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How Bluetooth Works
Bluetooth is a specification for the use of low power radio communications to wireless phones,computers, and other network wireless devices over short distances. The name Bluetooth is actually borrowed from Harald Bluetooth, a Denmark king more than 1,000 years ago.
The technology of Bluetooth was primarily designed to support simple wireless networking of devices and peripherals, which includes cell phones, PDAs,and wireless headsets. The wireless signals that are transmitted by Bluetooth cover short distances of up to 30 feet, generally communicating less than 1 MPps (Mega Byte per second).
The networks of Bluetooth feature dynamic topology called PAN or a piconet. The piconets contain aminumum of two and a maximum of eight peer devices. The devices will communicate using protocols that are part of the specification.
Even though the Bluetooth standard will utilize the same 2.4 GHz range as 802.11b and 802.11g, the technology isn't suitable for a Wi-Fi replacement. When compared to Wi-Fi, Bluetooth is much slower, limited in range, and actually supports less devices.
For short range devices, Bluetooth is rapidly becoming the best. The technology is more popular with cell phones, as Bluetooth headsets are the way to go these days. To use Bluetooth, your cell phone will need to have it enabled, or an infared device somewhere on the phone.
Upcoming devices are utilizing Bluetooth as well, such as PS3 and the Nintendo Revolution. The wireless controllers will be Bluetooth enabled,which will give players the cutting edge.
If you own a cell phone or other wireless device, you should look into Bluetooth. The technologyis nothing short of spectacular, making it something that will be around for years and years to come. As technology gets bigger and bigger, you can expect Bluetooth to advance as well.
Many people don't like cables. When people want to copy information from their old mobile phone to their new mobile phone many makes and models including Nokia, LG and Samsung allow the user to "blue tooth accross" their text messages, phone book enteries and sometimes phone settings.
Nokia bluetooth mobile handsets are particually good at this. When a person orders a mp3 ringtone or real tone, they can send it to thier friend for free over bluetooth instead of sending it as a text message through their mobile network which they may get changed for.
Certain mobile phone based chat clients can use blue tooth to communicate, with the benefit again of the mobile phone opeartors billing being totally cut out.
Many video streaming mobile phones are equipped with bluetooth. Even though having bluetooth switched on does cause a significant battery drian, bluetooth is a far better technology for power consumption over the other options including WiFi.
HAPPY 10 YEARS ANNIVERSARY TO BLUETOOTH TECHNOLOGY
Happy 10 Year Anniversary for Bluetooth Technology!
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"The first ten years of Bluetooth development has been amazing to watch,"said Michael Foley, Ph.D., executive director, the Bluetooth SIG. "From prototypes in 1998 to more than 1.5 billion devices on the market today, no other consumer technology has grown as fast in such a short period of time." "As consumers became more aware of Bluetooth technology and began to ask for it, handset-makers started to include it as a means of differentiating their products and increasing their margins. Adding a Bluetooth chip to a phone now costs very little and opens up a new market for high-margin accessories," says Stuart Carlaw of ABI Research, long-time Bluetooth technology analyst. "Greater adoption has, in turn, cleared the way for the inclusion of Bluetooth technology in all kinds of new products like Bluetooth enabled jackets, motorcycle helmets and sunglasses with built-in wireless headsets, and gaming controllers for Sony's PlayStation 3 and Nintendo's Wii. I expect additional success for Bluetooth technology in new application areas like home entertainment and medical and fitness devices." The future of Bluetooth technology looks extremely bright. The Bluetooth SIG is currently working with WiMedia Alliance to use ultra-wideband technology for High Speed Bluetooth as well as working with WiBree technology for ultra low power Bluetooth Specification. Both new versions of Bluetooth technology are expected to be available in the first half of 2009. |
Bluetooth Security
Bluetooth Security
Bluetooth Security
| · Bluetooth Technology Faces Security Threats Today, all communication technologies are facing the issue of privacy and identity theft. Bluetooth technology is no exception. The information and data we share through these communication technologies is both private and in many cases, critically important to us. Everyone knows that email services, company networks, and home networks all require security measures. What Bluetooth users need to realize, is: Bluetooth requires similar security measures. Recently, Bluetooth technology has been popping up in the news. Unfortunately, most of the news involves confusion and misinformation regarding the security of Bluetooth. Recent reports have surfaced describing ways for hackers to crack Bluetooth devices security codes. · Are the Threats Serious? The good news: most of the recent Bluetooth security scares, like most scares, are over-dramatized and blown out of proportion. The truth is, these issues are easily combatable, and various measures are already in place to provide for the secure use of Bluetooth technology. Yes, it is true: there have been some Bluetooth cell phones that have been hacked into. However, it is most likely the case that those who have experienced these security breaches have not taken the appropriate precautions to protect their devices. According to the Bluetooth Special Interest Group (SIG), in order to break into a Bluetooth device, a hacker must:
The hacker must of course be within range of the Bluetooth device and, according to the Bluetooth SIG, be using very expensive developers’ equipment. The SIG suggests users create a longer PIN (8 digit is recommended). |
· The Bluetooth SIG Focuses on Security
The Bluetooth SIG is constantly improving formats for combating security threats associated with Bluetooth technology. Offering a secure method to wirelessly communicate has always been one of the key benefits of Bluetooth technology. If you look at The History of Bluetooth, you will see that offering secure data transmission was one of the core principles for its creation.
In order to lead the security effort, a group of engineers within the Bluetooth SIG formed the Bluetooth Security Experts Group. As the Bluetooth Core Specification Versions continue to advance, the Bluetooth Security Experts Group is responsible for monitoring the advancement and testing for flaws in its security.
· The Fundamentals of Bluetooth Security
One of the most basic levels of security for Bluetooth devices is the “pairing” process.
Pairing = Two or more Bluetooth devices recognize each other by the Bluetooth Profiles they share, and in most cases, both must enter the same PIN.
The Bluetooth core specifications use an encryption algorithm, which is entirely secure. Once Bluetooth devices pair with one another, they too are entirely secure.
Bluetooth devices will not communicate with each other until they have successfully paired. So, because of this pairing process and the fact that it has a short range, Bluetooth technology is considered to be fundamentally secure.
Unfortunately, as recent news has indicated, experienced hackers have come up with a way to get around this basic level of security. However, there are precautions users can take to limit the chances of their Bluetooth device from being compromised by a hacker.
· How Developers Can Provide Security
Companies who develop Bluetooth enabled products have multiple options in order to provide security. There are three security modes for connecting two Bluetooth devices:
- Security Mode 1: non-secure
- Security Mode 2: service level enforced security
- Security Mode 3: link level enforced security
It is the company who develops each specific Bluetooth product that decides which security modes to use. Also, the devices and services have different security levels as well. For example, devices use two levels: "trusted device" and "untrusted device". After a trusted device is connected to another device, it has unrestricted access to all services. As far as services, there are three security levels which are defined: services that require authorization and authentication, services that require authentication only and services that are open to all devices.
· Why Have There Been Security Threats?
The recent Bluetooth security threats have been isolated to Bluetooth cell phones. The issues were due to specific problems with the cell phone’s platforms. In order to solve, and prevent against further security probelems, the Bluetooth SIG and all of its members work together to discover, inspect and solve reported problems.
If there is something wrong with the actual Bluetooth specification, then the Bluetooth SIG will confront the problem directly. However, if the problem is a result of the implementation of Bluetooth technology, then the SIG will work with the specific members in order to release patches and prevent future problems from occurring.
· What is Bluejacking?
Bluejacking allows phone users to send business cards anonymously to one another using Bluetooth technology. Bluejacking does NOT involve any altercations to your phone's data. These business cards usually consist of some clever message or joke. Bluejackers are simply looking for a reaction from the recipient. To ignore bluejackers, simply reject the business card, or if you want to avoid them entirely, set your phone to non-discoverable mode
· What is Bluesnarfing?
Bluesnarfing refers to a hacker who has gained access to data, which is stored on a Bluetooth enabled phone. Bluesnarfing allows the hacker to make phone calls, send and receive text messages, read and write phonebook contacts, eavesdrop on phone conversations, and connect to the Internet. The good news is, bluesnarfing requires advanced equipment and expertise or requires the hacker to be within a 30 ft. range. If your phone is in non-discoverable mode, it becomes significantly more difficult for hackers to bluesnarf your phone. According to the Bluetooth SIG, only some older Bluetooth enabled phones are vunerable to bluesnarfing.
· What is Bluebugging?
Bluebugging refers to a skilled hacker who has accessed a cell phone's commands using Bluetooth technology without the owner's permission or knowledge. Bluebugging allows the hacker to make phone calls, send messages, read and write contacts and calendar events, eavesdrop on phone conversations, and connect to the Internet. Just like all Bluetooth attacks, the hacker must be within a 30 ft. range. Bluebugging and bluesnarfing are separate security issues, and phones that are vulnerable to one are not necessarily vulnerable to the other.
· What are Phone Manufacturers Doing to Solve These Problems?
Two of the leading cell phone manufacturers, Nokia and Sony Ericsson, have developed software patches for phones susceptible to bluesnarfing and bluebugging. Also, both manufacturers have taken great measures to ensure new phones entering the market will not be susceptible to these attacks.
· Are There Any Other Threats With Bluetooth Technology?
According to the Bluetooth SIG, bluesnarfing and bluebugging are the only known security threats. The Bluetooth SIG is constantly researching security risks associated with the technology and figure out if the risk is even possible as the technology expands and develops.
· What Can Users Do to Protect Their Data?
There are several measures users can take in order to protect their device’s information:
- If a phone is vulnerable to bluesnarfing or bluebugging--contact the manufacturer or take the phone to a manufacturer-authorized dealer. There are software patches available for many older Bluetooth phones.
- Turn the device to non-discoverable mode when not using Bluetooth technology.
- Never pair with unknown devices or in public places.
- When possible, use an eight character or more alphanumeric PIN.
Specifications about Bluetooth
Bluetooth Specifications
* Bluetooth devices in a piconet share a common communication data channel. The channel has a total capacity of 1 megabit per second (Mbps). Headers and handshaking information consume about 20 percent of this capacity. * In the United States and Europe, the frequency range is 2,400 to 2,483.5 MHz, with 79 1-MHz radio frequency (RF) channels. In practice, the range is 2,402 MHz to 2,480 MHz. In Japan, the frequency range is 2,472 to 2,497 MHz with 23 1-MHz RF channels. * A data channel hops randomly 1,600 times per second between the 79 (or 23) RF channels. * Each channel is divided into time slots 625 microseconds long. * A piconet has a master and up to seven slaves. The master transmits in even time slots, slaves in odd time slots. * Packets can be up to five time slots wide. * Data in a packet can be up to 2,745 bits in length. * There are currently two types of data transfer between devices: SCO (synchronous connection oriented) and ACL (asynchronous connectionless). * In a piconet, there can be up to three SCO links of 64,000 bits per second each. To avoid timing and collision problems, the SCO links use reserved slots set up by the master. * Masters can support up to three SCO links with one, two or three slaves. * Slots not reserved for SCO links can be used for ACL links. * One master and slave can have a single ACL link. * ACL is either point-to-point (master to one slave) or broadcast to all the slaves. * ACL slaves can only transmit when requested by the master. |
Total Bluetooth Versions
Bluetooth Versions
Bluetooth Core Specification Versions
Several Bluetooth specification versions have been released since Bluetooth technology was introduced in 1998. Versions 1.0 and 1.0B had too many problems and restraints for manufacturers to successfully develop Bluetooth devices. The main issue was the lack of interoperability among devices. The Bluetooth Core Specification version 1.1 is the first truly successful operating version of Bluetooth technology. Bluetooth 1.1 corrected many of the problems found in the earlier versions. As a result: Devices using Bluetooth 1.1 have much greater interoperability.
Many new Bluetooth devices, like the latest cell phones, are being sold with the newer Bluetooth specification version 1.2. So, what new features/benefits does Bluetooth 1.2 offer? * Backward compatible with Bluetooth 1.1 There may be multiple communication technologies, but they all share one thing in common: Faster is better. The Bluetooth SIG realized this, and worked on improving the speeds of Bluetooth version 1.2. Bluetooth version 2.0 + EDR was announced by the Bluetooth SIG in June 2004 and began appearing in Bluetooth devices in late 2005. Here is a listing of the main enhancements/features you will find with Bluetooth Specification Version 2.0 + EDR: * Backward compatible with previous Bluetooth versions |
Why It Is Called As Bluetooth
- Why is It Called Bluetooth?
The developers of this wireless technology first used the name "Bluetooth" as a code name, but as time past, the name stuck.
The word "Bluetooth" is taken from the 10th century Danish King Harald Bluetooth. King Bluetooth had been influential in uniting Scandinavian Europe during an era when the region was torn apart by wars and feuding clans.
The founders of the Bluetooth SIG felt the name was fitting because:
1) Bluetooth technology was first developed in Scandinavia, and
2) Bluetooth technology is able to unite differing industries such as the cell phone, computing, and automotive markets. Bluetooth wireless technology simplifies and combines multiple forms of wireless communication into a single, secure, low-power, low-cost, globally available radio frequency.
- Where Did the Logo Come From?
A Scandinavian firm originally designed the logo at the time the SIG was formally introduced to the public. Keeping to the same origin as the Bluetooth name, the logo unites the Runic alphabetic characters "H", which looks similar to an asterisk, and a "B", which are the initials for Harald Bluetooth. If you look close enough you can see both embodied in the logo.
The Bluetooth Car
The Bluetooth Car
Bluetooth technology and its use in automobiles is becoming extremely popular in the United States. Many states have Laws Restricting Drivers from Using Cell Phones, thus making hands free calling a necessity. In Europe, similar laws exist, however Bluetooth technology is much more prevalent in cars and cell phones than in the U.S.
With legislation banning the use of cell phones while driving, car manufacturers have to find solutions to combat this problem. They are now looking at Bluetooth technology. Bluetooth is the perfect solution for this problem because it allows drivers to keep both hands on the steering wheel while simultaneously having conversations on their cell phones.
Vehicles can be enabled with Bluetooth hands free technology through various methods. There are standard or optional communications systems offered by automotive manufacturers, aftermarket car kits, wireless speakerphone accessories, and wireless headsets.
At the International Auto Show in Germany, October 2005, 22 automotive manufacturers worldwide, or more than 60% of the major car manufacturers surveyed, offered optional or standard Bluetooth communication systems in 61 different car models. The cars range from luxury models like Lexus, BMW, Acura, and Lincoln to more affordable cars like Toyota and Chrysler.
The new Acura TL offers Bluetooth wireless technology as part of its standard HandsFreeLink. To watch a demo from the Acura Website, please Click Here.
Not everyone who seeks the benefits of Bluetooth technology can afford a new car. Thankfully, there are other options through aftermarket kits. These kits usually require installation by professionals but offer most of the functionality of a factory installed Bluetooth kit. Please take a look at our section on Bluetooth Car Kits for more information.
The other option you have in order to enjoy Bluetooth hands free technology in your car is a Bluetooth Wireless Headset, which connects to your Bluetooth cell phone. With most Bluetooth headsets, you will still need to dial the phone number on your cell phone to make an outgoing call, but all incoming calls can be answered with a push of a button.
History of Bluetooth
HISTORY OF BLUETOOTH :-
- The Bluetooth SIG
The name “Bluetooth” and its logo are trademarked by the privately held trade association named the Bluetooth Special Interest Group (SIG).
Founded in September 1998, the Bluetooth SIG is a unification of leaders in the telecommunications, computing, network, industrial automation, and Automotive industries. Today, the Bluetooth SIG is responsible for encouraging and supporting research and development in Bluetooth technology.
The Bluetooth SIG includes promoter member companies Microsoft, Ericsson, IBM, Intel, Agere, Motorola, Nokia, and Toshiba, plus thousands of Associate and Adopter member companies (BlueTomorrow.com's parent company, SP Commerce LLC, is a licensed and certified Adopter member of the Bluetooth SIG).
What is Bluetooth
Bluetooth technology eliminates the need for wires that tangle our everyday lives. Streaming music and connecting devices are just a few of the powerful capabilities of Bluetooth technology. Let us teach you all about the wonderful world of Bluetooth.
Wireless transfer of large format entertainment data – music, video, and photos – between devices at short range is imminent. The Bluetooth Special Interest Group (SIG) today announced a new way it will provide for consumers’ growing need for speed.
The Bluetooth SIG is developing an innovative method of radio substitution. It will allow the well known Bluetooth protocols, profiles, security and pairing to be used in consumer devices while achieving faster throughput with momentary use of a secondary radio already present in the device. This architecture, called ‘Alternate MAC/PHY’ by Bluetooth SIG members working on the specification, is taking on a two-phased approach as SIG member companies drive the specification forward.
“This is the wireless technology equivalent of ‘low hanging fruit,’” said Michael Foley, Ph.D., executive director, the Bluetooth SIG. “What we’re doing is taking classic Bluetooth connections – using Bluetooth protocols, profiles, security and other architectural elements – and allowing it to jump on top of the already present 802.11 radio, when necessary, to send bulky entertainment data, faster. When the speed of 802.11 is overkill, the connection returns to normal operation on a Bluetooth radio for optimal power management and performance.”
In 2006, the Bluetooth SIG announced the selection of the WiMedia Alliance brand of ultra wideband technology as a high speed channel for Bluetooth technology. This development work continues between the two organizations in advance of widespread ultra wideband technology adoption – expected to be co-located in many Bluetooth devices. In the meantime, however, the SIG will make use of IEEE 802.11, a technology already present in many of the devices demanding greater speeds.
This two-phased roadmap for higher speeds will allow for a steady evolution in Bluetooth devices utilizing the presence of 802.11 today while continuing preparations for the presence of ultra wideband in the near future. “We’re committed to speedy wireless personal area network connections and we’ll always be looking for the best near term and long term way to accomplish that,” adds Foley. “The greatness of a generic alternate radio architecture being developed is that it’s adaptable.”
With the availability of high speed Bluetooth technology, device users can expect to move their entertainment data between their own devices and the trusted devices of friends, without the need for cables and wires. Some applications consumers will experience include:
- Wirelessly bulk synchronize music libraries between PC and MP3 player
- Bulk download photos to a printer or PC
- Send video files from camera or phone to computer or television
Meanwhile, Bluetooth devices will continue to offer the well known, low power and secure connections that make up the nearly 2 billion products already on the market. The core specification enabling the Alternate MAC/PHY is expected to be published to members in mid-2009 with work already well underway.
“The Bluetooth SIG is taking a logical step by applying Bluetooth protocols over an existing 802.11 radio to achieve efficient transfers of high data throughput applications," said Flint Pulskamp, wireless and mobile analyst at IDC. "Since Bluetooth and 802.11 already have significant traction in mobile devices, this coupled solution could prove to be an efficient interim solution, as the Bluetooth SIG continues to develop UWB for the future."
About the Bluetooth SIG
The Bluetooth Special Interest Group (SIG), comprised of leaders in the telecommunications, computing, consumer electronics, automotive and network industries, is driving development of Bluetooth wireless technology and bringing it to market. The Bluetooth SIG includes Promoter group companies Ericsson, Intel, Lenovo, Microsoft, Motorola, Nokia and Toshiba, along with over 10,000 Associate and Adopter member companies. The Bluetooth SIG, Inc. headquarters are located in Bellevue, Washington, U.S.A. For more information please visit www.bluetooth.com.
NANO TECHNOLOGY
It is a highly multidisciplinary field, drawing from fields such as applied physics, materials science, interface and colloid science, device physics, supramolecular chemistry (which refers to the area of chemistry that focuses on the noncovalent bonding interactions of molecules), self-replicating machines and robotics, chemical engineering, mechanical engineering, biological engineering, and electrical engineering. Much speculation exists as to what may result from these lines of research. Nanotechnology can be seen as an extension of existing sciences into the nanoscale, or as a recasting of existing sciences using a newer, more modern term.
Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control. The impetus for nanotechnology comes from a renewed interest in Interface and Colloid Science, coupled with a new generation of analytical tools such as the atomic force microscope (AFM), and the scanning tunneling microscope (STM). Combined with refined processes such as electron beam lithography and molecular beam epitaxy, these instruments allow the deliberate manipulation of nanostructures, and led to the observation of novel phenomena.
Examples of nanotechnology in modern use are the manufacture of polymers based on molecular structure, and the design of computer chip layouts based on surface science. Despite the great promise of numerous nanotechnologies such as quantum dots and nanotubes, real commercial applications have mainly used the advantages of colloidal nanoparticles in bulk form, such as suntan lotion, cosmetics, protective coatings, drug delivery[1], and stain resistant clothing.
Wikibooks has a book on the topic of
Nanotechnology
One nanometer (nm) is one billionth, or 10-9 of a meter. For comparison, typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the range .12-.15 nm, and a DNA double-helix has a diameter around 2 nm. On the other hand, the smallest cellular lifeforms, the bacteria of the genus Mycoplasma, are around 200 nm in length. To put that scale in to context the comparative size of a nanometer to a meter is the same as that of a marble to the size of the earth[3]. Or another way of putting it: a nanometer is the amount a man's beard grows in the time it takes him to raise the razor to his face[3].
Image of reconstruction on a clean Au(100) surface, as visualized using scanning tunneling microscopy. The individual atoms composing the surface are visible.
Main article: Nanomaterials
A number of physical phenomena become noticeably pronounced as the size of the system decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, it becomes dominant when the nanometer size range is reached. Additionally, a number of physical (mechanical, electrical, optical, etc.) properties change when compared to macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal and catalytic properties of materials. Novel mechanical properties of nanosystems are of interest in the nanomechanics research. The catalytic activity of nanomaterials also opens potential risks in their interaction with biomaterials.
Materials reduced to the nanoscale can suddenly show very different properties compared to what they exhibit on a macroscale, enabling unique applications. For instance, opaque substances become transparent (copper); inert materials become catalysts (platinum); stable materials turn combustible (aluminum); solids turn into liquids at room temperature (gold); insulators become conductors (silicon). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nanoscales. Much of the fascination with nanotechnology stems from these unique quantum and surface phenomena that matter exhibits at the nanoscale.
Main article: Molecular self-assembly
Modern synthetic chemistry has reached the point where it is possible to prepare small molecules to almost any structure. These methods are used today to produce a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. This ability raises the question of extending this kind of control to the next-larger level, seeking methods to assemble these single molecules into supramolecular assemblies consisting of many molecules arranged in a well defined manner.
These approaches utilize the concepts of molecular self-assembly and/or supramolecular chemistry to automatically arrange themselves into some useful conformation through a bottom-up approach. The concept of molecular recognition is especially important: molecules can be designed so that a specific conformation or arrangement is favored due to non-covalent intermolecular forces. The Watson-Crick basepairing rules are a direct result of this, as is the specificity of an enzyme being targeted to a single substrate, or the specific folding of the protein itself. Thus, two or more components can be designed to be complementary and mutually attractive so that they make a more complex and useful whole.
Such bottom-up approaches should, broadly speaking, be able to produce devices in parallel and much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases. Most useful structures require complex and thermodynamically unlikely arrangements of atoms. Nevertheless, there are many examples of self-assembly based on molecular recognition in biology, most notably Watson-Crick basepairing and enzyme-substrate interactions. The challenge for nanotechnology is whether these principles can be used to engineer novel constructs in addition to natural ones.
[edit] Molecular nanotechnology: a long-term view
Main article: Molecular nanotechnology
Molecular nanotechnology, sometimes called molecular manufacturing, is a term given to the concept of engineered nanosystems (nanoscale machines) operating on the molecular scale. It is especially associated with the concept of a molecular assembler, a machine that can produce a desired structure or device atom-by-atom using the principles of mechanosynthesis. Manufacturing in the context of productive nanosystems is not related to, and should be clearly distinguished from, the conventional technologies used to manufacture nanomaterials such as carbon nanotubes and nanoparticles.
When the term "nanotechnology" was independently coined and popularized by Eric Drexler (who at the time was unaware of an earlier usage by Norio Taniguchi) it referred to a future manufacturing technology based on molecular machine systems. The premise was that molecular-scale biological analogies of traditional machine components demonstrated molecular machines were possible: by the countless examples found in biology, it is known that sophisticated, stochastically optimised biological machines can be produced.
It is hoped that developments in nanotechnology will make possible their construction by some other means, perhaps using biomimetic principles. However, Drexler and other researchers[4] have proposed that advanced nanotechnology, although perhaps initially implemented by biomimetic means, ultimately could be based on mechanical engineering principles, namely, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would enable programmable, positional assembly to atomic specification (PNAS-1981). The physics and engineering performance of exemplar designs were analyzed in Drexler's book Nanosystems.
But Drexler's analysis is very qualitative and does not address very pressing issues, such as the "fat fingers" and "Sticky fingers" problems. In general it is very difficult to assemble devices on the atomic scale, as all one has to position atoms are other atoms of comparable size and stickyness. Another view, put forth by Carlo Montemagno],[5] is that future nanosystems will be hybrids of silicon technology and biological molecular machines. Yet another view, put forward by the late Richard Smalley, is that mechanosynthesis is impossible due to the difficulties in mechanically manipulating individual molecules.
This led to an exchange of letters in the ACS publication Chemical & Engineering News in 2003.[6] Though biology clearly demonstrates that molecular machine systems are possible, non-biological molecular machines are today only in their infancy. Leaders in research on non-biological molecular machines are Dr. Alex Zettl and his colleagues at Lawrence Berkeley Laboratories and UC Berkeley. They have constructed at least three distinct molecular devices whose motion is controlled from the desktop with changing voltage: a nanotube nanomotor, a molecular actuator, and a nanoelectromechanical relaxation oscillator.
An experiment indicating that positional molecular assembly is possible was performed by Ho and Lee at Cornell University in 1999. They used a scanning tunneling microscope to move an individual carbon monoxide molecule (CO) to an individual iron atom (Fe) sitting on a flat silver crystal, and chemically bound the CO to the Fe by applying a voltage.
Space-filling model of the nanocar on a surface, using fullerenes as wheels.
Graphical representation of a rotaxane, useful as a molecular switch.
This device transfers energy from nano-thin layers of quantum wells to nanocrystals above them, causing the nanocrystals to emit visible light.[7]
[edit] Nanomaterials
This includes subfields which develop or study materials having unique properties arising from their nanoscale dimensions.[8]
Interface and Colloid Science has given rise to many materials which may be useful in nanotechnology, such as carbon nanotubes and other fullerenes, and various nanoparticles and nanorods.
Nanoscale materials can also be used for bulk applications; most present commercial applications of nanotechnology are of this flavor.
Progress has been made in using these materials for medical applications; see Nanomedicine.
[edit] Bottom-up approaches
These seek to arrange smaller components into more complex assemblies.
DNA nanotechnology utilizes the specificity of Watson-Crick basepairing to construct well-defined structures out of DNA and other nucleic acids.
Approaches from the field of "classical" chemical synthesis also aim at designing molecules with well-defined shape (e.g. bis-peptides[9]).
More generally, molecular self-assembly seeks to use concepts of supramolecular chemistry, and molecular recognition in particular, to cause single-molecule components to automatically arrange themselves into some useful conformation.
[edit] Top-down approaches
These seek to create smaller devices by using larger ones to direct their assembly.
Many technologies descended from conventional solid-state silicon methods for fabricating microprocessors are now capable of creating features smaller than 100 nm, falling under the definition of nanotechnology. Giant magnetoresistance-based hard drives already on the market fit this description,[10] as do atomic layer deposition (ALD) techniques. Peter Grünberg and Albert Fert received Nobel Prize in Physics for their discovery of Giant magnetoresistance and contributions to the field of spintronics in 2007.[11]
Solid-state techniques can also be used to create devices known as nanoelectromechanical systems or NEMS, which are related to microelectromechanical systems or MEMS.
Atomic force microscope tips can be used as a nanoscale "write head" to deposit a chemical upon a surface in a desired pattern in a process called dip pen nanolithography. This fits into the larger subfield of nanolithography.
[edit] Functional approaches
These seek to develop components of a desired functionality without regard to how they might be assembled.
Molecular electronics seeks to develop molecules with useful electronic properties. These could then be used as single-molecule components in a nanoelectronic device.[12] For an example see rotaxane.
Synthetic chemical methods can also be used to create synthetic molecular motors, such as in a so-called nanocar.
[edit] Speculative
These subfields seek to anticipate what inventions nanotechnology might yield, or attempt to propose an agenda along which inquiry might progress. These often take a big-picture view of nanotechnology, with more emphasis on its societal implications than the details of how such inventions could actually be created.
Molecular nanotechnology is a proposed approach which involves manipulating single molecules in finely controlled, deterministic ways. This is more theoretical than the other subfields and is beyond current capabilities.
Nanorobotics centers on self-sufficient machines of some functionality operating at the nanoscale. There are hopes for applying nanorobots in medicine[13][14][15], but it may not be easy to do such a thing because of several drawbacks of such devices.[16] Nevertheless, progress on innovative materials and methodologies has been demonstrated with some patents granted about new nanomanufacturing devices for future commercial applications, which also progressively helps in the development towards nanorobots with the use of embedded nanobioelectronics concept.[17][18]
Programmable matter based on artificial atoms seeks to design materials whose properties can be easily and reversibly externally controlled.
Due to the popularity and media exposure of the term nanotechnology, the words picotechnology and femtotechnology have been coined in analogy to it, although these are only used rarely and informally.