Tag Archives: electrical engineering

In photo: sixteen year old inventor Arsh Shah Dilbagi demonstrating his breath to voice synthesizer.

Indian teenager invents cheap device that turns breath into speech

In photo: sixteen year old inventor  Arsh Shah Dilbagi demonstrating his breath to voice synthesizer.

In photo: sixteen year old inventor Arsh Shah Dilbagi demonstrating his breath to voice synthesizer.

About 1.4% of the world’s population today is speech impaired, due to conditions such as Amyotrophic lateral sclerosis (ALS), locked-in syndrome (LIS), Encephalopathy (SEM),Parkinson’s disease, and paralysis. Imagine all the people living in Germany today were unable to speak and you’ll come to realize just how far reaching this condition is. So, aside for those being paralyzed, there are a lot of people who can’t speak, making any kind of relationship with friends and family unbearable – the patient is essentially trapped in a situation where he/she is forced to live inside her head until the end of days. An Indian teenager sought to address this heartbreaking world problem and succeed in building a device that is easy to make, cheap and effective. Most of all, it’s extremely ingenious since it can translate orderly breaths into speech.

Follow my breath

If you followed the work of the esteemed physicist Stephen Hawking or have seen him on TV, you may have noticed that he uses a complex computer interface to speak. Oddly enough, his voice is one of the most recognized on the planet, and it’s all synthesized! The tech he employs is, however, extremely expensive.

Sixteen-year-old Arsh Shah Dilbagi took a different route. Instead of building complex and expensive IR sensors that trigger off of twitches in the cheek muscle under the eye, like those used by Hawking’s machine, Dilbagi designed a system that can translate a user’s breath into electrical signals. As such, the device is only made out of a pressure-sensitive diaphragm etched directly into a silicon chip, and an amplifying device to increase the sound of the user’s breath. This allowed him to keep the price tag at $80, compared to thousands someone would need to cash out for a device similar to Hawking’s.

The tech, called ‘TALK’, can identify two types of breaths, as well as  different intensities and timing so that the user can effectively spell out words using Morse code. An embedded microprocessor then reads the timed breaths as dots and dashes and translates them into words. A second microprocessor synthesizes the words to spell them into a voice. It’s remarkably simple and effective, even though the user needs to be trained to use Morse code, but it sure beats the alternative.

“After testing the final design with myself and friends and family, I was able to arrange a meeting with the Head of Neurology at Sir Ganga Ram Hospital, New Delhi and tested TALK (under supervision of doctor and in controlled environment) with a person suffering from SEM and Parkinson’s Disease,” Dilbagi reports. “The person was able to give two distinguishable signals using his breath and the device worked perfectly.”

Dilbagi is currently the only finalist in Asia enrolled in Google’s Global Science Fair, a competition that’s open to 13 to 18-year-olds from anywhere in the world. Let’s wish him the best of luck!

Silicon polymer and battery used for the research. Photo: University of California

Silly Putty ingredient helps improve batteries

silly putty

Photo: momfabfun.com

When you think about Silly Putty toys, the last thing that comes to mind is high-tech. A group of researchers, however, used a novel trick to incorporate  an ingredient in Silly Putty to improve lithium-ion battery life between charges by three times the industry standard.

For what’s it worth, Silly Putty is actually one of the most fascinating man-made materials. One of the most important resources needed for World War II war production was rubber. It was essential for tires (which kept the trucks moving) and boots (which kept the soldiers moving). Out of this need, scientists were charged with developing a synthetic version of rubber. In 1943, engineer James Wright combined boric acid and silicone oil, producing an interesting gob of goo.

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Upon testing the substance, Wright discovered it could bounce when dropped, stretch farther than regular rubber, didn’t collect mold, and had a very high melting temperature. A very peculiar and strange material, but unfortunately enough it didn’t pose the required practical characteristics to replace rubber. Instead, it became a source of entertainment when it was marketed as a children’s toy in the 1950’s. By then, it had grown very popular. Even Apollo astronauts can be seen in some rare footage quenching their boredom with this silly toy.

Silicon polymer and battery used for the research. Photo: University of California

Silicon polymer and battery used for the research. Photo: University of California

Researchers at University of California believe there are actually more uses to the Silly Putty than meets the eye. One of the main ingredients of the toy is silicon dioxide (SiO2), basically a powdered quartz that is extremely common to find, hence very cheap. Researchers used SiO2 to create a new battery anode, replacing the conventional carbon anode.

This isn’t the first time this sort of attempt has been made, but previous efforts have rendered very poor performance. The key this time was that the silicon dioxide was rolled into nanotubes which allowed them to produce three times the energy capacity compared to carbon-based anodes. In addition, the material is non-toxic and found in everything from children’s toys to fast foods.

More importantly, the Silly Putty-derived nanotube anodes can be cycled for hundreds of times beyond the tested limits, according to the University of California researchers. Next, they plan on scaling their findings for mass production.

Results appeared in the journal Nature.

Jeong-Yun Sun (left) and Christoph Keplinger show off an ionically conductive material that is very stretchy and completely transparent. Photo by Eliza Grinnell/SEAS Communications

Novel ionic conducting material acts like artificial muscle and plays music

In a breakthrough moment, researchers at Harvard School of Engineering and Applied Sciences  have developed a novel material resembling a simple transparent disk, which the researchers applied an electrical signal to and used it to play music. This is no ordinary speaker, though. The disk consists of a thin sheet of rubber sandwiched between two layers of a saltwater gel, and  represents the first demonstration that electrical charges carried by ions, rather than electrons, can be put to meaningful use in fast-moving, high-voltage devices.

Using ionic materials for high voltage applications has been thought to be intractable in the past, due to the high number of constraints.  High voltages can set off electrochemical reactions in ionic materials, producing gases and burning up the materials. Also, ions, being much larger than electrons, take longer to propagate through a circuit affecting signal quality. The system developed at Harvard overcomes both of these challenges, all while exposing a number of benefits inaccessible to traditional, electron carrying conductors.

“Ionic conductors could replace certain electronic systems; they even offer several advantages,” says co-lead author Jeong-Yun Sun, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences(SEAS).

Jeong-Yun Sun (left) and Christoph Keplinger show off an ionically conductive material that is very stretchy and completely transparent. Photo by Eliza Grinnell/SEAS Communications

Jeong-Yun Sun (left) and Christoph Keplinger show off an ionically conductive material that is very stretchy and completely transparent. Photo by Eliza Grinnell/SEAS Communications

And, we’re not talking here just about sound speakers. The researchers chose to design a speaker with their compound material simply because its the best proof of concept. To produce sound in the whole human audible spectrum – 20 Hz to 20kHz – a speaker needs to carry high voltage and be capable of contracting rapidly to produce vibrations and push the air in a specific manner, producing what we commonly refer to as sound. This wasn’t though possible in the past for ionic conductors.

“It must seem counterintuitive to many people, that ionic conductors could be used in a system that requires very fast actuation, like our speaker,” said Sun. “Yet by exploiting the rubber layer as an insulator, we’re able to control the voltage at the interfaces where the gel connects to the electrodes, so we don’t have to worry about unwanted chemical reactions. The input signal is an alternating current, and we use the rubber sheet as a capacitor, which blocks the flow of charge carriers through the circuit. As a result, we don’t have to continuously move the ions in one direction, which would be slow; we simply redistribute them, which we can do thousands of times per second.”

Ions that play music

Since it can suit the high demands a speaker poses, the material is versatile enough to be used in other applications, where other options aren’t available. Key traits of the Harvard ionic conductor include: the capacity to stretch to many times their normal area without an increase in resistivity (common issue in stretchy electronics); transparency (high reward of optics apps); bio-compatibility (!).

A video demonstration of the  gel-based audio speaker can be seen in the video embedded below.

Immediate applications includes devices that need a soft, transparent layer that deforms in response to electrical stimuli — for example, on the screen of a TV, laptop, or smartphone to generate sound or provide localized haptic feedback. Smart windows are also a highly interesting and appealing idea – you could potentially place this speaker on a window and achieve active noise cancellation, with complete silence inside.

“With wearable computing devices becoming a reality, you could imagine eventually having a pair of glasses that toggles between wide-angle, telephoto, or reading modes based on voice commands or gestures,” suggested Sam Liss, director of business development in Harvard’s Office of Technology Development

The term capabilities of the technology are far more interesting, however. The electrical signal that relays information to and fro the brain is actually carried by charged ions, not electrons. Seeing how the ionic conductor developed at Harvard is also biocompatible, it’s not difficult to imagine high-tech biotechnology like artificial muscles, limbs or organs meshing in this novel material.

“The big vision is soft machines,” said co-lead author Christoph Keplinger, who worked on the project as a postdoctoral fellow at SEAS and in the Department of Chemistry and Chemical Biology. “Engineered ionic systems can achieve a lot of functions that our body has: They can sense, they can conduct a signal, and they can actuate movement. We’re really approaching the type of soft machine that biology has to offer.”

The ion conductor was described in a paper published in the journal  Science.

 

 

Flexible electronics

Stretchy electronic circuits mimic nature and allow for flexible computers

Flexible electronics

(c) Rafael Libanori, Randall M. Erb and André R. Studart

Flexible electronics are still in their infancy, however scientists have raved about them for years now. Electronics that can bend and stretch a lot without breaking open up a slew of new possibilities, from smart clothing equipped with all kinds of sensors to flexible micro-devices. Recently, researchers at the  Swiss Federal Institute of Technology (ETH) made a great leap forward in turning flexible electronics into a practical application after they successfully made stretchy electronics by embedding delicate circuits into a flexible surface that can be stretched three times its normal length.

The researchers drew their inspiration from nature, namely from the way tendons connect to bones. Electronic circuits are very fragile and when subjected to bending on a flexible board, they break easily. Finding a balance between the two is far from being an easy task.

“You have two materials with very different mechanical properties,” Andre Studart, a researcher at the Swiss Federal Institute of Technology in Zurich, told Reuters. “The challenge is to bridge these different properties.”

The scientists tackled the issue by developing a novel surface that has both stiff, used to harbor the electronics, and flexible regions – like tiny islands. The material employed is polyurethane, the same substance used in skateboard wheels and floor coating. The soft part can stretch by 350 percent, while the electronics are safe from bending and torsion as they sit on a stiff surface,  created by impregnating the material with tiny platelets of aluminium oxide and a synthetic clay called laponite.

Islands of circuits

If you know a thing or two about strength of materials, you might wonder how the junction points between the stiff and flexible parts of the new sheet do no break. The researchers overcame this hurdle by applying multiple layers to comprise the sheet that incrementally become stiffer from bottom to top.

To illustrate their research, the scientists added LED circuits on the stiff islands. The LEDs stayed lit even when the sheet was stretched to 150 percent of its length.

The research findings are set to hit the commercial market quite earlier than thought, since MC10 Inc, a Massachusetts-based start-up born out of research by John Rogers and his team at the University of Illinois, is already planning on delivering products based on stretchable electronics. One of their feature products is a sensor-laden, flexible skullcap that monitors impacts to the head during sport, which was developed in cooperation with Reebok and is expected to go on sale next year.

A more interesting stretchy electronics device, however, is  a balloon catheter with built-in electronic sensors for heart patients, which researchers plan to start testing on people in the next year or so. Balloon catheters are regularly used by surgeons to unclog arteries “but those balloon catheters do not have any active surgical power,” says John Rogers, a materials scientists at the University of Illinois in Urbana-Champaign. “They are just dumb mechanical instruments.”

The device developed by Rogers’ company can monitor features such as temperature, pressure, blood flow and electrical activity, and can also remove damaged tissue.

The present research, who’s findings were detailed in the journal  Nature Communications, isn’t the only one to report success with flexible electronics, however. In the past we’ve written about how University of Pennsylvania researchers made flexible electronic circuits out of nanocrystals or how a novel coating technique allowed for the manufacturing of the first entirely plastic solar cell.

rdue and Harvard universities. The transistor is made from tiny nanowires of a material called indium-gallium-arsenide, which could replace silicon within a decade. The image was taken with a transmission electron microscope (Purdue University image)

Transistor nanowires stacked in ‘4-D’ hint to future tech

rdue and Harvard universities. The transistor is made from tiny nanowires of a material called indium-gallium-arsenide, which could replace silicon within a decade.  The image was taken with a transmission electron microscope (Purdue University image)

rdue and Harvard universities. The transistor is made from tiny nanowires of a material called indium-gallium-arsenide, which could replace silicon within a decade. The image was taken with a transmission electron microscope (Purdue University image)

It’s amazing how this cross-section view on the right showcasing a  new type of transistor from  Purdue and Harvard universities resembles a Christmass tree, just in the nick of the time for the holiday season. Its design, however, has little to do with a Christmas trees. Make no mistake, the transistor’s shape and design follows a pattern that allows it to operate faster and possibly lead to a new generation of computers powered by it.

“It’s a preview of things to come in the semiconductor industry,” said Peide “Peter” Ye, a professor of electrical and computer engineering at Purdue University.

The transistor are made out of three nanowires progressively smaller, yielding a tapered cross section resembling a Christmas tree. Typically, transistors are flat, however the researchers’ design follows previous work where a 3-D structure was used. This allows for a significant  improvement in performance by linking the transistors vertically in parallel.

“A one-story house can hold so many people, but more floors, more people, and it’s the same thing with transistors,” Ye said. “Stacking them results in more current and much faster operation for high-speed computing. This adds a whole new dimension, so I call them 4-D.”

Transistors are indispensable to electronic components since they regulate the flow of electricity, and thus information. These devices have what are called logic gates which either switch the transistor on and off and direct the flow of electrical current. The smaller the logic gate, the faster the operation time, and in turn performance.

In today’s high-end 3-D silicon transistors, the length of these gates is about 22 nanometers, or billionths of a meter. This is where silicon, however, has reached its limit and the future’s next generation transistors need to employ a different semiconductor in order to pass this threshold.

A new semiconductor shrinks transistors even further

Researchers from Purdue and Harvard universities created their transistor from a material that could replace silicon within a decade, called  indium-gallium-arsenide. The material is among several promising semiconductors being studied to replace silicon. Such semiconductors are called III-V materials because they combine elements from the third and fifth groups of the periodic table.

And that’s not all either. In order to shrink transistor even further, another important design parameter, the insulating, or “dielectric” layer that allows the gate to switch off, also needs to be changed. Nanowires in the new transistors are coated with a different type of composite insulator, a 4-nanometer-thick layer of lanthanum aluminate with an ultrathin, half-nanometer layer of aluminum oxide.

Ultimately, the researchers  transistors made of indium-gallium- arsenide with 20-nanometer gates, which is a milestone, Ye said.

Findings will be detailed in two papers to be presented during the International Electron Devices Meeting on Dec.  8-12 in San Francisco

 

A typical light emitting diode, captioned here only for illustrative purposes. Not the actual LED used in the presently discussed research.

MIT engineers create LED that has 230% efficiency. Thermodynamics laws still in place

A typical light emitting diode, captioned here only for illustrative purposes. Not the actual LED used in the presently discussed research.

A typical light emitting diode, captioned here only for illustrative purposes. Not the actual LED used in the presently discussed research.

A group of researchers at MIT have successfully managed to create a light emitting diode (LED) that has an electrical efficiency greater than 100%. This might sound preposterous, and against everything you learned in physics, however the system is still governed by fundamental laws of thermodynamics.

This extraordinary power conversion efficiency was obtained by a decrease in applied voltage to an LED with a small band gap. As the voltage was steadily halved, it was observed that the electrical power was reduced by a factor of four, but the light power emitted only dropped by a factor of two. Where this extra energy come from? The key here is lattice vibrations caused by heat coming from the surroundings. Thus, the device’s efficiency is inversely proportional to its output power and diverges as the applied voltage approaches zero. Over 100% efficiency was reached in the experiments, all without violating energy conservation principles.

The best efficiency was reached when such a LED was plugged to 30 picowatts, powering a LED which produced 69 picowatts of light, in the trillionth of a watt order – 230% efficiency. There’s a huge flaw in this otherwise miracle system – the power itself is simply too small to light anything. The principle itself is terribly exciting and the MIT scientists involved in the research are confident these findings will aid new advances in energy-efficiency electromagnetic communication.

Results were described in a recently published paper in the journal Physical Review Letters.

3D perspective of a single-atom transistor. (C) RC Centre for Quantum Computation and Communication, at UNSW.

Scientists develop single-atom transistor with ‘perfect’ precision

3D perspective of a single-atom transistor. (C) RC Centre for Quantum Computation and Communication, at UNSW.

3D perspective of a single-atom transistor. (C) RC Centre for Quantum Computation and Communication, at UNSW.

Australian scientists at University of New South Wales have successfully managed to build the first single-atom transistor, using a scalable, repeatable technique. The scientific community all over the world have already hailed this achievement as a highly important milestone, as single-atom transistors are considered as a critical building block for the eventual development of quantum computers.

The tiny device was created using a scanning-tunneling microscope (STM), which allowed the team of researchers, who have been working on this project for ten years, to manipulate hydrogen atoms around a phosphorus atom with extreme precision onto a silicon wafer – all in ultra-high vacuum conditions. The microscopic device was even fitted with tiny visible markers etched onto its surface so researchers can connect metal contacts and apply a voltage. The end result is a single-atom transistor, which puts quantum computing systems a step closer to becoming reality.

“Our group has proved that it is really possible to position one phosphorus atom in a silicon environment – exactly as we need it – with near-atomic precision, and at the same time register gates,”  Dr Martin Fuechsle from UNSW says.

Single-atom transistors have been created before, the first demonstration dating from as early as 2002, however the development method could have only been described as hit or miss – resulting devices were made only by chance. This latest technique developed by the UNSW scientists can produce single-atom transistors with very high precision and reliability. Also, their technique respects the current industry-standard for building circuitry.

“But this device is perfect”, says Professor Michelle Simmons, group leader and director of the ARC Centre for Quantum Computation and Communication at UNSW. “This is the first time anyone has shown control of a single atom in a substrate with this level of precise accuracy.”

Considering Moore’s Law, which states that the number of transistors inside a circuit should double every 18 months, it is predicted that transistors will reach the single-atom level (the ultimate limit) by 2020.  Currently, the smallest dimension in state-of-the-art computers made by Intel is 22 nanometers — less than 100 atoms in diameter.

Using a similar technique, Intel engineers recently managed to create a magnetic storage device using an array composed of a mere 12 atoms.

 

Time division multiplexing [TDM, left] uses very brief but broad-spectrum laser pulses to send data. Wavelength division multiplexing [WDM, center] packs in bits by using several frequencies of light at once. Orthognonal frequency division multiplexing [OFDM, right] does the same, but uses overlapping frequencies to make better use of the available spectrum. (c) Nature Photonics.

Fastest single laser transmission achieved – 26 terabites/second

In an amazing feat of electrical engineering, scientists have managed to set a new landmark in optical communications by transmitting data at the remarkable speed of 26 terabits per second, or about 700 DVDs downloaded in an instant, all using a single transmitting laser.

uses very brief but broad-spectrum laser pulses to send data. Wavelength division multiplexing [WDM, center] packs in bits by using several frequencies of light at once. Orthogonal frequency division multiplexing [OFDM, right] y. does the same, but uses overlapping frequencies to make better use of the available spectrum. (c) Nature Photonics.”] Time division multiplexing [TDM, left] uses very brief but broad-spectrum laser pulses to send data.  Wavelength division multiplexing [WDM, center] packs in bits by using several frequencies of light at once. Orthognonal frequency division multiplexing [OFDM, right] does the same, but uses overlapping frequencies to make better use of the available spectrum. (c) Nature Photonics. The research was lead by scientists from the Karlsruhe Institute of Technology, in Germany, who published the research paper in Nature Photonics.

 

 

For the device, German scientists worked upon an existing and fairly common technique used in wireless communications called orthogonal frequency-division multiplexing. The technique starts by encoding data onto carrier waves whose frequencies overlap quite a bit, then combining those waves to create a new waveform. “Now, instead of having four transmitters, you have one transmitter,” Juerg Leuthold, a professor at Karlsruhe Institute of Technology, explains. What makes the OFDM transmission technique so popular, mostly, is that it uses a much broader data transmission spectrum, meaning it have a much better efficiency when real data transmission speeds are concerned. The adding and extracting of the waves is done through a mathematical process called the Fast Fourier Transform (FFT) and its inverse.

“This is so awfully fast that there is no electronic receiver that could detect it,” Leuthold said, explaining a major problem the team had to overcome. The issue was solved by the German scientists who used optical FFT device instead of an electronic one.

While the transfer speed achieved is indeed remarkable, other much larger transmission speeds have achieved albeit with multiple lasers. NEC Laboratories, of Princeton, N.J., for instance, presented a paper at the annual Optical Fiber Communication Conference in March showing a rate of 101.7 terabits per second, also using OFDM, but with 370 lasers, each transmitting at 294 gigabits per second.

One of the NEC researchers, Tim Wong, has learned about Leuthold’s work and believes it is very well done and quite significant, however, he states that the multiple laser arrangement from NEC has a better spectral efficiency, meaning a much bigger useful bits capacity.

NEC researchers performed a trial with telecom carrier Verizon last year in which they were able to reach rates of 1 Tb/s over 3560 km of fiber. The Karlsruhe researchers have so far only managed to test the single laser across 50 km of fiber, but Leuthold hopes he’ll be able to test it across a much broader distance in the future.

Much of today’s equipment works at 10 or 40 Gb/s, and analysts believe that by the middle of the decade we’ll be well into the terabit Ethernet.

via IEEE Spectrum