Biometric Scanners(Finger print scanners)

This post will be about biometrics and there use in fingerprint scanners.

But first

What is biometrics ??

Biometrics refers to metrics related to human characteristics and traits. Biometrics authentication (or realistic authentication) is used in computer science as a form of identification and access control. It is also used to identify individuals in groups that are under surveillance!

Simply,

Biometrics are automated methods of recognizing a person based on a physiological or behavioral characteristic. Among the features measured are face, fingerprints, hand geometry, handwriting, iris, retinal, vein, and voice. Biometric data are separate and distinct from personal information. Biometric templates cannot be reverse-engineered to recreate personal information and they cannot be stolen and used to access personal information.

Using a unique, physical attribute of your body, such as your fingerprint or iris, to effortlessly identify and verify that you are who you claim to be, is the best and easiest solution in the market today. That is the simple truth and power of Biometrics Technology today. Although biometric technology has been around for many years, modern advances in this emerging technology, coupled with big reductions in cost, now make biometrics readily available and affordable to consumers, small business owner, larger corporations and public sector agencies alike.

It's pretty obvious why we have fingerprints—the tiny friction ridges on the ends of our fingers and thumbs make it easier to grip things. By making our fingers rougher, these ridges increase the force of friction between our hands and the objects we hold, making it harder to drop things. You have fingerprints even before you're born. In fact, fingerprints are completely formed by the time you're seven months old in the womb. Unless you have accidents with your hands, your fingerprints remain the same throughout your life.

Fingerprint scanner 

Computerized fingerprint scanners have been a mainstay of spy thrillers for decades, but up until recently, they were pretty exotic technology in the real world. Then the introduction of finger print scanner in iPhone 5s 

That was a cool and very attractive 

Well I am using an iPhone 5s and the fingerprint scanner is the best (tech) thing I liked in this phone !

I really liked the concept 

(But then the thoughts of someone cutting your finger at night to unlock your iPhone :P )

Fact- Motorola Atrix had a fingerprint scanner 2 years before iPhone 5s!

However, scanners have started popping up all over the place -- in police stations, high-security buildings and even on PC keyboards

Well biometrics is not only used for security but even for attendance, in schools(cool), institutes, banks, hotels, etc etc !

So how do a fingerprint scanner actually works??

Let's find out !!

A fingerprint scanner system has two basic jobs -- it needs to get an image of your finger, and it needs to determine whether the pattern of ridges and valleys in this image matches the pattern of ridges and valleys in pre-scanned images.

Looks simple ?

Yes it does 

But there's a lot of electronics and science behind it

Only specific characteristics, which are unique to every fingerprint, are filtered and saved as an encrypted biometric key or mathematical representation. No image of a fingerprint is ever saved, only a series of numbers (a binary code), which is used for verification. The algorithm cannot be reconverted to an image, so no one can duplicate your fingerprints.

(So it's all as 01010010101010100101010100 :P)

Fingerprint scanning is the most popular biometric technology (used in over half of all biometric security systems)—and it's easy to see why. We store more and more information on our computers and share it, online, in ever more risky ways. Much of the time, our bank information and personal details are protected by just the few hastily thought-out numbers in our passwords. Anyone can use your credit or debit card to get money from an ATM (automated teller machine or "cashpoint") if they know just four numbers! 

In future, it will be much more common to have to confirm your identity with biometric information: either your fingerprint, a scan of the iris or retina in your eye, or a scan of your face. Already, some laptop computers have built-in fingerprint recognition scanners to make them more secure. Soon we could be seeing these scanners on ATMs and cellphones in airport security scanners, on checkouts in grocery stores, and perhaps even replacing the keys in our automobiles!

Types of scanner

Photo- A typical optical fingerprint scanner—it's a bit like photocopying your hand or placing it on a computer scanner.

There are two main ways of scanning fingers. An optical scanner works by shining a bright light over your fingerprint and taking what is effectively a digital photograph. If you've ever photocopied your hand (ummm I have tried it and yes you can too ;-P ), you'll know exactly how this works. Instead of producing a dirty black photocopy, the image feeds into a computer scanner. 

The scanner uses a light-sensitive chip called a CCD (charge-coupled device) to produce a digital image. The computer analyses the image automatically, selecting just the fingerprint, and then uses sophisticated pattern-matching software to turn it into a code.

Another type of scanner, known as a capacitive scanner(used in phones and are faster methods of scanning), measures your finger electrically. When your finger rests on a surface, the ridges in your fingerprints touch the surface while the hollows between the ridges stand slightly clear of it. In other words, there are varying distances between each part of your finger and the surface below. A capacitive scanner builds up a picture of your fingerprint by measuring these distances. Scanners like this are a bit like the touchscreen on things like iPhones and iPads.

Few years before fingerprint scanners were awesome and rare and something hiFi . But now with all the new technology it has become common and we are using it for security purposes in our phones !!

Ahhhh that old days when I used to ask the tech guy to show me how does that fingerprint scanner worked at his office 

(Want to know more about touchscreen ?

View my earlier posts in this blog)

Solar Revolution

So I am back with my new post 

Been away from blogger for weeks ! Ahhh these studies ! Well okay back to the topic.

The hope for a "solar revolution" has been floating around for decades -- the idea that one day we'll all use free electricity from the sun. This is a seductive promise, because on a bright, sunny day, the sun's rays give off approximately 1,000 watts of energy per square meter of the planet's surface. If we could collect all of that energy, we could easily power our homes and offices for free.

I am pretty sure everyone had heard about a solar cell

A solar cell, also known as photovoltaic cell converts sunlight *directly* into electricy 

(That's cool, directly)

Some of you might know how does it produces electricity using solar light.

You've probably seen calculators with solar cells -- devices that never need batteries and in some cases, don't even have an off button. As long as there's enough light, they seem to work forever. You may also have seen larger solar panels, perhaps on emergency road signs, call boxes, buoys and even in parking lots to power the lights.

Basically, 

Current flows through the material to cancel the potential and this electricity is captured. An array of solar cells converts solar energy into a usable amount of direct current (DC) electricity.

Solar cells are even knows as photovoltaic cells !

Material ??

Photovoltaic cells are made of special materials called semiconductors such as silicon, which is currently used most commonly. Basically, when light strikes the cell, a certain portion of it is absorbed within the semiconductor material. This means that the energy of the absorbed light is transferred to the semiconductor. The energy knocks electrons loose, allowing them to flow freely.

Why silicon ?

Silicon is what is known as a semi-conductor, meaning that it shares some of the properties of metals and some of those of an electrical insulator, making it a key ingredient in solar cells. Let’s take a closer look at what happens when the sun shines onto a solar cell.

Sunlight is composed of miniscule particles called photons, which radiate from the sun. As these hit the silicon atoms of the solar cell, they transfer their energy to loose electrons, knocking them clean off the atoms. The photons could be compared to the white ball in a game of pool, which passes on its energy to the coloured balls it strikes.

Freeing up electrons is however only half the work of a solar cell: it then needs to herd these stray electrons into an electric current. This involves creating an electrical imbalance within the cell, which acts a bit like a slope down which the electrons will flow in the same direction.

Creating this imbalance is made possible by the internal organisation of silicon. Silicon atoms are arranged together in a tightly bound structure. By squeezing small quantities of other elements into this structure, two different types of silicon are created: n-type, which has spare electrons, and p-type, which is missing electrons, leaving ‘holes’ in their place. 

Solar cell is not only a way to convert sunlight to electricity !!!

One more famous way is Solar Thermal Energy !

Okay, I won't give a whole explanation on it 

But they basically convert solar heat or heat by the radiations of sun into electricity 

The thermal heat is concentrated at one place by using huge reflectors or partial reflecting solar pannels !!

The heat is used to boil water and then make steam and this steam is used to rotate dynamos to generate electricity !

(Ahhha partial reflecting solar pannels where both solar energy and solar thermal energy works)

Isn't that AWESOME !

So

I hope in the future !!

We descover more efficient (solar cells have an efficiency of only 3-6%) and cheaper ways to convert solar energy and storing it in form of electricity !!!!

 

Some ideas

This one is my favourite 

This one is awesome 

I am gonna make one of these !!

That's my dream 

NASA - two words~ Awesomeness Overloaded !!

So this is how our future gonna be 

Well we all will be dependent on sunlight in the near future 

That would be really great !

So join the Solar Revolution ! Now !!!!!

And ask others to join it too !

How does a microwave oven works ?

Microwave oven

I am pretty sure you have one !!

This box of metal changed and revolutionised the methods of cooking food !

We all know what a microwave is for, right? 

But do you know how it works ??

Okay so let's start 

Microwave ovens use radio waves at a specifically set frequency to agitate water molecules in food. As these water molecules get increasingly agitated they begin to vibrate at the atomic level and generate heat. 

(Well that's really cool, but it heats)

This heat is what actually cooks food in the oven. Because all particles in the food are vibrating and generating heat at the same time, food cooked in the microwave cooks much more swiftly than food cooked in a conventional oven where heat must slowly travel from the outside surface of the food inward.

The same radio waves that cook your food pass harmlessly through plastics, glass, and ceramics. It is this characteristic that keeps plastic plates from melting and glasses from exploding.(well now you know :P )

It is also this feature of microwaves that makes them so energy efficient; they heat only the food and nothing more.

Metals, on the other hand, reflect these radio waves, a characteristic very cleverly put to use in the walls of the microwave such that no waves escape and cook anyone in the kitchen!

Wait where the waves come from ???

A magnetron

All of the waves discussed so far are created inside a device called a magnetron. The magnetron pulls electrons (tiny negatively charged particles) off a fine heated wire and then uses magnets to rotate them around inside a vacuum (a space void of any other particles). As these electrons swirl around and around they generate radio waves that are then sent into the oven to cook food.

Now the next part is more interesting !!

Magnetron technology was not invented with the intention of giving the world a quick way to heat food. It was actually first fully developed for military radar systems. The switch from enemy detection to cooking came one day in 1946 when a radar system engineer named Percy Spencer was testing a new magnetron. He felt a strange tingling sensation and suddenly noticed that the candy bar in his pocket had melted. He then placed popcorn, eggs and other foods in front of the device and they all cooked - actually the egg exploded all over his friend's face! Needless to say culinary history was made. 

So a microwave oven has a magnetron Which produces microwaves 

These microwaves heat up or increase the kinetic energy of everything that has moisture in it and this this helps us to heat our food and cook it !

(Well that's cool, but remember it heats :)  )

how do fiber optic cables work ?

Fiver optics ?

You have heard of them ?

Yes you must have !

So here's a full guide about fiber optic cables !

Fiber optic cables are replacing copper wiring to increase the speed of digital information transmission. These cables are bundles of extremely pure glass threads that have been coated in two layers of reflective plastic. A light source -- typically a laser -- switches on and off rapidly at one end of the cable to transmit digital data. The light travels through the glass strands and continuously reflects off of the inside of the mirrored plastic coatings in a process known as total internal reflection. Systems based on fiber optics can transmit billions of bits of data per second, and they can even carry multiple signals along the same fiber by using lasers of different colors.

Fiber optics (optical fibers) are long, thin strands of very pure glass about the diameter of a human hair. They are arranged in bundles called optical cables and used to transmit light signals over long distances.

If you look closely at a single optical fiber, you will see that it has the following parts:

• Core - Thin glass center of the fiber where the light travels
• Cladding - Outer optical material surrounding the core that reflects the light back into the core
• Buffer coating - Plastic coating that protects the fiber from damage and moisture

Hundreds or thousands of these optical fibers are arranged in bundles in optical cables. The bundles are protected by the cable's outer covering, called a jacket.

Optical fibers come in two types:

• Single-mode fibers
• Multi-mode fibers
• Over the last 20 years or so, fiber optic lines have taken over and transformed the long distance telephone industry. Optical fibers are also a huge part of making the Internet available around the world. 
• To understand how a fiber optic cable works, imagine an immensely long drinking straw or flexible plastic pipe. For example, imagine a pipe that is several miles long. Now imagine that the inside surface of the pipe has been coated with a perfect mirror. Now imagine that you are looking into one end of the pipe. Several miles away at the other end, a friend turns on a flashlight and shines it into the pipe. Because the interior of the pipe is a perfect mirror, the flashlight's light will reflect off the sides of the pipe (even though the pipe may curve and twist) and you will see it at the other end. If your friend were to turn the flashlight on and off in a morse code fashion, your friend could communicate with you through the pipe. That is the essence of a fiber optic cable.
  Making a cable out of a mirrored tube would work, but it would be bulky and it would also be hard to coat the interior of the tube with a perfect mirror. A real fiber optic cable is therefore made out of glass. The glass is incredibly pure so that, even though it is several miles long, light can still make it through (imagine glass so transparent that a window several miles thick still looks clear). The glass is drawn into a very thin strand, with a thickness comparable to that of a human hair. The glass strand is then coated in two layers of plastic.
  
  By coating the glass in plastic, you get the equivalent of a mirror around the glass strand. This mirror creates total internal reflection, just like a perfect mirror coating on the inside of a tube does. You can experience this sort of reflection with a flashlight and a window in a dark room. If you direct the flashlight through the window at a 90 degree angle, it passes straight through the glass. However, if you shine the flashlight at a very shallow angle (nearly parallel to the glass), the glass will act as a mirror and you will see the beam reflect off the window and hit the wall inside the room. Light traveling through the fiber bounces at shallow angles like this and stays completely within the fiber.
  Okay so here how it transmits bits and bytes 
  So there is a laser at one end of the optic and at another end there is a sensor, think of the laser is turned on then it represents a bit (1) for the sensor and of it is turned off another(0) this turn on and turn off are done several billion times in a minute to transfer the bits !!and then these bits are transformed into codes and machine language etc
  Modern fiber optic cables can carry a signal quite a distance -- perhaps 60 miles (100 km). On a long distance line, there is an equipment hut every 40 to 60 miles. The hut contains equipment that picks up and retransmits the signal down the next segment at full strength.
  
  

How does a microphone works?

The Basics

Microphones are a type of transducer - a device which converts energy from one form to another. Microphones convert acoustical energy (sound waves) into electrical energy (the audio signal).

Different types of microphone have different ways of converting energy but they all share one thing in common: The diaphragm. This is a thin piece of material (such as paper, plastic or aluminium) which vibrates when it is struck by sound waves. In a typical hand-held mic like the one below, the diaphragm is located in the head of the microphone.

Most microphones today use electromagnetic induction (dynamic microphone), capacitance change (condenser microphone) or piezoelectric generation to produce an electrical signal from air pressure variations. Microphones typically need to be connected to a preamplifier before the signal can be amplified with an audio power amplifier or recorded.

Types of Microphone

There are a number of different types of microphone in common use. The differences can be divided into two areas:

(1) The type of conversion technology they use

This refers to the technical method the mic uses to convert sound into electricity. The most common technologies are dynamic, condenser, ribbon and crystal. Each has advantages and disadvantages, and each is generally more suited to certain types of application. The following pages will provide details.

(2) The type of application they are designed for

Some mics are designed for general use and can be used effectively in many different situations. Others are very specialised and are only really useful for their intended purpose. Characteristics to look for include directional properties, frequency response and impedance

Electronic symbol for a microphone

Dynamic Microphones

Dynamic microphones are versatile and ideal for general-purpose use. They use a simple design with few moving parts. They are relatively sturdy and resilient to rough handling. They are also better suited to handling high volume levels, such as from certain musical instruments or amplifiers. They have no internal amplifier and do not require batteries or external power.

How Dynamic Microphones Work

As you may recall from your school science, when a magnet is moved near a coil of wire an electrical current is generated in the wire. Using this electromagnet principle, the dynamic microphone uses a wire coil and magnet to create the audio signal.

The diaphragm is attached to the coil. When the diaphragm vibrates in response to incoming sound waves, the coil moves backwards and forwards past the magnet. This creates a current in the coil which is channeled from the microphone along wires. A common configuration is shown below.

Earlier we mentioned that loudspeakers perform the opposite function of microphones by converting electrical energy into sound waves. This is demonstrated perfectly in the dynamic microphone which is basically a loudspeaker in reverse. When you see a cross-section of a speaker you'll see the similarity with the diagram above. If fact, some intercom systems use the speaker as a microphone. You can also demonstrate this effect by plugging a microphone into the headphone output of your stereo, although we don't recommend it! ;p

How does a touch screen works?

So everybody this blog is for you all who are using or have seen touch screens but don't know how does it works so here's a good explanation

But before it some facts 

1)HP Series 100 HP-150 ca. 1983, the earliest commercial touchscreen computer.

2)The IBM Simon Personal Communicator, ca. 1993, the first touchscreen phone.

Ok 

If we divide touch screens into categories there are many type of touch screens 

But right now I am just going to tell you all about the most common touch screens 

1)Resistive touchscreen

A resistive touchscreen panel comprises several layers, the most important of which are two thin, transparent electrically-resistive layers separated by a thin space. These layers face each other with a thin gap between. The top screen (the screen that is touched) has a coating on the underside surface of the screen. Just beneath it is a similar resistive layer on top of its substrate. One layer has conductive connections along its sides, the other along top and bottom. A voltage is applied to one layer, and sensed by the other. When an object, such as a fingertip or stylus tip, presses down onto the outer surface, the two layers touch to become connected at that point: The panel then behaves as a pair of voltage dividers, one axis at a time. By rapidly switching between each layer, the position of a pressure on the screen can be read.
Resistive touch is used in restaurants, factories and hospitals due to its high resistance to liquids and contaminants. A major benefit of resistive touch technology is its low cost. Additionally, as only sufficient pressure is necessary for the touch to be sensed, they may be used with gloves on, or by using anything rigid as a finger/stylus substitute.

As shown above a resistive touchscreen 

2)Capacitive Touchscreen

A capacitive touchscreen panel consists of an insulator such as glass, coated with a transparent conductor such as indium tin oxide (ITO). As the human body is also an electrical conductor, touching the surface of the screen results in a distortion of the screen's electrostatic field, measurable as a change in capacitance. Different technologies may be used to determine the location of the touch. The location is then sent to the controller for processing.

Unlike a resistive touch screen, one cannot use a capacitive touchscreen through most types of electrically insulating material, such as gloves. This disadvantage especially affects usability in consumer electronics, such as touch tablet PCs and capacitive smartphones in cold weather. It can be overcome with a special capacitive stylus, or a special-application glove with an embroidered patch of conductive thread passing through it and contacting the user's fingertip.

A mobile touch screen

How does a digital camera works?

All you need to know about -A digital camera
Let's start from beginning

  The digital camera is one of the most remarkable instances of this shift because it is so truly different from its predecessor. Conventional cameras depend entirely on chemical and mechanical processes -- you don't even need electricity to operate them. On the other hand, all digital cameras have a built-in computer, and all of them record images electronically.

So here's one important fact !

Everything you are watching on your screen right now !

Is an illusion 

Yes , 

I am not kidding 

Everything here is just some million pixels working in a synchronised manner to produce the illusion of letters and '        '(Spaces) !

Hehehehe 

This is how you view everything in this Mordern world ! On screens !

Pixels, Pixels everywhere !!!

For more information view the last image below!

So digital camera is a great innovation or I may say invention by Steven Sasson

Now back to the working 

Let's say you want to take a picture and e mail it to a friend. To do this, you need the image to be represented in the language that computers recognize -- bits and bytes

Essentially, a digital image is just a long string of 1s and 0s that represent all the tiny colored dots -- or pixels -- that collectively make up the image. (For information on sampling and digital representations of data, see this explination of the digitization of sound waves. Digitizing light waves works in a similar way.)

And 

At its most basic level, this is all there is to a digital camera. Just like a conventinal camer , it has a series of lenses that focus light to create an image of a scene. But instead of focusing this light onto a piece of film, it focuses it onto a semiconductor device that records light electronically. A computer then breaks this electronic information down into digital data. All the fun and interesting features of digital cameras come as a direct result of this process.

Now

Each photosite on a CCD or CMOS chip is composed of a light-sensitive area made of crystal silicon in a photodiode which absorbs photons and releases electrons through the photoelectric effect. The electrons are stored in a well as an electrical charge that is accumulated over the length of the exposure. The charge that is generated is proportional to the number of photons that hit the sensor.

This electric charge is then transferred and converted to an analog voltage that is amplified and then sent to an Analog to Digital Converter where it is digitized (turned into a number).

This diagram  may further help you —

Photons from the sky are gathered by a telescope and focused on the sensor of a digital camera where photo-electrons are created, stored during an exposure, and finally digitized and turned into numbers that we work with on a computer.

Digital cameras sample light from our world, or outer space, spatially, tonally and by time. Spatial sampling means the angle of view that the camera sees is broken down into the rectangular grid of pixels. Tonal sampling means the continuously varying tones of brightness in nature are broken down into individual discrete steps of tone. If there are enough samples, both spatially and tonally, we perceive it as faithful representation of the original scene. Time sampling means we make an exposure of a given duration.

Our eyes also sample the world in a way that can be thought of as a "time exposure", usually on a relatively short basis of a few tenths of a second when the light levels are high as in the daytime. Under low light conditions, the eye's exposure, or integration time can increase to several seconds. This is why we can see more details through a telescope if we stare at a faint object for a period of time.

A digitized image is made up of a grid of pixels which are represented by numbers. The numbers specify the pixel's location in the grid, and the brightness of the red, green and blue color channels.