Technology category

backscatter-system

Researchers Develop Long Range Backscatter Sensors That Consume Almost No Power

Researchers at the University of Washington developed a new backscatter sensors that can operate over long ranges with very little power. The researchers demonstrated for the first time that the device runs on almost zero power and can transmit data across distances of up to 2.8 kilometers.

The long-range backscatter system developed by UW researchers
The long-range backscatter system developed by UW researchers

Backscatter communication works by emitting a radio signal and then monitoring the reflections of that signal from sensors. As the transmitter generates the signal, the sensors themselves require very little power. But this kind of system badly suffers from noise. Noise can be added anywhere – on the transmitter side, on the channel or on the sensor array. The key to solving this problem is a new type of signal modulation called chirp spread spectrum.

By using the chirp spread spectrum modulation technique, the team was able to transmit data up to 2.8 kilometers while the sensors themselves consumed only a few microwatts of power. Such extremely low power consumption lets them run by harvested ambient energy and very small printed batteries. The cost is surprisingly cheap too. The sensors would cost just 10 to 20 cents per unit if bulk purchased.

Today’s flexible electronics and other sensors need to operate with very low power typically can’t communicate with other devices more than a few feet or meters away. By contrast, the University of Washinton’s long-range backscatter system achieved pretty strong coverage throughout a 4800-square-foot house, an office area including 41 rooms, and a one-acre vegetable farm at extremely low power and low cost.

Shyam Gollakota, the lead faculty and associate professor in the Paul G. Allen School of Computer Science & Engineering, said,

Until now, devices that can communicate over long distances have consumed a lot of power. The tradeoff in a low-power device that consumes microwatts of power is that its communication range is short. Now we’ve shown that we can offer both, which will be pretty game-changing for a lot of different industries and applications.

These low-power sensors have endless potential applications. They can be used for everything from wearable health monitors to scientific data collection devices. Though there are no confirmed products yet, the team has created few prototypes in the form of flexible sensors worn on the skin, smart contact lenses, and more.

iEAT - A Portable allergen-detection system

iEAT – A Powerful Keychain Detector To Detect Food Allergens

For kids and adults with food allergies, having meals from restaurants or hotels can sometimes be very risky. Even when ultimate care is taken, freshly prepared meals can accidentally become cross-contaminated with an offending food and trigger an allergic reaction. Every year many people end up in the emergency room due to food allergies. Researchers of the Harvard Medical School developed an affordable device called iEAT for detecting allergens, which can reduce the anxiety of the people prone to allergies.

iEAT - A Portable allergen-detection system
iEAT – A Portable allergen-detection system

Conventional methods to detect the hidden allergens require massive laboratory equipment. They are slow and also do not work on a low concentration of allergens. Ralph Weissleder, Hakho Lee, and their colleagues at the Harvard Medical School wanted to make a more practical, consumer-friendly alternative. They reported in the journal ACS Nano the development of a new portable allergen-detection system that features a keychain analyzer for detecting allergens in food anywhere, anytime.

The portable allergen-detection system called integrated exogenous antigen testing or iEAT is small enough to fit in your pocket and it costs $40 only. The iEAT consists of a handheld device to extract allergens from food and an electronic keychain reader for sensing allergens. Then, the result is wirelessly sent to a smartphone. The prototype is able to detect five allergens within 10 minutes, one each from wheat, peanuts, hazelnuts, milk, and egg whites, even if they are in very low concentration.

The main device uses a disposable sample collector which is inserted into the small-sized main unit. The device is so sensitive that the scientists were able to detect gluten in foods advertised as being “gluten-free”. For example, the device detected gluten in salad and an egg protein in beer. Although the prototype was primarily designed to sense five allergens only, the researchers say the device could be expanded to test for many additional compounds, including other allergens and non-food contaminants such as pesticides.

TE

Terahertz Electronics – Way To Bridge The largely-untapped Region Between 100GHz and 10THz

The terahertz (THz) region, which is based on 1THz frequency, separates electronics from photonics and has been difficult to access for ages. Semiconductor electronics cannot handle frequencies equal to or greater than 100GHz due to various transport-time related limitations. In other hand, photonics devices fail to work below 10THz as photon’s energy significantly drops to thermal energy. Terahertz Electronics (TE) is a new technology that extends the range of electronics into the THz-frequency region.

The Terahertz Gap
The Terahertz Gap

The main goal of Terahertz Electronics is to build a bridge between low-frequency “Electronics” and high-frequency “Photonics”. Since these devices use photon-electron particle interactions, as photon energy “hv” decreases below thermal energy “kT”, the device ceases to operate efficiently unless it is cooled down. At the low-frequency end, electronics cannot operate above 100GHz as transport time is dependent on drift and diffusion speeds of electrons/holes. As a result, a large region between 100GHz and 10THz remained inaccessible. Terahertz Electronics solves this problem efficiently by cleverly incorporating electronics with photonics.

Terahertz electronics technology offers practical applications in high-speed data transfer, THz imaging, and highly-integrated radar and communication systems. Surprisingly enough, It does not use semiconductors. Instead, it is based on metal-insulator tunneling structures to form diodes for detectors and ultra-high-speed transistors for oscillator based transmitters.

One drawback of the Terahertz Electronics is, it requires high-frequency radiation sources. Lack of a small, low-cost, moderate-power THz source is one of the main reasons that THz applications have not fully materialized yet. Scientists are trying to find a solution to this problem. They created a compact device that can lead to portable, battery-operated sources of THz radiation. This new solid-state T-ray source uses high-temperature superconducting crystals that contain stacks of Josephson junctions. So, even a small voltage, around two millivolts per junction, can induce frequencies in the THz range.

Mercury arc lamps generate light in terahertz
Mercury arc lamps generate light in terahertz

TE devices are extremely fast and they are made entirely of thin-film materials—metals and insulator. Hence, it is possible to fabricate Terahertz Electronics devices on top of complementary metal oxide semiconductor (CMOS) circuitry—a technology for creating integrated-circuits circuitry or on an extensive variety of substrate materials. In TE devices, charge transport through the junction occurs via electron tunneling. Further research and development will make Terahertz Electronics a reality in not-so-distant future.

enlarged cross-section of an experimental chip made of ultrathin semiconductors

New Ultrathin Semiconductors Can Make More Efficient and Ten Times Smaller Transistors Than Silicon

The researchers at Stanford University have discovered two ultrathin semiconductors – hafnium diselenide and zirconium diselenide. They share or even exceed some of the very important characteristics of silicon. Silicon has a great property of forming “rust” or silicon dioxide (SiO2) by reacting with oxygen. As the SiO2 acts as an insulator, chip manufacturers implement this property to isolate their circuits on a die. The most interesting fact about these newly discovered semiconductors is, they also form “rust” just like silicon.

enlarged cross-section of an experimental chip made of ultrathin semiconductors
An enlarged cross-section of an experimental chip made of ultrathin semiconductors

The new materials can also be contracted to functional circuits just three atoms thick and they require much less energy than silicon circuits. Hafnium diselenide and zirconium diselenide “rust” even better than silicon and form so-called high-K insulator. The researchers hope to use these materials to design thinner and more energy-efficient chips for satisfying the needs of future devices.

Apart from having the ability to “rust”, the newly discovered ultrathin semiconductors also have the perfect range of energy band gap – a secret feature of silicon. The band gap is the energy needed to switch transistors on and it is a critical factor in computing. Too low band gap causes the circuits to leak and make unreliable. Too high and the chip takes excessive energy to operate and becomes inefficient. Surprisingly, Hafnium diselenide and zirconium diselenide are in the same optimal range of band gap as silicon.

All this and the diselenides can also be used to make circuits which are just three atoms thick, or about two-thirds of a nanometer, something silicon can never do. Eric Pop, an associate professor of electrical engineering, who co-authored with post-doctoral scholar Michal Mleczko in a study paper, said,

Engineers have been unable to make silicon transistors thinner than about five nanometers, before the material properties begin to change in undesirable ways.

If these semiconductors can be integrated with silicon, much longer battery life and much more complex functionality can be achieved in consumer electronics. The combination of thinner circuits and desirable high-K insulation means that these ultrathin semiconductors could be made into transistors 10 times tinier than anything possible with silicon today. As Eric Pop said,

There’s more research to do, but a new path to thinner, smaller circuits – and more energy-efficient electronics – is within reach.

Rechargeable Magnesium Batteries – Safer And Cheaper Than Li-ion Batteries

Researchers at the University of Houston reported in the journal Nature Communications the discovery of a new design that significantly improves the development of a battery based on magnesium. Magnesium batteries are considered as safe resources of power supply – unlike traditional lithium-ion batteries. They are not flammable or subject to exploding – but their ability to store energy is very limited. But the latest discovery of the new design for the battery cathode drastically increases the storage capacity.

Energy diagrams for the intercalation and diffusion of Mg2+ and MgCl+
Energy diagrams for the intercalation and diffusion of Mg2+ and MgCl+ in magnesium batteries

In order to make magnesium batteries, the magnesium-chloride bond must be broken before inserting magnesium into the host, and this is very hard to do. Hyun Deog Yoo, the first author of the paper, said,

First of all, it is very difficult to break magnesium-chloride bonds. More than that, magnesium ions produced in that way move extremely slowly in the host. That altogether lowers the battery’s efficiency.

The new battery technology stores energy by inserting magnesium monochloride into titanium disulfide, which acts as a host. By keeping the magnesium-chloride bond intact, the cathode showed much faster diffusion than traditional magnesium batteries.

The researchers managed to achieve a storage capacity density of 400 mAh/g – a quadruple increase compared with 100 mAh/g for earlier magnesium batteries. This achievement even overpowered the 200 mAh/g cathode capacity of commercially available lithium-ion batteries. Yoo, who is also the head investigator with the Texas Center for Superconductivity at UH, confirmed this fact.

The cell voltage of a magnesium cell is only 1V which is significantly less than a lithium-ion battery which has 3.7V cell voltage. Higher cell voltage and high cathode capacity made Li-ion batteries the standard. Li-ion batteries suffer from an internal structural breach, known as dendrite growth what makes them catch fire. Being an earth-abundant material, magnesium is less expensive than lithium and is not prone to dendrite growth.

The magnesium monochloride molecules are too large to be inserted into the titanium disulfide using conventional methods. The trick they developed is to expand the titanium disulfide to allow magnesium chloride to be inserted rather than breaking the magnesium-chloride bonds and inserting the magnesium alone. Retaining the magnesium-chloride bond doubled the charge the cathode could store. Yoo said,

We hope this is a general strategy. Inserting various polyatomic ions in higher voltage hosts, we eventually aim to create higher-energy batteries at a lower price, especially for electric vehicles.

Microchip SST26WF064C Flash Memory Chip

SST26WF064C – Low-voltage 64-Megabit SuperFlash® Memory Device From Microchip

Microchip introduced a new 64Mbit Serial Quad I/O memory device—SST26WF064C with proprietary SuperFlash® technology. The SST26WF064C writes with a single power supply of 1.65-1.95V and significantly lower power consumption. This makes it ideal for wireless, mobile, and battery-powered applications.

Microchip SST26WF064C Flash Memory Chip
Microchip SST26WF064C Flash Memory Chip

This 64Mbit memory device also features DTR or Dual Transfer Rate technology. DTR lets the user access data of the chip on both rising and falling edges of the clock, reducing overall data access time and power consumption significantly. The SST26WF064C utilizes a 4-bit multiplexed I/O serial interface to boost performance while maintaining the tiny form factor of standard serial flash devices.

Microchip’s high-performance CMOS SuperFlash technology provides the fastest chip erase time, consequently, reduces overall power consumption. It also improves performance and reliability of the memory chip. The SST26WF064C’s typical chip-erase time is 35-50 milliseconds, where other chips take nearly 30 seconds to be completely erased.

This chip combines a hardware controlled RESET function which is not present in common flash chips available in the market due to their limited pin count. In SST26WF064C, the user can program the HOLD pin to use for the RESET function. This feature lets the host microcontroller to reset the chip by sending a pulse to it.

SST26WF064C supports full command-set compatibility with traditional Serial Peripheral Interface (SPI) protocol. Operating at frequencies reaching 104 MHz, the SST26WF064C enables minimum latency execute-in-place (XIP) capability without the need for code shadowing on a SRAM. To learn about code shadowing, read this article.

The key features of the SST26WF064C are:

  • Single Voltage Read and Write Operations – 1.65-1.95V
  • Serial Interface Architecture
  • High-Speed Clock Frequency (104 MHz max.)
  • Burst Modes
  • Superior Reliability
  • Low Power Consumption
  • Fast Erase Time
  • Flexible Erase Capability
  • Suspend Program or Erase operation to access another block/sector
  • Software and Hardware Reset mode
  • Software Protection
  • Security ID
  • One-Time Programmable (OTP) 2KByte Secure ID
  • 64 bit unique, factory pre-programmed identifier
  • User-programmable area

To learn more about this memory chip or to purchase some, visit http://www.microchip.com/wwwproducts/en/SST26WF064C.

Turn Your iPad Into A Second Screen with Luna

It is possible now to turn your iPad into a second display using Luna Display! Luna Display is a hardware solution that extends your Mac desktop to your iPad, creating a wireless second monitor maintaining high resolution.

In fact, Luna is one of Astro HQ products, a startup working on delivering tools for designers and animation creators. It is originally  founded by two ex-Apple engineers, a reason to understand the loyalty for Apple products!

With no complicated settings, you can set up Luna in seconds using your already available Wi-Fi. This feature is Powered by Astro HQ LIQUID technology. Anyway if Wi-Fi is not available, USB can be the alternative.

 LIQUID technology provides:

  • Uncompromised image quality
  • Lightning fast speeds
  • Lag-free performance at 60 frames per second
  • GPU acceleration, so your Mac stays fast and optimized
  • Hand optimized ARM assembly to maximize battery life
  • Velocity Control, which analyzes network conditions dozens of times per second

System Requirements

Works with any modern Mac – Luna requires a Mac running macOS 10.10, Yosemite (or later). Recommended configurations: MacBook Air (2012 and later), MacBook Pro (2012 and later), Mac mini (2012 and later), iMac (2012 and later), Mac Pro (Late 2013).

Works with any modern iPad – Luna requires an iPad running iOS 9.1 (or later): iPad 2 (or later), any iPad Mini and any iPad Pro.

 

You can perfectly use Luna Display with the software Astropad, a software that allows you to draw directly into your Mac apps using your iPad and it works over wifi or USB.

“Luna extends both Astropad Standard and Astropad Studio to provide the ultimate drawing experience with the best second screen solution for iPad. If you are a creative professional, Luna has been designed with you in mind.”
Unlike other solutions, Luna uses the raw power of your graphics card, and harnesses it in order to allow you have the full potential of graphics acceleration. Check this video about the technology used in Luna Display, battery use and energy.

To know more about Luna, you can check the Kickstarter campaign they launched earlier.
Fortunately, the 1,450% funded campaign is still running and still has 39 days to go. You can pre-order your Luna Display gadget for 65$, or the Artist bundle for $99, including 1 Luna Display and 1 year Astropad Studio.

For more information and details, you can check the official website of Astropad and Astro HQ. Also, take a look at the campaign video here.

Coulomb Transistor — A New Concept Where Metal Nanoparticles Are Used In Place Of Semiconductor

A research group at the University of Hamburg has created a unique coulomb transistor that operates on the principle of the voltage control of the electron band gap in metallic quantum-dot nanoparticles. This Single-electron transistor represents an approach to develop less power-consuming microelectronic devices. It will be possible if industry-compatible fabrication and room temperature operation are achieved.

The concept is based on building stripes of small, colloidal, metal nanoparticles on a back-gate device architecture. Being very tiny, the metallic nanoparticles exhibit semiconductor properties that can be controlled by voltage. The body of this transistor can be operated as a second gate. It results in well-defined and controllable transistor characteristics.

Design of coulomb transistor
Design of Coulomb transistor

This newly invented Coulomb transistor has three main advantages. The advantages are: on/off ratios above 90%, very reliable and sinusoidal Coulomb oscillations, and room temperature operation. The concept allows for tuning of the device properties such as Coulomb energy gap and threshold voltage, as well as the period, position, and strength of the oscillations.

Though the single-electron transistor (SET) is quite similar to a common field-effect transistor (FET), it does not rely on the semiconductor band gap but instead on the Coulomb energy gap. Transfer characteristics of the SET show periodic on and off states known as Coulomb oscillations. Researchers hope that might render new applications possible in the future.

When a bias voltage is applied to the nanoparticle channel, it becomes clear that conduction in this system is not purely metallic but is controlled by tunnel barriers between individual particles. The transport of charged particles is hindered due to very high potential barrier which depends on the charging energy. Tuning the voltage of an additional gate results in a field effect that continuously shifts the energy levels of the particles and allows for tunneling to occur. This additional gate electrode is separated from the channel by a dielectric layer.

Output characteristics of coulomb transistor
Output characteristics of Coulomb transistor

The single-electron transistors require further research and more development, but the work shows that there are alternatives to traditional transistor concepts that can be used in the future in various fields of application. Christian Klinke, the lead researcher, said in a statement,

The devices developed in our group can not only be used as transistors, but they are also very interesting as chemical sensors because the interstices between the nanoparticles, which act as so-called tunnel barriers, react highly sensitive to chemical deposits.

Diamond-Based MOSFETs Are Now Real

A research group at Japan’s National Institute for Materials Science (NIMS) has developed logic circuits equipped with diamond-based metal-oxide-semiconductor field-effect-transistors (MOSFETs) at two different operation modes – a first step toward the development of diamond integrated circuits operational under extreme environments.

Is Diamond Suitable for this?

In fact, diamond has high carrier mobility, a high breakdown electric field and high thermal conductivity. Therefore, it is a promising material to use in the development of current switches and integrated circuits. Specifically to operate stably at high-temperature, high-frequency, and high-power. However, it had been difficult to enable diamond-based MOSFETs to control the polarity of the threshold voltage. In addition, fabricating MOSFETs of two different modes on the same substrate was a challenge. The modes are:  a depletion mode (D mode) and an enhancement mode (E mode).

Thus, the research group has successfully developed a logic circuit equipped with modes. Thanks to threshold control technique that allowed them create hydrogenated diamond NOT and NOR logic circuits composed of D-mode and E-mode MOSFETs.

Micrograph of a fabricated logic circuit equipped with diamond-based transistors

This study was published in the online version of IEEE Electron Device Letters and it is available at the IEEE Electron Digital Library website. Also, check the official announcement for more details.

Water Splitting With Solar Energy

Using solar energy to split water provides an efficient way for large scale renewable energy conversion and storage. A group of researchers from TUDelft and AMOLF have successfully developed an efficient and stable photo-electrode that could improve water splitting with solar energy.

Decomposition of water using solar energy

This photoelectrode absorbs light and directly decomposes water into hydrogen and oxygen. In addition to the efficiency, the system is also cheap because of using silicon wafers as the light absorbing material.

The Process

Photoelectrochemical (PEC) splitting of water is a direct conversion of solar to chemical energy to produce renewable and clean fuel. The hydrogen, for example, can be used directly in fuel cells, or combined with other molecules to create durable materials.

Together with colleagues from AMOLF (Amsterdam), we have engineered a photo-electrode, a material that absorbs light and directly splits water, that has a very high efficiency and over 200 hours of stability’, says Wilson Smith, Associate Professor in the Department of Chemical Engineering at TU Delft. ‘This is remarkable in a field where people normally show only a few hours of stability.  We use silicon wafers as the light absorbing material, so the photoelectrode is also very cheap.

Researchers had also designed a new insulator layer to stabilize the semiconductor (Si) photo-electrode, while keeping the high efficiency of water splitting by using two metals. This approach known as making a metal-insulator-semiconductor (MIS) junction. It is a simple system that combines the stability and catalysis bottlenecks in photoelectrochemical water splitting.

For more information, the researchers had published this research in Nature Communications.