Category Archives: Newsworthy

Butterfly Technology Boosts Solar Panel Output

We normally do not relate butterflies to solar panels. After all, bees and butterflies are good for pollinating flowers and transforming them to fruits so that nature can propagate. On the other hand, solar panels are human creations that collect energy from the sun for the use of humankind. The link between the two seems rather distant, apart from the fact that the sun is the basic force that drives all life on our planet. However, science finds the humble butterfly could be holding the key to unlock new techniques for making solar energy cheaper and more efficient.

Cabbage White butterflies need to heat up their flight muscles before they can take off. Researchers at the University of Exeter have observed that the butterflies adopt a specific posture to maximize solar heat capture. The butterflies position their wings in a V-shape, which, when the researchers adapted for their solar panels, increased the power-to-weight ratio of the panels by about 17 times, making them more efficient.

Scientific Reports, a leading scientific journal has published the research. The research team contained members from both the Centre for Ecology and Conservation and the Environment and Sustainability Institute, based at the University of Exeter in the Penryn Campus in Cornwall. According to Tapas Mallick, the lead author of the research, although bio mimicry is popular in engineering, such unparalleled multidisciplinary research is opening pathways for developing low cost solar panels.

Butterflies usually depend on the sun to heat up their flight muscles before they can take off. However, researchers found the Cabbage White butterflies taking flight before other butterflies did, even on cloudy days. The energy from the sun is limited on cloudy days, forcing insects to make maximum use of the available energy to heat up their flight muscles.

Researchers observed that Cabbage White butterflies adopted a v-shaped posture, known as reflectance basking. That allows the butterflies to maximize the concentration of solar energy onto their thorax, so necessary for fast heating up the flight muscles. The wings of the butterflies have a specific sub-structure that allows maximum light from the sun to be most efficiently reflected onto their muscles, which warm up to the optimal temperature as quickly as possible.

The scientists then investigated the process of replication of the butterfly wings for developing a new, lightweight reflective material solar energy products could use. They found that by replicating the simple monolayer of scale cells on the butterfly wings, they could optimize the power-to weight ration of solar concentrators. That made the solar cells lighter and more efficient.

The team also found the optimal angle at which the butterfly held its wings. When the butterflies tilted their wings by about 17 degrees to the body, they were able to increase the temperature of their bodies by 7.3°C more than when they held their wings flat. By positioning the reflectors at 17 degrees within the solar cells, researchers found the output from the solar cells increased by 50 times.

Therefore, by studying the manner in which the lowly butterfly maximized its use of solar energy, scientists could not only double the output of their solar cells. They were also able to improve its power-to-weight ratio significantly.

A Primary Display HAT for the Raspberry Pi

A portable single board computer such as the Raspberry Pi or the RBPi ought to have a portable screen, preferably a touch screen that is comfortable to use. This is a long overdue, much sought-after request from users, especially from developers, who see and use several smartphones and tablets with capacitive and or resistive touch screens.

The Pi Foundation has been hard at work on developing a seven-inch touch screen as an add-on to the RBPi. This would be appropriate for a number of projects where you would want to pit the RBPi against a portable tablet or even a laptop. However, for development of embedded systems, people prefer a smaller and more compact version of display. The 2.4-inch TouchScreen display from 4D Systems fills this void perfectly and affordably, being compatible with the RBPi models A+, B+ and RBPi2.

The TouchScreen is almost as large as the RBPi board and covers it as far as the USB and Internet ports, while sitting perfectly on the bank of GPIO pins and covering all of them. At present, the other end of the TouchScreen hangs as there is no support and there is a possibility of its backside touching the connectors. You can expect a set of stand-offs to come soon and these will secure the screen above the connectors and pins of the RBPi.

According to an intentional design decision between 4D Systems and element14, the TouchScreen fits very neatly within the official case of the RBPi. That leaves out only the portable power, which, if the official case could support, would have made the RBPi truly portable.

The 30 gm. TouchScreen module dimensions measure 56.5×65.0x14.2 mm. It has a viewing area of 49.0×36.7 mm, with four mounting holes of 2.6 mm diameter. The QVGA TFT screen has a resolution of 240×320 pixels and sports 65K true to life colors. Integrated with the screen is a 4-wire resistive touch panel. You can display the full GUI output or the primary output on the TouchScreen, just as would a monitor connected to the RBPi. The display uses a PWM control for the backlight and on board, there are three backlight choices, selectable with jumpers – On, Off and PWM.

The display module connects to the RBPi via a high-speed SPI interface working at 46MHz and using SPI compression technology. If you have a kernel that compresses images, expect higher frame rates than the typical value of 17 frames per second. The module does not require a separate power supply as it powers itself directly from the RBPi.

Although the screen has full capabilities, its limitations are because of the way Linux handles framebuffers. For example, although the display can play full motion video, you cannot render OpenGL to the screen. That means you cannot expect hardware acceleration from the SPI screen. Someday, this may be possible if someone tweaks the Broadcom code for the VideoCore and OpenGL.

What is 3D Flash Memory?

Slowly, but steadily, the memory market is veering away from magnetic disc storage systems to solid-state drives or SSDs. Not only are prices falling fast, manufacturers are producing SSDs with improved technologies, leading to denser memories, higher reliability and lower costs. For example, Samsung has recently announced SSD and systems designs that will drive their new 3-D NAND into mass markets.

Samsung’s latest SSDs are the 850 EVO series. According to Jim Eliot, a marketing executive for Samsung, these are 48-layer, 256 Gbit 3-D NAND cells, with 3-bits per cell. The new chips show more than 50% better power efficiency and twice the performance when compared to the 32-layer chips Samsung is now producing. In the future, Samsung is targeting Tbit-class chips made with more than 100 layers.

On a similar note, an engineer with SK Hynix says that by the third quarter, the company will start production of 3-D NAND chips with more than 30 layers. By 2019, SK Hynix will be making chips containing more than 190 layers.

At present, 3-D NAND production is still low in yield and the cost of production is higher than for producing traditional planar flash chips. However, these dense chips bring promises of several generations of continuing decreases in costs and improvements in the performance of flash. According to analysts and vendors, it might take another year or so before the new technology is ready for use in the mainstream.

Samsung was the first to announce 3-D NAND production, with rivals catching up fast. Toshiba has already announced its intentions of producing 256 Gbit 3-D NAND chips in September. These will also have 48 layers and 3-bits per cell.

According to Jim Handy, an analyst at the Objective Analysis, Los Gatos, California, sales of the 3-D NAND will not pick up before 2017. With Samsung shipping its V-NAND SSDs at a loss, they are gearing up to put the 48-layer devices in volume production. This will enable them to beat the cost of traditional flash.

The reason is not hard to find. Wafers of 3-D chips with 32-layers cost 70% higher than wafers for traditional flash. On the other hand, wafers for 48-layer versions cost only 5-10% higher, but have 50% more layers. Therefore, although the 48-layer chips tend to start with a 50% yield, they will easily approach the planar flash yield levels with a year or so.

According to expert analysts, it takes a couple of years for any new technology to mature. Therefore, the prediction that 3D NAND will reach a majority of flash bit sales only after 2018.

The number of 3D layers providing an optimal product is still under experimentation. Also, included is the development of a new class of controllers and firmware for managing the larger block sizes. Vendors are still exploring other unique characteristics of these 3D chips.

For example, Samsung has designed controllers and firmware that addresses the unique requirements of 3-D NAND and is selling its chips only in SSD form. According to the head of Samsung’s Memory Solutions Lab, Bob Brennan, SSDs provide higher profit margins as compared to merchant chips, and are the fastest way to market.

UPS-PIco for Uninterruptible Power for the Raspberry Pi

The innovative Raspberry Pi or RBPi, the tiny single board computer, has endeared itself to the young and old alike. When used for critical applications, it is often necessary to supply the RBPi with continuous power, for which, an advanced uninterruptible power supply such as the UPS PIco offers several innovative power back up and development features.

With a 300mAh LiPO battery, the standard UPS PIco offers a safe shutdown during a power cut. However, you can easily upgrade this battery to an extended version of 3000 mAh. This will allow you to use the RBPi for a prolonged 8 hours, even if no power supply is available.

An embedded measurement system within the UPS PIco works continuously to check the powering voltage of the RBPi. As soon as it detects the absence or the inadequacy of the cable power of the RBPi, or senses a power failure, the UPS PIco switches over to its battery source automatically. The module continues to check the voltage on the RBPi cable, and if the power is once again available or adequate, it switches over from the battery and allows the regular cable supply to power the RBPi.

You do not need any additional cabling or a separate power supply for charging the battery, as the UPS PIco is a powered unit, with the GPIO pins on the RBPi powering and charging the battery pack intelligently.

The UPS PIco complies with the HAT standards for the RBPi models A+/B+ and 2B. Mechanically, it is compatible with the original models A & B of the RBPi, provided you use an extension header. Additionally, the UPS PIco is compatible with most cases housing the RBPI, especially as it fits within the footprint of the RBPi and does not require any additional powering.

An additional feature on the UPS PIco allows remote operation. An optional infrared receiver does the trick. The PCB routes the infrared receiver directly to the GPIO18. With this feature, you control the RBPi and UPS PIco remotely.

Finally, if you are likely to operate the RBPi in a very high temperature environment, you will need to cool it with external methods. The UPS PIco allows you to implement a PWM fan controller with an automatic temperature control feature. With a micro-fan fitted on the RBPi, the UPS PIco keeps your CPU cool.

Apart from being HAT compliant with RBPi models A+/B+ and 2B, the smart uninterruptible power supply or UPS is fully plug and play. Although the integrated LiPO battery provides 8-10 minutes of back-up power, an additional 3000 mAh battery pack extends this run-time to nearly 8 hours, providing a power backup of 5V, 2A with a peak output of 5V, 3A.

A real time clock simulated with software, with the battery backup offers a functionality offering a file-safe shutdown. The UPS PIco has a pair of user-defined buttons and a pair of user-defined LEDs, along with integrated buzzer for UPS and user applications. With I2C Pico and RS232 RBPi Interfaces, the user can easily monitor and control the operations of the UPS. Add-on boards are easy to use, as the UPS PIco has a stackable header.

Quadriplegics Can Control Exoskeletons with Their Brain

Artificial limbs help people who have lost a part of their arms or legs to regain partial functionality of their extremities. However, for those who have lost control of a major part of their bodies and thus rendered quadriplegic, artificial limbs are not of much use. For addressing such and other whole-body disabilities, exoskeletons are showing great promise.

Scientists working at the Technische Universitat Berlin and Korea University are creating such lower-limb exoskeletons. The control system here is completely hands-free. Rather, it is a brain-to-computer interface, which controls the exoskeleton, by decoding and making use of signals from the wearer’s brain. According to the researchers, volunteers who were given the exoskeleton to use took only a few minutes for learning to operate the system. Therefore, substantially paralyzed people may hope to walk again with the help of this exoskeleton.

Research on such exoskeleton systems is not new and several types are in development and in limited production in many parts of the world. However, most achieve controls by detecting subtle movements in the upper body of the wearer. However, the difference in the KU/TU Berlin unit is the control is entirely dependent on brain signals. Therefore, this is useable even by a completely paralyzed person.

The human brain generates different signals when the person stares at a specific LED. These signals are detected and interpreted to be used for controlling the hands-free exoskeleton. An EEG brain control interface connects wirelessly to the main computer of the control system.

In actual practice, the wearer stares at any one of five flashing LEDs. This initiates waves in the wearer’s brain and an electroencephalogram or EEG worn as a cap reads the signals. Because each LED flashes at a different rate, focusing on any one at a time produces a specific signal pattern in the brain of the user corresponding to a desired mode of movement. The computer system interprets the readings of these signals sent to it from the EEG cap and converts them to system instructions for operating the exoskeleton.

As this method of control does not require detection of movement from any other body part, it is eminently suitable for even those who have lost the capacity for voluntary body control, except for eye movements. Ordinarily, such people would not be able to use or control a standard exoskeleton. According to the researchers, their system has a much better signal-to noise ratio.

The brain generates signals depending on external signals it receives from its surroundings. This acts like noise to the actual control signal desired for movement. By concentrating on a flashing LED, the researchers are effectively separating the user’s brain control signals from being cluttered with external stimuli. The result is a more accurate exoskeleton operation than what a conventional hard-wired system could have achieved.

Exoskeleton systems are notorious for creating loss of electrical noise, especially affecting the EEG signals. However, the frequency of the flickering LED acts as a filter to separate the EEG signal effectively. This exoskeleton system helps people with high spinal cord injuries or those with motor neuron disease who face difficulties in communicating or using their limbs.

Liquid Droplets That Levitate On a Blue Light Pad

Scientists in France have found a novel technique to levitate liquid droplets on a cushion or pad of blue light. The effect sets off a striking light show with the droplets generating sparks as they drift over the blue gap.

The effect is quite like the Leidenfrost Levitation in which a liquid drop is made to levitate on its vapor layer created over a hot surface. However, while in the Leidenfrost effect, the temperature is the initiating factor, here it is electricity creating the interesting spectacle.

Plasma creation

The researchers discovered that a high pulse of electricity applied to a gas could vaporize it so the gas glows with a bluish light. This remarkable find may present an economical technique to produce movable micro plasma layers. Furthermore, the study yields remarkable insights into basic principles of physics.

Physicist Cedric Poulain of French Alternative Energies and Atomic Energy Commission explains that the technique is a simple and an innovative way to create plasma.

In the experiment tried out by the research workers, over 50 volts of electric power was applied across a droplet of dilute hydrochloric acid suspended above a metallic plate. This made the droplet levitate over a region radiating a light blue glow.

Cushion of vapor

At voltages above 50V, the base of the acid droplet started to produce sparks. The drop rose, increasing the gap above the metal plate and a blue light filled up the gap. The scientists first assumed that the droplet was lying on a cushion of gaseous hydrogen produced by the electrolysis of the acidified water. Further scientific analysis established that the gas cushion primarily consisted of water vapor.

Poulain explained that extremely small space between the metal plate and the droplet makes it easy to set up the high electric field needed to produce the plasma layer, even with moderate electric voltages.

Contrasting boiling with electrolysis of water

The team compared the electrolytic dissociation of water with boiling. Poulain brought forward the example of a water drop placed on the surface of a heated vessel. He pointed out that at temperatures higher than 100 degrees Centigrade, the drop spreads out and bubbles form on the surface. At temperatures exceeding 280 degrees Centigrade, a vapor cushion can be seen forming in between the drop and the vessel surface. This makes the water drop levitate so that there is no contact between the drop and the vessel surface.

The team described the transition in electrolysis as somewhat similar.

Figuring out the blue light phenomenon

According to the team of researchers working on the project, the emission of blue light was the most striking feature of the study. For a proper conception of the phenomenon, the scientists plan to explore the makeup of the plasma layer. They believe that two types of plasma are superposed, though they cannot yet understand the effect.

The scientists also intend to scrutinize the liquid dynamics at the lower surface of the droplet when the sparks just start to fly out. This should give further information regarding the nature of the plasma layer.

Is Your Solar Panel Installed the Right Way?

Although few people would have noticed, the costs of solar photovoltaic cells have been dropping over the years. As the technology took off, costs plummeted in the first 12 years. However, between 2005 and 2009, global market demand surged, making it difficult for supply to keep up. As manufacturing picked up post 2009, solar PV cell prices have continued their downward trend steadily. Now, it makes sense for companies to switch to PV cells purely based on economics.

As solar grows to become a more attractive option, we see a clear preference in its adoption over adding new wind capacity. Navigant Research has predicted in their recent report that declining prices will result in the global solar PV market exceed $134 billion by 2020 – a phenomenal increase of 50% from this year. That means a solar capacity addition of nearly 435 Gigawatts.

However, getting the maximum benefit from solar PV cells requires mounting them the right way. As the sun traverses the sky in the daytime, the PV cells must either follow the trajectory of the sun or be mounted in the most optimum way for them to catch most of the sunlight. Automatically turning the PV cells to face the sun requires elaborate sensing and expensive movement mechanisms. Therefore, most people prefer fixed installations that are simple to put up and maintain.

Another thing to consider is the latitude tilt of the location where you intend to install the solar cells. If your location is below the 25 degrees latitude, tilt the solar panel towards the sun the same amount as the latitude number. At 25 degrees latitude, your panel must tilt by 25 degrees. Above 25 degrees, you will need to add five degrees for each additional five degrees of latitude up to 40 degrees. At and beyond 40 degrees latitude, add 20 degrees of tilt to the latitude number. The above is the general thumb rule people follow for solar PV panel installation. Consequently, most installations have the solar panels facing south to catch the maximum amount of sunlight.

Researchers at the Pecan Street Research Institute have discovered ways to additionally fine-tune the positioning and tilt of the solar panels to extract somewhat more power. During their research on impact of residential solar power on the power grid, they discovered that if the solar panels faced west rather than the customary south, they could generate about 2% more power.

So long, homeowners, utilities and architects believed that in the northern hemisphere, solar panels directed south would receive the maximum exposure from the sun. However, when studying home installations in Austin, Texas, Pecan Street researchers found that this was not true. In fact, they noticed south-facing panels generating less energy. They found west-facing panels generated more power in the afternoon, when the energy demand peaked.

As energy demand peaks, a typical home in Austin using solar panels reduces its reliance on the power grid by as much as 54%. However, for homes with west-facing panels, this number shot up to 65% – a significant power saving. Therefore, by merely shifting the angle, you may be able to achieve significant gain in solar power generation.

Conducting Elastic Fibers for Artificial Muscles and Electronic Devices

A study at the Dallas based University of Texas shows how scientists have wrapped electrically conducting carbon nanotube sheets around a rubber core to create super elastic fibers. In addition, these fibers conduct electricity and have some special electronic properties as well.

The elasticity of the fibers is phenomenal. They can be more than 14 times longer than their original lengths by stretching and the process is reversible. The fibers regain their initial lengths once the stretching force goes away. While the fibers can extend to 14 times their length, the electrical conductivity steps up by 200 times.

Scientists have conceived of several uses for these fibers. Their high elasticity and conductivity when they stretch could make them ideal for use as minute interconnects in electronic circuits. This could help in upgrading diverse applications like flexible charging cables for mobile devices, robots with longer ranges and trouble-free pacemaker leads.

These fibers are different from conventional fibers in a major aspect. The conductivity of the ordinary fibers falls when they stretch, because of the reduced area of cross section offered to the path of electricity. On the other hand, conductivity of the new fibers increases when stretched.

Dr. Ray Baughman, director of the Nano Tech Institute at Dallas, has authored a paper on the subject. He explains the enhanced elasticity is owing to the buckled structure that develops while the nanotube sheets wrap around the rubber core. Buckles form along the length and circumference of the fibers.

According to Dr. Zunfeng Liu, a research associate in the institute, the two dimensional buckling maintains the alignment of the rubber core and the nanotube. This prevents the resistance of the fibers from rising while they stretch.

Liu reveals that until now, no material has been able to function over so large a range of strain. This feature makes possible the creation of artificial muscles with rotational properties. Dr. Haines, a research associate of the university and a coauthor of the paper said that this aspect of the artificial muscles could be useful for rotating mirrors in optical circuits.

Scientific workers have found several other uses for the nanotube sheaths or elastomers. A particularly valuable device formed from the new material is a fiber capacitor. In this device, a thin coating of rubber covers a core of nanotube fibers. Over this, there is another sheath of nanotube fibers. The inner and outer nanotube layers form the two electrodes, while the rubber core serves as the dielectric.

Nan Jiang is a member of the scientific team working on the project. He demonstrated in the laboratory of the Nanotech Institute the manner of construction of these conductive elastomers in varying sizes, ranging from 150 microns to considerably larger sizes. The width of the rubber core determines the size.

The easy availability and low cost of the rubber cores make it easy for commercialization of the technology. Baughman’s team at the institute has developed a process that aims to convert the carbon nanotubes into large sheets. This could facilitate the fabrication of diverse applications with the elastic conducting fibers.

Raspberry Pi Zero for a Real-Time Sensor Dashboard

Using the Raspberry Pi or RBPi, the single board computer (SBC), and a few applications from Google, you can have a functional dashboard showing real-time parameters from sensors. Google offers its App Engine in the form of a Platform as a Service or PaaS. The advantage is you can deploy and run your own applications using the Google infrastructure without bothering about exclusive ways of setting up hardware, servers, or Operating Systems.

Google also offers the free and powerful Google Charts that you can use as simple charting tools for plotting the data from the sensors into line charts. An HTML5 templates generator such as the Initializr is also useful for generating templates for the dashboard. Initalizr has several useful frontend resources such as Bootstrap and jQuery.

RBPi Zero is the perfect hardware platform to use for this project. This SBC is a full-fledged computer, but smaller than a credit card. It features a single-core CPU running at 1 GHz and 512 MB RAM. Along with a 40-pin GPIO header, the RBPi Zero has USB and a mini HDMI port.

When you connect a few sensors to the GPIO pins, the RBPi Zero sends their data over to the Google App Engine. On the dashboard, you can see the values and the charts updating in real-time as new data arrives from the sensors. Github carries the instructions for building and deploying the project for the RBPi Zero app and the App Engine dashboard.

For this project, Java is the programming language, as both the RBPi Zero and the Google App Engine support it – both use the Pi4J library. However, those who prefer Python can easily change the code, as both RBPi and the Google App Engine support Python as well. As the latest version of Raspbian, the Operating System of the RBPi comes pre-installed with Oracle Java 8, it is easy to deploy and run an executable JAR on the RBPi Zero.

The JAR acts as the go-between with the sensors and the Google App Engine – it reads inputs from the sensors and passes them on to the Google App Engine. You can use the Apache Maven to compile and build the code on the RBPi Zero. Of course, you may also build the code on your laptop or desktop and copy the resulting JAR over to the RBPi Zero.

You can use Cloud Endpoint on the Google App Engine side. This is a powerful service for creating a backend API by using annotations. This includes the client libraries for web and mobiles. It generates a Java based Android client for use with the RBPi Zero application. Google Qauth 2.0 authenticates the API for installed applications.

The RBPi Zero based hardware provides readings from three sensors – voltage generated by a solar cell, temperature from an analog temperature sensor, and illuminance or LUX from a photocell. A 10-bit Analog to Digital converter with SPI interface is necessary to covert the analog signal to a digital format suitable for the RBPi Zero. All the sensors work with a supply of 3.3V, and the RBPi Zero is capable of sourcing this.

Emulating Brain Functions with a Memristor Computer

Chip designs at the atomic level may require emulating the functioning of the human brain, while upholding Moore’s Law. In fact, this might be the only way forward. All forward-looking semiconductor design organizations such as Intel, HP, Samsung, and others know this and this has sparked an exponential interest in the study of memristors.

Among all known electronic components, memristors alone are capable of emulating the brain. It is common knowledge now that a human brain performs far better than the fastest supercomputer, while consuming only about 20 watts of power. Supercomputers cannot emulate, rather only simulate the brain, but they consume thousands of watts and are expensive to the tune of millions of dollars.

At Santa Fe, N.M., Knowm Inc. has expanded its portfolio by adding three different types of memristors. They offer a new high-density die-only option, along with all the raw data manufacturers will need to perform their characterization. Although another organization HP/Hynix is also trying to build commercial memristors, Knowm has beaten them to the market by diversifying its offering of memristors. Knowm is now offering three models with slow, medium, or fast hysteresis, based on the material they are made of – tungsten, tin, or chromium.

Regardless of the basic metal-ion used for its manufacture, all memristors work in the same way. The device consists of two electrodes, with a layer of metal located close to one of them. As a voltage is applied across the electrodes, metal ions move through the device towards the electrode with the lower potential. The device has a layer of amorphous chalcogenide material, which is also its active layer. Metal ions moving through this active layer form a conductive pathway between the electrodes. As the pathways spin through the active material layer, the device resistance drops. When the direction of the applied potential is reversed, the conductive channels dissolve and the device resistance increases.

This characteristic makes the memristor a bipolar device. The memristor also emulates the way neurons in the brain learn. Neurons send pulses through their synapses to strengthen them, equivalent to lowering the resistance, or they do not send pulses, thus causing the synapses to atrophy, equivalent to increasing their resistance.

IBM, together with DARPA or the Defense Advance Research Agency, is developing programs to simulate the process with digital computers. Their software will span the spectrum of accuracy in modeling the way synapses work. However, memristors are the only true emulators of the brain and its functions, so far. Some researchers are going to the extent of erecting scaffoldings for connecting memristor-based emulators to large-scale models. This is creating the need for components such as those Knowm is now offering.

Knowm’s offer is a treasure trove for researchers, being raw data from over 1000 experiments. It helps tremendously, as there is actually no well-defined specification to characterize the memristors properly. That allows researchers to generate their own characterization data, based on the properties of their choice from among the slow, medium, or fast hysteresis types. Knowm offers 16 memristors packaged in a ceramic single dual-in-line package. Their die only option holds 180 memristors.