Friday, November 28, 2008

Tracked Robot Fabrication tutorials

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

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

The belts that we have used are reinforced rubber belts .Some of the remarkable characteristics are wearing resistant, high strength, waterproof, heat resistance, crack resistance, aging resistance and longer use life.  
The ball bearings that support the rear wheels need to be housed in a housing that could support the ball bearings and it also provides adjustable facility so that the slack that occurs in the belt over a period of time can be adjusted .It also facilitates the easy removal of the belt are loosening it.

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

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


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

Thursday, November 27, 2008

Final Year Project Robot design

Final Year Tracked Robot Sketch Up Drawing 
Google sketch up is a very useful tool for drawing fine and detailed drawings of your robots .Its easy to use as well Below is the 3d view of my final year project .
Isometric View

Side View

The real picture of my robot ..

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

Wednesday, November 26, 2008

Internet Controlled Telerobot Using Flat File System

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

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


Heres the word document of my paper  .You can modify it as you like .
I am willing to give you the code on special request .

The Abstract and Introduction are given below .

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


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

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

Tuesday, November 25, 2008

Robot Locomotion Mechanisms And Natural Movements

Locomotion Mechanisms
Hello everyone ,It has been very long since I posted in this blog .I have been busy with my new job and training .
I am going to write about different locomotion mechanisms.So far I've worked mainly with wheeled robots and a few legged robots.There are other types of motions like (Given below )
  • Flow in a Channel
  • Crawl
  • Sliding
  • Running
  • Jumping
  • Walking

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

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

Monday, November 10, 2008

Sex with robots ....IS it possible ?

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

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

Read these two articles from Scientific American

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

Who won ROBOCON 2008 ?

Nirma Wins ROBOCON 2008

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


Indian Institute of Technology, Delhi.

Nirma Institute Of Technology, Ahmedabad.

Maharashtra Institute Of Technology, Pune.

Vishwakarma Institute of Technology, Pune.


Nirma Institute Of Technology, Ahmedabad.

Maharashtra Institute Of Technology, Pune.

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

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

Sunday, November 9, 2008

Sensor types Analog and Digital Sensors


There are two types of sensors

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

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

Friday, November 7, 2008

How to Program a PIC Microcontroller ?

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

  1. ICSP
  2. JDM Programmer
  3. Microchip USB Programmer(ICD)
  4. USB Programmer (Not exactly a clone of ICD)

Watch this video and get started with PIC Programming

Thursday, November 6, 2008

Getting started with pic16f877a interrupt programming .

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

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

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

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

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

Here is the famous telephone conversation example for interrupts .

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

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

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

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

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