Saturday, August 1. 2009
This post is the fourth in a series based on my book, The History of Wireless: How Creative Minds Produced Technology for the Masses, published in 2008. Each week I’ll present the most interesting and surprising facts about the history and future of wireless from one of fourteen chapters.
The Wave Makers
Who was first to demonstrate radio waves? The German physicist Heinrich Hertz gets official credit, but the English physicist Oliver Lodge proved Maxwell’s theory at around the same time. Why one became internationally famous practically over night and the other only earned an honorable mention is a fascinating story.
Hertz declined the challenge by Hermann von Helmholtz, the dean of German science, to prove an obscure but crucial aspect of Maxwell’s theory (displacement current). Hertz’s explanation at the time was that he did not know enough about Maxwell’s theory and, in any event, could not think of any relevant experiments.
Then Hertz observed an unexpected but subtle phenomenon while preparing a demonstration for his students. It wasn’t long before he demonstrated radio waves—proving Maxwell’s theory—and discovered the photoelectric effect to boot in the process.
Hertz set out to teach his students about electric induction. (Today, induction is used for purposes such as stepping down 110 volts from a power outlet to 12 volts.) In the school’s laboratory he found a couple of heavy wire coils that terminated in spark gaps and immediately realized they could be used to provide a visual demonstration. A surge of electricity in the first coil would cause it to spark and induce a sufficient current in the second coil to make it spark, too. But when he tried it he was surprised at how easy it was to make the second coil spark. He suspected something other than induction was at work.
He straightened out the first coil but kept the spark gap; in place of the second coil, he used a ring of heavy wire that didn’t quite make a full circle (creating another spark gap). He found he could “induce” a spark in the wire ring even from across the room. As he moved the ring further away, the size of the sparks might increase, then decrease, and then increase again—suggesting he was observing the peaks and nulls of a wave. To better see the sparks, he sometimes placed the ring in a wooden box with a little window. He noticed the sparks were smaller in the darkened box and concluded that light affected the size of the sparks, as well.
After months of experimenting, he knew that he had proved Maxwell’s theory, and published a paper that caused an immediate sensation. Ironically, when asked by newspaper reporters about the waves, Hertz assured them it was just an interesting phenomenon with no practical applications.
Oliver Lodge was also a talented physicist, but he seemed to have a knack for coming up short. He did an experiment that involved discharging a Leyden jar and produced peaks and nulls along a long wire. Satisfied his experiments proved Maxwell’s theory he promptly left on vacation, figuring there would be plenty of time to publish when he got back. He returned to hear the news that Hertz had beat him to the punch. (Later, he realized that the wire only served to guide the waves; it would have been a more dramatic experiment without the wire.)
Lodge also demonstrated wireless signaling before Marconi but neglected to use Morse code. Then Lodge invented a method for dividing the radio spectrum into different frequency channels—what he called “syntony” and we now call "channel surfing." This time he was smart: he patented his invention and eventually sold the rights to Marconi.
Though Lodge did not think it would ever be possible to communicate across the Atlantic Ocean using radio waves, he did believe it is possible to communicate with the dead.
Next time: How Morse and Bell Invented Wire Communications--Setting the Stage for Wireless
Friday, July 24. 2009
This post is the third in a series based on my book, The History of Wireless: How Creative Minds Produced Technology for the Masses, published in 2008. Each week I’ll present the most interesting and surprising facts about the history and future of wireless from one of fourteen chapters.
The Surprising Story of How James Clerk Maxwell Discovered Radio Waves
The Scottish theoretician James Clerk Maxwell is famous for his beautiful and concise equations summarizing the relationships between electricity, magnetism, and electromagnetic fields.
But did you know...
- Maxwell's equations as taught today are not the equations as Maxwell wrote them. His equations were consolidated and updated by Heinrich Hertz and Oliver Heaviside.
- Maxwell discovered electromagnetic waves on paper using a mechanical analogy replete with spinning gears and idle wheels. The only empirical evidence that Maxwell had was that the measured speed of light, which he suspected was a form of electromagnetic radiation, was close to the speed he calculated for electromagnetic waves.
- Maxwell's theory of the electromagnetic field assumed the existence of a "luminiferous ether" permeating all of space. To this day, there is no way to explain how Maxwell could have been right when the ether theory was wrong. (Maxwell assumed the motion of charged particles in the ether.)
- Maxwell was the first scientist to discover that not all physical laws must be obeyed in all cases. This idea, which he conceived while thinking about gases and heat, prepared the way for quantum mechanics and information theory.
- Maxwell appreciated empirical research, but he also felt that theory was needed to help "reduce the facts to order." He didn't see theories as provisional facts as many do today; he saw theories as models to help guide further research.
Monday, July 6. 2009
This post is the second in a series based on my book, The History of Wireless: How Creative Minds Produced Technology for the Masses, published in 2008. Each week I’ll present the most interesting and surprising facts about the history and future of wireless from one of fourteen chapters.
Michael Faraday is widely considered the greatest experimentalist in history. However, he broke the mold in two major respects. While he sought facts and had little patience for theories, his religious views clearly inspired some of his biggest discoveries. His life story also challenges contemporary assumptions about formal education.
The historical record shows that great scientists may be atheists or deeply religious, or they may fall somewhere in the middle. That does not mean, however, that religious beliefs are irrelevant. For reasons I don’t claim to understand, religious belief and non-belief seem equally capable of inspiring scientists, though one may be more appropriate than the other for making specific breakthroughs at specific moments in history.
Faraday believed that nature was designed and the researcher’s job is to discover the details. His conviction that there is an underlying unity to nature led him to devise experiments demonstrating the links between electricity, magnetism, and light. He believed so strongly in the relationship between light and magnetism that he spent decades pursuing it.
Faraday also did not hesitate to assert the reality of something non-material: force fields. However, it wasn’t just an assertion; Faraday produced vast evidence in the form of verifiable and repeatable experiments. He demolished the then popular idea that science need only be concerned with matter and motion.
People who believe that scientists should deal exclusively with empirical facts are fond of citing Faraday as an example. However, there was more to Michael Faraday than they might care to admit. Faraday emphasized the priority of facts given the many vague and far-flung theories circulating at the time. But he also acknowledged that intuition and theory can prove their worth by suggesting new experiments. No doubt Faraday’s religious convictions helped guide his own choice of experiments.
Today’s science establishment seems convinced that tomorrow’s scientists will be made in K-12 classrooms. Michael Faraday is a shining counter example: he received little formal education and was primarily self-taught. The counter-counter argument is that what worked for Faraday in the 19th century will not work today. However, that ignores the fact that Faraday was never fully accepted by his peers.
Michael Faraday demonstrated that an intelligent and determined individual can succeed in science despite lacking the credentials, status, and foundation of knowledge generally considered necessary. (For starters, Faraday was not conversant in higher mathematics.) What today's science establishment fails to see is that there is always a need for people who—like most entrepreneurs and dissidents—travel a different path. To wit, scientific progress depends on the interplay between conventional and non-conventional ideas and methods.
Next time: James Clerk Maxwell Avoids the Laboratory and Discovers Electromagnetic Waves in his Mind
Friday, June 26. 2009
This post is the first in a series based on my book, The History of Wireless: How Creative Minds Produced Technology for the Masses, published in 2008. Each week I’ll present the most interesting and surprising facts about the history and future of wireless from one of fourteen chapters.
Most encyclopedias credit Italian professor Alessandro Volta with inventing the electric battery. That’s true, but it almost entirely misses the point.
What Volta really invented was the first source of continuous current. Up until then, natural philosophers (now called “scientists”) could only generate and store static charges. Static electricity is good for producing sparks and shocking people and animals, but that’s about it. Using Volta’s continuous current apparatus, investigators across Europe found they could create light and heat, drive chemical reactions, and perform a wider range of experiments. That, in turn, led to the telegraph, telephone, and wireless.
Volta laid the foundation for electronics; demand for AA batteries came much later.
There are two other interesting facets to Volta’s story. Volta did not set out to invent a device producing continuous current. He was merely trying to win a debate with the Italian physiologist Luigi Galvani. Galvani made a frog’s leg muscle contract just by touching the attached nerve with his scalpel; he theorized that touching the nerve disturbed the creature’s “animal electricity.” Volta knew that a tiny amount of electricity can trigger muscle contractions. He also knew that tiny amounts of electricity can be generated just by bringing certain materials (such as dissimilar metals and moist tissue) into contact with each other.
To wit, the electric battery issued from a clash of ideas.
The electric battery was actually Volta’s second invention exploiting the production of electricity through simple contact. His first was the celebrated electrophorus. Prior to the electrophorus, the only way to generate electric charges was to rub certain materials together. Rubbed once, the electrophorus could produce electric charges multiple times. Like many great scientists and inventors, Volta found new ways to milk a single good idea. Had he lived to see Faraday’s dynamo--which converted motion into electricity—he might have dismissed it as a throwback to persistent rubbing.
Next time: How a Blacksmith’s Son Discovered Force Fields
Monday, April 20. 2009
What will wireless look like in 5 or 10 years? For over 25 years the wireless industry has repeatedly trounced every subscriber forecast. There are now more than 4.1 billion mobile phone subscribers worldwide. Mobile phone markets in China and India are still growing by tens of millions of users each month.
There is a huge market for replacement handsets. Operators push handset upgrades to reduce churn (subscribers switching to other service providers) and drive premium services (such as mobile TV). Smartphone shipments are increasing while standard phones are becoming smarter. Inside the industry, mobile applications (and application stores) are hot.
As consultant Chetan Sharma puts it, “the mobile phone will become the remote control of our lives.” The number and variety of applications is overwhelming. With more than 4 billion potential customers, even applications that seem esoteric or silly could make developers rich. Major categories include mobile entertainment, mobile health, social networking, location-based services, and mobile commerce.
So what will mobile devices and services look like in 5 or 10 years? I suspect that will be largely determined locally. It will also depend on who is first to grab mind share. There are way too many choices; the average subscriber will let early adopters and power users sort them out.
I find turn-by-turn driving directions to be compelling. But it may not be compelling to people who live in small towns or depend on public transportation. Mobile health is also powerful, but it won’t take off until hospitals, physician groups, and pharmacies buy in.
I suspect that more “things” will become connected to wireless networks. Hospitals are already equipping wheelchairs and IV pumps with wireless transmitters so they can be located when needed. Amazon’s Kindle downloads titles via a mobile phone network; the user does not need an individual subscription. I wouldn’t be surprised if in 5 or 10 years most automobiles, portable computers, and air conditioners follow Kindle’s lead.
The flipside is that most mobile phones will support Bluetooth and/or Wi-Fi to communicate with local devices. Near field communications (NFC) makes sense for secure and quick transactions. Together, these technologies permit mobile operators to offload certain types of communications while making subscribers even more dependent on their existing service providers. When it’s time for a handset upgrade, guess who can ensure seamless transfer of your personal data and settings?
A century ago, William Ayrton predicted a future in which people are always in contact via wireless technology. To paraphrase Ayrton, "If you try to reach someone and they don’t respond, then it can only mean they are dead." When I first read that I was impressed, but now I’m not so sure. In the future your wireless phone may just keep responding without you.
-- I discuss these and other cool wireless technologies in my book The History of Wireless.
Monday, June 23. 2008
Mobile phones and wireless local area networks (WLANs) draw more attention, but short range wireless technologies have tremendous potential. Bluetooth and wireless USB enable a wide range of gadgets to communicate with each other, personal computers, and electronic kiosks. ZigBee and near field communications (NFC) portend sensors and controllers embedded in our environment and even our bodies.
Short range wireless technologies are designed to provide communications over small distances—from tens of feet down to an inch or less—with levels of security, low cost, convenience, and long battery life not attainable using other wireless solutions. The goal is to make wireless so inconspicuous and inexpensive that it becomes a pervasive feature of not only mobile phones and notebook PCs, but everything from digital cameras to advertising displays to heart pacemakers to the doors and windows in homes and offices.
Bluetooth and wireless USB could be headed for a showdown. Bluetooth was primarily conceived to enable mobile phones to communicate locally with personal computers and each other for tasks such as configuring the phone, synchronizing address books, and mobile commerce. Though Bluetooth has finally gained market traction after more than a decade of development, mobile phones and PCs have evolved over that period, as well. The universal serial bus (USB) has become a popular solution for connecting a wide assortment of peripherals to personal computers. Wireless USB enjoys a performance advantage over Bluetooth: wireless USB runs 110 Mbits/s and faster, while the current Bluetooth 2.0 specification runs just 2.1 Mbits/s. With more and more mobile devices downloading music and video content, speed becomes crucial.
But don’t write off Bluetooth just yet. A big challenge for short range wireless technologies is achieving critical mass in the market; Bluetooth is the only one of the short range wireless technologies I’m discussing that has accomplished this. Plans are in the works for adding high speed and ultra low power to the Bluetooth standard.
ZigBee and near field communication (NFC) standards have been in development for some time. Though products are just coming to market, they address sizable opportunities such as mobile commerce and home security. Because these technologies are designed to consume minimal power, they offer intriguing possibilities for sensors embedded in our environment and even our bodies. If just one of these applications takes off, it could quickly demand millions of devices.
I recently spoke with executives at two companies pioneering short range wireless: Terry Moore, CEO of MCCI Corp. and Cees Links, CEO of GreenPeak Technologies.
MCCI Corporation (www.mcci.com) is moving aggressively into wireless USB—having already produced software connecting hundreds of millions of mobile devices to PCs via USB cables. Wireless USB is even more compelling: it eliminates cables and docking units, reduces the number of physical ports required, and is ideal for nomadic devices. The challenge is producing wireless USB solutions that are secure, easy to configure, and reliable. Given MCCI’s considerable experience connecting nomadic devices via USB cables, the company is well positioned to serve the emerging wireless USB market.
GreenPeak Technologies (www.greenpeak.com) is developing ultra low power wireless modules for sense and control applications. Cees Links, a veteran of the wireless LAN market, believes that installation and maintenance concerns have inhibited market development. Needed are wireless devices that can run ten years off coin-size batteries or—better yet—devices that can harvest energy from their surroundings.
MCCI and GreenPeak are developing short range solutions with long range ramifications. If wireless USB catches on, then we can expect nearly all portable electronic devices to connect to PCs and the Internet. That, in turn, could engender new devices (such as electronic shopping assistants) and enhance existing devices (for example, a wrist watch with built-in music player). And if ultra low power ZigBee takes off, it could dramatically increase network density, with each Internet-connected PC branching off into dozens of sensors and controllers.
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