Night Vision Gyaan

What is it?

A high-precision optical instrument which makes use of light amplification technique to in order to operate in little or no light environments.

Who dunnit?

Night vision devices or NVDs were first developed by AEG, a German Electric company in 1935 for the German military during World War II. USA Government pitched in around the same time to develop its own version to aid its military. This is believed to be the “GEN 0” (Generation 0) period in night vision technology which utilised the infrared light source to develop active devices.

“GEN I” era during the mid 1960’s saw the use of ambient light to develop rather passive units with image intensifiers producing a light amplification of 1000x.

Later in the 1970’s the “GEN II” devices improved the passive devices to work in much low ambient light like moonless nights with a 20 times improved magnification capability.

“GEN III” devices developed in the 1990’s brought in much better resolution and sensitivity and magnification factor increased by a factor of 50 than the original “GEN I” devices.

The present “GEN III+” and “GEN IV” technology brings in much better performance in low as well as high-level light environment. Additionally it provides an improved signal to noise ratio along with seamless adjustment to fluctuating light conditions.

Technology

Night vision technology works in three different ways:

1) Thermal Imaging: Generally we are able to see the visible portion of what the spectrum of light offers but “Thermal imaging” or “Thermography”, is the means by which we can see the infrared portion of the spectrum. This technology in particular exploits the upper portion (3 microns – 30 microns in wavelength) of the infrared light or the “Thermal-IR” band. As we know that light is emitted (in the form of photons) when the electrons in an object are excited to high-energy states created by heating. Thermal-IR band however, accounts for the invisible light (to human eye) emitted by objects owing to their natural heat.

The main tool for this task is a thermographic camera which can pick up electromagnetic waves between 0.9 – 14 microns. The infrared light emitted by objects in view is captured by special lens, scanned using detector elements to create a detailed temperature pattern called “thermogram” and converted to electrical impulses which are finally processed for display in various colours depending upon radiation intensity.

Thermal-imaging devices can again be of two types:-

• Un-cooled: The most common type in which the detector elements can operate in room temperature. It is completely quiet, activates quickly and has a built-in battery.
• Cryogenically cooled: They are typically housed in a vacuum-sealed case and cryogenically coo below zero degrees. They have incredible resolution and sensitivity that result from cooling the elements and hence can sense a temperature difference of the order of 0.1 C from more than 300 m away.

2) Image intensifiers: This method of night vision amplifies the available ambient light to achieve better vision. The device consists of a conventional lens which sends the captured infrared light to an image-intensifier tube. The tube consists of a photocathode which converts the photons into electrons. These electrons further release thousands of other electrons when made to accelerate across micro-channels in a tiny glass disc known as “Microchannel Plate” (MCP) using high voltage. Finally these electrons hit a screen coated with phosphors while maintaining their position in relation to the channel it passed through and hence being in alignment with the original photons. Further the phosphors release photons and create a green image on the screen. This green image is viewed using an ocular lens which allows us to magnify and focus the image.

All image intensifiers operate in the above fashion. Technological differences over the past 40 years have resulted in substantial improvement to the performance of these devices which have categorized them into generations as mentioned above.

3) Active illumination: Active illumination technologies work on the principle of coupling imaging intensification technology with an active source of illumination in the near infrared (NIR) or shortwave infrared (SWIR) band. Examples of such technologies include inexpensive low light cameras.

Applications

Modern Night vision devices work surprisingly very effectively even in complete darkness. From being “GEN 0” devices that only aided the military on the battlefield, they have travelled a long distance of evolution to be used in various arenas like surveillance, wildlife observation, security, navigation, law-enforcement and entertainment. It is still used extensively by the military for that purpose, as well as for navigation, surveillance and targeting. Police and security often use both thermal-imaging and image-enhancement technology, particularly for surveillance. Wildlife photographers and nature enthusiasts use NVDs to maneuver through the woods at night. Detectives and private investigators depend heavily on night vision to track people.. Many businesses have permanently-mounted cameras equipped with night vision to monitor the surroundings.

NVDs are typically used in the form of Scopes (or monoculars), Goggles (or binoculars) and cameras. Infact now days many of the new camcorders have a built-in night vision feature like the Sony DCR-TRV17.

It is interesting to note that an animal's ability to see in low light levels may be similar to what humans see when using first- or perhaps second-generation image intensifiers !!

Bluetooth Gyaan

What is it?

A short-range, non-line-of-sight wireless technology operating over a typical distance of around 30 feet and geared towards easy data exchange between fixed and mobile electronic devices.

Who dunnit?

Developed by Jaap Haartsen and Sven Mattisson from Ericsson in 1994 as an alternative to wired connections in common products like phones and headsets or computers, keyboards and mice.

Several leading companies like Ericsson, Microsoft, Intel, Motorola, Nokia, Toshiba etc formed the “Special Interest Group” (SIG) codenamed “Bluetooth” in May, 1998 to promote the technology as a way to make their products compatible.

SIG initiated the “Bluetooth Innovation World Cup” in June, 2009 for three years to encourage new innovations and ideas in various domains utilizing Bluetooth applications.

Interestingly, the name “Bluetooth” derives its origin from 10th century Danish king, Harald Blatand (or Harold Bluetooth in English) who was instrumental in uniting hostile tribes just as Bluetooth technology is developed to allow collaboration between differing industries!!

Technology

Any wireless technology employs a modulation scheme to transmit the desired signal by piggybacking it on a high-frequency carrier wave. The modulation scheme adopted by Bluetooth is “Adaptive Frequency-hopping Spread Spectrum” (AFH).

Generally speaking, “Frequency-hopping Spread Spectrum” technique uses a carrier wave that hops in a random but predictable sequence known to both transmitter and receiver. In Bluetooth these random values may be typically 79 in number hopping as frequently as 1600 times per second to avoid radio frequency interference with similar devices. AFH furthermore improves resistance to interference by avoiding crowded or unwanted frequencies in the hopping sequence.

Bluetooth operates between 2.402 GHz -2.480 GHz in the unlicensed ISM (Industrial-Scientific-Medical) frequency band and is primarily designed for low power consumption typically around 1 milliwatt. It provides three different “Classes” of service depending on the range of communication varying between 1, 10 and 100 meters. Also it is available in different versions with the “Enhanced Data Rate (EDR) 2.0” version offering as high as 3 Mbps data capacity.

Bluetooth operates over a small area known as Personal Area Network (PAN) or Piconet. It is a packet-based protocol following “Master-Slave” architecture where a Master can communicate with up to 7 slaves in the Piconet; all devices sharing the Master’s clock ticking at 312.5 µs slot intervals. Packets may be 1, 3 or 5 slots long but the master always transmits in even slots while the slave in odd slots. Transmission can however be either half-duplex or full-duplex but uniquely recognized in the Piconet.

Bluetooth doesn't require you to think about setting up a connection or to push any buttons. When two or more Bluetooth devices enter the desired range, they begin to communicate automatically in order to setup the Piconet. They take care of the entire setup and discovery process, and you can go about your business.

In order for one Bluetooth device to connect to another, both devices must share at least one common among the many Bluetooth profiles. For example, a Bluetooth enabled printer is going to support the Basic Printing Profile but a PDA with Bluetooth technology supports several profiles, such as the Synchronization Profile, LAN Access Profile, File Transfer Profile and others. According to SIG such profiles must include some essential information like recommended user interface formats and Bluetooth protocol stack.

Bluetooth offers several security modes, and device manufacturers determine which mode to include in the gadget. Still some recent issues like “Bluejacking”, “Bluebugging”,"Bluesnarfing" and “Car Whisperer” have cropped up which are dealt with firmware upgrades from manufacturers.

Applications

Bluetooth has now become a commonplace technology in almost all electronic gadgets these days. The typical symbol signifying that Bluetooth is enabled can be found in all mobiles and laptops allowing us to use hands-free headset and wireless mouse, keyboard, headphones etc. Since its inception it has continued to mature as a universal standard and has allowed new connections which weren’t possible using wires earlier, like connecting a mobile phone to car stereo, or printing a picture directly from your camera phone.

Microsoft, Apple and Linux have supported Bluetooth stacks since many years. Nowdays, even if notebooks or laptops don't offer embedded Bluetooth chips, there is choice of using Bluetooth dongles for plug-and-play service.

Today Bluetooth is even embedded in products like PlayStation, modems, high-end watches etc. As more and more devices begin to exploit the advantages of Bluetooth, consumer electronics manufacturers will be increasingly eager to make their products compatible. With continuous effort of around 13,000 members in the SIG, without doubt Bluetooth is here to stay.

Check out a list of top 5 Bluetooth gadgets:
http://electronics.howstuffworks.com/bluetooth-gadgets.htm

Automatic Gear-shifting Gyaan

What is it?

A type of motor vehicle transmission that can automatically change gear ratios for a moving vehicle, freeing the driver from having to shift gears manually.

Who dunnit?

It’s been around for over a century!!

It was first developed in 1904 by Boston’s Sturtevant brothers for horseless carriages but had major problems.

In 1934, both REO and General Motors developed semi-automatic transmissions that were less difficult to operate than a fully manual unit.

Later developments in automatic gearbox and fluid coupling technology eventually led to General Motors’ “Hydra-Matic”, the world's first mass-produced automatic transmission in 1939.

The automatic transmission that resembles what’s on today’s cars got its start in 1948 by General Motor’s Buick Motor Division as two-speed “Dynaflow”.

By the late 1960s, the fluid-coupling transmissions gave way to three-speed torque converters.

In the 80’s, overdrive transmissions with four forward speeds and a lockup feature were introduced that increased fuel efficiency. Transaxles and CVTs (continuously variable transmissions) are recent developments.

Technology

To understand the concept of automatic transmission it makes sense to understand manual transmission first.

A standard transmission or manual transmission is the traditional type of transmission used in automobiles. It consists of a series of heliacal gears, synchro rings, roller bearings, counter shafts and gear selectors. The main clutch assembly is used to engage and disengage the engine from the transmission. Heliacal cut gears are used to select the ratio desired while the selector fork moves the gears from one to another by using the gearshift knob. Synchro rings are used to slow the gear to a stop before it is engaged to avoid gear grinding. The counter shaft holds the gears in place and against the main input and output shaft. A stick shift transmission has no torque converter so there is no need for a transmission cooler. A stick shift transmission needs a simple fluid change for proper service.

Besides standard transmission, there are automatic transmissions mechanisms which can be classified into three basic types:

1. Hydraulic Automatic Transmission: In a hydraulic automatic transmission, instead of a clutch, a fluid coupling or “torque converter” is used to connect the transmission and engine hydraulically. Also a combination of brake bands and clutch packs control the planetary gearset which selects the gear ratio. The key difference from a standard transmission is that the manual transmission locks and unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic transmission; the same set of gears produces all of the different gear ratios. Such systems are usually less energy efficient than manual transmissions owing to pumping losses during torque conversion but might provide more on-road acceleration in turbocharged diesel applications. This technique has been used by famous manufacturers like Ford, Honda, Nissan, General Motors, Volkswagen etc.

2. Continuously Variable Transmission: A continuously variable transmission system can steplessly alter through infinite gear ratios by varying the diameter of a pair of belt or chain-linked pulleys, wheels or cones. Some CVTs use a hydrostatic drive consisting of a variable displacement pump and a hydraulic motor to transmit power without gears. CVT designs are usually as fuel efficient as manual transmissions in city driving, as it enables the engine to run at its most efficient revolutions per minute (RPM) for a range of vehicle speeds. It is being deployed in latest hybrid cars by manufacturers like Nissan, Toyota, Honda, Ford, Suzuki etc.

3. Semi-automatic Transmission: If there is a provision to select a gear ratio manually in automatic transmissions, the system is called a semi-automatic transmission. It uses electronic sensors, pneumatics, processors and actuators to execute gear shifts on the command of the driver. This removes the need for a clutch pedal, since the clutch itself is actuated by electronic equipment which can synchronize the timing and torque required to make gear shifts quick and smooth. It has been deployed for racing and conventional uses by manufacturers like Mercedes-Benz, Chrysler, Volkswagen, Renault, Honda, Ferrari etc.

Applications

Automatic cars are more expensive, tend to wear down faster, and are more complicated than manual transmissions but are far better convenient in city traffic. Think about avoiding all the manual effort of gear changing every second minute!

Although they are less popular in other parts of the world including India, most cars sold in America since the 1950s have been automatics. The main reasons for less popularity are:

• Standard transmissions are more efficient and less expensive to produce than automatic transmissions.
• Standard transmissions are generally stronger than automatic transmissions and off road vehicles take advantage of a direct gear selection so they can withstand rough conditions.
• Manual transmission requires less active cooling because less power is wasted.

Check out a list of latest automatic transmission cars in India like Hyundai i10 and Maruti A-Star:

http://www.cardekho.com/cars-search/automatic-transmission-cars-in-india-2010

With automatic transmission becoming more energy efficient like cars with manul transmission, the trend is surely set to prevail on Indian roads in the near future.

3D Television Gyaan

What is it?

A television technology which despite creating two dimensional images like any normal television, creates an illusion of realistic three dimensions with or without the use of special glasses.

Who dunnit?

3D television might be the latest buzzword in consumer electronics these days but 3D concept in itself is a technology which dates back to the beginning of photography!!
In 1844, Scottish inventor David Brewster introduced the Stereoscope, a device that could take photographic pictures in 3D.
Stereoscopic 3D television was demonstrated for the first time on August 10th, 1928 by John Logie Baird.
Major television manufacturers began developing 3D home television technology in 2009.

Technology

Basically 3D TV works by separating the left and right images and presenting them in a way that the brain merges them back together and interprets them as a 3D view of a scene. All of them use the same basic principle: they have to produce two separate, moving images and send one of them to the viewer's left eye and the other to the right. To give the proper illusion of 3D, the left eye's image mustn't be seen by the right eye and vice versa.

There are two basic techniques:

i) Using Glasses

This technique can again be designed to project stereoscopic images in three different ways:-

1. Anaglyphic : It involves wearing passive eyeglasses with one red and one cyan colored lenses, also known as anaglyph glasses. The red lens is a light filter that allows only red light to pass through, while the cyan lens allows any light except red. The point is simply that each eye isn't being allowed to see parts of the image that are being viewed by the other one, so each eye gets a slightly different picture of its own. While simple and inexpensive, this technique produces a relatively poor quality, monochrome picture and often makes viewers feel nauseous.

2. Polarizing : It involves wearing passive polarizing eyeglasses which capture two pictures that are projected from the screen using differently polarized light. The left lens receives only light vibrating in vertical plane while the right lens receives light vibrating in horizontal plane. The main drawback is that the TV set has to be fitted with polarizing filters as well, which bumps the cost up quite considerably.

3. Alternate-frame sequencing : The video signal of the TV stores an image meant for the left eye on its even field, and an image meant for the right eye on its odd field. The TV itself is synchronized with the active shutter glasses via infra-red or RF technology. The shutter glasses contain liquid crystal and a polarizing filter which is automatically applied with a slight current that makes it dark, as if a shutter was drawn (hence the name) upon receiving the synced signal. So at a time, only one eye is seeing one image. By viewing these two images from different orientations, a 3D image is built up by the viewer’s brain. Although the user experience is seamless, smooth and rich, due to the rapid drawing of ‘shutters’, lesser light reaches the eye, thus making the image seem darker than it is.

ii) Without using Glasses

The extra need to wear glasses has compelled manufacturers to devise some smart way of avoiding the same. Commercially termed as ‘Auto 3D’, this process allows for autostereoscopic displays. Examples of autostereoscopic displays include parallax barrier, lenticular, volumetric, electro-holographic, and light field displays. Currently most flat-panel solutions employ ‘lenticular lenses’ or ‘parallax barriers’. Let us discuss these two in detail:-

1.  Lenticular lenses : It uses lenticules, which are tiny cylindrical plastic lenses that bend images either to the left or the right.. These are pasted in an array on a transparent sheet, which is then stuck on the display surface of the LCD screen to deliver a magnified image. However, this technology requires a very specific ‘sweet spot’ for getting the 3D effect, and straying even a bit to either side will make the TV’s images seem distorted. Depending on the number of lenticules and the refresh rate of the screen, there can be multiple ‘sweet spots’.

2. Parallax barrier : It is a fine grating of liquid crystal placed in front of the screen, with slits in it that correspond to certain columns of pixels of the TFT screen. These positions are carved so as to transmit alternating images to each eye of the viewer, who is again sitting in an optimal ‘sweet spot’. When a slight voltage is applied to the parallax barrier, its slits direct light from each image slightly differently to the two eyes creating an illusion of depth and thus a 3D image in the brain.

Applications

3D viewing has always fascinated the world in the form of movies, sports and television broadcasts or 3D gaming.
Audiences first got a glimpse of a 3D movie way back in 1922 with the release of "The Power of Love" and off late with the release of “Avatar” it has got an entire new meaning.
Starting on June 11, 2010 ESPN launched a new channel, ‘ESPN 3D’, dedicated to 3D sports with up to 85 live events a year in 3D. The French Open this year was filmed in 3D (center court only) and broadcast live via ADSL and fiber to Orange subscribers throughout France in a dedicated Orange TV channel. Also 25 matches in the FIFA World Cup 2010 were broadcast in 3D.
Nintendo is implementing the Parallax Barrier 3D technology on their latest portable gaming console, the Nintendo 3DS.
Now with a range of 3D enabled television sets hitting the market, the power of 3D technology is sure to enter our homes and our lifestyles. All major manufacturers like Samsung, LG, Toshiba, Sony, and Panasonic are introducing 3D capabilities mostly in higher-end models. Most of them still use the conventional 3D viewing with active shutter glasses as providing 3D images without glasses to many users simultaneously is still a concern (Read the Philips WOWvx story). Sony and Samsung are releasing home-theater setups that can display 3D movies in full high-def glory using a combo of Blu-ray players, TVs and glasses.
Even though 3D viewing has been around for more than century in one form or another it really is still in its infancy and leaves a big hole in the wallet. We can expect more commercial 3D breakthroughs in the coming years as its popularity is on the rise again.

Android Smartphone Gyaan

What is it?

An Android OS based cellphone developed by Google which offers more advanced computing ability and sophisticated applications allowing features of mobile phones and handheld computers to be integrated into single device.

 

Who dunnit ?

It started in July 2005, with the acquisition of Android Inc., a mobile software development startup by Google.

In September 2007, Google filed several patents in the area of mobile telephony.

In November 2007, a consortium of several companies known as OHA (Open Handset Alliance) led by Google was established to promote open standards for mobile devices. It also unveiled Android, an open source mobile phone platform based on Linux kernel version 2.6.

It is interesting to note that development of smartphones by various companies dates back to 1992 most notable being the Symbian based Nokia Communicator in 1996, RIM based Blackberry in 2002 and the Apple OS based iPhone in 2007.

 

Technology

The software stack contains Java applications running on a Java based framework. The runtime includes Java core libraries on top of a proprietary virtual machine known as ‘Dalvik’ featuring JIT (just-in-time) compilation.

Middleware includes libraries written in C which accounts for the main firepower. The WebKit engine powers the Chrome Lite browser. The OpenGL ES 2.0 3D graphics API and SGL 2D graphics engine make up the graphics core. SQLite lightweight relational database provides efficient storage capability. 

 

                                       The Android Architecture

An Android phone can also run multiple applications at the same time in the background, making multitasking easier and the functionality of the phone more fluid than other cellphones.

Android OS has been available as open source mobile platform since October 2008 promoting mobile application development all over the world. Google has also promoted its growth by releasing an Android SDK (Software Development Kit) and App Inventor for developers along with a SIM and hardware unlocked Android Dev Phone for advanced developers. It also launched competitions like ‘Android Developer Challenge’ for promoting innovative applications.

 

 Applications

 For an end user, Android boasts of the following available smart features/applications besides the regular stuff available for most mobile phones:

• All possible connectivities including GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi, and WiMAX.
• Support for all possible audio/video/still media formats.
• Additional hardware support including touchscreens, GPS, accelerometers, gyroscopes, thermometers etc.
• Google applications like ‘Google Voice’, ‘Sky Map’, ‘MyMaps’, ‘Google Goggles’ and many others.
• Third party applications like ‘Shazam’, ‘Doodle Jump’, WeatherBug’ etc.
• Using the phone as a wireless/wired hotspot.

Analysis suggests that worldwide smartphone market share for Android stood at 3.5% by Q3 2009. Based on the popularity, Android promises to bring out many more amazing features in the forthcoming versions for the next generation smartphones.

And talking about versions the Android OS versions are really a yummy treat if you go by the names. Starting off with ‘Cupcake’ (version 1.5) the series includes ‘Donut’, ‘Éclair’ to the present ‘Froyo’ (version 2.2). Even the future versions named ‘Gingerbread’ and ‘Honeycomb’ promise to please a certain taste buds.

 Check out the latest list of Android based handsets available in the market:

 http://phandroid.com/phones/

 http://androidos.in/2010/01/price-list-android-phones-in-india/

 

Touchscreen Gyaan

What is it ?

A technology which allows commands to be issued on an electronic device by merely touching the user-interactive display on the screen.


Who dunnit ?

Pretty mature stuff. Existing for around 30 years!!

In 1970 a professor from the University of Kentucky, Dr. Sam Hurst, filed a patent for a "touch sensor", called the Elograph. The "Elograph" was not transparent like modern touch screens; however, it was a significant milestone in touch screen technology.
Patent : US3662105: Electrical Sensor Of Plane Coordinates

The first true touchscreen patent was filed by Dr. Hurst in 1972. Using his patented five-wire resistive technology, this patent would go on to be the most widely used form of touchscreen technology. In 1974, the first true touch screen incorporating a transparent surface came on the scene.
Patent : US3798370: Electrographic Sensor For Determining Planar Coordinates


Technology

Consists of three main components :-

i) A “Touch Sensor” which is a clear glass panel with a touch responsive surface. The sensor has an electric current passing across it. Touching the screen causes a voltage change. This allows determining the exact position or coordinates of the touch. A Touch Sensor can function in three major ways namely resistive, capacitive and Surface Acoustic Wave (SAW). However, there are other technologies like Dispersive Signal (DST), Infrared and Optical too.

a) Resistive: It consists of conductive and resistive metallic layers separated by spacers and a scratch-   resistant layer is placed on top of this whole setup. An electrical current runs through the two layers while the monitor is operational. When a user touches the screen, the two layers make contact in that exact spot to deliver the X and Y coordinates. It allows decent clarity allowing 75% light from the monitor.

b) Capacitive: It consists of a layer that stores electric charge placed on top of the monitor. When a user touches the panel, some of the capacitive charge gets dissipated to the user. This relative decrease in charge is measured using circuits at each corner of the monitor. This helps to pinpoint the exact coordinates of the human touch. It allows good clarity allowing 90% light from the monitor.

c) Surface Acoustic Wave: It consists of two transducers mounted at the edge of a glass overlay to emit ultrasonic sound waves along two sides. These waves are reflected across the surface of the glass and received by sensors. A finger or other soft tipped stylus absorbs some of the acoustic energy and the controller measures the amplitude change of the wave to determine touch location. It allows perfect clarity allowing almost 100% light from the monitor.

ii) A “Controller” which is small installable card to transmit touch information from the sensor to the OS. It can connect to a Serial or USB port on the PC running the OS.

iii) And ofcourse a “Software Driver” for successful installation of the controller peripheral. It allows for interpretation of touch event information by the OS.


Applications

Commercially, touch screen computers service a wide range of purposes. Most common public information booths such as information kiosks, customer self-service and various displays offer a way for almost anybody to access information with little or no experience using a computer. This is due to the fact that a touch screen interface allows the user to interact not with keyboard and mouse like a typical computer, but with tools they are most comfortable with-their fingers. The popularity of smart phones, PDAs, portable game consoles and many types of information appliances is driving the demand for, and acceptance of, touch screens. There are many pros and cons of the various touchscreen technologies based on which their deployment is considered. For e.g. highly durable and less expensive resistive technology is most often used in public ATMs and kiosks. Capacitive technology is being considered more for smart phones and mobile gaming devices due to their better clarity.

It is very likely to expect more innovative products applying the touch screen technology in the near future.