Project Abstract :Telephone based remote heater ON/OFF

Suppose you have an heater in a room and you want that the heater should be made on or off based on from a remote location and  heater on/OFF can be made
The methodology described here can be used is applicable for any remote device activation and deactivation.Now consider a security scenario suppose you have to record some of the activities of your room (as you are not at home and want to record activities within the room )This can also be achieved by remote activation using device switching mechanism using telephone line.So what you need to have a working landline to implement this method.
This method has many other advantages also,just think you can control almost any electronic device from the remote location by just making a simple call to your home.Another situation:say when you left the home you just forgot that whether you have switched off all your light ,fans etc.
Now if you have this mechanism available to you from remote location where ever you are if you can mange a telephone line to call to your phone you can make the lights and fans off just like any electrical device you can do.

So this way any device can me made on/OFF based on telephone line and remote switching.This kind  of remote switching can be achieved by the use of DTMF decoder IC,The task  of DTMF decoder IC is to decode the DTMF tones coming from remote phone which are used to activate the devices in the home. So at room the DTMF decoder is placed and the decoder then after decoding the DTMF signals(which are  coming through the telephone lines form remote end(say you are at the remote end are pressing the switches/telephone keys))Then  the decoded signal is used to activate the relay(DC relay/Ac realy depending on what kind of device you want to activate).So this is the concept of this project.

Simple nMOS fabrication:Process steps

Simple nMos:

1 .Thin wafer from single crystal silicon taken

2. 1 micron silicon dioxide grown over the surface for protecting from other dopant during different
during different phases of the  diffusion.

3.  Surface now covered with phtoresist of uniform thickness

4. Photoresist now exposed to ultravolet light through mask.(Mask define the areas where diffusion  has to be taken placce).UV exposed parts get polymerized(hardened) and other parst not hardened

5. After etching the required areas (where diffusion will take place later on)bare wafer surface is now open and ready for diffusion.

6. Remaining photoresist removed a thin silicon dioxide (0.1 micron) layer grown over entire chip surface ,then poly silicon is deposited to form the gate gate structure.

7. For patterning of polysilicon further photoresist coating and masking done.Then thin silicon dioxide (0.1 micron typical)removed to get a window foir diffusion.

8. These diffusion will create source and drain.Diffusion achieved by heating the wafer and passing  a gas  containing  a type impurity.

9. Silicon dioxide grown over all again  and then masked with photoresist and etched to expose selected areas of the polysilicon gate and drain and source  for contact cuts(i.e from where contacts will be taken).

10.    Then metal deposition done (1 micron  typical).The metal layer is then masked and etched to from the required interconection pattern.

Avatar 2010:A review:Worth to watch

Avatar the movie  i just watched. Just want to tell something about the movie. First of all after seeing the movie i thought what i have just seen ,what moments i observed, its so lovely each and every  part of the movie, its just incredibly good.

What world has been created by the  James Cameron as well as what a story & what a representation(WOW!) and what special effects. In each and every category i think this movie is the best of 2010.

I just want to share the portions of the movie which i liked most .
Just try to remember the sin when the girl(heroine) running the big bird and let the hero watch her that how to ride on that big bird.

Another sin where when the hero is trying to get his first flying bird and trying to make him his pet and friend that touched me a little bit.

Other sin which touched me most when the girl trying to protect the body of the hero when his mind is transferred again back to human body. This touched me too much in terms of love. As well as i felt very sad when first time missiles and rockets are fired and a big tree destroyed ,i felt how hard it is for them who had their homes on that tree.

Next the  sin at last when the inhabitants(at the time of final war) may seems to be retreating  and suddenly all the creatures together revolted and get the win back to the inhabitants.

The furious animal  (black leopard type Big animal) also decided to be the friend of the of the girl and let her ride on him against the cornel ,that’s just wonderful-conveys the message that when threat is on existence of a species on a planet all all united against the aliens(here humans are acted as aliens to that planet with their invation on that planet).

The story in brief is that ( just telling the parts where people may not understand ) because this is  a hi tech thinking movie. There is some way people have developed technology to transfer the mind over to the inhabitants of the planet. Then that way a marine who lost his legs is used to transfer his mind to a inhabitant to know the secret information  but he revolted.

All the film is totally enjoyable and its worth to spend money to watch this film.

Next some confusion remained -may be i have not understood.
How the native girl(i mean the heroine ) learned to talk in English?

Only that part i have not understood ,except that  each and every part of the movie is worth watching.

A simple tone generator by 8051 microcontroller

Design idea:
This can be done very easily.
First of all what is a bell –to hear the sound of a bell we need a speaker and an audio amplifier. So what task microcontroller do is to generate wave of particular frequency.
So what we need ?We need to write a program to generate pulse trains of a particular frequency. This can be found in any 8051 book. Now the thing is what frequency this will generate ,the answer is the frequency that has to be generated must be of audible range(20HZ to 20KHZ).Now after wave  or pulse train is generated(in audible frequency range) by the microcontroller then that is fed to the audio amplifier IC and then the output of the audio amplifier IC is fed to speaker.

Now there is another way of doing this project. We can use IC555 to generate tones of different frequency by just changing the resistor and capacitor values. So we will use IC 555 as a astable multivivbrator mode and the then after the generation of the tone pulse trains they are fed to the IC 741 (which is an OPAMP IC) for signal amplification then again fed to speaker(8Ohm) and we will hear a sound.

Now question is why we are using IC555 in the mode of astable multivibrator.  Because we know that only the astable  multivibrator is capable generating continous pulse as it has two stats and each state is not a stable one.

Now there is another method for generating pulse with audio frequency is that just use a IC 324 (an opamp IC) and configure it to generate audiable frequency wave in that way waves can be generated and connection to speaker is the same as before.

A simple line follower robot:How to do with concept

In the line follower robot the  robot(here a car which have some wheels in it  and which can move)moves along a black line. This project is not a new thing, many toys are there which have implemented this technology or rather build this line follower. This  project have the following are some important important section I want to discuss

A line detect section:
In this section an IR transceiver is fitted at the bottom of the car and this  IR transceiver( i.e. IR Transmitter and the IR receiver  together) is responsible for sensing the black line. The IR transmitter sends the  IR ray and the receiver catches the reflected ray. Now the amount of reflection will vary if the IR reflected from white surface or from the black surface(black is the color of the line which is going to be followed by the car).So the IR sensor generates two different voltages on the two situations just described here .Then  a comparator used to compare whether black line or white surface.

Decision section:
The decision section generally consists of some microcontroller which is responsible for giving proper signals to the motor etc and the car control circuits so that the car can follow the black line.
When say black line sensed then say comparator output is zero then the microcontroller will decide what to do ,and if  white surface then microcontroller will give different signal to the motors and the motor controlling circuit.

What is the real problem with this design??
The real problem is the how to fix the comparator reference voltage. The sensor’s output some times vary with the day light and ambient, I mean you can get different voltage outputs based on which environment you are using the IR receiving sensors. If using light sensors and light /laser transmitter then the problem I is more acute ,but as IR sensors rely on modulation of the IR Transmitters so the problem is less acute but still many trial an trials are required to fix the reference voltage of the comparator.

Robinhood 2010:A movie to watch

First of all I want to make it clear that this is  a movie which is lengthy.This movie duration is almost 2 hours and 35 minutes. What are the beautiful things in the movie ? The answer is the sceneries and the presentation of the movie is nice.
When I started to watch this move what I found that it not seems to be the story we know on Robinhood ? Is this the same movie story we know about Robinhood or we are going to  watch a remake of the older Robinhood movies ? The answer is no ?The story of  movie tells about the story how Robinhood becomes the Robinhood, before he has taken his shelter in the forest and started his fight against Notinghum  sheriff. This movie also shows that how he faught on the side of the king against the france invasion across the sea areas before he became the Robinhood. What are the circumstances that made him to choose the life of Robinhood and made him to stay in the forest.
So reason behind this  and shown in a good representative way in the movie .No doubt the Naughtinghum village shown here is too good –I am again saying I liked the film location.
Next the Curt Russel in the role of Robinhood as good as he  as an actor. But he  looked a little bit older .As this film shows the  early days of Robinhoods life,  at the early stages of his life so he should look a little bit younger.

Next the fighting sins should be a little bit more elaborate and good.
More or less they are so so category in comparison with the movies like “cronicles of Narnia “

The ending of the movie doesn’t satisfied me –may be just ended saying that next life of Robinhood starts from there but that may add a success to the film maker in the sense that I wanted to see more of that though the film ended.

But as a  overall grade I will give 75 out of 100 for this movie.
But again this is a personal opinion.

A stop watch design with 89c51 microcontroller:made easy

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.

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 .

Predator 2010:New movie a review

All I am writing is my personal opinion many people may differ with that.The new version of predator is released.
Film is good no doubt. But as what we have seen in Arnold Schwarzenegger the main actor seems not as taugh  as that.
Its my personal opinion. The movie is good in the sense that it has a suspense all around the movie but as we know what creature is ultimately will come so its known at that sense that we are going to see that old predator uniform again.
The movie special effects are good but not too good, we have seen this kind of thing in many other movies but still the overall is good.
The story is so so ,in some parts the story seems  a little bit slow.
At last seen the story is just like it starts again when the paratroopers dropped again just like at the starting of the film
Its not very clear to me that why the people or how the people  get to that planet. Some questions remained at the last –that what will be next ,are there many other predators on there ,if yes how the main actor handle that without many weapons etc as the weapons etc are almost nil now.
But still the movie make its viewers a good taste as it is fully adventures movie.
I liked the movie .

Bengali Movie 2010:Sedin Dekha Hoechilo

Why i liked the movie sedin dekha hoechilo:

first of all the movie can be seen many times only to see the beautiful sceneries

The movie songs are excellent.

More of all I liked the actress shrabanti she is just great in look and as well as his expressions: its great.

The hero hero of the film worked well no doubt as well in the dancing scenes he worked extremely well.

This movie can be watched many times just because of the following three terms

Best location

Best songs

And Shrabonti

According to my personal opinion.

So the movie make yourself feel that there are many things in life you can watch and feel.

I generally don’t watch Bengali movies to much but I felt with love with this movie not because of the story etc but for songs and the scenery of the films .

More of all I will recommend to go and watch this film to see how beautiful shrabonti is looking at this film (as shrabonti is my favorite actress and I want her to do more Bengali films. )

I have seen some of her films earlier (part of the films) but in none of the films I found her so much beautiful as she looks in this film(believe me), may be I prefer faces like shrabonti very much (like raveena and twinkle in bollywood).

FET:Field effect transistor some questions

Some questions i am asking and i am expecting some body to answer it or get the
answers from your teacher

Q1. Why it is called field effect?
Q2. What is the field mentioned here ,how the field mentioned here and is it related with the voltage
Q3. if related with the voltage with which voltage
Q4. What is our aim for studying the transistors
Q5. How FET transistors are different form those  of BJTS
Q6. Which one is better BJT or FET
Q7. In which application scenarios we use FET
Q8. What is unipolar and bipolar device
Q9. In FET Characteristic curve why after pinch-off the current saturates
Q10. What is the reason behind the saturation because as the channel get constricted then why current remain saturated
Q11. What are the applications where the saturation property of FET can be utilized.
Q12. What are the source and drain and how do we identify them though the device is a symmetrical device.
Q13. FET and MOSFET how they are different
Q14. FET and BJT which one consumes less power.

Now to answer those questions what bare things you need to read.

Must read the basic device of FET from any text book and then try to answer those.