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VIRTUAL KEYBOARD

2008-10-22T09:56:00.000-07:00

The Virtual Laser Keyboard (VKB) is a revolutionary accessory (The only keyboard that operates in total darkness - see the picture below) for Blackberry, Smartphone, PDA, MAC & Tablet PC.
These are virtual keyboards that can be projected and touched on any surface. The keyboard watches your fingers move and translates that action into keystrokes in the device. Most systems can also function as a virtual mouse.

Keyboard projector
A holographic element illuminated by a red diode laser produces
a template of the keyboard.

Illumination Module
An infrared plane of invisible light is generated just above and
parallel to the surface of the keyboard.When a key is touched
light is reflected from this plane and directed towards the
sensor module.
Sensor module
Reflected light from the illumination module is passed through an
infrared filter and imaged on to a sensor chip which determines
the location of the light.It can process and interpret several
keystrokes simultaneously.
Working
The device detects movement when fingers are pressed down. Those
movements are measured and the device accurately determines the
intended keystrokes.Once the keystroke has been decoded, it is
sent to the portable device via wireless.

The ground breaking Virtual Keyboard (VKB) by I-Tech, uses state of the art infrared & laser technology to project a full-size keyboard onto any flat surface.

For the first time mobile device Users can actually type normally on this virtual keyboard (VKB), enabling them to work quickly and effectively, taking the pain and frustration out of existing minuscule keyboards and handwriting recognition software.

Lumio was initially well known for developing and licensing the 1st virtual laser keyboard (The VKB). Introduced first as a prototype at CeBIT with Siemens, the product was launched in early 2005 with Bluetooth and was recently voted "Best Innovation" 2007 at the Consumer Electronics Show (CES).

RING BASED HOME AUTOMATION SYSTEM

2008-07-30T08:43:00.000-07:00

The project, Ring based home automation system, aims at controlling the status of devices using series of missed calls made to a land phone. The system can either turn on or off any number of devices. Any device either electrical or electronic or both may be controlled, which makes the system ideal for offices or factories also. The mode of operation and the device itself is selected using missed calls only. Since no call is connected, there is no operational cost for the system baring the power losses. Three sets of missed calls must be made; the first one is for activating the system which also acts as a password for the system. The second set is for selecting the mode of operation and the third one is for selecting the device to be controlled. Even though automatic systems are common, it has not taken to a level to control simple operations such as controlling the electrical appliances of a home, but this system will be a difference. The system is cheapest and easiest automation solution for homes, offices, halls and perimeter areas.

IPL

2008-05-17T10:36:00.000-07:00

RAJASTHAN ROYALS LOGO

KINGS XI PANJAB LOGO
DECCAN CHARGERS LOGO

ROYAL CHALLENGERS BANGALORE LOGO

DELHI DAREDEVILS LOGO

KOLKATA KNIGHT RIDERS LOGO

CHENNAI SUPERKINGS LOGO

THE MUMBAI INDIANS LOGO

Vishualisation of EM radiation

2008-01-14T08:39:00.000-08:00

Is there any possibility f observing any radiation other than light
with our eyes?The answer is yes, but our bandwidth is limited &
the light sensor (eye) we have senses only the radiation falling in
the range of bandwidth.So a possibility is here to translate the
frequencies we want to observe to the frequencies we can see.Such
a device may make sense in the later world ,but now it may feel
not digesting.Me and Arun Prabhakar observed the IR rays with
the help of sony erricson mobile camera,even though the actual
reason ,we didn't know,the process happened anyway.After some
years there will be ppl wearing some helmet that could permit
easy view of the whole em spectrum.

My Mini Project - iRooM

2008-01-13T08:32:00.000-08:00

The project is to implement a part of the intelligent room .The absolute aim of the project is to implement an automatic lighting system , an automatic temperature control system and iRooM status monitoring system.

The automatic lighting system is implemented with the help of a state synthesizer, which generates the next state with the help of present state and sensor inputs. For the purpose a program is written and the artificial intelligence is created by burning that program into a microcontroller that emulates the function of a state synthesizer. Here due to the project limitations we are introducing the intelligence to four sections of the room in which automatic lighting is to be brought. The room is logically divided into 3,namely c0,c1,c2(c=cell)equally.

And the logical partition is based on two quantity-sensor pairs (like laser-LDR or IR-IR Sensor) namely,l0&l1.There is two sets of quantity-sensor pairs at the door side to detect the direction of travel of the humans(l2&l3).

After the state identification, we need to glow the corresponding array of LED’s .Also the project includes the room light intensity control according to the ambient light so that the total light inside the room is a constant.

The light intensity control is done through the help of a PWM generator, which generates the PWM corresponding to the input value given as input to the PWM generator, so that the light intensity of the LED array varies according to the ambient light inversely .The PWM generator is implemented with the help of a microcontroller with sensor input to PWM program burned in it.

The temperature control is done through the speed control of fan. For the demonstration purpose we are introducing a dc motor and speed control of it. For the purpose we generate PWM according to the temperature value and drive the motor. The result will be a varying fan speed according to the temperature.

DISPLAY INTERFACE:

Display interface is to be done with the help of a pc or a microcontroller with LCD display. Display unit mainly displays the current status of the room like in which section the human concentration is high and the total number of persons inside the room, and finally the temperature of the room.

The program for the state synth and other details are available in electronic error.

Punched card technology

2008-01-06T10:54:00.000-08:00

A medium for feeding data into a computer, essentially a card punched with holes or notches to represent letters and numbers or with a pattern of holes to represent related data. Also called Hollerith card.This definition is old now the definition is another one with code lock implementation.punched cards can be used as door-open cards provided there is a ckt designed to decode the code using any logic the coding can be done in a number of ways as in the case of program encryption.
A simple punched card-reader mechanism can be emulated with the help of an array of LED -LDR pairs connected so as to make the card an intermediate b/w the pairs .ie card can be inserted in b/w these two to open the door.presence or absence of a hole can be detected by the ldr very easily.
But the reader will be a bulky one to make this compact we may use some approximations with the ldr array we can process the signals from ldrs and find some real number corresponding to the punches and their positions.

LDR :-Light dependent resistors

2007-11-23T09:09:00.000-08:00

A Light Dependent Resistor ( LDR, photoconductor, or photocell) is a device which has a resistance which varies according to the amount of light falling on its surface.
They will be having a resistance of 1 MOhm in total darkness, and a resistance of a 1 to 10 of kOhm in bright light.
A photoelectric device can be either intrinsic or extrinsic.
Applications:
An LDR can even be used in a simple remote control circuit using the backlight of a mobile phone to turn on a device - call the mobile from anywhere in the world, it lights up the LDR, and lighting can be turned on remotely!

Light Dependent Resistor Circuits:

There are two basic circuits using light dependent resistors - the first is activated by darkness, the second is activated by light.

In the circuit diagram on the left , the led lights up whenever the LDR is in darkness. The 10K variable resistor is used to fine-tune the level of darkness required before the LED lights up. The 10K standard resistor can be changed as required to achieve the desired effect, although any replacement must be at least 1K to protect the transistor from being damaged by excessive current.

By swapping the LDR over with the 10K and 10K variable resistors , the circuit will be activated instead by light. Whenever sufficient light falls on the LDR (manually fine-tuned using the 10K variable resistor), the LED will light up.

The circuits shown above are not practically useful. In a real world circuit, the LED (and resistor) between the positive voltage input (Vin) and the collector (C) of the transistor would be replaced with the device to be powered.

Typically a relay is used - particularly when the low voltage light detecting circuit is used to switch on (or off) a 240V mains powered device. A diagram of that part of the circuit is shown above. When darkness falls (if the LDR circuit is configured that way around), the relay is triggered and the 240V device - for example a security light - switches on.

Measure Light Intensity using Light Dependent Resistor (LDR):

The relationship between the resistance R_L and light intensity Lux for a typical LDR is

R_L = 500 / Lux Kohm

With the LDR connected to 5V through a 3.3K resistor, the output voltage of the LDR is

Vo = 5*R_L / (R_L+3.3)

Reworking the equation, we obtain the light intensity

Lux = (2500/Vo - 500)/3.3

Laser network security system using simple ckt

2007-07-29T11:48:00.000-07:00

Figure shows the connection diagram !
its a 311 opamp with 4 th terminal gnded
R2 is an LDR whose dark resistance is greater than 10kohm
A laser torch can be used to power the ckt which is directed at the
LDR !
when the light is falling on the LDR its resistance will be less than
10k ohm,then the voltage drop across the resistance will be less !
hence the o/p voltage of the opamp will be 0.When the light is
interrupted the resistance of the LDR increases hence droping more
voltage ,and the o/p will be approximately supply voltage .The o/p
can be connected across a buzzer and can be connected to a relay
if the alarm ,we want is of non stoping .ie ,it can be turned of only
by another process not by turning the light again.

the pin out of the 311

However the sytem provides no other extra security!
becoz if someone shows a light on the ldr and intrudes the laser then the
system may not be able to realise wat happened !So we must use some
extra security tecniques !
Those includes 1)frequency coding
2) Amplitude coding
etc
The fact here is that we can use any electronic component to implement a comparator
but a basic ckt may not be able to realise the practical situations in some cases we
may be using opamp active differetiators using R and c instead of RC passive differentiators.In such cases the opamp provides impedance matching along with amplification of the signal.So we must be able to realise which component of our design should dominate while its working and design accordingly!

A software generating morse code:cw_player

2007-07-05T08:42:00.000-07:00

CW_Player
click on the image for a better view

This freeware program generates the standard Morse caracters, Q codes,
abbreviations, random series of characters and text files. It controls
your knowledge through a Quiz test and helps you to get a good keying
by monitoring your CW signals. Keying off air and verifying your
transmission on the screen will let you go on air with less stress and
more confidence.
It generates Wave sound files (*.wav) of morse characters that can be
played by any media software.

Local characters can be created by yourself.
20 lessons are proposed to learn the Morse code. You can modify their
contents as you like.
MIRROR:click on the fig below to download cw_player
:

Say bye to digital computers

2007-07-04T10:33:00.000-07:00

A quantum computer is based on the amazing properties of quantum systems. In these a quantum bit, also known as a qubit, exists in two states at the same time and the information from two qubits is entangled in a way that has no equivalent whatsoever in the normal world.
David Deutsch, Oxford University theoretical physicist, is credited with being the father of quantum computing.
Deutsch invented the idea of the quantum computer in the 1970s as a way to experimentally test the "Many Universes Theory" of quantum physics -- the idea that when a particle changes, it changes into all possible forms, across multiple universes.

In the classical model of a computer the most fundamental building block, the bit, can only exist in one of two distinct states, a '0' or a '1'. In a quantum computer the rules are changed. Not only can a 'quantum bit', usually referred to as a 'qubit', exist in the classical '0' and '1' states, but it can also be in a superposition of both! In this coherent state, the bit exists as a '0' and a '1' in a manner which may at first seem hard to accept. Let's consider a register of three classical bits: it would be possible to use this register to represent any one of the numbers from 0 to 7 at any one time. If we then consider a register of three qubits, we can see that if each bit is in the superposition or coherent state, the register can represent all the numbers from 0 to 7 simultaneously!
A processor that can use registers of qubits will in effect be able to perform calculations using all the possible values of the input registers simultaneously. This phenomenon is called quantum parallelism, and is the motivating force behind the research being carried out in quantum computing.
Quantum computers have superior qualities in comparison to the type of computers currently in use. If they are realised, then quantum computers will be able to carry out tasks that are beyond the abilities of all normal computers.
It is highly likely that workable quantum computers will need to be produced using existing manufacturing techniques from the chip industry. Working on this basis, scientists at Delft University of Technology are currently studying two types of qubits: one type makes use of tiny superconducting rings, and the other makes use of 'quantum dots'.
Now for the first time a 'controlled-NOT' calculation with two qubits has been realised with the superconducting rings. This is important because it allows any given quantum calculation to be realised.
The result was achieved by the PhD student Jelle Plantenberg in the team led by Kees Harmans and Hans Mooij. The research took place within the FOM (Dutch Foundation for Fundamental Research on Matter) concentration group for Solid State Quantum Information Processing.
Quantum computers hold the possibility of solving what computer science calls "NP-complete" problems, the problems that are impossible or nearly impossible to calculate on a classical computer. Picking out a single pattern from a collection of patterns, such as your mother from a photo of people, is easy for you, but beyond the reach of your PC.
Despite many common concepts with classical computer science, quantum computing is still widely considered as a special discipline within the broad field of theoretical physics. One reason for the slow adoption of QC by the computer science community is the confusing variety of formalisms (Dirac notation, matrices, gates, operators, etc.), none of which has any similarity with classical programming languages, as well as the rather ``physical'' terminology in most of the available literature.

QCL (Quantum Computation Language) tries to fill this gap: QCL is a high level, architecture independent programming language for quantum computers, with a syntax derived from classical procedural languages like C or Pascal. This allows for the complete implementation and simulation of quantum algorithms (including classical components) in one consistent formalism.

T-Rays vs. X-rays

2007-07-03T09:04:00.000-07:00

Knife and guns appear visible through the t-ray technology becoz its sharp edges scatter the radiation. And yet, unlike X-rays, T-ray screeners could be used routinely on people, because the radiation is harmless.

But some terahertz imagers have another ability, one not even claimed by the comic-book specs: not only can they see hidden objects, but they can tell what those objects are made of. Many explosives, including all the plastic explosives popular with terrorist groups, reflect and transmit a characteristic combination of terahertz waves that make them distinguishable from other materials, even those that might seem identical to the eye and hand.

They have “standoff capability,” meaning they can see a few meters away, a very desirable feature in the security business.In just two or three years, versions that can see at a distance of tens of meters should be available, which would be a great safety boon to security personnel. There are lots of uses outside of the security arena for T-rays, too. Drug companies are buying T-ray imagers for their ability to distinguish good pills from bad by their spectral signatures. T-rays can distinguish normal skin tissue from tumors even when a trained dermatologist cannot. Manufacturers can do the mundane job of checking the contents of a box without opening it, or they can perform such crucial tasks as finding the invisible defects in the protective coatings on an aircraft’s wings. NASA recently commissioned a T-ray imaging company, Picometrix, in Ann Arbor, Mich., to build a scanner to look for tiny holes and other structural failings inside the foam that lines the external fuel tanks in the space shuttle fleet. A chunk of that foam fell away in 2003 and led to the deaths of seven astronauts and the fiery destruction of the Columbia.
they’re not quite what we think of as radio and not quite what we expect from light. They can radiate from metal antennas as radio waves do, but they also bounce off ordinary mirrors as light does. They can be focused with silicon lenses but are typically sensed in a circuit by their electric field.(range =500 gigahertz and 10 terahertz That region is largely beyond the reach of pure radio frequency technology such as microwave circuits, requiring combinations of electronics and optics instead.)

for more details visit t-rays

Coupling & transmission

2007-05-22T10:14:00.000-07:00

Well ,there is a great difference between these two words
but may feel same practically! Once my friend Manu thomas
was completing his excel project ,perhaps violated some ckt
connections .Anyway a "man" call for me had been made .At
that time we were completing our project on robotics .
Stunned looking at the result!
The project included a laser based voice transmitter and receiver .
When he had removed the laser somewhat due to some power
supply problems related to the laser ,becoz he used the laser torch
which is available in market for just 30.00RS at marine drive ,
and instead of battery ,he used the 3v from the transmitter ,
connected only for the demonstration .Anyway demonstration
completed successfully.The transmission quality was great with
the help of laser .When the wire connecting the laser to the
transmitter broken it was found that there was a slight change
in quality of the sound transmitted,instead of vanishing of received
signal.(he used mobile phone music as sound source).
Astonished!proving nothing in theories!sound had been transmitted
without modulation without antenna which requires large height!
Is it possible?
With the help of a simple fixed bias ckt and simple loop antenna of
1/2 meter we have transmitted (exception)the sound signal
(audio frequency ) for 1 meter without the help of large antenna and modulation .
Initialy the target was a laser based transmission system ,
although the mission was achieved ,a fact came to know that there is
is a "coupling" existing between the transmitter and the receiver
when the distance is very less .

Here is the transmitter and the receiver.It was given
in the efy official web site.Here in the transmitter ,when
the laser torch was removed ,it was seen that the signal
at the microphone ,is transmitted (assumption)to abt 1
meter .All guys astonished feeling the result "without a
modulation scheme,without an antenna,without a carrier
,it is not possible to transmit the base band signal at all".
The fact was a truth we were not able to distinguish
between the coupling and the transmission until,
prof:T.K.Mani explained the phenomenon with proof.
That day i have realised that we are in the world of a mixed
signals all around us but not identifying them .For the purpose
we may require a frequency translator (mixer)to make them
feel with our natural sensors.
The transmitter was simplified by us to only a fixed bias ckt.
Thus realised that the problem is not with the transmitter .
"receivers are difficult to design than transmitters" that was
a natural truth.In the receiver the amplifier stage we
have used here is a one with high gain hence any noise or
anything which is coupled through anything(need not be a peice
of wire human body itself is a coupler)will be amplified and a
resulting sound is produced .

Comparison of human beings and robots

2007-05-17T04:27:00.000-07:00

1.Human beings have ears as their sound sensors .Actually they are filters designed for the audio frequencies.Their frequency response is similar to an LC filter with a specific bandwidth.
2.Eyes are filters designed to filter the light frequencies .
3.Skin is a touch sensor .
4.Nose a biological proximity detector.
5.Brain" a biological processor".
6.A great programme running on the brain which teaches it what to do & when.

The "Product Detector"

2007-05-05T12:12:00.000-07:00

This device is just another mixer - used for demodulating a signal in a receiver. The term "product" refers to the multiplication of the two input signals - with sum and difference outputs.
In the product detector the product signal ie, the dual sideband or single side band signal is again multiplied with the local carrier .
NOTE
In case of suppressed carrier systems (dont confuse carrier fully suppressed)
there is a need to get the carrier at the receiver at same frequency as that of the transmitter and the phase must be same.Hence we need highly stable oscillators free from drift.Such a process called synchronization must be done at the receiver ,which makes the receiver complex.For these reasons a pilot carrier system is preferred ,where the carrier is generated by the LO referring to the pilot carrier.
Receiver blockdiagram is available
here
In the case of AM signals a synchronous demodulator is preferrable because it offers more stability to the s/n ratio.In the synchronous demodulator we multiply the signal received by the
locally generated carrier hence the signal can be recovered
At the modulator side ,
Sin(Wct)Cos(Wmt)+Cos(Wct)Sin(Wmt)=Sin((Wc-Wm)t) {the modulated signal}
or the side band corresponding to upper frequencies.
where the Cos(Wmt) is obtained from Sin(Wmt) or vice versa thro Hilbert's Transform.
At the demodulator side,
Sin(Wct)Cos(Wmt)+Cos(Wct)Sin(Wmt)=Sin((Wc-Wm)t)
is multiplied by Sin(Wct)
so that a (Sin(Wct))square term appears which can be expressed interms of double angle
by the trig relation sothat the signal Cos(Wmt) can be filters at the output by using alow pass filter

Theory of mixers

2007-05-05T11:59:00.000-07:00

A mixer circuit normally has two inputs - from two separate signal sources. In the diagram below, the sources are two oscillators. Each oscillator is a generator producing a sinewave output, one at frequency f1 and the other at frequency f2.
The mixer multiplies the signals together,while the balanced modulator is a combination of 2 mixers.
Remember that the output comprises a complex mixture of separate sinewaves at many different frequencies beco'z of the square law equation of the current .

The main point to note is that the output comprises the two separate input frequencies f 1 and f 2 and their sum, (f 1 + f2), and their difference, (f 1 - f2). In practice, there are other component signals too - but we can ignore those.

A filter - which can be any one of various sorts - selects the required output from the mixer. In this diagram, a simple parallel tuned circuit is shown. The output will normally be tuned to the SUM, (f 1 + f2), or tuned to the DIFFERENCE, (f 1 - f2), signal as required.
The output from a mixer contains many more combinations of frequencies - generated from the harmonics of the input signals mixing with the component signals.
Almost any electronic device, diode, transistor, valve, can be used as a mixer. A "square-law" characteristic device is preferred - to minimise unwanted outputs.
The principle is: In a mixer stage, the output contains the SUM and the DIFFERENCE of the input signal frequencies.

let me correct a common mistake ...mixer is not a sum and difference frequency signal producer!

its any device having non-linear transfer characteristics .it is simply like our "mixer".it produces many components of frequencies sum ,difference ,secondorder sum second oerder difference .the no: of frequency components generated depends on the extent nonlinerarity of the device transfer characteristics .We filter out the desired frequency component using filters.Any way mixers contribute to most of the noise produced in the receiver or we can say that mixers are the sources of noice at the receiver end of a transmission system

Amplitude modulators

2007-05-05T07:04:00.000-07:00

Amplitude modulator can be classified as
1.Linear modulators
a)collector modulator
b)base modulator
2.square law modulators
a)Square law diode modulator
b)square law balanced modulator or simply balanced modulator

1.Linear modulators
a)collector modulator

collector modulator is a modulator in which the AF signal is applied at the collector of the BJT &RF signal is applied at the base .(high frequency BJT).

b) base modulators

In base modulator the RF & AF signal is applied at the base of the BJT .

2.square law modulators
a)square law diode modulators

In sauare law diode modulators the modulated current follows the square law
I_p=a₁e_s+a₂e_s²........
e_s=e_m+e_c
where I_p is the current through the diode
e_s the sum of the modulating and carrier voltages
b)balanced modulator

In balanced modulator the product of the input frequencies is produced along with other frequency components .Simply a balanced modulator is a combination of 2 mixers

DIFFERENT MODULATION TECHNIQUES

DSB-LC-AM
There are three components to any DSB-LC waveform, the upper and lower sidebands and the carrier frequency. If the powers in all three of these are added up, the total power in the modulated signal will be
P = Pc + Pusb + Plsb
the o/p contains product of the signals + carrier
DSB SC AM
The sceme is same as above with suppression of the carrier.The o/p contains product of the signals
SSB
Only a sideband is transmitted along with carrier. The o/p contains sum or difference frequencies of base band signal and carrier along with the carrier frequency.
SSB-SC-AM
A sideband along with suppressed carrier is transmitted,only sum or diff: freq
Pilot carrier
A sideband or 2 is transmitted with carrier power reduced or carrier attenuated to a reasonable extent.
It is used as a ref: for the generation of carrier at the receiver.
The suppressed carrier balanced modulator
It producess carrier suppression along with the multiplication
In general almost all the amplitude modulators are mixers.
"In general modulation is the process of obtaining a product of the signals ,of both carrier and base band signal."

Frequency domain & time domain representations

2007-05-04T07:59:00.000-07:00

*TIME DOMAIN REPRESENTATION

It is the representation with signal amplitude on the vertical axis and with time on the horizontal axis - (an oscilloscope diagram). This is sometimes referred to as the "time domain representation".
*FREQUENCY DOMAIN REPRESENTATION

Its the representation with signal amplitude on the vertical axis but with frequency on horizontal axis - a Spectrum Diagram. This is sometimes referred to as the "frequency domain".

Modulation

2007-05-04T07:33:00.000-07:00

The technique to impress information (voice, music, picture, or data) on a radio-frequency carrier wave by varying one or more characteristics of the wave in accordance with the intelligence signal is called modulation. There are various forms of modulation, each designed to alter a particular characteristic of the carrier wave. For our study purposes, the most commonly altered characteristics are amplitude and frequency.

There are mainly 3 modulation schemes

1.Amplitude modulation

1.Amplitude modulation block

2.frequency modulation

2.frequency modulation block

3.phase modulation

Bandwidth & Brainwidth

2007-05-04T07:15:00.001-07:00

Measurement of the capacity of a communications signal. For digital signals, the bandwidth is the data speed or rate, measured in bits per second (bps). For analog signals, it is the difference between the highest and lowest frequency components, measured in hertz (cycles per second). for better results click here

Brainwidth is analagous to bandwidth but used strictly for human capacity to process information and especially to multitask.