Wrist Device Makes Controlling Gadgets a Snap [Video]

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DIGITS: To track hand movement, Digits uses an infrared (IR) camera, laser, LED and an inertial measurement unit. The laser projects an IR line across the inside of the hand. The laser projects an IR line across the inside of the hand, intersecting the fingers and thumb as they bend inwards and marking the distance.

Microsoft’s Kinect technology lets gamers kick a virtual soccer ball or ride a digital skateboard using natural movements rather than a controller. Yet it can detect and interpret only full-body motion—it is relatively clueless about interpreting the movements of smaller body parts such as fingers. Now Microsoft researchers are developing a wrist-worn sensor to control video games—along with mobile phones, tablets, computers and TVs—with a flick of the wrist or snap of the fingers.

Like Spider-Man’s web shooters, the aptly named Digits straps to the inside of the wrist. To track hand movement, it uses an infrared (IR) camera, laser, light-emitting diode (LED) and an inertial measurement unit. The laser projects an IR line across the inside of the hand, intersecting the fingers and thumb as they bend inwards and marking the distance. As the hand closes, the laser intersects the fingers nearer to the palm and records those measurements as well.

By triangulating the positions of the camera, laser and different points on the hand that the laser hits, the device can reconstruct a virtual hand that mimics movement of the hand wearing the Digits device, to within 0.1 millimeter. This virtual hand would appear onscreen when the wearer is using it with a mobile phone or some other device (see video below, courtesy of Microsoft Research).

A Digits wearer could control different features on mobile devices—for instance, switching mp3 files by mimicking the turning of a dial, adjusting volume by moving a hand up or down to manipulate an invisible slider, or answering phone calls via a thumbs-up gesture—without even removing those devices from a pocket or handbag.

The researchers’ goal is to reach a level of fidelity that captures the full dexterity of the human hand, enabling fine-grained interactions with electrical devices down to the individual finger, says David Kim, a researcher in Microsoft Research’s Sensors and Devices Group.* Kim, also a member of the Digital Interaction Group at Newcastle University’s Culture Lab, and several colleagues presented the Digits research last week at the ACM Symposium on User Interface Software and Technology in Cambridge, Mass.

“This is body-worn and could be taken anywhere,” Kim says. “So you could be interacting in your physical world—working, cooking or reading—and then spontaneously interact with virtual content whenever you want to.”

The researchers began working on Digits in January, building a working version by the following month that could perform the basic functions and a more complete model in April. They attribute their ability to turn out a prototype so quickly to their experience working on other natural user interface projects including KinectFusion and Holodesk.

Although the prototype is too big and bulky to wear all the time, the researchers say it is possible to shrink Digits to watch size. The main challenge to miniaturizing the 125-gram device to the size of a wristwatch is using smaller components—the Web camera housing, the laser and the LED. The researchers made the housing for the latest prototype using a 3-D printer, which means creating a new one could be done quickly and cheaply. Miniaturizing the other components would depend on finding a smaller laser and LED out on the market. The researchers are also considering the possibility of a pop-up version of the device that rests flat on the wrist when not in use. This would likely require the development of more customized components.

Also, the researchers have to expand the scope of hand movements that Digits can capture. “Right now we can’t cover the entire range of movement,” Kim acknowledges. “If you straighten your fingers and stretch them too far backward the laser would not illuminate your fingertips, which means the infrared camera would not be able to see them. One work-around for this would be to have a second set of components on the back of the wrist to cover the whole range of finger movement.” In the prototype, one finger also can occlude other fingers, blocking the view for the laser and camera, says Otmar Hilliges, also a researcher in Microsoft Research’s Sensors and Devices Group.*

It is also unclear whether Digits functions properly in direct sunlight, or if sunlight would interfere with the IR laser—Microsoft has yet to test this scenario. Given how often smart phones and other gadgets are used in the light of day and the technology’s other limitations, it may be a while before hand signals are the de facto move for controlling wireless gadgets.

*Editor’s Note (10/16/12): Researchers David Kim and Otmar Hilliges are currently part of Microsoft Research’s Interactive 3D Technologies Group, which spun out of Microsoft Research’s Sensors and Devices earlier this year to focus on various forms of 3-D interaction based on novel hardware and algorithms.

Will TV Stations Power the Internet of Things?


Wouldn’t it be nice if sensor networks using radio frequency (RF) signals for monitoring air quality, the structural integrity of bridges and roads, and traffic or weather conditions—creating the so-called “Internet of things”—could simply draw their power out of thin air?

Now, using a technique called “ambient backscatter,” University of Washington researchers are doing just that: They have transformed existing wireless signals into both a power source and a communication medium for a sensor network. Each device within the researchers’ network is a very basic sensor made up of a credit-card-size circuit board with a transmitter, a receiver and a component for harvesting energy from TV signals, all connected to the same antenna. Embedded in roadways or bridges, such networks could monitor structural integrity and signal authorities about faults via e-mails or text messages. Someday they might even provide back up messaging capability if your phone’s battery is dead.

Earlier efforts had leveraged RF signals specifically for sensor power. This is done by capturing energy from TV or cellular signals and converting that energy into electricity to power a circuit. “What’s new here—we’re doing that [harvesting signals for power], but we’re also communicating by reflecting those TV signals,” says Joshua Smith, a computer scientist and electrical engineer of the University of Washington. The researchers presented their work (pdf) last week at the Association for Computing Machinery’s Special Interest Group on Data Communication 2013 conference in Hong Kong.

Devices in the researchers’ sensor network send and receive messages to one another by either absorbing or reflecting ultra high radio frequency TV signals produced by a nearby tower. Each device also has an LED light that flashes to indicate to observers when it has received a signal from another sensor in the network.

Repurposing existing RF signals does not interfere with their intended purpose, whether it is delivering TV programs or mobile communications. “All we’re doing here is creating additional reflections of existing wireless signals around us, whether they are TV, wi-fi or cellular,” says Shyam Gollakota, a University of Washington computer scientist who worked with Smith on the project. The sensors in the network require little power because they are not creating any radio signals of their own.

The researchers tested their proof-of-concept sensor network in several locations—inside an apartment building, on a street corner and on the top level of a parking garage—all within about 10 kilometers of a TV tower in the Seattle area. Outdoors, the sensors communicated up to 0.75 meters from one another at a rate of 1 kilobit per second. That’s enough throughput to transmit a small amount of data—the basic info that might be contained in a sensor reading or a text message. Indoors, the signals are weakened a bit, meaning the devices could exchange information at this rate within a slightly shorter range of half a meter. The researchers might increase transmission range in subsequent experiments by developing a more efficient coding scheme or by having the sensors send redundant signals that improve the chances of a message getting through.

The researchers expect they will eventually be able to increase data transfer rates to 600 kilobits per second or even 1 megabit per second.  One way of achieving this could be leveraging the structure in the TV signals instead of treating them as completely random and uncontrollable.

The primary restriction of ambient radio signal harvesting is that devices can draw limited amounts of power—measured in microwatts—even from large numbers of signals. Although the technique is feasible for powering small sensors, it is impractical for, say, recharging mobile phones or tablets. Nevertheless Smith imagines a scenario in which a mobile phone could use ambient backscattering to send and receive e-mails or text messages even if its battery is dead. “Or,” he adds, “you could build this type of capability into a smartphone just to reduce overall power consumption and improve battery life.”

Death of a Comet: What We Learned from the Passing of ISON

Time-lapse SOHO photo of Comet ISON's death plunge near the sun

Scientists were less than thankful this year on Thanksgiving Day (November 28) when they watched the famous Comet c/2012 S1, aka ISON, expire during its fiery pass by the sun. Yet seeing ISON meet its fate taught researchers about the structure and composition of the comet and gave them a clearer picture of why it broke up near the sun.

Comet ISON was a rare interloper in the inner solar system from the faraway Oort Cloud, a sphere of comets that surrounds the sun and planets about a light-year away. Its trajectory brought it within just three solar radii of the sun’s surface, putting it in a class of brazen comets called “sun grazers.” “We’ve never seen an Oort Cloud [castoff] sun-grazing comet before,” Karl Battams of the Naval Research Laboratory in Washington, D.C., said during a postmortem press conference Tuesday at the American Geophysical Union meeting in San Francisco. “It was an unprecedented object.”

Discovered just last September, ISON’s flight toward the sun prompted an observing campaign grander than any comet watch before. Telescopes all over the world as well as 13 space observatories and hundreds of amateur astronomers trained their sights on ISON over the past several months.

Whether ISON would survive its solar encounter to become a naked-eye spectacle was an open question. Ultimately, the comet broke up under the intense heat and tidal forces near the sun, disappointing stargazers who had hoped to catch a view of what some predicted would be the “comet of the century.” By watching ISON’s death unfold, researchers say they understand more about why it collapsed.

One of the bitterest twists in ISON’s end was that it briefly appeared to brighten after moving beyond the sun, raising false hopes that it had survived its closest pass, known as perihelion. By carefully analyzing satellite videos, scientists now have a theory for why that happened. “One possible explanation is that fragmentation occurred before the nucleus reached perihelion,” said Geraint Jones of University College London. If it broke up early, its pieces would have spread out because of the tidal forces near the sun: the closer pieces would be pulled more strongly by gravity, luring them farther in, whereas the pieces on the back side of the clump would lag due to a lessened gravitational pull. Coming out the other side of the sun, the same process would happen in reverse. When the cloud briefly coalesced again, the clump might have appeared to rebrighten before dimming out again.

One reason Comet ISON was thought to have a chance of survival was because a previous sun-grazing comet called C/2011 W3 (Lovejoy) did withstand an even closer pass by the sun in 2011. By comparing observations of both comets, scientists have theorized about what Lovejoy had that ISON lacked. “Comet Lovejoy was not an Oort Cloud comet,” Battams said. “It had been past the sun at least a couple times. It had perhaps built up a thick skin. Maybe that’s a factor.” ISON’s outer layer was raw and possibly volatile whereas Lovejoy had been burnt by the sun and could have had a hardier crust to withstand the solar heat and pull, scientists said.

Another factor might be ISON’s size. Determining the width of its nucleus is difficult, but the best estimates come from observations made by NASA’s Mars Reconnaissance Orbiter (MRO) when ISON made its closest pass by Mars in October. Based on these observations, researchers think ISON’s nucleus was probably smaller than 600 meters in diameter, making it relatively compact, “so its breakup and evaporation is not surprising,” said Alfred McEwen of the University of Arizona in Tucson, principal investigator for the HiRISE (High-Resolution Imaging Science Experiment) camera on the MRO.

When a Medical Test Reveals an Unwelcome Surprise

In a split second someone can be transformed into a patient-in-waiting.

A genetic scan ordered to test for one suspected condition picks up an elevated risk for a different, unexpected disease. Or a brain scan for a concussion detects a suspicious shadow. There’s no guarantee that those abnormalities may develop into something. There may not even be a treatment or therapy for the resulting condition. The pressing question then is: Should the patient be told about the results of such incidental findings? And the answer is more complicated than it seems.

As the cost of sequencing an entire genome drops, the day will soon arrive when documenting a full record of a patient’s DNA may become as routine as a cholesterol test. The results will inevitably lead to unexpected findings, and in many cases the medical establishment is ill-prepared to counsel patients about some uncertain surprises. No federal or state statutes directly address a clinician’s duty to return such findings to patients. And apart from legal or administrative considerations, there is no clear answer about what to do when faced with these difficult dilemmas in the lab, hospital or company boardroom.

Encountering these challenges is a “growing certainty” that will affect everybody, says Amy Gutmann, the chair of the Presidential Commission for the Study of Bioethical Issues. And such decisions may also have ripple effects for family members who may be carriers of the same genetic mutations.

The commission took a stab at these complicated questions, issuing new analysis and recommendations for how to manage these increasingly complex issues in medicine, research and with direct-to-consumer tests that allow a patient to send in a cheek swab and get health information (like the personalized genome services kit offered by 23andMe, that was recently blocked by the U.S. Food and Drug Administration). The recommendations do not prescribe specific directions. Rather, they are a call to action that presses professional organizations to draw up their own protocols for everything from abdominal scans to brain imaging. Each medical test may have its own range of findings that could pertain to the immediate condition for which a patient is being treated, but alternatively could lead to uncertainty and distress when an unexpected result emerges. In short, no simple answer exists, notes the commission report.

The document emphasized that more information is not always better for every patient. And an incidental finding of a gene mutation or other abnormality may not always lead to a particular disease. “For example, each of us has scores of deleterious mutations in our genes, and these will be picked up every time a whole genome sequence is obtained,” says committee member Stephen Hauser, chair of the Department of Neurology at the University of California, San Francisco. “The vast majority of these mutations do not lead to disease because we have backup systems in place, and we do not yet fully understand these backup systems,” he says. When each surgery or therapy is a balancing act, what if an exploratory surgery motivated by an incidental finding leads to serious complications?” the report asked.

Some 32 professional organizations and working groups have begun to address the issue ahead of the report, half of them in the U.S. Their plans in different areas helped informed the commission’s findings, alongside public comments and expert presentations to the panel. Take the American College of Medical Genetics and Genomics (ACMG). This year it developed guidelines for what to do when tests give rise to more information than the patient (and clinician) bargained for and how to manage the data. The ACMG advised that laboratories always look for and return findings for 24 genetic conditions that arise from large-scale genetic sequencing regardless of individual patient preferences because those two dozen conditions, gene variants or mutations all have existing medical interventions. As clinical sequencing becomes more common, pretest counseling will become more impractical and “lack of standardization and its application to patients of all circumstances might result in deeply varying levels of truly informed preference setting,” the group reasoned. In deciding what to list, the ACMG said the condition “needed to be fairly well understood and that only variants in the associated genes that met a standard of relatively high likelihood of being disease-causing are to be reported.”

Jupiter's Moon Europa Spotted Spouting Water

The Hubble Space Telescope has observed possible plumes emanating from the moon’s south pole

Jupiter’s icy moon Europa, home to a probable buried ocean, just added another twist to its exotic cool. The Hubble Space Telescope has spotted possible plumes of water spraying from Europa’s south pole.

The jets resemble the giant icy geyser seen on Saturn’s moon Enceladus. Plumes on Europa could be even more exciting because they hint at the ability to tap a subsurface habitat that might even harbor extraterrestrial life.

“If this pans out, it’s potentially the biggest news in the outer Solar System since the discovery of the Enceladus plume,” says Robert Pappalardo, a planetary scientist at the Jet Propulsion Laboratory in Pasadena, California, who was not involved in the research.

The work, reported today in Science, comes with plenty of caveats. Although previous theoretical work suggested that plumes could exist on Europa, earlier tantalizing hints of them have come to nothing. This time, Hubble spotted the potential plumes in just one observation. And if they do turn out to be real, the plumes might not even be connected to the moon’s deep subsurface ocean.

“It’s a first-time discovery, and we need to go back and look some more,” says team member Joachim Saur, a planetary scientist at the University of Cologne in Germany.

Moon shot
Saur and his colleagues have looked for Europan plumes before, to no avail. In 2012, the group decided to take another shot. Using an ultraviolet camera on Hubble, they scrutinized Europa once in November and once in December of that year. The November study found nothing, but the 2.7-hour exposure in December spotted blobs of hydrogen and oxygen near Europa’s south pole.

Their size, shape and chemical make-up is best explained by two plumes of water vapor roughly 200 kilometers high, says team leader Lorenz Roth, a planetary scientist at the Southwest Research Institute in San Antonio, Texas. That is many times the height of potential Europa plumes calculated by some theorists. It would mean that Europa’s jets reach higher than the volcanic eruptions on Jupiter’s moon Io, but not as high as the towering plume that spouts from Enceladus.

Roth’s team spotted the plumes when Europa was at its greatest distance from Jupiter. Changing stresses in the moon’s crust, caused by tidal forces between the moon and planet, may explain why the researchers didn’t see any plumes in the November observation when Europa and Jupiter were close. “Maybe Europa is just burping once in a while,” Pappalardo says.

It is possible that the plumes may not tap into the deep subsurface, says Saur. The frictional heat of ice rubbing against itself might melt parts of the icy crust and feed the plumes.

Either way, the discovery could be a shot in the arm for upcoming missions. In 2022, the European Space Agency is planning to launch a probe that would explore Europa as well as Jupiter and its other moons. And Pappalardo leads a mission concept team at NASA that is outlining a possible US spacecraft to Europa.