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How o build a stalker:khitish problem solution 2012

January 18th, 2012 Remo No comments

A simple robot based on khitish criteria.
A robotics contest to be held on khitish at IIT kharagpur.
How to build a line follower robot with another robot following the line follower  robot in another surface.
So if another robot has to follow the robot1 (which is a line folower robot).The another robot  which is follwoing the robot-1 can be any robot but must not be a robot which is not controlled manually.
It should be autonomous and follwing the robot-1 autonomously.
Now robot -1 is following a  a white line in the black surface.In the black surface the robot -1 is moving  and following the white path. Now robot-2 has to follow that path but in  a different surface. The surface may be at te  top of the robot-1 surface.Robot-1 and robot-2 will communicate among each other via wired ln link or wireless link. 
So the probable solution for that is is as follows:
======================================================  
So how we proceed to design such a systems whare robot 2 is following the robot-1 ?
The basic task first just construct the line follower robot. The line follower robot is a well exposed area.there are many good documets about the creation of the line follower robot is given  2 such places i know is here .

///// give line follower robot links
http://projectus.freehost7.com/Line-follower-robot/?a-line-follower-robot
http://blinki.freehost7.com/education/electronics-project-idea/a-simple-line-folloer-robothow-to-do-with-concept/

Now after the line follower robot construction is over then we need to optimise the performance of the line follwer robot as in the following way.
Now how we optimize the performance of the line folllower robot?
How the performance can be optimized that is one of the main crutial task.
So for that reason what we need to do ?
When ever a small turning etc done in the robot-1 that should be  recorded.
NOTE: recorded in this sense means that suppose a 20 degree right turn is made by the robot-1 due to the  white  path nature on the black surface.So if there is a 20 degree turn for the  white line in the black  surface.Then the line follower robot(robot-1)also  have to do a 20 degree turn on the right side.So this information that robot-1 has made a 20 degree right turn is to be passed to robot-2 which is following the robot-1. So the line follwoing robot-1 has to  send the info that 20 degree right turn has made.
How robot-2 is send a signal that 20  degree right turn is made,Say the microcontroller used in robot-1  is responsible for turning at right i mean 
give signal to turn at the right side  by the amoun of 20 degree .

Now question is how to turn a small car at right side??
Answer is: stop the front right motor and rotate the front left motor so that 20 degree turning can be done.
Say for example:A  1/2 rotation of the left front wheel motor make a total 20 degree rotation, so that is recorded( i mean 1/2 rotation).
So that is recorded and send to follower robot-2.Now the follower robot will receive that the info turn right and rotate left front wheel 1/2 rotation.
So this way robot 2 can exactly follow the path of robot 1.
If anybody want the full details of this how to do ??
just join the forum,before joining te forum you can email me .After you email me  and after that i will create the forum account for you,where you can get free suggesstion for that.
I can also supply te the things like circuit digram free with suggesstions. 7 professionals are ready to give you the answers.
So must join the forum and ask others to join the forum.

Harbhajan singh’s likings:An Interview

February 23rd, 2011 Remo No comments

HarVajan Singh:A small report on his likings etc

Harbhajans Singh is one of the best cricketer that India have.

His spinning and bowling is incredibly good and can make many more matches to win in favor of India.

Here are some likings etc report for the Harbhajan sigh.all therse are collected from different news papers,Interviews at different times given by the Bhajji.

 

 

He like to play in Eden gardens with huge crowd support and he enjoys that.So he is a little bit upset when he heard possibly India is not going to play in eden gardens in 2011 world cup.

 

His favorite Eden Garden Memories:

He had a a hatrick on eden  garden as well as become the first Indian to get a hatrick on test match.

Winning the game against Australia in 2001 also pleased him too much.

 

He also liked that India beated south Africa  in Feb 2010 and become the number 1 team in test cricket.

 

 

When asked about  him about the legend sachein tendulekar he said that he met  with sachin on 1996 at the nets of Mohali,he also considered that moment as his one of the biggest moment he ever had.At that time he was young and called to bowl at the Indian net.He termed sachin as a great motivator as well as a role model.

 

Who is Bhaji’s favorite spin bowler ??

According to him his favorite bowlers (spin bowlers) are Muralitharan,Anil Kumble,Saqlin  Saqlain Mushtaq.

 

Bhajji said Vivian  Richards is one of the player for  whom he his ready to pay and watch his match even if it’s an exhibition match.

Bhajji is associated with Reebock and using their ZuigTEch Bats.

 

He also likes other sports like tennis and Roger Federer is his favorite.

His favorite actress :Madhuri Dixit.

 

He likes the following Bengali dishes

MistiDoi,Rasgulla

 

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Jeet:Tollywood actor is going to be married soon

February 23rd, 2011 Remo No comments

Ok so the busiest tollywood hero is  going to be married. Now this report is based on a interview taken by some reporter  and published in some  magagazine/newspaper.

Why he opt for settled marriage ?

As the actor said that he  always a liked the arranged marriage .Then he said that he left the responsibility to choose the right partner for him to his parents as he know that parents will always choose the best for    him.

 

 According to the ACTOR Jeet the arranged marriage just like an adventure where many good phases has to be revealed after the marriage.People will discover each other after they marry.

 

 

When asked about that what his to be bride think about his profession then he said that his to be bride have seen few of his movies and they also discussed about that and she also respect his profession as well as she can be a good critic of his films .According to the Jeet the career of family background of both the families are almost the same and certainly this will help in adjusting the going to be relation ship between the two families.

 

How did Jeet found out his life partner?

 

As the actor said there was a lady in lucknow who was his sisters relative, According to the actor that lady suggested   him to marry the to be bride of jeet.

Then after the actor meets her, he begins to like her    and amazed to her simplicity and found that she can be fitted as his life partner.

 

When asked about that whether the actor thinks that his bride(to be) may come in film-then actor said that he don’t think so .

What is the date of the marriage:

As  the actor said it may be on February 2011.

Now  who is the  girl??

She is a lucknow based school teacher name Mohna.

We all welcome Mohna to WestBengal.

 

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HDLC and supervisory frame

February 10th, 2011 Remo No comments

HDLC is the protocol which is now considered an umbrella under which many Wide Area protocols sit. ITU-T developed HDLC in 1979, and within HDLC there are three types of stations defined:

  • Primary Station - this completely controls all data link operations issuing commands from secondary stations and has the ability to hold separate sessions with different stations.
  • Secondary Station - this can only send responses to one primary station. Secondary stations only talk to each other via a Primary station.
  • Combined Station - this can transmit and receive commands and responses from one other station.

When transferring data, stations are in one of three modes:

  • Normal Response Mode (NRM) where the secondary station needs permission from the primary station before it can transmit data. Mainly used on multi-point lines.
  • Asynchronous Response Mode (ARM) where the secondary station can send data without receiving permission from the primary station. This is hardly ever used.
  • Asynchronous Balanced Mode (ABM) where either station can initiate transmission without permission from the other. This is the most common mode used on point-to-point links.

fig1

There are three types of HDLC frame types defined by the control field:

  • Information Frames are used for the data transfer between stations. The send sequence, or next send N(S), and the receive sequence, or next receive N(R), hold the frame sequence numbers. The Poll/Final bit is called Poll when used by the primary station to obtain a response from a secondary station, and Final when used by the secondary station to indicate a response or the end of transmission.
  • Supervisory Frames are used to acknowledge frames, request for retransmissions or to ask for suspension of transmission. The Supervisory code denotes the type of supervisory frame being sent.
  • Unnumbered Frames are used for link initialisation or link disconnection. The Unnumbered bits indicate the type of Unnumbered frame being used.

A stop watch design with 89c51 microcontroller:made easy

January 29th, 2011 Remo No comments

First of all what is a stop watch  and the idea how we can build that with the help of low cost microcontroller named atmel 89c51 .
Here only the ideas are given. And also what are the things required as well as the concepts are given here. There are plenty of materials on the internet to get the circuit etc but they won’t explain the circuit and general concept ,that’s why this note is required to get some idea about the concept on what you are going to build rather copying only the circuit and soldering etc.

Stop watch is just a watch which we start and timing starts and when stopped it shows the time elapsed. This is type of watch is very good for sports etc events as well as whenever you want to measure some “how much time elapsed in an event “.

You need to write microcontroller codes to show the time on a LCD display.
So what are the things you need to write as code (89c51 code)

We know that 8051 can be used to generate pulses with a particular duration.
So just be writing some code we can generate a pulse having proper width. Say we want to generate some delay with the microcontroller 8051(note:I am mentioning  8051 as 89c51 is the part number by atmel and actually there is 8051 core inside).
So once we can generate a delay ,so it is also possible to create a delay of  x seconds ,and also possible to generate delay of  60 seconds and so 1 min and so on. We just need to update and display the things on the LCD, The main things involved in the embedded program is that the delay generation part as well as the LCD part.
Before you start the clock just reset switch(a pin of 89c51) when reset switch pressed then all the digits made zero and then started from ? 00:00:00.
The display routine will do that I mean when reset pressed then make all the digits 0 in LCD module.

Display:
We need to write a display routine for the LCD  module.
How ? How we  can write display module routine. The answer is just see the LCD display functions and details of pin etc and interface that with the 89c51 microcontroller  and write your interface routine  by 89c51 codes.
Then just  have to display properly display update the digits.
Say after 60 seconds update the minute part in LCD (i.e increase by one ) after 60 minute update the hour part in the display so on.

When you stop the watch just  stop the delay  generating part as well as LCD updating part. So the watch will show the time elapsed.
If you want to implement this project please write your query as comment, I will try to answer that .

Categories: Electronics project idea, News Tags:

AM Transmitter A simple One with explanation

January 28th, 2011 admin No comments

Circuit Diagram

Circuit diagram

Working Principle

The improved Micropower AM Transmitter circuit has four sections as follows:

1. Crystal Oscillator Section

2. Audio Amplifier Section

3. Differential Amplifier Section

4. Antenna Matching Circuit

Each section is briefly described next.


Crystal Oscillator

A piezoelectric crystal such as quartz, exhibits electromechanical-resonance characteristics that are very stable and highly selective. The circuit symbol of crystal and its equivalent circuit is shown below.

The circuit of fig.(b) has two resonant frequencies.

A) Series resonant frequency ( fs )

B) Parallel resonant frequency ( fp )

The mathematical formulas given below

fs = ?s /2? = 1/(2??(LCs))

fp = (?p /2?)=(1/2?) ?( (Cp+ Cs) / LCpCs)

It is found that ?p > ?s as Cp >> CS. The reactance of the crystal is inductive over very narrow frequency band ?s & ?p . For a given crystal this frequency band is well defined .Thus we may use the crystal to replace the inductor of the Colpitts Oscillator.

In this circuit a Colpitts Oscillator is incorporated with crystal oscillator. The resulting circuit will oscillate at the resonance frequency of the crystal inductance L with the series equivalent of CS and Cp + {C1 C2 / (C1 + C2)}.

C1 & C2 are the 120 pF & 560 pF capacitors.

Since Cs is much smaller than the three other capacitance, it will be dominant and

?0 ~ 1 /?(LCs) = ?s

This oscillator circuit produces the carrier frequency of 1.8 MHz. We get this carrier frequency at the base of the Q1 transistor.

Audio Amplifier Section

In this section the audio signal is fed through the 10?F capacitor. Then this audio signal is fed to the base of the Q2 transistor. By the help of DC biasing, the transistor Q2 is kept in active region. This Q2 transistor amplifies the input audio signal & we get the amplified audio signal at the collector of the Q2. This collector point is connected to the common emitter point of the Differential Amplifier.

Differential Amplifier Section

In this section, transistors Q3 and Q4 comprise an emitter coupled differential amplifier. Here Q3 and Q4 are matched transistors forming a symmetric circuit. If we remove the audio signal then Q2 and corresponding biasing circuit will act as a constant current source. In DC bias condition if base voltages of Q3 & Q4 are equal (VCM) and if a constant current source is connected to the emitter of Q3 & Q4 then due to symmetry the current will divide equally between Q4 & Q3 and the common emitter point voltage will be almost VCM – VBE or (VCM - 0.7)V and the voltages of two collectors will be equal and the difference in voltage between collector is zero.

The gain of the differential amplifier is

Ad = -gm Rc [gm transconductance of Q1 & Q2 ]

The single ended gain is : Ad = - (1/2)gm Rc

The base of the Q4 is kept at a certain fixed voltage by proper dc biasing and the carrier signal of about 1.8MHz is given at the base of Q3 and the amplified output of the audio signal is fed to the common emitter point. Due to the varying emitter current at the audio rate, the transconductance varies at the audio rate affecting the gain. As a result, the amplitude of the carrier is varied according to the audio input signal and we get the amplified amplitude modulated wave at the output collector, which is fed to the matching circuit.

Antenna Matching Circuit

Antenna matching is very essential otherwise it may cause distortion in the transmitted signal. In this circuit the 0.1 ?F capacitor blocks the DC component and along with the variable capacitor ( 10 – 100 pF) it works as a matching circuit for the antenna. Here the 0.1 ?F capacitor is connected in series while variable capacitor is connected in parallel.

Applications:

  1. A continuous-loop tape could give sales information to passing cars. Place a sign that says, “tune to xxxAM for information,” next to the house or car that is for sale.

v Transmit special seasonal music at Christmas or Halloween to enhance your decorations. (Use a similar sign.)

2. Transmit a cassette player or other audio source to the car radio for better sound.

3. Make a pair of toy AM band two-way radios by adding inexpensive AM radios. Or talk between cars on a trip using the car radio for reception.

4.  Build a fully functional radio station for the kids - complete with vu meters, slide faders, and an “on the air” light.


Categories: Electronics project idea, News Tags: