Tag Archives: electronics

What are sensors, how they work, and why they’re everywhere

A sensor is any device that measures an event or change in an environment and transforms it into an electronic signal that can be read and computed.

For instance, a sensor can take in physical parameters such as humidity, speed, or temperature (to name just a few), and make that data readable by a computer or other device. It takes an “input”, which can be almost anything, and converts it into an “output” that our electronics can understand. Or to put it in a different way, a sensor can detect an aspect of the physical environment and turn it into useful information.

Image credits: Jorge Ramirez.

Sensors, sensors everywhere — now also in XS size

We live in a world of sensors. From the tactile elevator buttons to the thermometers in our homes, they’re everywhere. Our smartphones, for instance, are equipped with an array of performant sensors. Whenever you fly a plane, there’s a whole arsenal there, telling the pilot everything about air pressure, speed, tilt, anything that can really help fly the plane.

Look around you (even ignoring the device you’re reading this on): how many sensors can you see around you?

At first glance, you may think there’s not too many. But look deeper. Are you in a car, or are there cars around you? Obviously, cars have a flurry of sensors, even the older ones. Public transit in many places is equipped with sensors. The thermostat inside the building — you’ve guessed it, also a sensor. In fact, it’s probably safe to say that unless you’re reading this while camping in the middle of nowhere, you’re probably surrounded by sensors that you don’t even notice.

It wasn’t always like this. Sensors used to be large, bulky, and expensive. Now, they’re small and easy to carry around. Researchers and engineers aren’t just looking at how well the sensor works — they’re looking at its energy consumption, necessary materials, sturdiness, and cost. Micro and nanotechnology and novel materials are making sensors smaller, smarter, and more adapted. As a result, we’re seeing sensors being applied in many new and exciting fields. For instance, some sensors can now be used as medical devices, either as wearables (for detecting things like glucose or insulin levels) or even inside the human body.

But before we get too carried away, let’s look at how sensors actually work.

How sensors work

A digital pressure sensor.

You first start with something that you want to sense — the quantity you’re measuring. The human body, for instance, is great at sensing light (with our eyes), smells (with our nose), and tastes (with our mouth). In essence, our body is equipped with a set of sensors, but each carries out a specific task.

Similarly, if you want to build an electronic sensor, you first think about what you want to measure, or sense. Let’s say you want to build a light sensor. You need an instrument to transform light into an electrical signal. That instrument is called a photodiode, and it does just what you want it to do: it converts light energy into electrical current. But let’s dig a bit deeper: how does the photodiode do this?

Without going into too many technicalities, photodiodes are built from specific materials and when photons hit the surface of these materials, they create something called the photoelectric effect, which disrupts the previously stable energy configuration of the material. This can generate an electric signal which is then picked up (and sometimes amplified) so it can be read by the system.

If you want to build a motion sensor, you need different types of materials, that can produce small amounts of current when they are moved or distorted. The rest of the mechanism is the same.

An example of an (almost) wearable sensor that tracks alcohol in the body. Image credits: UC San Diego.

So in essence, sensors generally work in a similar fashion: you need something (like a photodiode) that can transform your desired input into an electric current. You then pick up that electric current, amplify it if necessary, and pass it on to your computer.

A good sensor must have the ability to tell current very precisely. For instance, if the light increases slightly, so too will the current produced by the photodiode, and the sensor must be able to tell this. The better the ability, the better the sensitivity. But sensors also need to be able to withstand vibrations and temperature changes, which often affect the quality of the output.

Types of sensors

Image credits: Jorge Ramirez.

Sensors can be classified based on several different aspects. For instance, sensors can be either:

  • active (which require an external signal); or
  • passive (which work without any external signal).

Sensors can also be:

  • analog (produce an analog output, ie a continuous signal); or
  • digital (which work with discrete, digital data).

Most commonly, however, sensors are classified based on the physical property they measure. Here are some examples:

  • light sensors (which we’ve already discussed) are used everywhere, including on phones;
  • motion sensors;
  • proximity sensors, which can use different physical methods, like optical with laser, ultrasonic, or capacitive, etc;
  • temperature sensors;
  • chemical sensors, which can work for various types of chemical substances, like alcohol, smoke or gas, for instance;
  • humidity sensors (excellent for agriculture);
  • tilt sensors.

The sensor world has never been so active and diversified, which is why many now believe that sensors will usher in a new type of technological revolution.

Internet of Things and beyond

Sensors are no longer used just in engineering — in medicine and biotechnology, they are important tools that measure biological or physical processes. Environmental science as we know it today wouldn’t exist without accurate sensors, and practically every field that needs physical information uses sensors to get it. Every smart object is smart thanks to its sensors, and the more we look around us, the more objects are becoming smart.

You may have heard of the Internet of things (or IoT) — the idea of having objects around us connected in an internet-like network. This would mean that the “things” would be embedded with sensors and software, and could communicate with each other. For instance, a smarthome is a great example of how the IoT would work: your smart thermostat would turn on the heat automatically once temperature falls below a certain value, or, say, 30 minutes before you leave work, so your home is nice and cozy when you arrive. Lighting would have sensors to detect and automatically turn off when not used, and smoke/gas detectors would constantly work in the background.

Of course, the smart home isn’t the only idea of the IoT. Driverless cars would also need to be connected to the IoT so that they don’t collide with each other and keep the drivers safe. Virtually everything that benefits from automation, from medicine to high-end technology, could benefit from an IoT approach. But for all of this futuristic stuff to work, you need accurate, robust, and connected sensors.

Our world is full of sensors, and it’s unlikely to change anytime soon — if anything, we can expect sensors to play an even more important role in our lives.

What is the future of PCB development?

An integral feature in the electronics industry, a PCB connects electrical components by way of conductive pathways that are placed on a non-conductive layer.

Their fundamental purpose makes them an essential element in electrical manufacturing, and it is thought that the worth of the global PCB market is set to reach almost $90 billion by 2024. That figure would represent a compound annual growth rate of 4.3% from where we are now.

So, with such huge progression on the horizon, what is the future of PCB development?

3D printing

There is no denying that 3D printing has seen some remarkable advancements across a whole range of industries, and its effect on the PCB market has been – and will continue to be – equally significant. 3D printing has the ability to deliver huge benefits in the creation of PCBs in that it can help to produce innovative and original designs that were previously not feasible via traditional methods.

Not only that, but 3D printing is far more efficient in its use of materials – enabling the production of PCBs to be more environmentally friendly (more on that later) – as well as removing some elements of human error via increased automation.

Camera Technology

Mounted straight onto a circuit board, these tiny cameras are revolutionising the way we use our electronic devices. Able to take high-resolutions pictures and videos, these cameras can be found in mobile phones and medical equipment, to name just two examples, while the technology driving them is being continually developed to make them smaller, more powerful and more efficient.

Testing

Of course, PCBs are only useful if they are working effectively and efficiently, which means they need testing. This can be done using oscilloscopes, which can identify and troubleshoot any issues and can be used to verify voltage if the PCB is powered. An oscilloscope can magnify the signal in a PCB but, more than that, advancements in their technology mean they can now be used for the development of PCBs rather than just repairs.

Environmentally friendly materials

The topic of climate change is a hot one around the globe right now and the amount of electronic waste – from the likes of computers, phones and televisions – is a widespread concern. The materials in PCBs do not degrade well and their presence in landfills contributes a large chunk of all the e-waste across the planet.

With that in mind, it has been suggested that changes are made to the production of PCBs using biodegradable materials as well as sourcing other ways of finishing the assembly without using harmful chemicals. It has also been suggested that the precious metals in electronic waste could be extracted and recycled for future use.

Atom-thick heat shield could make smartphones even thinner

A model of graphene’s structure. Credit: Public Domain.

Smartphones, laptops, and other electronics naturally give off heat during their operation. To protect these devices from malfunction, engineers have to incorporate a thermally insulating material in their designs, which can be glass, plastic, or even an air gap.

In a new study, researchers at Stanford University have pushed the boundaries of thermal insulation by stacking atom-thick materials like sheets of paper atop hot spots. The resulting material is only 10 atoms thick but provides the same insulation as a sheet of glass 100 times thicker.

This achievement might have massive implications for the electronics industry. Thinner heat shields free up space so that electronics can get even more compact.

The atom heat shield

For their study, Eric Pop, who is a professor of electrical engineering at Stanford, and colleagues had to think outside of the box. This meant that they had to think of heat in a radically new way — as like it was sound.

Both heat and sound are actually waves of energy — it’s just that heat is a form of high-frequency sound. When viewed through this lens, you can treat heat insulation the same way a studio engineer dampens acoustic waves to achieve a clean sound. Pop, who used to be a radio DJ at Stanford’s KZSU 90.1 FM, was well aware of this dynamic.

But it was ultimately home construction that provided the missing puzzle piece. Modern homes employ multi-paned windows which are made of sheets of glass with varying thickness with layers of air trapped between them.

The researchers adapted this idea and used a layer of graphene and three other atom-thick materials. The resulting four-layered insulator is just 10 atoms deep.

Despite its ridiculous thinness, the insulator is effective because heat is dampened as it passes through each layer.

“As engineers, we know quite a lot about how to control electricity, and we’re getting better with light, but we’re just starting to understand how to manipulate the high-frequency sound that manifests itself as heat at the atomic scale,” Pop said.

The challenge now lies in finding a cheap manufacturing method that can incorporate such a thin insulator in electronics.

But beyond commercial applications, the researchers hope to reach an even more ambitious goal: to one-day control heat flowing through solid objects similarly to how we now control electricity and light passing through wires.

The findings appeared in the journal Science Advances.

Scientists create gold one million times thinner than a fingernail

One million times thinner than a human fingernail — that’s how thin is the new form of gold created by a group of scientists at the University of Leeds. It’s the thinnest unsupported gold ever created.

Credit: Flickr

The material is essentially regarded as 2-D (like graphene) because it comprises just two layers of atoms sitting on top of one another. This form gives the newly discovered gold the potential to be used more efficiently, with wide-scale applications in the medical and electronic industries.

The gold flakes are flexible, which means they could be used in bendable screens, electronic inks and transparent conducting displays, plus tests indicate that the material is 10 times more efficient as a catalytic substrate than the currently used gold nanoparticles.

“This work amounts to a landmark achievement. Not only does it open up the possibility that gold can be used more efficiently in existing technologies, but it is also providing a route which would allow material scientists to develop other 2-D metals,” said Dr. Sunjie Ye, lead author of the paper, published in the journal Advanced Science.

Synthesizing the gold nanosheet takes place in an aqueous solution and starts with chloroauric acid, an inorganic substance that contains gold. It is reduced to its metallic form in the presence of a ‘confinement agent’ – a chemical that encourages the gold to form as a sheet, just two atoms thick.

Because of the gold’s nanoscale dimensions, it appears green in water—and given its shape, the researchers describe it as gold nano-seaweed. Images taken from an electron microscope reveal the way the gold atoms have formed into a highly organized lattice. Other images show gold nano-seaweed that has been artificially colored.

The invention billed as a “landmark achievement” by researchers, also sheds more light on the creation of 2D materials altogether. According to the team, the method used to create the gold “could innovate nanomaterial manufacturing,” and the researchers are now focusing on ways to scale up the process.

Graphene, for example, was the much-lauded poster child of 2D materials when it was created in 2004 — but has faced a number of hurdles in large-scale use. With 2D gold, however, its potential is much clearer, researchers say.

“I think with 2-D gold we have got some very definite ideas about where it could be used, particularly in catalytic reactions and enzymatic reactions,” Professor Stephen Evans, who supervised the research, said. “We know it will be more effective than existing technologies—so we have something that we believe people will be interested in developing with us.”

Stretchable electronics could be as ‘multipurpose as your phone’

A group of researchers managed to stack and connect layers of electronics on top of each other to essentially build 3D stretchable electronics that can serve complex and diverse functions while remaining low in size.

The proof of concept, compared to a US dollar coin. Image credits: Zhenlong Huang / University of California San Diego.

Smart everything

Few things have revolutionized our world like electronics. In our pockets, we carry smartphones — devices which not only allow us to call essentially anyone in the world but also to access all the world’s knowledge and content at the click of a button; they’re good for playing silly games, too. But phones aren’t the only things getting smart. We have smart cars, smart homes, and even smart clothes — all thanks to the ever-advancing electronics.

But there are limits. Building 3D electronics that are small enough and able to carry out complex functions has proven very challenging.

“Our vision is to make 3D stretchable electronics that are as multifunctional and high-performing as today’s rigid electronics,” said senior author Sheng Xu, a professor in the Department of NanoEngineering and the Center for Wearable Sensors at the UC San Diego Jacobs School of Engineering.

The new technology can have far-reaching implications. For instance, consider smart sensors — a stretchable electronic bandage could be used to monitor patient’s body functions such as respiration, body motion, temperature, eye movement, heart and brain activity. Xu and colleagues built a prototype, which can do all this and control a robotic arm.

“Rigid electronics can offer a lot of functionality on a small footprint–they can easily be manufactured with as many as 50 layers of circuits that are all intricately connected, with a lot of chips and components packed densely inside. Our goal is to achieve that with stretchable electronics,” said Xu.

The new device consists of four layers of interconnected, stretchable, flexible circuit boards, featuring so-called “island-bridge” design. The “island” is a small, rigid electronic part (sensor, antenna, Bluetooth chip, amplifier, accelerometer, resistor, capacitor, inductor, etc.), while the “bridge” is made of thin copper wires which allow the circuits to twist and bend without losing functionality.

Researchers say they don’t have a specific purpose in mind, but the potential applications are limitless — wherever flexible circuits and electronics are necessary, the new technology could do wonders.

“We didn’t have a specific end use for all these functions combined together, but the point is that we can integrate all these different sensing capabilities on the same small bandage,” added co-first author Zhenlong Huang, a visiting Ph.D. student in Xu’s research group.

The new device has been shown to function for six months without losing any of its functionality or power. The team is now working with to improve and finesse the technology. Hopefully, it won’t be long before the technology is tested in a clinical setting.

The study has been published in Nature Electronics.

Bendy circuit.

Stretchy, bendy electronic circuits paves way to new wearable tech, bioimplants

Elastic circuits that can bend and stretch are here — and they mean business.

Bendy circuit.

LED circuits interconnected by MPC can undergo repeated bending, twisting, and stretching.
Image credits Tang et al., 2018, iScience.

Chinese researchers have developed a novel hybrid material — part elastic polymer, part liquid metal — that can bend, stretch, and still work as an electric circuit. The material can be cast in most two-dimensional shapes and, based on the polymer used, can be completely non-toxic.

Circuits, with a twist

“These are the first flexible electronics that are at once highly conductive and stretchable, fully biocompatible, and able to be fabricated conveniently across size scales with micro-feature precision,” says senior author Xingyu Jiang.

“We believe that they will have broad applications for both wearable electronics and implantable devices.”

The material the team developed is known as a metal-polymer conductor (MPC). As the name suggests, it’s a combination of two components. The metal bit of the mix carries electric charges — handling the ‘circuit’ part. However, the team didn’t use materials commonly seen in circuits, such as copper, silver, or gold, but settled on gallium and indium. These two metals form a thick fluid that’s a good electric conductor — meaning the circuits can ‘flow’ and still function while accommodating any stretching. The second component is a silicone-based polymer. This imparts mechanical resilience to the circuit, keeping the fluid ‘wires’ all neat and orderly.

Jiang’s team found that embedding globs of this gallium-indium mixture into the polymer substrate created a mechanically-strong material that can function as a circuit. Close-up, the MPC looks like a collection of metal islands in a sea of polymer. A liquid metal mantle runs underneath these islands to ensure conductivity is maintained at all times.

The team successfully trialed different MPC formulations in a wide range of applications — from sensors in wearable keyboard gloves to electrodes embedded in cells. There’s a huge range of applications these MPCs can be used for, they note, limited only by their particular polymer substrate.

“We cast super-elastic polymers to make MPCs for stretchable circuits. We use biocompatible and biodegradable polymers when we want MPCs for implantable devices,” says first author Lixue Tang.

“In the future, we could even build soft robots by combining electroactive polymers.”

The team is also confident that the MPC manufacturing method they developed — it involves screen printing and microfluidic patterning — can be used to produce any two-dimensional geometry. It can also handle different thicknesses and electric properties — which are a function of metal concentration in the circuits. This versatility could allow researchers to rapidly develop flexible circuits for a wide range of uses, the team notes, from wearable tech to bioimplants.

“We wanted to develop biocompatible materials that could be used to build wearable or implantable devices for diagnosing and treating disease without compromising quality of life, and we believe that this is a first step toward changing the way that cardiovascular diseases and other afflictions are managed,” says Jiang.

The paper “Printable Metal-Polymer Conductors for Highly Stretchable Bio-Devices” has been published in the journal iScience.

Scientists tested a DNA circuit capable of splitting and combining current, much like an adapter that can connect multiple appliances to a wall outlet. Credit: Limin Xiang.

Scientists build electrical circuit out of four-stranded DNA

Besides carrying the genetic blueprint for all living organisms, DNA is also a  versatile building block for practical affairs. Scientists are experimenting, for instance, with DNA as a storage device. One promising method can encode 215 petabytes of data — twice as much as Google and Facebook combined hold in their servers — on a single gram of DNA. Now, American researchers have found a way to use DNA in microelectronic circuits after they showed how to design, create, and use a DNA circuit capable of splitting and combining current. It works much like an adapter that can connect multiple appliances to a wall outlet.

Scientists tested a DNA circuit capable of splitting and combining current, much like an adapter that can connect multiple appliances to a wall outlet. Credit: Limin Xiang.

Scientists tested a DNA circuit capable of splitting and combining current, much like an adapter that can connect multiple appliances to a wall outlet. Credit: Limin Xiang.

DNA has remarkable self-assembly properties, which scientists previously exploited to great effect to assemble graphene transistors and to design new drugs. This works rather easily because the molecule’s four nucleotide bases (A, T, C, and G) can be programmed to self-assemble into the iconic double-helices, snapping together like matched puzzle pieces, A always bonding with T and C with G. Indeed, various 2-D and 3-D DNA structures have been synthetically designed by scientists in the past using this straightforward principle.

The double-helix molecule can also conduct electric charge over considerable distances. Combine this with self-assembly and you’ve got a very promising candidate for niche applications in electronics such as nanobots, photonic devices, or various tiny electronic circuits.

“The ability of DNA to transport electrical charge has been under investigation for some time,” said Nongjian “N.J.” Tao, a co-author of the new study researchers at Arizona State University. “Splitting and recombining current is a basic property of conventional electronic circuits. We’d like to mimic this ability in DNA, but until now, this has been quite challenging.”

There’s one problem though: In its most common duplex form, DNA poorly splits current into three or more terminals as the charge tends to dissipate at the splitting junctions or convergence points. This doesn’t bode well for electronics applications. However, scientists at Arizona State University, New York University, and Duke University, used a special form of DNA known as G-quadruplex (G4) DNA. As the name implies, G4-DNA is composed of four rather than two strands of DNA, which are rich in the nucleotide guanine (G).

“DNA is capable of conducting charge, but to be useful for nanoelectronics, it must be able to direct charge along more than one path by splitting or combining it. We have solved this problem by using the guanine quadruplex (G4) in which a charge can arrive on a duplex on one side of this unit and go out either of two duplexes on the other side” says Peng Zhang, an assistant research professor of chemistry at Duke University and a co-author of the new study.

“This is the first step needed to transport charge through a branching structure made exclusively of DNA. It is likely that further steps will result in successful DNA-based nanoelectronics that include transistor-like devices in self-assembling ‘pre-programmed’ materials,” Zhang says.

Guanine-rich quadruplex DNA occurs naturally, a configuration that can be found in telomeres — the ends of linear chromosomes, which play a key role in aging. Some research is targeting G4 quadruplexes with drugs for therapeutic reasons. Previously, research showed that DNA quadruplexes in telomeres decrease the activity of an enzyme responsible for telomere length and which is involved in 85 percent of all cancers.

Among other things, G4 DNA — stacked guanine bases that form hydrogen bonds with their immediate neighbors — have improved charge transport properties. This allowed the researchers to used G4 DNA and double-stranded wires to form the terminals for either splitting or merging electrical current flow. Previously, scientists who tried to make Y-shaped electrical junctions with conventional double-helix DNA failed because of the inherent poor charge transport properties.

The conductance of charge of the G4-DNA nanostructure was measured with a scanning tunneling microscope (STM), whose tip came in and out of contact with the molecule, breaking and reforming the junction while the current through each terminal is recorded. This “break junction” method allowed the researchers to fine-tune all sorts of prototype circuits to achieve maximal charge transport.

Besides opening the doors for innovative G4-based electronics, the paper published in Nature Nanotechnology sheds new light on the way nature maintains genetic integrity within cells, and could also teach us how various diseases break down DNA error-correcting mechanisms.

Sample circuit printed on fabric. Credit: Felice Torrisi

Scientists embed flexible, washable integrated circuits into fabric

Researchers used special graphene inks to print electronics on fabric, opening new avenues of opportunity for smart clothing and wearable electronics. The integrated circuits are flexible, washable, and breathable, making them perfectly adapted for fabric-based applications.

Sample circuit printed on fabric. Credit: Felice Torrisi

Sample circuit printed on fabric. Credit: Felice Torrisi

“Digital textile printing has been around for decades to print simple colourants on textiles, but our result demonstrates for the first time that such technology can also be used to print the entire electronic integrated circuits on textiles,” said co-author Professor Roman Sordan of Politecnico di Milano.

“Although we demonstrated very simple integrated circuits, our process is scalable and there are no fundamental obstacles to the technological development of wearable electronic devices both in terms of their complexity and performance.“

The team, which involved researchers from Britan, Italy, and China, employed a graphene ink formulated during earlier work. The ink was directly printed onto polyester fabric, resulting in a fully integrated electronic circuit with both active and passive components. Tests suggest the all-printed electronics on fiber can survive up to 20 cycles in a typical washing machine.

Wearable electronics on the market today rely on rigid electronics mounted on rubber or plastic. For this reason, the clothing or wearable electronics are easily damaged when washing or offer limited compatibility with the skin.

The graphene-based ink is cheap, safe, and environmentally friendly, as opposed to previous attempts that generally involve toxic solvents, which makes them unsuitable for human contact. Moreover, the integrated circuits require low power, making them ideal for wearable electronics applications.

“Turning textile fibres into functional electronic components can open to an entirely new set of applications from healthcare and wellbeing to the Internet of Things,” said Torrisi. “Thanks to nanotechnology, in the future our clothes could incorporate these textile-based electronics, such as displays or sensors and become interactive.”

Scientific reference: Tian Carey et al. ‘Fully inkjet-printed two-dimensional material field-effect heterojunctions for wearable and textile electronics.’ Nature Communications (2017). DOI: 10.1038/s41467-017-01210-2

Overview of the gesture-decoding glove. Credit: Timothy O'Connor et al (2017).

Cheap but smart glove translates American Sign Language into text

Overview of the gesture-decoding glove. Credit: Timothy O'Connor et al (2017).

Overview of the gesture-decoding glove. Credit: Timothy O’Connor et al (2017).

People with speech impairments will be able to communicate better with the rest of the world thanks to an experimental glove packed with bendable electronics. The glove translates gestures corresponding to the American Sign Language alphabet and then wirelessly transmits the information in text form to electronic devices that can show it on a display. The whole cost less than $100 to build — and could become way cheaper in a series production — and has a low power requirement.

Talk to the hand

There are many ways to track the movement of the human body and most methods rely on optical systems involving cameras or infrared emitters/receivers. These yield good results but the drawback is that they consume a lot of power. Moreover, these systems can be cumbersome and even immovable. On the other hand, wearable electronics overcome these constraints, especially if the tracking system is integrated inside a glove which can be used intuitively — you just have to move the hand and digits.

Gloves that track people’s gestures are already proving very useful in applications from virtual reality to telesurgery to military applications involving piloting drones. Now, researchers from the University of California, San Diego, are toying with the idea of reading American Sign Language (ASL) gestures through a similar glove.

Their glove has nine flexible strain sensors, two for each finger and one for the thumb. These sensors are responsible for registering motion by detecting knuckle articulation. An embedded microprocessor interprets the data from the sensors to translate each gesture into ASL letters. Finally, a Bluetooth radio transmits the meaning of the gestures in text format to a device for display, such as a smartphone.

During experiments, the UCSD team proved they could determine all 26 letters of the ASL alphabet accurately. After the knuckles bend for more than 1,000 times during a session, the system loses accuracy, as reported in the journal PLOS ONE.

What’s more, the researchers demonstrated their accuracy by modeling a virtual hand that mimicked real ASL gestures made with the smart glove. Not bad for a $100 prototype.

Paper-thin speaker.

Paper-thin device turns touch into electricity, flags into loudspeakers, bracelets into microphones

Michigan State University engineers have put together a flexible, paper-thin transducer — a device which can turn physical motion into electrical energy and vice-versa. The material could be used to create a whole new range of electronics powered from motion, as well as ultra-thin microphones and loudspeakers.

Paper-thin speaker.

Nelson Sepulveda and the paper-thin speaker.
Image credits Michigan State University.

Harry Potter may have had animated newspapers but you know what Hogwarts never had? Newspaper boomboxes. So I guess it’s score one for the muggles, since we’re about to get just that. Along with newspaper microphones, or anything else that’s really thin and works either as a sound recording or replay device. Our imagination’s the limit.

Fold-a-speaker

It’s all thanks to a team of nanotech engineers from Michigan State University, who designed and produced a prototype ultra-thin transducer. The device is fully flexible and foldable, can easily be scaled up and is bidirectional — meaning it can convert mechanical energy to electrical energy and electrical energy to mechanical energy.

The device’s fabrication process starts with a silicone wafer with several thin layers or sheets of environmentally friendly substances including silver, polyimide, and polypropylene ferroelectret added over it. Ions (which are charged particles) are added onto each individual layer so that they produce an electrical current when compressed.

Known as a ferroelectret nanogenerator (abbreviated FENG), it was first showcased in late 2016 as a sheet which could turn users’ touch into energy to power a keyboard, LED lights and an LCD touch-screen.

Since then, the FENG got some new tricks. The team discovered that in addition to its touch-to-energy transformation ability, the material can be used as a microphone — by turning the mechanical energy of sound into electrical energy — and as a loudspeaker — by doing the reverse.

“Every technology starts with a breakthrough and this is a breakthrough for this particular technology,” said Nelson Sepulveda, MSU associate professor of electrical and computer engineering and primary investigator of the federally funded project.

“This is the first transducer that is ultrathin, flexible, scalable and bidirectional, meaning it can convert mechanical energy to electrical energy and electrical energy to mechanical energy.”

Multiple uses

As a proof-of-concept for sound recording, the team developed a FENG security patch which uses voice recognition software to unlock a computer. Tests revealed that the patch can pick up on voices with a high fidelity, being sensitive enough to capture several frequency channels in the human voice.

To test how well the material would function as a loudspeaker, some FENG fabric was embedded into the faculty’s own Spartan flag. It was supplied with a signal from an iPad through an amplifier. The team reports that it reproduced the sound flawlessly, the flag itself becoming a loudspeaker. One day, you could be carrying speakers around everywhere, comfortably folded in your pocket until you need them. Or you could have a poster of FENG at home, ready to hook up to your PC, taking up virtually no desk space.

“So we could use it in the future by taking traditional speakers, which are big, bulky and use a lot of power, and replacing them with this very flexible, thin, small device.”

“Or imagine a newspaper,” Sepulveda added, “where the sheets are microphones and loudspeakers. You could essentially have a voice-activated newspaper that talks back to you.”

Other applications could include a noise-canceling sheeting that also produces some energy in the bargain, or voice-operated wearable health-monitoring devices. The team says they’re also interested in developing in the “speaking and listening aspects” of the technology.

The full paper “Nanogenerator-based dual-functional and self-powered thin patch loudspeaker or microphone for flexible electronics” has been published in the journal Nature Communications.

Atomic-sandwich material could make computers 100 times more energy efficient

A new material could pave the way for an entirely new generation of computers — one that packs in a lot more processing power while consuming only a fraction of the energy.


A false-colored electron microscopy image shows alternating lutetium (yellow) and iron (blue) atomic planes.
Image credits Emily Ryan and Megan Holtz / Cornell.

Known as a magnetoelectric multiferroic material, the new substance is made out of distinct atom-thick layers sandwiched together which shows magnetic and electrical properties at room temperature. The thin film is magnetically polarized, and this property can be flipped — the two states encoding the 1’s and 0’s that underpin our digital systems.

The researchers started with a thin, atomically-precise film of hexagonal lutetium iron oxide, or LuFeO3 — a material known to be ferroelectric, but not particularly magnetic. It’ consists of alternating layers of lutetium- and iron-oxide layers. Then, through a technique known as molecular-beam epitaxy, they “spray-painted” one extra monolayer of iron oxide for every 10 atomic repeats of the single-single monolayer pattern.

“We were essentially spray painting individual atoms of iron, lutetium and oxygen to achieve a new atomic structure that exhibits stronger magnetic properties,” said Darrell Schlom, a materials science and engineering professor at Cornell and senior author of a study.

The result was a new material that combines a phenomenon in lutetium oxide called “planar rumpling” with the magnetic properties of iron oxide to achieve multiferroic properties at room temperature. Heron explains that lutetium shows displacements on an atomic level called rumples. These can be moved around using an electric field and can shift the magnetic field of the neighboring iron oxide layer from positive to negative. So in essence, the team developed a material whose magnetic properties can be altered accurately with electricity — a “magnetoelectric multiferroic”.

“Before this work, there was only one other room-temperature multiferroic whose magnetic properties could be controlled by electricity,” said John Heron, assistant professor in the Department of Materials Science and Engineering at the University of Michigan.

“That electrical control is what excites electronics makers, so this is a huge step forward.”

Room-temperature multiferroics require much less power to write on and read than the semiconductor-based systems we use today. And, if you cut the power, the data remains encoded. Combine these two properties and you get computers that use only brief pulses of energy to function instead of the constant flow required by our current computers — as little as 100 times less energy. So, needless to say, electronics experts are always on the lookout for new room-temperature multiferoics.

“Electronics are the fastest-growing consumer of energy worldwide,” said Ramamoorthy Ramesh, associate laboratory director for energy technologies at Lawrence Berkeley National Laboratory.

“Today, about 5 percent of our total global energy consumption is spent on electronics, and that’s projected to grow to 40-50 percent by 2030 if we continue at the current pace and if there are no major advances in the field that lead to lower energy consumption.”

Heron thinks that we’re still a ways off from a viable multiferroic, likely a few years off. But the team’s work brings the field of electronics closer to developing devices which can maintain high computing speeds while consuming less power. If the industry will keep following Moore’s law — which predicts that the computing power of integrated circuits will double every year — such advances will be vital. Moore has been right since the 1960, but silicon-chip technology may be reaching its limits — whatever happens, we may not be able to power it for very long.

The full paper “Atomically engineered ferroic layers yield a room-temperature magnetoelectric multiferroic” has been published in the journal Nature.

 

This is the first CMOS full duplex receiver IC with integrated magnetic-free circulator. Credit: Negar Reiskarimian, Columbia Engineering

Researchers double WiFi broadband while halving chip size

A new circuit was demonstrated at the 2016 IEEE International Solid- State Circuits Conference this past February that can, among other things, double Wi-Fi speed, while halving the size of the chip. The researchers at Columbia Engineering invented a new technology they call “full-duplex radio integrated circuits” which uses only one antenna to simultaneously transmit and receive at the same wireless radio frequency.

This is the first CMOS full duplex receiver IC with integrated magnetic-free circulator. Credit: Negar Reiskarimian, Columbia Engineering

This is the first CMOS full duplex receiver IC with integrated magnetic-free circulator. Credit: Negar Reiskarimian, Columbia Engineering

“This technology could revolutionize the field of telecommunications,” says Krishnaswamy, director of the Columbia High-Speed and Mm-wave IC (CoSMIC) Lab. “Our circulator is the first to be put on a silicon chip, and we get literally orders of magnitude better performance than prior work. Full-duplex communications, where the transmitter and the receiver operate at the same time and at the same frequency, has become a critical research area and now we’ve shown that WiFi capacity can be doubled on a nanoscale silicon chip with a single antenna. This has enormous implications for devices like smartphones and tablets.”

Key to full-duplex communications which virtually double the useful bandwidth in wireless communications is the circulator. This device transmits the signal entering a port to the next port in rotation. For instance, a three-port circulator where the three ports are “transmit” (1), “receive” (2) and “antenna” (3) works by routing (1) to (3), and (3) to (2). This way, you don’t get (1) to (2) which would’ve meant hearing yourself in a closed loop.

For more than 60 years, these sort of circulators have been used by the industry to provide two-way communications on the same frequency channel, but they are not widely adopted because of the large size, weight and cost associated with using magnets and magnetic materials. These magnets are essential to a working circulator because they “break” Lorentz Reciprocity — a physical constraint of most electronic structures that forces electromagnetic waves to travel in the same manner in forward and reverse directions.

(a) A simplified circuit diagram of the circulator is shown. Electronic commutation across a bank of N=8 capacitors is performed using reciprocal, passive transistor-based switches without direct-current bias. The staggered commutated network enables miniaturization of the unmodulated 3λ/4 ring using three C-L-C sections. (b) The microphotograph of the fabricated IC is shown along with a close-up photograph of the fabricated printed circuit board with the IC housed in a quad-flat no-leads (QFN) package and interfaced with the off-chip inductors. The largest dimension of the prototype is 5 mm or λ/80 at the operating frequency of 750 MHz. Credit: Nature Communications

(a) A simplified circuit diagram of the circulator is shown. Electronic commutation across a bank of N=8 capacitors is performed using reciprocal, passive transistor-based switches without direct-current bias. The staggered commutated network enables miniaturization of the unmodulated 3λ/4 ring using three C-L-C sections. (b) The microphotograph of the fabricated IC is shown along with a close-up photograph of the fabricated printed circuit board with the IC housed in a quad-flat no-leads (QFN) package and interfaced with the off-chip inductors. The largest dimension of the prototype is 5 mm or λ/80 at the operating frequency of 750 MHz. Credit: Nature Communications

Electrical Engineering Associate Professor Harish Krishnaswam and colleagues made a breakthrough by scrapping the magnets and using a mini-circulator that rotates the signal across a set of capacitors. They then devised a working prototype of a full-duplex system on a nanoscale silicon chip.

“Being able to put the circulator on the same chip as the rest of the radio has the potential to significantly reduce the size of the system, enhance its performance, and introduce new functionalities critical to full duplex,” says PhD student Jin Zhou, who integrated the circulator with the full-duplex receiver that featured additional echo cancellation.

There’s a myriad of potential applications, from better radar, to faster WiFi, to isolator that prevent high-power transmitters from being damaged by back-reflections from the antenna. Anything that uses half-duplex functions, or virtually all cell phones and WiFi routers, could double performance.

“What really excites me about this research is that we were able to make a contribution at a theoretically fundamental level, which led to the publication in Nature Communications, and also able to demonstrate a practical RF circulator integrated with a full-duplex receiver that exhibited a factor of nearly a billion in echo cancellation, making it the first practical full-duplex receiver chip and which led to the publication in the 2016 IEEE ISSCC,” Krishnaswamy adds. “It is rare for a single piece of research, or even a research group, to bridge fundamental theoretical contributions with implementations of practical relevance. It is extremely rewarding to supervise graduate students who were able to do that!”

Findings appeared in Nature Communications.

A runner steps on a special pavement in London made by a company called Pavegen Systems. More than one million people tramped over Pavegen tiles as they passed through West Ham underground station en route for the Olympic Park, generating the power required to keep the station's lights on.

Device harvests energy from walking to charge your mobile and wearable electronics

Researchers demonstrated  a universal self-charging system driven by random body motion. Simply by walking or running, the system uses the tribolectric effect to generate electricity out of physically manipulating two materials with opposing surface charges. The current is enough to power sensors, microcontrollers, memories, arithmetic logic units, displays and even wireless transmitters, the researchers showed. More complicated electronics like smart watches, cell phones, navigation system, tablets, personal computers and sensor nodes in internet of things can also be charged using the same system if high-frequency mechanical agitations are utilized to drastically improve the triboelectric nanogenerators (TENG) output power.

Free energy is everywhere – you just need to know where to look

A runner steps on a special pavement in London made by a company called Pavegen Systems. More than one million people tramped over Pavegen tiles as they passed through West Ham underground station en route for the Olympic Park, generating the power required to keep the station's lights on.

A runner steps on a special pavement in London made by a company called Pavegen Systems. More than one million people tramped over Pavegen tiles as they passed through West Ham underground station en route for the Olympic Park, generating the power required to keep the station’s lights on.

As wearable electronics and the internet of things become more prevalent, there’s an increasing need for more energy storage on the go. As if it wasn’t enough that now we have to charge smartphones at least once a day, some might also need extra batteries to power smartwatches, heart and blood pressure sensors (the athletes love these) and other gadgets. Instead of buying a massive charging station at home, some engineers are devising alternative means to still enjoy your gadgets, while not having to worry about carrying that many batteries around.

We’re surrounded by ambient energy: mechanical, thermal, chemical, electromagnetic and solar. To name a few ambient energy sources, these include gentle airflow, ambient sound, vibration, human body motion, ocean waves. Strapping a tiny wind turbine (this sounds cool, though) or solar panel on your back doesn’t sound that practical, though.

A group of Chinese researchers have a better idea: use tiny, triboelectric nanogenerators that use contact electrification and electrostatic induction to generate output power in the mW-W range.

The triboelectric effect is well known for many years, but it’s only been recently that scientists and engineers have started exploring its potential. Previously, a group from Georgia Institute of Technology showed how a square meter of single-layer material can produce as much as 300 watts. Elsewhere, University of Wisconsin-Madison researchers empoyed a triboelectric system to harvest 10% of the energy lost by tires to friction.

To embed TENGs into electronic system for practical applications, the team had to overcome some major challenges. Because the mechanical energy source is variable and random, the output of a TENG is in this situation is a pulsed A.C. signal. TENG generate hundreds of volts, but the current is in the order of microamps. The high impedance of TENGs means energy conversion efficiency is very low when using conventional transformers (<1%). Because the TENGs generally do not provide steady energy, these require an energy storage unit (battery) to collect the variable charges, manage them and disperse them in a regulated manner.

Eventually, they overcame these challenges and devised a  system that includes a TENG, a power management circuit and a low-leakage energy storage device. The power management circuit was especially important since it’s designed to solve the impedance mismatch problem. The power management circuit can achieve 90% board efficiency and 60% total efficiency, about two orders of magnitude improvement compared with direct charging.

a) System diagram of a TENG-based self-powered system. (b) Working mechanism of an attached-electrode contact-mode TENG. (c) Structure of the designed multilayer TENG. (d) Photo of an as-fabricated TENG. (e) Short-circuit current output and (f) open-circuit voltage output of the as-fabricated TENG.

a) System diagram of a TENG-based self-powered system. (b) Working mechanism of an attached-electrode contact-mode TENG. (c) Structure of the designed multilayer TENG. (d) Photo of an as-fabricated TENG. (e) Short-circuit current output and (f) open-circuit voltage output of the as-fabricated TENG.

Power electronics with your body

The stack of TENGs presented above collect the energy from human walking and running. No signs of significant degradation was observed after 180,000 cycles. Humidity and moisture have little impact on the performance of the system, the researchers note in their paper published in Nature.

(a) System configuration of self-powered human activity sensors. (b) Demonstration of a self-powered temperature sensor. (c) Demonstration of a self-powered heart rate monitor (ECG) system. (d) Demonstration of a self-powered pedometer.

(a) System configuration of self-powered human activity sensors. (b) Demonstration of a self-powered temperature sensor. (c) Demonstration of a self-powered heart rate monitor (ECG) system. (d) Demonstration of a self-powered pedometer.

(a) Demonstration of a self-powered wearable watch and calculator. (b) Demonstration of a self-powered scientific calculator. (c) Demonstration of a self-powered RKE system. (d) Extension of this TENG-based self-charging unit for various applications as a universal adaptable power source.

(a) Demonstration of a self-powered wearable watch and calculator. (b) Demonstration of a self-powered scientific calculator. (c) Demonstration of a self-powered RKE system. (d) Extension of this TENG-based self-charging unit for various applications as a universal adaptable power source.

The researchers conclude:

“This self-charging unit is a paradigm shift towards infinite-lifetime energy sources that can never be achieved solely by batteries. The concept proposed in this paper can also be easily extended into other energy harvesters based on piezoelectric and pyroelectric effects. This study overcomes a bottleneck problem towards self-powered systems, which can have broad applications in mobile/wearable electronics, internet of things, remote environmental monitor devices and wireless sensor networks.”

 

The Electronic Rose

When is a rose not a rose? When it’s a transistorized electronic circuit, of course. Scientists at Sweden’s Linköping University have implanted a rose with conductive polymers and arranged the resulting circuitry into a real transistor system – complete with a digital switch.

Here’s how materials scientist Magnus Berggren turned a rose into a piece of electronics. He started with a rather ordinary rose, the sort of cut flower that a research scientist might give to a mom on her birthday. One such rose was sunk into PEDOT, a water-soluble conductive polymer used to make printed electronic circuits. The rose sucked up the polymer through its xylem (vascular tissue) via the capillary effect, as if the polymer were water. Once inside the rose stem, the polymer precipitated out of solution, becoming a sort of wire, capable of carrying a small charge of electricity. The plant retained most of its vascular system so it continued to look and smell like a rose. The researchers attached gold probes to the new wires and fashioned the assemblage with switches, creating an electronic rose. In their write-up, released in Science Advances, they suggest  that the result is digitally analogous to a printed circuit board.

rose in hand: permission D Sharon PruittPhoto by permission: D Sharon Pruitt

At this stage, the experiment is basically a proof-of-concept project.  This is pure research, motivated by curiosity. It’s not the sort of experimental work that is expected to yield immediate financial returns. For funding, Professor Berggren used independent research money from the Knut and Alice Wallenberg Foundation. A grant of about $2 million was awarded in late 2012 and could be used on any research Berggren wanted to conduct. “It’s an unbelievable luxury with this kind of money, where you are free to choose who you work with, and also to halt research quickly when it’s not working,” Berggren said.

For 25 years, Magnus Berggren has been a professor at Linköping University’s Organic Electronics Lab where he researches electronic circuitry. Until the Wallenberg Foundation grant, there were no donors interested in what might appear to be esoteric research. The money allowed Dr Berggren to hire three post-doctoral research scientists and then begin the tedious work of testing polymers and designing the botanical circuitry.

Organic electronic plants researchersLinköping University’s Laboratory of Organic Electronics Research Team:
from the left, Daniel Simon, Roger Gabrielsson, Eleni Stavrinidou, Eliot Gomez, and Magnus Berggren.

The electronic flower survives as long as any other cut rose in a vase, but the researchers are not yet claiming practical applications. The Swedish scientists are working with biologists to see if plants with internal circuitry may be useful for monitoring plant growth and studying physiology. Future applications may turn plants into living fuel cells, using sugars produced by photosynthesis to produce – and deliver – electricity. Or perhaps the technology could turn Christmas trees into power plants that flash their own coloured lights – with no extension cords required.

3d printed drone

Check out the world’s first 3D electronics printer

I love disruptive technologies, and 3D printing is undoubtedly one of the leading such movements in the 21st century. This kind of tech will democratize manufacturing, moving it  away from 3rd world sweatshops to your own garage. And no, you don’t have to be a geek to own one. Ten years from now, it should be as easy to use and as widespread in homes as a regular ink printer. But for now, 3D printing is limited, particularly as far as electronics are concerned. Usually, you have to print the plastic parts, then order electronic parts like circuits, chips or motors, before finally assembling it all together yourself. You can’t have a global manufacturing revolution if you need to be a lab wiz to print a new TV remote control to replace the one the dog just shred to pieces. But this is all changed. We’re just now seeing the first steps that might one day lead people to print their own smartphones.

3d printed drone

A 3d printed drone (CAT scan) using Voxel8’s printer.

A company called Voxel8 just introduced its latest flagship product: the 3D printer capable of printing electronics. Using this printer, its developers say, anyone can print their own phones, drones or RC cars all in one piece, with the electronics printed inside.

The Volxe8 3d electronics printer.

The Volxe8 3d electronics printer.

It uses a modular design where two different printer heads are used; one to extrude plastic and the other that layers conductive silver ink. When the printer reaches the electronics part of the process, it lays down the conductive ink. Inevitably, at some point the printer stops and notifies you that you need to insert a resistance or condenser, depending on the design you just used. Once you place the part, the printer automatically goes on with its business. With carefully laid instructions, almost anyone could manufacture an electronic device right at home. That’s not all, a future Voxel8 version of the printer should be able to print things like resistors and even battery parts directly.

Shut up and take my money. Not so fast, though. The kit ships in late 2015 for … $8999. Don’t feel too dishearten though. In time, as more competitors arise, the price will go down. Remember how expensive the first 3D printers were? You can now buy one for only a couple hundred dollars. The electronics printers will follow soon. The future sounds bright – can’t wait!

flexible_semiconducting_polymer

A first step towards making ‘plastic’ semiconductors for stretchy-electronics

Stanford chemical engineers have developed a theoretical model that sheds light on the electrical conductivity properties of polymers. Their work provides a valuable first step for other researchers to build on, providing an experimental setting for those looking to expand the electrical conductivity of certain polymers (typically plastics) for use in the industry.

The word “polymer” is derived from the Greek for “many parts” which aptly describes their simple molecular structure, which consists of identical units, called monomers, that string together, end to end, like so many sausages. Humans have long used natural polymers such as silk and wool, while newer industrial processes have adapted this same technique to turn end-to-end chains of hydrocarbon molecules, ultimately derived from petroleum byproducts, into plastics.

The constitutive elements that go in your typical electronics like your smartphone or notebook include things like circuitry, transistors, condensers and so on, all typically made out of metallic materials, since these need to be electrically conductive. At the same time, however, these materials, like the reigning king silicon, are brittle and fairly stiff.

Fad or not, in recent years scientists have made various attempts at developing electronics capable of being stretched a significant or even multiple times their width, as well rolling. Imagine clothing electronics, tablets that can fold like a newspaper, a whole range of new possibilities. As such, many have experimented with polymers which are more flexible. It’s clear that there’s a serious trade-off problem here that engineers need to tackle: metals can’t stretch but they conduct electricity better, polymers can stretch, but conduct electricity poorly. Things don’t need to be all black and white, though. The best and quickest solutions are found when engineers have access to as much data and information about the problem they’re trying to solve as possible.

Stanford chemical engineering professor Andrew Spakowitz and colleagues  the first theoretical framework that includes the molecular-level structural inhomogeneity of polymers. Metals have a regular molecular structure that allows electrical current to flow smoothly, but this is also what makes them rigid. Polymers on the other hand, at a molecular level, look more like a bowl of spaghetti: strands are coiled  or run relatively true, even if curved, like lanes on a highway. This variability of molecular structure is reflected in the variability of electrical conductivity as well. In the process of experimenting with polymeric semiconductors, researchers discovered that these flexible materials exhibited “anomalous transport behavior” or, simply put, variability in the speed at which electrons flowed through the system.

“Prior theories of electrical flow in polymeric semiconductors are largely extrapolated from our understanding of metals and inorganic semiconductors like silicon,” Spakowitz said, adding that he and his collaborators began by taking a molecular-level view of the electron transport issue.

flexible_semiconducting_polymer

The yellow electric charge races through a ”speed lane” in this stylized view of a polymer semiconductor, but pauses before leaping to the next fast path. Stanford engineers are studying why this occurs with an eye toward building flexible electronics. (Credit: Professor Andrew Spakowitz)

This insight is fundamental to future experiments and research dwelling into building stretchy electronics. One other important hallmark of the Stanford scientists’ paper is that they provide a simple algorithm that begins to suggest how to control the process for making polymers, with an emphasis on how manipulating their electrical conductivity properties.

“There are many, many types of monomers and many variables in the process,” Spakowitz said. The model presented by the Stanford team simplifies this problem greatly by reducing it to a small number of variables describing the structural and electronic properties of semiconducting polymers.

“A simple theory that works is a good start,” said Spakowitz, who envisions much work ahead to bring bending smart phones and folding e-readers to reality.

The author’s theory was published recently in the journal Proceedings of the National Academy of Sciences.

An e-waste dump in Nigeria.

How electronics waste is causing a global ecological time bomb

An e-waste dump in Nigeria.

An e-waste dump in Nigeria.

Some 50 million tones of hazardous e-waste, various electronics that have long met their life cycle and now need to be disposed, are being generated each year. The figure has risen dramatically compared to previous years and will continue to do so in the future as well, in part because manufacturers have constantly lowered their product’s life cycles, from five years on average to two years on average, for increased profits. With this in mind, the issue is far from being new, what’s clear is that people, and especially governments and major electronics manufacturers, need to be reminded of this great peril some parts of the world might be facing. A major reminder came recently at the CleanUp 2013 conference in Melbourne, where Professor Ming Wong, director of the Croucher Institute for Environmental Sciences, at the Hong Kong Baptist University, held a keynote.

“I would call it a global time bomb,” says Wong, referring to the growing pile of waste produced by old mobile phones, computers and other electronic devices.

“[It] is the world’s fastest growing waste stream, rising by 3 to 5 per cent every year, due to the decreased lifespan of the average computer from six years to two,” says Wong.

“In countries such as Australia the disposal of e-waste in landfills generates a potent leachate, which has high concentrations of flame retardant chemicals and heavy metals. These can migrate through soils and groundwater and eventually reach people.”

Regarding Australia’s practice, this is actually the de facto method used by countries all over the world. According to the EPA, over four billion pounds of e-waste was discarded in the United States in 2005, accounting for between 2% and 4% of the municipal solid waste stream. As much as 87.5% of this was incinerated or dumped in landfills – none of these practices can be considered sustainable. Only about 12.5% of the total was recycled.

E-waste contains toxic materials such as lead, mercury, cadmium and brominated flame retardants. These materials are considered bio-accumulative, which means they concentrate in fatty tissues where they can have severe, negative impacts on fetal development and on nursing infants.  It has been estimated that consumer electronics may be responsible for up to 40% of the lead found in landfills.

Often times, governments of developed countries wash their hands off and send their e-waste over to developing countries, where labor is cheaper and environmental laws are more permissive. Here, in parts of the world like Africa or Asia, precious metals that go into e-waste (gold, silver and platinum from microchips, motherboards etc.) are basically scavenged under precarious working conditions, leading to extensive pollution of air, water, food and people.

“The toxic chemicals generated through open burning of e-waste include PCDD, PBDEs, PAHs, PCBs and heavy metals,” says Wong. “[These] have given rise to serious environmental contamination.”

“Some of these toxic chemicals are known to build up in fish especially, which may then be traded locally and around the world.”

“At the same time these e-waste contaminated sites are extremely hard to clean up due to the complex chemical mixtures they contain,” he says.

“It is clear there is an urgent need to manage e-waste more efficiently in all countries and through better international collaboration … China is looking at this issue very seriously.”

At the conference, Wong proposed a series of solutions that basically can be summed up into a call for genuine joint responsibility between the world’s develop countries’ governments and major electronics manufacturers. For one, manufacturers need to make their electronics last longer and at the same time make it easier for key components to become reusable. Countries at their own term need to introduce legal policies that restrict the export of e-waste to less affluent states.  “Countries should take responsibility for their own e-waste,” says Wong.

 

(c) Anatoliy N. Sokolov et al./Nature Communications

Graphene transistors made using DNA assembly

To the right is a honeycomb of graphene atoms. To the left is a double strand of DNA. The white spheres represent copper ions integral to the chemical assembly process. The fire represents the heat that is an essential ingredient in the technique. (Credit: Anatoliy Sokolov/Stanford University)

To the right is a honeycomb of graphene atoms. To the left is a double strand of DNA. The white spheres represent copper ions integral to the chemical assembly process. The fire represents the heat that is an essential ingredient in the technique. (Credit: Anatoliy Sokolov/Stanford University)

As electronics become ever thinner, smaller and faster, scientists always need to think ahead and develop solutions to accommodate the computing needs of the future. For one, it becomes clearer with each passing day that silicon – the most used material in electronics – can’t be used anymore for tomorrow’s tech since we’re nearing its maximum potential. Graphene, the wonder material consisting of carbon atoms arranged in a regular hexagon pattern, is considered by many silicon’s successor, ushering in a new age of electronics.

Graphene has been receiving a great deal of attention, and it’s no wonder why frankly. It’s enough to read some of the articles on ZME Science about it, or consider the fact that graphene research was awarded a $1 billion grant. Besides, its many uses, graphene has extraordinary electrical properties. Working with a material just one atom thick can be tricky, though, and developing working electronics with it on a mass scale (that’s the point after all) has proven to be a challenge.

Researchers at Stanford recently announced they successfully built smaller field-effect transistors (FETs) that use less power but operate faster, using ribbons of single-layer graphene laid side-by-side to create semiconductor circuits. What’s truly fantastic about their work is that they’ve created the graphene ribbons through a series of chemical reactions using DNA as an assembly mechanism.

DNA is ideal for assembling graphene since its roughly of the same dimensions. Chemically, DNA molecules contain carbon atoms, the material that forms graphene, so that’s another plus.

(c)  Anatoliy N. Sokolov et al./Nature Communications

(c) Anatoliy N. Sokolov et al./Nature Communications

 

Stanford professor Zhenan Bao along with his team first started with a tiny platter of silicon to provide a support (substrate) for their experimental transistor. They dipped the silicon platter into a solution of DNA derived from bacteria and used a known technique to comb the DNA strands into relatively straight lines.

The DNA was then exposed to a copper salt solution, resulting in the copper ions being absorbed into the DNA. The platter was then bathed in methane gas (contains carbon atoms), and subjected to an increase in temperature until enough heat was generated for the sought after chemical reaction. The reaction freed some of the carbon atoms from the DNA and methane, which quickly joined together to form the infamous honeycomb graphene. Moreoever, since the separated carbon atoms more or less maintain their same position before breaking free, they formed ribbons that followed the structure of DNA.

Baking graphene with DNA

These ribbons are paramount to making working transistors that go into computer chips. Graphene in its typical structure can’t be used as a transistor, since it doesn’t have any bandgap (no electron state energy range) and thus can’t function as a semiconductor (switch on/off current). ZME Science reported a while ago how scientists at University of Riverside, California  demonstrated that graphene transistors could work if one would exploit negative resistance.

The Stanford approach seems much simpler. Graphene, laterally confined within narrow ribbons less than 10 nanometers in width, exhibits a bandgap, meaning it can function as a semiconductor and thus solves graphene’s native issues.

The assembly process, two years in the making now, is far from being perfect. Not all carbon atoms formed honeycombed ribbons a single atom thick , and in some places the carbon atoms were displaced from their honeycombed structure altogether forming irregular patterns, leading the researchers to label the material graphitic instead of graphene.

“Our DNA-based fabrication method is highly scalable, offers high resolution and low manufacturing cost,” said co-author Fung Ling Yap. “All these advantages make the method very attractive for industrial adoption.”

Findings appeared in Nature Communications.

The Impact of Electronics

This generation is really very blessed because of the evolution of electronics. Most often, all types of person from all over the globe has different electronics in their household. This is mainly because the electronics role is to serve the purpose of communicating with other people. Thus, this is to disregard the different electronic devices found in the household to help with the chores. Like for example a fridge, washing machine, TV or anything like that. Electronics in this aspect talk about the handy devices that help people monitor and interact with other people.

Baby boomers tend to have a detachment with such devices because they have not grown up with it. While the millennial babies actually have an extra attachment because they grew up to have had been used to it. Most statistics show that baby boomers (if they use gadgets) own a structured type of gadgets that are basically easy to use and understand. Unlike the latter, they prefer complicated and even settle to disorganized conversations more. Thus, this just goes to show that electronics by itself already has its own pace and line of age in selling in the market.

Some of the most common electronics found at home are laptops, mobile phones, PC or table computer and most often (according to statistics) iPad or tablets. These electronics showcase different features for the customers to use. They usually have different types of usage and functionalities.

Laptops

Most often used by people at work or at school. Laptops are indeed great and handy help towards the formality of reports, or typing of projects. They make it easy for users to give out their ideas and put it into writing (or in this aspect, typing). Additionally, laptops nowadays also serve more than that since more and more features are added up to it often. Now, users can edit videos or avail of the different web based applications that are suitable for Microsoft.

Mobile Phones

Mobile phones on the other note are the most convenient and common type of gadget. Everyone basically has a phone (well, it actually depends). Hence, primarily mobile phones function as a communicating device to interact with other people. Likewise as generations pass by, more and more applications are added up to a single smart phone. This is to address not only to games but also to applications that help in going beyond just ordinary communicating, like Voice over Internet Protocol for example that VoIP providers like RingCentral offers.

PCs or Desktop Computers

These are the first of them all. These babies are mostly what is being used in the office or school environment. It helps so much in formalizing things (just like laptop) and to also, communicate around the globe if you have an Internet access.

Tablets

These are just the most recent type of gadget that hit the market like wildfire. Just like mobile phones, everyone also seems to have one of these. This is best for gaming and for carrying a handy notebook suitable for almost every type of person. What is great about this gadget is that its capacitive touch and slim body, it makes anyone enjoy the beauty of a laptop in one handy screen.

These are just some of the electronics that most people use nowadays. They have different functions but they basically do the same as the other. There are however, many applications that cannot be rendered in PC or table computers because it needs capacitive touch screen to function well. Thus, if you are about to buy your own electronic, be certain that you have chosen what you need.

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.