Plasma Display

What is it?

A type of display technology well suited to making large, flat screen displays. Plasma screens are now very popular in large televisions, having made cathode ray tubes largely obsolete.

The technology was invented in the 1960's but it is only recently that full colour screens have become practical.

What is a Plasma?

'Plasma' is an electrically charged gas that gives off light (the 'light' might be ultraviolet and so is invisible to humans - but there are ways around that)

Factoid: Sometimes a plasma is said to be the fourth state of matter after Solid, Liquid and Gas.

A lightning bolt is a huge example of a plasma being created. An electric current flows from the clouds down to the ground and as it does so, the air molecules are ripped apart by the sheer amount of energy flowing, so forming a plasma. When they come back together again, light is given off, which is why you see a lightning flash.

A plasma display makes use of this effect (although much less dramatically!).

How does it work?

One picture element (sub-pixel) of the display is made up of a tiny hollow glass cube/cell filled with a noble gas such as Xenon and Neon. An electric current is made to flow through the gas which creates a plasma. The glass on the front of the cube is coated with a special material called a 'phosphor' that gives off a coloured light when struck by particles (photons) coming out of the plasma.

The sub-pixels are arranged in a group of Red, Green and Blue very close to one another to form a single 'pixel'. When they each shine with different intensity, your eye combines the Red, Green and Blue light so you sense a different colour. With Red Green and Blue you can produce the illusion of any colour including white. Black is simply all the element being off.

Do they wear out?

Yes eventually, just like a fluorescent tube. It is estimated they last about 60,000 hours or about 25 years in heavy use.

Why large displays rather than small ones?

The gas-filled glass cubes need to be certain size to work well and this lends itself well to large displays, as each pixel can be larger. Trying to make even tinier cubes for small displays is much more expensive and difficult.

How does Plasma compare to other technologies?

Compared to a Cathode Ray Tube (CRT)

• It is much thinner
• It is much lighter for large screens
• Easier to make into large screens.

Compared to a Liquid Crystal Display

• It is not as suitable for small displays
• It uses more power
• It has a faster response, good for fast moving images
• It is brighter
• It has higher contrast (difference between black and white)
• It has a better 'black', which is good for watching movies.

And the future?

It is all down to economics.

Makers of television and display screens have to decide what is the most economic technology to use for a given sized screen.

At the moment Plasma has the edge over Liquid Crystal for sizes above 36 inches or so. But the developers of LCD technology are fighting back, making their systems lighter, faster and cheaper so perhaps Plasma will be replaced by LCD technology in the future.

What is ........ RFID?

What is it?

Is an abbreviation for Radio Frequency Identification.

This is a term used to describe a type of wireless technology used to identify objects, animals (or people).

What does it look like?

There are two parts to the system.

1. The tag.
The simplest version is a tiny microchip that contains a code identifying the thing to which it is attached / glued to.

The microchip is often connected to a flat spiral aerial that allows it to work by radio signals.

2. The Reader.
This machine sends a radio signal to the tag asking for its code. The tag senses the request and sends back its unique code. The reader can then connect to a computer or database and uses the code to identify what the object is (or the identity of the person the tag is attached to).

The system works over a foot or so, which is fine when the tags are guaranteed to be close to the reader.

The handy thing about the tag is that it needs no power at all - no battery needed. This is because the reader sends it enough radio power to turn on whilst it is being interrogated.

Are there other types of RFID?

Yes, the no-battery versions are great for cheap, non-critical tags as might be used in a book-sleeve or shirt package.

But if it is really important to have reliable identification then there are more expensive and larger battery-powered versions. These use higher radio power and so they transmit over a much greater distance (100's of metres).

These kind of tags are used for very expensive items such as military stores or toll booth systems where you will be charged for using a road or rail system.

Who uses it?

1. Businesses that want to keep track of their stock as it moves from one place to another.
For example, many parcel delivery companies now offer the ability for you to check where your parcel is as it is being delivered. They can do this by attaching an RFID tag on the parcel, then a reader at each main point of its journey keeps track of its progress.

2. Security systems that can sense the identity of the person wanting access to a restricted area.
The person wears an RFID tag, so when they approach a reader, it can request an identity check without the person having to do anything.

3. Anti-theft
Many shops use RFID to deter shop-lifting. Have you noticed some shops have some tall objects standing either side of the doors? You have to walk between them in order to leave the shop. This is part of an RFID system. Many of the more expensive items in the shop will have hidden RFID tags. If you try and walk out of the shop, the Readers either side will request the tag for its code - that code is checked against a database to see if it has been paid for yet. If not, the alarm sounds. Another reader is located beneath the desk by the till. As you pay, they slide the object over the reader to register it is as having been been paid for.

4. Passports.
Many countries, including the UK now use RFID tags inside passports. The tag not only identifies the person, but also stores a digital photograph and a record of their movement in and out of the country. In order to reduce the chance of someone 'skimming' that information, the passport contains a metal film to prevent them being read when closed.

Video News

See the BBC video news item on RFID here

What is ........ Virtual Reality?

What is it?

When many people think about the term 'virtual reality', they imagine a scene like the one on the right where somebody is wired up to a computer wearing an odd helmet and making weird movements in the air. However, there is a lot more to virtual reality and it has some incredibly practical uses, so read on.

'Virtual' reality means that the user is fully immersed in a world or artificial environment that the computer has generated.

As you walk around the virtual world your view changes in line with what you would expect in real life. Things get bigger as you walk towards them and smaller as you walk away. Also the direction of sounds move as you move around, once again giving you the impression of a real scene.

How does it work.

There a number of systems but they have some common features that include:-

1. A set of goggles that controls what your left and right eyes see. By providing slightly different views into each eye, your brain is fooled into thinking that the scene is 3D. Virtual chairs look solid and so on.

2. Other wearable input devices are used such as gloves that detect your finger movements. As you wiggle or tap your fingers on a virtual control then the computer carries out the command, such as turning on a virtual television.

3. Headphones to control what you hear.

The other part is a powerful computer that can create the graphics and sound in 'real time'. These images may be projected onto the walls and floor of the room. So you can walk around freely.

How good is it now?

It is good enough to physically affect someone in it. For example, when they may be shown a scary situation such as a fire appearing in front of them, their heart will beat faster and breathing speed up.

This shows that the VR is convincing enough to cause an effect. Which is the whole point of VR really.

The graphics are "OK" but not realistic by any means. But the odd thing is that people react strongly even in a low-res scene. It is the situation that matters, not what it looks like.

Is it a game?

Not really, a game is made for entertainment and excitement. But VR is used for more serious purposes (although you could imagine a VR game world).

For example, architects have used basic VR systems for a while to allow clients to 'walk' around their new design.

VR is being used by researchers / therapists to help patients overcome phobias and anxieties. The person is placed in a VR scene where they experience a tame, controlled version of what they are afraid of. For example, someone might be painfully shy, so the therapist may put them in a busy virtual place where 'people' come up to them and try and talk (these avatars would be controlled by the therapy team as well). Slowly the person becomes used to the situation and can relax.

Some soldiers have suffered distress on the battlefield and need help to cope and so VR is being used to take them through a carefully controlled version of what gave them a problem.

Some doctors and dentists are using virtual reality with their patients. People with severe burns suffer from incredible pain when their wounds need redressing. Researchers have found that by allowing them to use virtual reality during treatment, their awareness of pain was greatly reduced.

Another important use of VR is training for dangerous situations where it is unethical or impractical to practice the real thing. For example a large fire on an oil rig would never be set up, but in a VR system that is perfectly possible and so workers can practice the emergency in a safe environment.

See the medical burns story http://arstechnica.com/news.ars/post/20081114-snowy-game-vr-goggles-take-burn-victims-minds-off-of-pain.html

What are the downsides to VR?

If you have ever been sea-sick or travel-sick then a poor VR set-up might make you feel the same way. This is because you are seeing one thing but your brain is getting a different story from your sense of balance. When what you see and what you feel do not match (like on a ship) then you may feel ill.

Another downside is that VR is very complicated and so needs expensive equipment to set up and run. So proper VR games are a long way away.

And the future?

Display technology will continue to improve and so VR will become ever more realistic visually. Sufficient computing power is here already for that. But it is the input and output devices that will have to improve. For example researchers are working on better devices to control the sense of touch and smell.

In the future it may be practical to use VR to safely fly a remote control aircraft as if the pilot was really in the machine. For example flying the remote-control aircraft into a hurricane or volcanic eruption to take scientific readings. Sensors on the real aircraft would allow the pilot to see, hear and even feel what is going on in the virtual reality version but without any danger to life and limb.

It could also be applied to remote controlled submarines that explore the sea looking for oil and mineral reserves or perhaps exploring other planets such as Mars and Titan in the far future.

What is .......... GPS?

What is it?

It stands for Global Positioning System.

GPS is a satellite based system that allows you to know your position anywhere on Earth.

Why was it developed?

It was developed for the USA military to allow soldiers to know exactly where they were regardless of whether it was day or night, deep in a jungle or in a barren desert. It is still owned and controlled by the USA military.

How does it work?

It makes use of a method called 'triangulation'. You often see this being used in action films where the villains are being tracked on a map as they move about.

Tracking a villain.... Imagine that you have a machine that can tell you the distance between yourself and the villain. That's all it can tell you - just the distance. So you draw a circle with you as the centre. The villain is somewhere on that circled line.

Now a colleague also lets you know how far the villain is away from them. So draw another circle around him. So you know that the villain must be at point A or Point B. But which one?

So you need a third colleague to let you know their distance and this pinpoints the villain's location. Hence the word 'triangulation' - three measurements can pinpoint a location.

So how do satellites help?

Well, if you can measure the distance between yourself and at least three satellites (preferably four), then your location on Earth can be worked out. How accurately you can pinpoint your location depends on how accurately you can measure the distances to the satellites. Commercial Sat-Nav systems can measure to within a few metres.

Where is GPS used?

It now has a vast number of uses. For example

* In cars - satellite navigation systems are becoming common

* Lorry Fleets: Used to track and locate vehicles

* Military - its original purpose, to help soldiers in the field.

* Shipping - to navigate the seas.

* Farming - to track crop growth and fertilizer application.

* Leisure - Mountaineers, hikers, explorers.

* Crime - offenders can now be 'tagged' with a GPS device to make sure they stay where they should.

What is the future?

GPS has become so widespread in everyday life, that some regions want to control their own GPS for their citizens. For example the European Union have been developing a similar system called Galileo.

What is Bluetooth?

What is it?

Bluetooth is a type of radio communication and networking protocol combined.

Why was it developed?

It was developed so devices close to one another could exchange data.

By close, we mean within about 10 metres of one another even if there is a wall in-between.

Advantages of Bluetooth

One advantage with Bluetooth working within a short range is that it only needs a tiny amount of radio power to work, less than a thousandth' of a Watt. ( A torch light uses about 1 Watt to light the bulb) so you can see this is a tiny amount of power. This means it is ideal for battery operated devices such as mobile phones.

Another advantage of Bluetooth is that it is completely automatic - every Bluetooth enabled device will sense the presence of another device within range. They can do this because they share a 'network protocol' that allows them to share data.

Another clever thing about the protocol is that it can reduce interference from other Bluetooth devices that are also exchanging data nearby. For example if Sam's mobile is exchanging data with Tom's mobile this will not interfere with Sarah's mobile also exchanging data with Mary's mobile nearby.

Another very common way of sending data over a short distance is to use Infra-Red. This is used widely in TV remote controls. The disadvantage of Infra-Red over Bluetooth is that you must point the control directly at the device.

Examples of how it is used.

A Bluetooth enabled phone will detect phones nearby and provide you with a list of usernames. You can then send a message, photograph or movie sitting on your phone to any of the usernames. They, of course, have to accept the offer but the rest of it is automatic.

Another common use of Bluetooth is 'hand-free' operation of mobiles in the car. You wear a bluetooth headset that senses your mobile nearby. This allows you to talk using the mobile, but most importantly, keeping your hands on the steering wheel!

Bluetooth is also used to exchange files between a PDA and a desktop computer - great for keeping your diary and work in synch.

Trivia Facts

Fact 1: Harold Blatand
"Bluetooth" refers to Harold Blatand, the 10th-Century Danish king who brought together the Danes and Norwegians.


Fact 2: Andretti Green Racing Team
The famous Andretti Green Racing team stays connected while racing using Bluetooth devices.


Fact 3: One billion devices
By the end of 2006 the number of Bluetooth devices in circulation will rise to more than one billion.


Fact 4: Bluetooth in the car
It is predicted that by the year 2012 one-third of all new cars will have built-in Bluetooth connections.


Fact 5: Bluetooth enabled medical equipment
Bluetooth enabled medical equipment is being employed by an increasing number of hospitals around the world, in an effort to improve patient care.


Fact 6: Digital images sent over Bluetooth technology
You can view digital pictures on your television by sending images from laptops or mobile phones over a Bluetooth connection to a media viewer.


Fact 7: Printing with Bluetooth technology
You can send files from a computer to a printer wirelessly using Bluetooth technology.


Fact 8: Multi-point pairing
Multi-point pairing enables you to simultaneously connect two Bluetooth enabled devices (e.g. a phone can be connected to both a PC & a pair of headphones).

Source of factoids: Thanks to Motorola.