarok, i did

sudo apt-get install amarok

So finally after taking a full day, i downloaded 43 MB and installed amarok. I listened to one or two songs and then had a good night sleep. For all this i had to forgo my dinner and lunch. So next day, on waking up, i opened my kubuntu and saw SEGMENTATION FAULT and my OS came crashing down. It was like a dragger stabbed i my heart. My effort gone in vain. The post mortem revealed that i installed 4.4 version of amarok in my 4.3 version and there was some mismatch between the libraries. Ahh, what a fool i am.

But as a good student, i didn’t lose my hope and started on a mission to install again. So the nerdy senior which i mentioned before, came to my rescue and told me to install it inside windows and he will give his disk image and hence all the packages will work fine as his system is up to date. So finally i did that , but wait, he had Nvidia drivers and i didn’ t. So basically my display won’t start without removing them. Hence he knew grub scripting and did all the changes and my system was set up and running. Then i heard songs on amarok and went to sleep after a fruitful day. Next morning, i opened my windows 7, and “OMG” n “WTF” were my reactions as my windows was not starting. On one hand, i had linux happily sitting inside my windows and my damn windows didn’t show up. The problem was that something had happened and i don’t know what that after i login in my windows, what i can see is just a black screen. I restarted around 20 times juggling from safe mode to normal mode, resotring my system, downloading registry checkers, closing all startup programs, but the black screen would not disappear. Hence in fear of losing windows forever, i formatted the partition in which kubuntu was installed. AND IT WORKED. I don’t know what was the problem, was it the grub problem or drivers or kubuntu itself ???

Finally, after 3 days of hard work, i was again at starting point . Without linux and in this mad process, i formatted twice, installed kubuntu twice and restarted my laptop like 30-40 times. My poor laptop borne the result of my greed, but its still working fine. So i shared my experience of how not to do things that you are not sure of and take advice from trusted sources = friends in whom you have full faith and confidence. Don’t worry, i have not given up yet.

I finally waitied and today on 30^th april, formatted my Windows 7, reinstalled it and then installed the lastest version of kubuntu 10.04 My system works fine till now when I am writing this post, but don’t know how much it will last.

Happy Formatting!!!

As i am free now for 2 months, i will post new tutorials and some useful resource soon.

I, Cyborg

2010-04-18T16:50:00.000+05:30

I, Cyborg is an article written by Aditya about the world of Cyborgs, Artificial Intelligence and its related technologies. He likes those kind of things and as a result he wrote this article. This article mainly consists of experiments done all over the world in field of Brain Computer Interaction and related things.
Prof Ishiguro surrogate and Prof Kevin Warwick's Neural Machine Interface is also explained in this article.

The link is I, Cyborg

It is a good article which will explains the future technologies. Must read !!
Special thanks to Aditya for this article. Visit adityabhatt.wordpress.com to know more about aditya's work.

A Cool Robotics Video

2010-04-16T17:43:00.000+05:30

This is a video of Dennis Hong from TED talk. He displays his seven award-winnning, all-terrain robots -- like the humanoid, soccer-playing DARwIn and the cliff-gripping CLIMBeR -- all built by his team at RoMeLa, Virginia Tech.

The link is http://www.ted.com/talks/lang/eng/dennis_hong_my_seven_species_of_robot.html

It's a very inspirational and knowledge giving talk.

Re-Kriti

2010-04-06T20:47:00.001+05:30

I and my friends participated in Re-Kriti. It is an event organized during Synapse 2009 and was supported by National Innovation Foundation. Our team presented a design of Self Dispensing Jug. We got the consolation prize for it. The presentation can be seen from this link:

Self Dispensing Jug

My teammates were Maullik and Kedar.

Timers and Counters

2010-04-03T01:06:00.000+05:30

Timers and counters are usually a very important part of a microcontroller. They do all the timing, and hence your application is heavily dependent on it. The main use if timers is for PWM i.e. Pulse Width Modulation. We can control the speeds of our DC motors with the help of this pwm. Also delay can be also be given by counters.
I am attaching a pdf in which codes for timers and counters are written and tested. There is a code for counting using CTC mode. Also code for blinking led's for a finite duration is given.

Timers and Counters

The syntax i.e. names of the registers can be looked up in Atmega32 datasheet which is available on www.atmel.com
I had made a project on robotics after my 12th std board exams. I was really in pursuing robotics..
I will upload that document soon.

AMPLIFIER : Creative Assignment

2010-03-19T15:10:00.001+05:30

We had a creative assignment in our Electronics course and we made a song on Amplifier. I will upload the song soon. The lyrics are below

My Amplifia

You're my amplifier

the one desire

believe, when i say

i'll make you in my own way

you have three modes of operation

cutoff, active and saturation

believe, when i say

active mode is the only way

now i can say

resistors and capacitors

will guide you in your way

You're my amplifier

the one desire

you are

(RAP)

and I have got this thing to say

you have just got three terminals for me to play

still bit confused

ac input will go into your base

positive supply to collector resistor

and output to collector always

you have moderate input output resistances

and your gain depends on its ratio of impedances

we'll connect two things to emitter

resistor and capacitor

and negative power supply to the resistor

now you have become my amplifier

and your task is to magnify

but you magnify and invert

don't worry we know how to convert

(RAP)

remember this thing that i'm gonna say

you alone cannot fulfill everyone's desire

but with CC and CB amplifiers

you become every designer's desire

now you have become my make

you'll amplify for my sake (2 times)

By:

Darsh Shah,Shantanu Godbole,Kapil Bhatt, Vivek Singh

Its kind of funny but alteast its creative!!!

Serial Communication using Matlab

2010-03-12T22:43:00.000+05:30

I did my LCD - Hyperterminal project using serial cable and posted it's code earlier. We can use Matlab instead of Hyperterminal and its quite easy. I implemented it. I got this document on the internet and its very helpful in understanding the concepts and commands for usinf Serial cable with Matlab. The document is:

Serial Communication using Matlab

This document is not modified by me and the credit should be given to its author.
More coming up in a week. Right know busy with exams..

NI ELVIS II

2010-03-10T00:07:00.000+05:30

NI ( National Instruments) have launched a new product previous year called ELVIS. It is a virtual lab, in which you have a breadboard having a data acquisition system and its output is connect to a computer. The computer has a virtual multimeter, oscilloscope, and many other virtual instruments.
So we had done a project in which we did around 15 experiments exploring various features of ELVIS and made a report. The NI liked it very much. Have a look:

NI ELVIS II

I will be uploading pictures of my robot, LCD, microcontroller board, LEGO robot,etc soon.

Videos

2010-03-09T23:35:00.000+05:30

I have given the code for Line follower and LCD in my previous posts. But i didn't explain or put up the schematics. It will take a week or so as right now i am busy with my exams.

So I have posted the video of line follower on youtube. The link is given below

Line Follower Robot

Also my other videos are posted there. You can access the site by click youtube on sidebar.

Microcontroller

2010-03-05T17:24:00.001+05:30

I had made a presentation for my class on microcontroller. It contains information about Atmega16 and how to use ICC-AVR. Use this link to download it.

Microcontroller.pdf

Hyperterminal to LCD

2010-02-27T18:22:00.002+05:30

I am making a code which will display the text written on the hyperterminal of the computer on the LCD connected with my microcontroller. The code is almost done. I have posted it below

/*made by darsh

code for implementation of usart. connect lcd to your microcontroller. open hyperterminal and set baud rate 2400 and com1 and flow none.

#include

#include "lcd.h"

void InitUART( unsigned int BaudRate );

unsigned char ReceiveByte( void );

void TransmitByte( unsigned char data );

int main(void)

{

unsigned char a;

unsigned int i,j;

DDRD=0X0F; // txd and rxd pins are present

DDRC=0xFF;// leds for debugging

InitUART( 25 ); // 2400 bps @ 1MHz hence value of UBBR=25 . refer datasheet

lcd_init(LCD_DISP_ON); /* initialize display, cursor off */

for (;;) /* loop forever */

{

for(i=0;i<2;i++) // 2 lines of lcd

{

for(j=0;j<16;j++) // 16 characters in each line

{

a=ReceiveByte(); // recieves data from hyperterminal

_delay_ms(10);

lcd_gotoxy(j,i); // goes to specified position

lcd_putc(a); // display the character

_delay_ms(50);// delay imp so that value can be displayed on lcd

PORTC=0xff; // led on after display

TransmitByte(a); // transit it back to hyperterminal

_delay_ms(10);

PORTC=0x00;

}

// -----------------INITIALIZE USART---------------------------------------

void InitUART( unsigned int BaudRate)

{

UBRRH=0x00;

UBRRL = (unsigned char)BaudRate; /* Set the baud rate */

UCSRB = 0b00011000; // enable transmitter and reciever

UCSRC = 0b10000110; // 8 bit data, no parity bit, 1 stop bit.

}

//------------FUNCTIONS TO READ USART-------------------------------

unsigned char ReceiveByte( void )

{

unsigned char data;

while ( (UCSRA & 0x80) == 0x00 )

{;} /* Wait for incomming data */

data=UDR;

return data;/* Return the data */

}

//------------FUNCTIONS TO WRITE USART-----

void TransmitByte( unsigned char data )

{

while ( (UCSRA & 0x20) == 0x00)

{;} /* Wait for empty transmit buffer */

UDR = data; /* Start transmittion */

}

Line follower code.

2010-01-29T19:50:00.000+05:30

//made by darsh
// line follower robot. sensor 1 has threshold 75 and sensor 2 has 25 as suited
#include
#include
#include

void reverse(void); // function prototypes
void right(void);
void left(void);

void InitADC(void)
{
ADMUX = 0;
ADMUX |= (1 << REFS0); // Set ADC reference to AVCC
//ADMUX |= (1 << ADLAR); // Left adjust ADC result to allow easy 8 bit reading

ADCSRA = 0xC3;// 11000011 = prescale by 8. and aden and adsc set

while(!(ADCSRA & 0x10)); // conversion going on as flag is not set

ADCSRA |= 0x10;// write flag to 1 to reset it and start a new conversion
}

// ReadADC

unsigned int ReadADC(unsigned char channel)
{
unsigned int volt,volt_low,volt_high;

ADMUX = channel;

ADCSRA = 0xC3;

while(!(ADCSRA & 0x10));

ADCSRA |= 0x10;
//volt=ADCH;
volt_low = ADCL;
volt_high = ((unsigned int) (ADCH <<8));

volt = volt_low | volt_high;

return volt;
}

int main(void)
{DDRC=0xff;
DDRD=0xff;
   int x,y;

   TCCR1A = 0b10100001; // enable 8 bit PWM, select fast non inverting PWM


TCCR1B = _BV(CS11) | _BV(WGM12);


   while(1)
   {
InitADC();
x=ReadADC(0);
y=ReadADC(1);
//forward();
if(x>75 && y>25)
{
PORTC=0xff;
forward();
_delay_ms(25);
}
else if(x<75 && y>25)
{ PORTC=0x00;
left();
_delay_ms(25);
}
else if(x>75 && y<25)
{ PORTC=0x00;
right();
_delay_ms(25);
}
else if(x<75 && y<25)
{ PORTC=0x00;
forward();
_delay_ms(25);
}
else
{_delay_ms(25);
}
}

}
void forward()
{
PORTD=0b01110100;
OCR1AL = 75;
OCR1BL = 75;

}

void left()
{
PORTD= 0b01110000;
OCR1AL = 75;
OCR1BL = 75;

}

void right()
{
PORTD=0b00110100;
OCR1AL = 75;
OCR1BL = 75;

}

Guys mail me if you have any queries!!!

Analog to Digital Converter

2010-01-27T23:10:00.000+05:30

I will write and explain the code of analog to digital converter

// ADC by DARSH
void InitADC(void)
{
ADMUX = 0;
ADMUX |= (1 << REFS0); // Set ADC reference to AVCC
//ADMUX |= (1 << ADLAR); // Left adjust ADC result to allow easy 8 bit reading
ADCSRA = 0xC3; // 11000011 = prescale by 8. and aden and adsc set
while(!(ADCSRA & 0x10)); // conversion going on as flag is not set
ADCSRA |= 0x10; // write flag to 1 to reset it and start a new conversion
}

// ReadADC

unsigned int ReadADC(unsigned char channel)
{
unsigned int volt,volt_low,volt_high;
ADMUX = channel; // Select the channel
ADCSRA = 0xC3; // 11000011 = prescale by 8. and aden and adsc set
while(!(ADCSRA & 0x10)); // conversion going on as flag is not set

ADCSRA |= 0x10; // write flag to 1 to reset it and start a new conversion

volt_low = ADCL; // store the return value in volt_low
volt_high = ((unsigned int) (ADCH <<8)); // left shift the 8 bits of ADCh and store in volt_high
volt = volt_low | volt_high; // combine both to form 16bit
return volt;
}

int main(void)
{DDRC=0xff;
   int x;
   InitADC(); // to initialize adc
   while(1)
   { InitADC();
x=ReadADC(0); // read from channel 0 i.e. PORT A0
if(x<25) // value less than 25, output high
{
PORTC=0xff;
}
else
{
PORTC=0x00; // else low
}
}
}

Hii

2010-01-27T22:59:00.000+05:30

Hey all,
Sorry, I got busy with my college. I am posting LCD tutorial. Please give your queries if any.

LCD Tutorials

This tutorial explains how to program the LCD in an abstract view i.e. directly using the library functions without going into the depth of it.
Firstly I am using JHD162A LCD module which is compatible with HD44780. Now the LCD can come in various sizes. I am using a 16x2 LCD, which means 2 lines are there and each line can display a maximum of 16 characters. The lcd can be used in 4 bit mode or 8 bit mode depending upon your pin availability on our microcontroller or development board.
In 8 bit mode 8 data pins are there which sends a character(1 byte) directly to the lcd. In 4 bit mode the upper nibble is sent first and then lower nibble.
The 16 pins on JHD162A are
1 Vss
2 Vcc
3 Vee
4 RS
5 R/W
6 EN
7 DB0
8 DB1
9 DB2
10 DB3
11 DB4
12 DB5
13 DB6
14 DB7
15 LED+
16 LED-

DB0-DB7: Data Pins( use DB4-DB7 in 4 bit mode)

RS(Register Select) : 1 - Data is sent , 0 - Command is sent .

R/W(Read/Write) :1 - Read the lcd , 0 - Write to lcd. this pin is almost always low.

EN(Enable): to enable an operation . first make low(0) to send data and then set the other two control lines and when they are configured, bring EN high (1) and wait for the minimum amount of time required by the lcd and bring it low (0) again.

Vee: Contrast Adjust Pin. connect to a potentiometer.

Now to use it in 8 bit mode we need 8 data pins DB0-DB7 and 3 control pins. So total 11 pins are required. In 4 bit mode, we need DB4-DB7 and 3 control pins. So total 7 pins and required.Note that the data pins DB0-DB3 are left open and are not shorted to ground.The Vee pin is connected to the potentiometer and is varied from Vcc and Gnd. Pin 15 and 16 are used for backlight of lcd and can be connected to Vcc and Gnd respectively.
So till now, you have the basic idea to setup a lcd and connect it with your microcontroller. In this tutorial I am using lcd in 4 bit mode.

Before writing any code, first download the library written by Peter Fleury from his homepage - http://www.jump.to/fleury. The library written by him has excellent functions by which we can directly control the lcd without knowing what is going behind the scenes and using the built-in functions provided in the library.
First set the mode as 4 bit mode by writing LCD_IO_MODE=1 in the lcd.h file.
Change LCD_PORT if you want to use a different port for the LCD pins.
The four LCD data lines and the three control lines RS, R/W, EN can be on the same port or on different ports. Change LCD_RS_PORT, LCD_RW_PORT, LCD_E_PORT if you want the control lines on different ports.

Code:
int main(void)
{
lcd_init(LCD_DISP_ON); /* initialize display, cursor off */
while (1) /* loop forever */
{
lcd_clrscr(); /* clear the screen*/
lcd_puts(“test program”); /* displays the string on lcd*/
_delay_ms(50);
}
}
This codes displays “test program“ on your lcd.(without quotes)
I have used delay because some time is required for the display to settle in.

The functions in the library which could be used are -

lcd_init (uint8_t dispAttr)-initialize display and select type of cursor.
lcd_putc(char c) - to print a single charater on current cursor position
lcd_puts(const char* s) - to print a string without auto linefeed.
lcd_gotoxy(uint8_t x, uint8_t y) - xth position on the yth line. X varies from 0 to 15 and y is 0 or 1.
lcd_clrscr() - clears the screen .
lcd_home() – goes to the initial position, i.e. equivalent to lcd_gotoxy(0,0)
lcd_puts_p (const char *progmem_s) - display string from program memory without auto linefeed.
lcd_command (uint8_t cmd)-send LCD controller instruction command.
lcd_data (uint8_t data)-send data byte to LCD controller

With the help of these basic functionalities you can display text on your lcd on both lines.
Please beware of delays. Proper delays are required for the text to properly display on screen or else it will blink or just displays once and go away. Play around with different types of functions given in the library.
e.g. lcd_command(LCD_MOVE_DISP_RIGHT) – moves the whole display one position right side.
Experiment it to display various kinds of symbols and text. One good code would be to show your text moving on the lcd. i.e. it enters from right and leaves from left – kind of rolling effect.

Problems which I have faced or mainly occurs with lcd-

The first problem to arise is you don’t see anything on lcd although its on – change the value of contrast using potentiometer.

Black squares are seen – See that proper connection is there. i.e. if any two pins touch each other than this may occur. Also see the contrast pin.

Displays blinks- use a proper delay. Try out different values of delays

Typical symbols are displayed instead of text – see the connections again. If two pins are shorted, this might occur.

Hope you like and understood the tutorial and start programming the lcd and play around with it.please give your feedback so that i can improve it.

Robotics and Microcontrollers

2009-12-21T15:17:00.000+05:30

I m quite interested in robotics and my first step towards it is to start by understanding the brain of a machine. This brain is called microcontroller. It comes in many forms and many companies make it. eg - Pic,Motorola, Atmel,etc. But the most cheaply available and useful for robot hobbyist is Atmel's Atmega32. It comes with enough functionality that we can easily experiment on it. So from now onwards i am going to upload codes and tutorials related Atmega32. Thanks

Hello

2009-12-21T15:09:00.000+05:30

Hey friends,
i m new to blogging but have created this site to share my views on topics which are relevant to me. Hope you find this useful.

- darsh