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Toner-print removal from paper would allow paper to be re-used instead of being recycled, incinerated or disposed of in landfill. This could significantly reduce the environmental impact of paper production and use. Previous work on the subject has explored the applicability of ultraviolet, visible and infrared (IR) lasers under nanosecond pulses for toner removal. This article expands on this work by testing a wider range of ultrafast and long-pulsed lasers. Results from 10 distinct laser set-ups are used to propose an operating window for the toner-removal process. Colour analysis under theL*a*b* colour space, scanning electron microscope examination and attenuated total reflectance–Fourier transform IR spectroscopy measurements of the outcome show that, with the right laser, it is possible to remove toner from paper to enable its re-use. Theoretical models to predict the laser ablation of toner are discussed, and, while imperfect, provide sufficient evidence to support a physical explanation of toner ablation.
Researchers at the University of Cambridge have developed what they call a laser ‘unprinter’ – a device that is able to remove toner ink from paper. A production model would allow businesses to reuse copier paper rather than sending it off for recycling, a process that is good for the environment but admittedly uses a lot of resources in the process.
The procedure works by firing green laser pulses in four billionths of a second increments at the ink. The laser effectively vaporizes the plastic polymer found in toner, leaving only a small trace of the ink behind. A ventilation system was used to remove nanoparticles and mostly harmless gases produced during the procedure.
Bending, curling and accelerated-aging tests on the ‘unprinted’ paper show no long-term signs of damage and was comparable to a regular piece of paper.
This isn’t the first time that someone has developed a device to remove ink from paper, but this latest ‘unprinter’ does so without some of the restrictions that other devices bring to the table. Toshiba currently offers a laser printer that offers a similar function but users must utilize a special ‘e-blue’ ink when printing, effectively limiting its useful scope. Other methods tend to damange the paper or leave it discolored.
The researchers are now planning to build a prototype device which they suspect can be done for around $25,000. This price would likely fall by a large margin should the 'unprinter' find its way into production at a later stage.
Leap represents an entirely new way to interact with your computers.
It’s more accurate than a mouse, as reliable as a keyboard and more
sensitive than a touchscreen. For the first time, you can control a
computer in three dimensions with your natural hand and finger
movements.
This isn’t a game system that roughly maps your hand movements. The
Leap technology is 200 times more accurate than anything else on the
market — at any price point. Just about the size of a flash drive, the
Leap can distinguish your individual fingers and track your movements
down to a 1/100th of a millimeter.
This is like day one of the mouse. Except, no one needs an instruction manual for their hands
In the beginning was the command line. And vacuum tubes, punch cards,
keyboards, and mice. After all these years, we still use the standard
tools to control out computers. But what if there was something more?
There is, and it is here: The Leap. A revolutionary piece of hardware
no larger than your iPod that’s two hundred times more accurate than
any product currently on the market. We believe that with The Leap,
tomorrow we will no longer be tethered to hardware. With The Leap,
imaginations will run wild, and possibilities will be endless. Cheesy
marketing speak, you say? Perhaps. But at Leap Motion, we believe
strongly and passionately that software can change the world. We believe
you shouldn’t have to break the bank to make powerful software using
powerful technology. We believe in possibility. And we cannot wait to
see what the future will bring to the world of natural user interface
and gesture control.
Get the most out of your Leap.
Control browser scroll: Now you can scroll the web using your finger up and down, or on your desktop up and down and side to side. Pinch to zoom: Zoom in somewhere easily – great for presentations or just for fun to get a better look. Rotation: Try playing around with Google Earth and see how easy it is to rotate using your finger. Your finger as your mouse: Go anywhere on your desktop or the web using your finger, just as you use your mouse. Point, scroll, click – you got it
Hands-free motion control, a technology pioneered by Nintendo's
Wii
and later improved upon by Microsoft's Kinect, just took a very big
leap forward. Industries from gaming to surgery to architecture,
engineering, and design may never be the same.
With the unveiling today of its Leap 3D motion control system, a San Francisco startup called Leap Motion
has, well, leapfrogged the state of the art in this young field, giving
users the ability to control what's on their computers with hundredth
of a millimeter accuracy and introducing touch-free gestures like
pinch-to-zoom.
Leap, which comprises both a small USB input device and a sophisticated
software platform, is expected to cost $70. But while users will have to
wait until early next year to get their hands on it, what the company
is showing today seems likely to get developers and users in a wide
range of industries very, very excited.
By now, most people have seen Kinect in action. The Microsoft system has become a huge success
by allowing developers to make games and other software that let people
control what's on their screens with their bodies. That's great for
dancing, fighting, and sports games, plus many others, but Kinect's
ability to recognize motion ends at users' hands.
Leap, by comparison, can sense motion down to the most subtle movements
of a finger, which the company says is 200 times more sensitive than
anything else on the market. The system creates a "three-dimensional
interaction space" of four cubic feet and is more precise and responsive
than a touchscreen or a mouse, and just as reliable as a keyboard.
That means everyone from game designers to surgeons to architects and
engineers may soon have a host of revolutionary applications that will
soon be coming their way.
In a demonstration to CNET, Leap Motion CTO David Holz showed how the Leap is adept at a range of functions, such as:
Navigating an operating system or browsing Web pages with the flick of a finger
Finger-pinching to zoom in on maps
Letting engineers interact with a 3D model of clay
Precision drawing in either two- or three-dimensions
Manipulating complex 3D data visualizations
Playing games, including those that require very "fast-twitch" control
Signing digital documents by writing in air
But that's just the beginning. Leap Motion, which announced $12.75 million in Series A funding led by Andy Miller
of Highland Capital Partners earlier this month, decided from the
get-go to make its technology into an ecosystem that would support a
large number of third-party applications, as opposed to trying to build
and popularize those apps itself.
What exactly is The Leap?
The Leap is a small iPod sized USB peripheral that
creates a 3D interaction space of 4 cubic feet to precisely interact
with and control software on your laptop or desktop computer. It’s like
being able to reach into the computer and pull out information as easily
as reaching into a cookie jar.
The Leap senses your individual hand and finger
movements independently, as well as items like a pen. In fact, it’s 200x
more sensitive than existing touch-free products and technologies. It’s
the difference between sensing an arm swiping through the air and being
able to create a precise digital signature with a fingertip or pen.
What can I do with The Leap?
The possibilities are endless, really. Computer
power has grown exponentially over the years, but the way we interact
with those computers has not. With LEAP, virtually every kind of
application, across every industry, can be re-imagined.
Art. Healthcare. Engineering. Operating Systems.
Gaming. If you can imagine it, we’re pretty confident there’s a
remarkable member of our developer community who is already working to
create it.
What is Leap Motion technology?
Leap Motion technology is a breakthrough in
computer interaction, using a patented mathematical approach to 3D,
touch-free motion sensing and motion control software that’s unlike
anything that currently exists on the market or in academia. Developed
over the past 4 years, Leap Motion moves far beyond the current
technologies designed for distant arm waving.
How much does The Leap cost?
The Leap will retail for $69.99, and a limited number are currently available for pre-order at LeapMotion.com.
How does The Leap impact computing?
For decades people have been given a dream of what
computers would be – from Star Trek holosuites to Tom Cruise swiping
through Minority Report’s 3D computer interface. But it’s never made it
out of the lab and into real life – until now. The ability to control
any computer with nuanced hand and finger movements will fundamentally
transform the way people interact with computers.
Who is The Leap ideal for?
Everyone! We envision a day in the near future
when our motion control technology will be used in most consumer
products – not just computers, but cars, appliances, medical devices,
light switches and more.
In a demonstration to CNET, Leap Motion CTO David Holz showed how the Leap is adept at a range of functions, such as:
Navigating an operating system or browsing Web pages with the flick of a finger
Finger-pinching to zoom in on maps
Letting engineers interact with a 3D model of clay
Precision drawing in either two- or three-dimensions
Manipulating complex 3D data visualizations
Playing games, including those that require very "fast-twitch" control
Over the past decade, smartphones have taken the world by storm and recently, tablets have entered into the arena as well. These mobile devices are having a significant impact on our lives and are in fact redefining the way we access information and communicate with others. This is due to not only the hardware but the specialized software that these devices run and most importantly, their operating systems. In what follows, we will take an informative tour of modern mobile operating systems, their different types and usage across smartphone and tablet platforms.
Just like a PC can run different operating systems (like Windows, Linux, BSD etc.) or different versions of the same operating system (like Windows XP, Windows Vista, Windows 7 etc.), most smartphones can also run different versions of the operating system they were made for and in exceptional cases, they might even be able to run operating systems they weren’t made for. In general however, an Android phone will only run a version of Android while an iPhone will only run an iOS version.
To give you an idea of what we will be covering in this guide, here is the table of contents:
Manufacturer-built proprietary operating systems
Apple iOS
RIM BlackBerry OS
HP WebOS
Third party proprietary operating systems
Microsoft Windows Phone 7
Microsoft Windows Mobile
Free & open source operating systems
Android
MeeGo
Symbian
Which smartphone OS is the best
Manufacturer-Built Proprietary Operating Systems
Some device manufacturers use their own proprietary operating system for their phones and tablets. A good example is Apple, with iOS being the operating system developed by them for their iPod Touch, iPhone and iPad devices. Other examples include RIM who use their proprietary BlackBerry OS for all BlackBerry phones and tablets, and HP, using their proprietary Palm Web OS for their Palm series of smartphones and tablets. A characteristic of such operating systems is that they have a very consistent look and feel across all devices that they run on, the way Mac OS X appears and behaves the same way on a Macbook Pro as it does on an iMac or a Macbook Air.
Let’s now take a look at some popular operating systems in this category.
- Apple iOS
iOS is the operating system used by Apple in all variants of iPod Touch, iPhone and iPad. While smartphones have been around since the 90’s, it was Apple that successfully managed convincing masses to switch to them with the release of the first iPhone in 2007 running the first version of iOS. At the time of its release, iOS wasn’t even capable of performing what most other smartphones operating systems had been doing for almost a decade – things such as true multitasking, data connection tethering, task switching, Bluetooth pairing, PC-like application installation using installer files, and dozens others – yet the first iPhone was received with immense enthusiasm by the masses, perhaps for not knowing any better.
The key to this success lay in an interface we would call ‘idiot-friendly’ that was targeted primarily at the least smart users to enable them to use a smartphone that was only a pseudo-smartphone back then. Other factors contributing to the success of iOS included smooth graphics, consistent user interface elements across apps, built-in iPod application, iTunes integration, an App Store for buying and installing apps and perhaps most importantly, a multi-touch finger-friendly capacitive touch screen that eliminated the use of a stylus while offering finger based gestures such as pinch-to-zoom, twist-to-rotate etc. These, coupled with the similarity with the hugely popular iPod Touch, resulted in the iPhone going viral and ended up in most people buying it as more of a status symbol of owning an iPhone, than for the utility of having a smartphone.
The introduction of the iPad in 2010 only added to the popularity of iOS. Much like the case of smartphones, tablets had been widely available for over a decade but it was again Apple that built upon the success of iPhone to bring them to the masses in form of the iPad, creating a modern tablet boom and leading to other competitors joining the market. With the iPad and the iPad 2, Apple still leads the tablet market share by a huge margin.
Due to its restricted nature, iOS limited users to only the features Apple decided appropriate. That’s when the development community decided to intervene and came up with Jailbreaking. This allowed power users to install additional apps not available in the official App Store and customize their iPhones beyond the standard features provided by Apple.
By now, iOS has improved a lot and as of the current version 4.3.3, it supports multi-tasking, audio and video playback to AirPlay devices, data tethering and several other enhancements, in addition to the above-mentioned features. Jailbreaking continues to play an important role in iOS devices and enables users to take their iPhones beyond the often ridiculous limitations set by Apple.
- RIM BlackBerry OS
This is the operating system used in all BlackBerry devices. Despite having been popular in corporate sector, BlackBerry devices are losing market share to Android and iPhone. However, they still have a loyal following of users who are used to the signature hardware keyboard of BlackBerry devices and the convenience of the built-in corporate features of BlackBerry OS. RIM’s attempts at entering the touch screen smartphone market haven’t been too successful due to the limited number of quality apps available, though their recently released tablet called BlackBerry Playbook appears promising. Playbook is the first BlackBerry device to ship with their latest OS called QNX which is set to replace the older BlackBerry OS. Future phones by BlackBerry are also expected to ship with QNX.
A recent development that might change things for the better for RIM is the Android App Player that promises to bring support for running hundreds of thousands of Android apps on BlackBerry OS devices, as demoed at the recent BlackBerry World 2011 keynote.
- HP WebOS (Previously Palm WebOS)
Palm – despite being one of the initial players of the smartphone market – experienced declining market share and dropping revenues due to their old PalmOS devices not being able to keep up with iOS and Android. Palm tried to counter it by replacing its dying PalmOS with an entirely new operating system built from scratch – WebOS. Although WebOS was built by Palm as a pretty solid and feature-rich operating system having a killer interface to match, it wasn’t enough to keep the company’s lost reputation. Eventually, at the verge of bankruptcy, Palm ended up getting acquired by HP in 2010. The acquisition was followed by HP’s announcement of continuing development of the Palm devices as well as WebOS under HP’s brand name.
At its core, WebOS derives heavily from Linux and uses several open source components, maintained at the Palm Open Source website. HP is heavily promoting Palm OS and releasing several devices running it, including HP Veer & HP Pre 3 smartphones and HP TouchPad tablet. While WebOS doesn’t have a prominent market share at the moment, things seem promising for this platform’s future.
Third Party Proprietary Operating Systems
Another scenario is proprietary operating systems built by companies that do not manufacture devices, but license their operating system to manufacturers for running it on theirs. The biggest examples are Windows Mobile and Windows Phone 7, built by Microsoft and found running on smartphones by HTC, Samsung, Dell and LG, amongst others. These operating systems also have usually a consistent appearance and behavior across all devices, just like Windows 7 appears and behaves the same regardless of what brand of computer you are running it on.
Let’s take a look at these operating systems in detail.
- Microsoft Windows Mobile
You might be wondering what this now-obsolete operating system is doing in an article on modern mobile operating systems. However, no discussion on mobile operating systems can be complete without the mention of Windows Mobile. Back when PalmOS devices featured a grid of icons offering only the most basic built-in apps, BlackBerry OS and Symbian devices didn’t even have touch screens. and iOS wasn’t even around, Windows Mobile devices did almost all that modern smartphone operating systems do, and then some.
Windows Mobile devices were called Pocket PCs and were true to their name! The operating system had true multitasking, installation of apps using cab files, full file system access, registry access, options for replacing the entire user interface with another, integrated data tethering support, personal information synchronization and a complete office suite.
The platform enjoyed a loyal following amongst enthusiasts and lead to the creation of the famous XDA-Developers community where developers and power users from the whole world gathered to share their customizations and hacks for Windows Mobile devices. Later on, this community expanded to Android devices and is today the largest smartphone customization community online. Installing a heavily customized version of Windows Mobile to a device was as simple as connecting it to the computer via USB and running a standard software installation wizard on the computer, no ridiculous jailbreaking/rooting/recovery/commandline use required.
The primary reasons behind the fall of Windows Mobile were the inability of Microsoft to market it to the masses, little-to-no focus from Microsoft on developing an app ecosystem that would encourage developers to build apps for the platform, and the popularity gained by Apple’s iPhone, which Windows Mobile couldn’t compete against due to an interface that wasn’t finger-friendly and required the use of a stylus.
In 2010, Microsoft decided to abandon Windows Mobile altogether in favor of Windows Phone 7. It’s legacy however, remains. HTC Sense – hugely popular on Android – was initially made for Windows Mobile devices. Furthermore, Android’s default interface involving multiple home screens, home screen previews and widgets on each screen derives heavily from the interface of SPB Mobile Shell – a third party Windows Mobile interface that innovatively introduced users to this concept.
- Microsoft Windows Phone 7
Windows Phone 7 was Microsoft’s answer to the flourishing smartphone world. With Windows Mobile left abandoned, Microsoft built Windows Phone 7 from scratch, and presented users with an interface like no other. Given the name of Metro, this user interface takes a break from the conventional icon grids used by most competitors and brought the concept of live tiles on the home screen, focusing heavily on the presentation of information to users in a fluid, unobtrusive way. The result looked impressive, to say the least. However, many of the signature features of Windows Mobile such as true multitasking, app sideloading etc. were dropped, drawing heavy criticism by loyal Windows Mobile users.
Although Windows Phone 7 hasn’t gained a major market share by now, things look very promising as Microsoft has announced a major update for fall 2011, bringing true multitasking and several other important features to the platform in a few months. Developments on bringing app sideloading are also under way. Apart from this, Microsoft is concentrating heavily on the app ecosystem in cooperating with developers and the Windows Live Marketplace has become the fastest growing app market today. Furthermore, Nokia has decided to switch from Symbian/MeeGo to Windows Phone 7 as its smartphone platform, and this alone promises to boost the market share of this operating system to a significant extent across the globe.
At present, there are over a dozen Windows Phone 7 devices available in the market, built by manufacturers such as HTC, Samsung, Dell and LG. Several other manufacturers including Nokia have also decided to join in, and many new Windows Phone 7 devices are expected to be released this year.
Free & Open Source Operating Systems
Last but not the least, there are open source operating systems built by a company, a group of companies or a community of developers and made available for everyone to modify them in any way they choose, and install them on their choice of devices.
Examples of these operating systems include Symbian, the upcoming MeeGo and most importantly, Android. Device manufacturers fine-tune such operating systems to best suit their devices and often add additional features or interfaces to set them apart from other versions of the same operating system, and this often becomes their selling point. HTC has had a history of customizing Android for its phones and including a graphically enhanced interface called HTC Sense in an effort to enhance user experience.
Furthermore, such operating systems have a lot more customizations available in form of installable software that changes their look, feel and behavior, providing different entirely user experiences. Being open source, these operating systems also offer independent developers the opportunity to modify them from scratch and run them on devices not supported officially, or to bring an entirely new user experience to officially supported devices.
Let’s now individually examine major operating systems in this category.
- Android
When an operating system is open source, based on Linux, owned by Google, backed by all major mobile device manufacturers including HTC, Samsung, Motorola, Dell, Sony Ericsson, LG and countless more, and allows for endless customization, it is bound to make an impact. Initially developed by Android Inc. and purchased by Google in 2005, Android has become the leading smartphone OS in the world today, and is our smartphone platform of choice here at AddictiveTips. While it appeals more to the techies amongst us, Android has been received well by the non-techies as well, and with an app market boasting over 200,000 apps, there’s plenty to do with it as well.
Android runs on literally hundreds of devices including smartphones and tablets. With multiple new releases each year, the operating system is continuously evolving. At present, the latest version for smartphones is 2.3.4 Gingerbread while that for tablets is 3.1 Honeycomb. The upcoming major release scheduled for Q3 or Q4 this year is called Ice Cream Sandwich and aims to bring both phone and tablet versions together.What truly rocks about Android is the level to which it can be customized. With different launchers and widgets, the entire way in which a user interacts with the device can be changed. If you are an Android user or plan on switching to it, you must check out our Android customization series to see how to personalize it beyond recognition!
Android has already beaten iOS to become the most widely used smartphone OS in the world, though its app Market still lags behind the Apple App Store in terms of the number of apps by roughly 100,000 apps, plus iOS apps in general tend to be more refined than Android apps, and this is the only reason we can see for any rational person to choose an iOS device over an Android device, but that’s our personal opinion.
- MeeGo
A few years back, Nokia and Intel decided to merge their Linux-based Maemo and Moblin operating systems to form MeeGo, and several other high-profile companies also joined in to contribute to the open source project. Things seemed to be promising, smartphone and tablet enthusiasts – including us – were eagerly anticipating developments to bear fruit in form of another Android to bring competition to the market and provide a further incentive for innovation, when all of a sudden a key player i.e. Nokia decided to abandon it and switch over to Windows Phone 7 as its primary smartphone platform.
While Nokia has still announced to stick with its promise of releasing one MeeGo device this year before abandoning the project entirely, things aren’t looking too well for the platform and unless Intel and the other companies involved really give it their level best, MeeGo might end up like one of those obscure Linux distributions that only the developers and their six friends use or worse, it could be entirely abandoned, though we hope that isn’t the case.
- Symbian
There is a saying, “If you don’t succeed at the first attempt, skydiving isn’t for you!”, and it applies too well in Symbian’s case. Symbian – in its various forms – has been the operating system of thousands of devices by dozens of manufacturers but despite its commercial success, it has failed to achieve any critical acclaim in the smartphone arena despite Nokia’s repeated efforts of trying to get it right. We are including it here only due to the number of smartphones running Symbian globally, despite a negligible share in the United States. In all other aspects, it doesn’t even come close to any of the other smartphone operating systems mentioned in this guide.
Nokia finally decided to let go of Symbian along with MeeGo to switch to Windows Phone 7 as its smartphone platform but without entirely abandoning it, as the company will continue to use it for its feature phones (phones that aren’t smartphones).
The future of Symbian in the smartphone world is practically over. With Nokia’s abandonment and more and more users switching to Android, iOS and Windows Phone 7 globally, it is safe to conclude that Symbian no longer has a place in the smartphone world.
Which Smartphone OS Is The Best?
Now that you are acquainted with all major smartphone operating systems out there, it’s time for this important question. The answer is: whichever works best for you! Here at AddictiveTips, we are all for Android and I personally don’t even like iOS one bit, yet I recommend iPhone to many people as it appears to suit them better. We would love to see MeeGo get released on a few high-end devices, HP WebOS gain more attention as well as apps and Windows Phone 7 become more open. Till then however, considering the development, the app ecosystem and the customization options, for most users, Android is currently the smartphone OS to go for.
MiFi is a portable broadband wireless device about the size of a credit card that combines functions of a modem, router and access point. The internal modem accesses a wireless signal and the internal router shares that connection among users and devices. MiFi is sometimes called a personal hotspot.
MiFi was designed to simplify setting up a small local area network (LAN). The device supports five users and can also network Wi-Fi-capable devices including digital cameras, notebooks, MP3 players and gaming systems. A MiFi device could be used to set up an ad-hoc network with a shared Internet connection anywhere with cellular connectivity.
Here are some of MiFi's other features:
Storage capacity.
The ability to host applications.
Support for EV-DO or UMTS/HSDPA 3G technologies.
Four hours active use, forty hours standby before the internal battery needs to be recharged.
Can be configured for automatic email synching and virtual private network (VPN) connection.
Support for remote management.
Novatel, who developed MiFi and trademarked the name, call their associated product line "Intelligent Mobile Hotspots." Novatel markets the devices, which require a data plan, through carriers. According to Novatel, MiFi stands for "my Wi-Fi" and is pronounced as "my-Fi."
MiFi is a line of compact wireless routers produced by Novatel Wireless that act as mobile Wi-Fi hotspots. MiFi stands for 'My Wi-Fi'. The MiFi can be connected to a mobile phone (cellular) carrier and provide internet access for up to 5 devices. The MiFi works at a distance up to 10 m (30 ft) and will provide internet or network access to any WiFi enabled peripheral device.
This "cloud" of high-speed Internet connectivity that MiFi offers can be shared not only between users, but between devices such as laptops, cameras, gaming devices and multimedia players. Perfect for carpooling and relieving boredom in the back seat during that long road trip with kids - think Nintendo DS or Sony PSP - the MiFi will support up to five users simultaneously.
The pocket sized MiFi is capable of connecting users and devices
In addition to being a portable Internet hotspot, the EVDO blog notes that the MiFi has an onboard Linux processor capable of hosting software applications and additional content storage capabilities via MicroSD.
Novatel claims the internal battery will provide over forty hours standby and up to four hours of active use on a single charge, and that certain configurations will support applications like auto VPN, automatic syncing of e-mail and remote management capabilities.
Li-Fi is a term often used to describe Visible Light Communications technology applied to high speed wireless communications.
It acquired this name due to the similarity to Wi-Fi, only using light instead of radio.
Wi-Fi is great for general wireless coverage within buildings, and Li-Fi is ideal for high density wireless data coverage in confined areas and for relieving radio interference issues, so the two technologies can be considered complimentary.
Image from Wired UK Feb 2012
Li-Fi is typically implemented using white LED light bulbs at the downlink transmitter. These devices are normally used for illumination only by applying a constant current. However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. Unseen by the human eye, this variation is used to carry high speed data.
Why you need to get a Li-Fi!
Radio spectrum is congested but the demand for wireless data doubles each year. Everything, it seems, wants to use wireless data but the capacity is drying up. Wireless radio frequencies are getting higher, complexities are growing and RF interference continues to grow. So what can carry this excess demand in the future?
The solution is Li-Fi. Direct modulation of LED devices is a low cost, secure, and safe way to transmit data, and there is an abundance of free visible light spectrum. High intensity LEDs used in light bulbs, flash lights and cameras can transmit very high data rates, faster than Wi-Fi!
FLICKERING lights are annoying but they may have an upside. Visible light communication (VLC) uses rapid pulses of light to transmit information wirelessly. Now it may be ready to compete with conventional Wi-Fi.
"At the heart of this technology is a new generation of high-brightness light-emitting diodes," says Harald Haas from the University of Edinburgh, UK. "Very simply, if the LED is on, you transmit a digital 1, if it's off you transmit a 0," Haas says. "They can be switched on and off very quickly, which gives nice opportunities for transmitting data."
It is possible to encode data in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s. The LED intensity is modulated so rapidly that human eyes cannot notice, so the output appears constant.
More sophisticated techniques could dramatically increase VLC data rates. Teams at the University of Oxford and the University of Edinburgh are focusing on parallel data transmission using arrays of LEDs, where each LED transmits a different data stream. Other groups are using mixtures of red, green and blue LEDs to alter the light's frequency, with each frequency encoding a different data channel.
Li-Fi, as it has been dubbed, has already achieved blisteringly high speeds in the lab. Researchers at the Heinrich Hertz Institute in Berlin, Germany, have reached data rates of over 500 megabytes per second using a standard white-light LED. Haas has set up a spin-off firm to sell a consumer VLC transmitter that is due for launch next year. It is capable of transmitting data at 100 MB/s - faster than most UK broadband connections.
Once established, VLC could solve some major communication problems. In 2009, the US Federal Communications Commission warned of a looming spectrum crisis: because our mobile devices are so data-hungry we will soon run out of radio-frequency bandwidth. Li-Fi could free up bandwidth, especially as much of the infrastructure is already in place.
"There are around 14 billion light bulbs worldwide, they just need to be replaced with LED ones that transmit data," says Haas. "We reckon VLC is a factor of ten cheaper than Wi-Fi." Because it uses light rather than radio-frequency signals, VLC could be used safely in aircraft, integrated into medical devices and hospitals where Wi-Fi is banned, or even underwater, where Wi-Fi doesn't work at all.
"The time is right for VLC, I strongly believe that," says Haas, who presented his work at TED Global in Edinburgh last week.
But some sound a cautious note about VLC's prospects. It only works in direct line of sight, for example, although this also makes it harder to intercept than Wi-Fi. "There has been a lot of early hype, and there are some very good applications," says Mark Leeson from the University of Warwick, UK. But I'm doubtful it's a panacea. This isn't technology without a point, but I don't think it sweeps all before it, either.
Wearable health monitoring systems integrated into a telemedicine system are novel information technology that will be able to support early detection of abnormal conditions and prevention of its serious consequences.
Many patients can benefit from continuous ambulatory monitoring as a part of a diagnostic procedure, optimal maintenance of a chronic condition or during supervised recovery from an acute event or surgical procedure.
Important limitations for wider acceptance of the existing systems for continuous monitoring are:
unwieldy wires between sensors and a processing unit,
lack of system integration of individual sensors,
interference on a wireless communication channel shared by multiple devices, and
nonexistent support for massive data collection and knowledge discovery.
Traditionally, personal medical monitoring systems, such as Holter monitors, have been used only to collect data for off-line processing. Systems with multiple sensors for physical rehabilitation feature unwieldy wires between electrodes and the monitoring system. These wires may limit the patient's activity and level of comfort and thus negatively influence the measured results.
A wearable health-monitoring device using a Personal Area Network (PAN) or Body Area Network (BAN) can be integrated into a user's clothing.
Recent technology advances in wireless networking, micro-fabrication, and integration of physical sensors, embedded microcontrollers and radio interfaces on a single chip, promise a new generation of wireless sensors suitable for many applications, such as stroke rehabilitation, physical rehabilitation after hip or knee surgeries, myocardial infarction rehabilitation, and traumatic brain injury rehabilitation.
Increased system processing power allows sophisticated real-time data processing on sensors, which reduces wireless channel utilization and power consumption. We propose a wireless BAN composed of off-the-shelf sensor platforms with application-specific signal conditioning modules.
System Overview
A general multi-tier system architecture is shown in Figure 1; the lowest level encompasses a set of intelligent physiological sensors; the second level is the personal server (Internet enabled PDA, cell-phone, or home computer); and the third level encompasses a network of remote health care servers and related services (Caregiver, Physician, Clinic, Emergency, Weather).
Each level represents a fairly complex subsystem with a local hierarchy employed to ensure efficiency, portability, security, and reduced cost. The personal server, running on a PDA or a 3G cell phone, provides the human-computer interface and communicates with the remote server(s).
Wireless Body Area Network of Intelligent Sensors for Ambulatory Health Monitoring
Wireless Intelligent Sensors
We developed several generations of wireless intelligents sensors at the University of Alabama in Huntsville. We started with MSP430 family and custom wireless interface in 2000; we currently use off-the-shelf wireless sensors with the same microcontroller family and custom signal processing boards. Some of our projects are presented below.
ISPM_v3 (Intelligent Signal Processing Module), 2005
Features MSP430F1611 microcontroller, one ECG channel, one 3D accelerometer; Designed as a daugther card for Tmote Sky wireless platform.
SPM_v3 sensor card with one bioamplifier channel and on-board 3D accelerometer (U2 on the back side).
