Monthly Archives: June 2017

Seaweed For Making Superconductors and Supercapacitors

Seaweed, a kind of algae, and a part of cuisines in many parts of the world could be worked to supply power to electronics and other devices. Researchers have developed a material from seaweed to produce better superconductors, batteries, and fuel cells.

The research has been presented at a meeting of the American Chemical Society (ACS) on April 5, 2017.

Dongjiang Yang, PhD, a team member explains that carbon rich materials offer the most efficient energy storage solutions. Since the team wanted to use a green method for making superconductors, they chose seaweed, which is highly renewable as the base material. The scientists have intended to use seaweed extract as a template for fabricating a chain of porous materials that could be used to build the superconductors and energy storage solutions.

Although conventional carbon materials like graphite and graphene dominate the prevalent energy scenario, upcoming advances in storage devices could call for more sustainable materials. Yang, who is at Qingdao University in China, says that abundantly available seaweed could provide a more lasting solution in this regard. He has worked with colleagues in Griffith University in Australia and in Los Alamos National Laboratory in the US to devise a special kind of structure from the algae.

Egg-Box Structure

The scientists drew out porous carbon nanofibers from the seaweed extract by the process of chelating or binding. This process involved attaching cobalt ions to the alginate molecules of the seaweed. These molecules enveloped the cobalt metallic ions, which resulted in the formation of the nanofibers with a special structure resembling an egg-box. This structure contributes to the stability of the material so that the synthesis can be controlled.

Wide Range of Functions

Tests performed on the material showed that its reversible capacity is very high, around 625 mA hours per gram. This is much more than 372 mA hours per gram, which is the corresponding value for that of traditional graphite anodes used in lithium ion batteries.

Furthermore, the material performed as an efficient superconductor with a capacitance as high as 197 Farads per gram. This could be exploited in supercapacitors and zinc-air batteries. Tests also revealed that the performance of these egg-box nanofibers is as good as platinum-based catalysts used in fuel cells.

The scientists had first made public their findings on the egg-box structure in 2015. Since then they have been upgrading the technology involved. It is expected that there would be further improvements of the material.

For instance, the researchers explain that they have worked on the egg-box structure to reduce certain flaws in the seaweed structure that increased the motion of lithium ions. This helped to fabricate improved cathodes used in lithium ion batteries enhancing the performance.

In a more recent development, the researchers have forwarded a technique by which they have combined carrageenann, a variety derived from red algae with iron to prepare a carbon aerogel doped with sulfur. It has a very porous surface making for an extremely large surface area. The researchers say that this could be used very effectively in supercapacitors and in lithium sulfur batteries.

The researchers are now working towards commercial production of the seaweed-based devices.

How Vulnerable is your Raspberry Pi

The IoT revolution has brought with it many Internet-connected computing devices, including several Single Board Computers, such as the Raspberry Pi (RBPi), going beyond the traditional mobile devices, laptops, desktops, and servers. It is common to see on the network devices such as Internet radio, refrigerators, thermostats, DVRs, and TVs, apart from SBCs such as the RBPi.

As projects rush towards completion, Internet security is ignored, resulting in severe consequences—this is applicable to both commercial products and hobby projects. The online search for IoT security may reveal results suitable for commercial products, with a long intimidating list of requirements. However, the commercial arena has to deal with several regulatory consequences for security breaches. As the RBPi is a Linux computer system, security advices for larger systems apply to it as well.

Hobby projects on the RBPi are fine, but leaving your device open to an attacker will allow them to use it as a stepping-stone to attack someone else from your network. Moreover, there is always the possibility that you have some data on your device you would prefer to keep private. Therefore, you need some tools for your toolbox and some ways to think about circumventing the problem.

As all RBPis have the same default username and password, this is the first thing the attackers look for. Therefore, change the default password to something difficult to crack. Always keep the system updated, including all the packages installed. Use the commands “sudo apt-get update && sudo apt-get upgrade” for Debian systems, and “sudo dnf update” for Fedora systems.

The security of your Raspberry Pi depends on what it does and what is on it. So you will have to figure out what is it that makes it a target. Attacks may come from different sources, such as an individual manually attacking your device, worms that automatically enter from the network, or viruses installed by someone operating the system.

In general, DIY IoT devices usually do not have medical or financial data, but possibilities do exist. However, there may be other type of data on the RBPi. Stored passwords may be used to attack other systems. The attacker may get access to a web interface that he/she could analyze for finding out more attack methods.

Other vulnerabilities on the RBPi can be the hardware under its control, the devices that it communicates with, or the information it displays. For instance, the attacker may take over the camera connected to your RBPi, monitor the network traffic if you are using your RBPi as a network router, display wrong messages, or vandalize the display. If not anything else, the attacker may take over your RBPi and make it a part of a botnet, or use it as an anonymous relay to attack other sites.

Using encryption for networked connections works very well—the RBPi is powerful enough to handle encryption. For instance, configure web servers to use HTTPS with SSL/TLS. For remote logins, use SSH. Use software packages for the encryption. That way, you will not have to learn to be a cryptographer, but always keep the key a secret.

How Does An All Solid State Battery Work?

At the University of Texas at Austin, a 94-year old professor of engineering and his team continues to work on their invention—batteries. John Goodenough, one of the inventors of the most commonly used batteries — the lithium-ion battery. At present, Goodenough is working on an all solid state battery, a low-cost cell that offers a long life cycle, fast discharging and charging rates, and high energy density.

According to Professor Goodenough, one of the reasons for battery-driven cars not being widely adopted is the drawbacks associated with the commercially available lithium-ion batteries. Among the factors he includes are safety, cost, energy density, life cycle, and the rates of charging and discharging of the battery. Goodenough is of the view the all solid state battery will address all these problems.

As the journal, Energy & Environmental Science describes it, the non-combustible battery has an energy density of nearly three times that of lithium-ion batteries currently in use. As an electric vehicle derives its driving range from the energy density of the battery cell, a higher energy density helps to propel the vehicle more kilometers between charges. The number of discharging and charging cycles that the UT Austin battery allows is also greater, and that equates to batteries that are longer lasting. Where the typical charging time for batteries in use today is in hours, the researchers claim their battery attains full charge within minutes.

The difference between the two types of batteries lies in their electrolyte. At present, batteries we commonly use contain a liquid electrolyte for transporting ions between their anode and cathode. When charged very quickly, metal whiskers or dendrites form on the electrodes, and these can traverse through the liquid electrolyte to form a short circuit. The result can result in explosions and fires.

The new battery replaces the liquid electrolyte with a glass-based one, and normal electrodes with alkali-metal anodes. According to Goodenough and his senior research fellow, Maria Helena Braga, this prevents the creation of dendrites, mitigating the hazard of short circuits.

Additionally, in the glass electrolyte, there is no lithium. Rather, the researchers have used low-cost sodium instead. Sodium is cheaper, as it can be easily extracted from widely available seawater. According to Braga, that makes the new batteries much more environment friendly compared to those containing lithium-ions.

Conventional batteries cannot use alkali-metal anodes with lithium, sodium, or potassium. However, this technology allows the new batteries to attain their high energy densities and longer life cycles.

Plummeting temperatures freeze up the liquid electrolyte, preventing normal batteries from operating in low temperatures. This has been a major obstacle in practical use of batteries. However, the all-soli-state glass electrolyte has no such drawbacks, and can easily operate down to extremely cold temperatures of -20°C.

Braga began working on solid-state electrolytes while still in the University of Porto in Portugal. She has been collaborating with Professor Goodenough and Andrew J Murchinson, another researcher at UT Austin, since two years ago.
The glass electrolyte simplifies fabrication of the battery cell, as it allows them to plate the alkali metals and strip them on both the anode and the cathode sides, without creating dendrites.

Is Chirp Microsystems Usurping UI?

User Interface (UI) is on the verge of a major shakeup as it was evident at the Mobile World Congress (MWC) this year. Leaving behind other UI interfaces such as motion, touch, and voice, touch-less is now looming large and lucrative as the new UI of choice for consumer devices. Touch-less means you can operate your device simply by waving your hands near it, without actually touching it.

The CEO of Chirp Microsystems, Michelle Kiang is of the opinion that the UI revolution has been bringing on constant consumer electronics breakthroughs. Chirp is offering a single-chip sensor working as a time-of-flight (ToF) ultrasonic unit, to allow users to interact with wearable devices even without actually touching their screens, or interacting with devices that work without screens.

Although the touch-less technology, based on ultrasonic sensing, is not yet ready to replace other existing UIs, Kiang is of the view that it will certainly add another level of modality to automotive, smartphones, AR/VR, and wearables.

Chirp Microsystems is a startup from Berkeley, California, with a UC Berkeley and Davis heritage. At the MWC, they presented the company’s first high-accuracy ultrasonic sensing development platform. As they have especially targeted the platform for wearables, it has ultra-low power consumption. The breakthrough by the team of engineers and researchers at the University of Berkeley and Davis—miniaturization of the MEMS-based ultrasonic sensor—formed the foundation of the startup.

According to Kiang, most smartwatches and other wearables suffer from small screen sizes that have limited surface, and do not work well with fat fingers. The MEMS-based ToF ultrasonic sensors embedded inside the smartwatch helps users with any type of fingers to use gestures. They can control the functions of the watch, even without touching the screen.

For instance, the wearable wristband has no space for a screen on it. That makes it powerless to interface with its wearer directly. However, the ToF ultrasonic sensor is tiny enough to be embedded within the band or even in a ring. Now, all popular wearable bands can interact with their wearers.

The ToF ultrasonic sensor from Chirp comes in a 3.5 mm package called Land Grid Array (LGA). According to the company, the chip operates on a 1.8 V supply, and is similar to a MEMS based microphone. Integration into consumer electronics products is simple, as the IC has an I2C interface.

Along with the MEMS ultrasound transducer, Chirp has also developed an accompanying mixed-signal CMOS ASIC. Then they combined both into a system-in-package, making it easier to use.

The on-board microprocessor with the ToF sensor works in an always-on mode for applications requiring wake-up sensing. According to the company, the pulse-echo sensing range is greater than a meter, but consumes only 9 µA, working at 1 Hz sampling rate.

After the transfer of the IP and the key researchers from the University to Chirp, including David Horsley, several PhD students and postdocs from the University have also joined Chirp. David Horsley was a professor at the University of California and Davis, in the department of mechanical and aerospace engineering, and is now the CIO at Chirp Microsystems.

Moving 3-D Sensing Into Smartphones and Vehicles

Chirp Microsystems, a new startup from Berkeley, California, has developed a new Time of Flight (ToF) ultrasonic sensing platform for use in wearables and Virtual and Augmented Reality (VR/AR) systems. They have selected some big customers to whom they have made available their development platform.

At present, the high-end VR/AR systems are typically confined to a prescribed space, or tethered to a base station. The limit comes from the requirements of additional equipment in the space for creating better tracking experience. Usually, the additional equipment is often a magnetic sensor or a camera-based system that can correct drifting by using the inertial measurement unit (IMU) within the head units of the VR/AR system.

Chirp has demonstrated they can embed their miniaturized MEMS ultrasound sensors within the AR/VR head unit. With the sensors in place, the user has a 360-degree immersive experience, as the tracking system moves along with the user. Supporting inside-out tracking, the ultrasound sensors from Chirp can have controllers or input devices working with six-degrees of freedom—offering 3-D sensing.

VR/AR systems already use the optical or camera-based system for tracking. However, the camera is only a 2-D device, incapable of providing any sort of depth information. Even to detect if objects have shifted from one frame to another, a camera needs to use the point cloud, while applying very complicated calculations.

On the other hand, ToF ultrasound sensors can easily detect 3-D movement. This is because the technology is adept at triangulating data easily, and simpler calculations demand much less power.

Although it is another option for 3-D sensing, infrared technology has limited use when the sensor is outdoors—the heat outdoors tends to wash out infrared sensing. However, ultrasound sensors are robust and consume low power, and able to perform well in VR/AR systems outdoors, even in the presence of a bright sun.

While using the ToF ultrasound sensors in VR/AR systems, Chirp hopes the low-end VR/AR systems will improve the interactive experience, and smartphones and vehicles can start using the untethered high-end VR/AR systems.

For instance, smartphones use infrared technology currently as a proximity sensor. This actually prevents the user’s cheek from dialing the phone by itself. However, this requires the smartphone to have a tiny hole for the infrared sensor embedded on the face of the smartphone.

According to Chirp, some smartphone vendors have shown interest in replacing infrared with ultrasound. This would improve the aesthetics of the smartphone by removing the tiny hole on the face of the phone. Additionally, the ultrasound sensors can also add features such as autofocus when taking selfies, and add simple gesture functions to the phone.

At present, vehicles use bulky ultrasound sensors, for say, backing up. Chirp hopes to replace them with its ToF ultrasound sensors. They can also use the sensors as a User Interface (UI) inside cars for infotainment systems. However, as automotive applications tend to use long design-in cycles, Chirp is keeping this in low-priority for the time being. Chirp is planning to ramp up production of its ultrasound MEMS sensors and accompanying ASICS later this year.

NanoPI NEO Challenges the Raspberry Pi

If you were looking for Raspberry Pi (RBPi) alternative, the NanoPi NEO would be a good fit. For a starting price of about $7, and measuring just 1.6×1.6 inches, it is smaller than the smallest RBPi Zero W, and is equally capable of running Linux. At its basic price, the RAM it carries is 256 MB. However, for a couple of dollars more, there is another version available and it has 512 MB RAM on it.

The best thing about this tiny challenger to the RBPiZW is the bunch of accessories available. This includes a battery, compass, LCD, and camera add ons. In addition, the maker has also launched a case, with which, you can easily build a networked-attached storage (NAS) from the tiny computer, the NanoPI NEO.

The NAS kit for the NanoPi NEO is made of aluminum, has a heat sink, and a board to allow you to connect an SSD hard drive or a 2.5-inch SATA hard disk. The case dimensions are 6 x 3.9 x 1.9 inches, and for silent operation, there is no provision for a fan. However, it needs a 12 VDC, 2 A power supply, which you have to buy separately. The price for the case does not include the price of the hard disk, so you have a wide choice there.

On the hardware side, the internal processor is an Allwinner H3 quad core with three UARTs. The board has a micro SD card slot, one USB port, a micro USB OTG port. Two additional USB ports are available via headers. On the expansion port, there are the usual I2C and SPI available. The board has no Wi-Fi or Bluetooth, but has an Ethernet port. It also does not have an HDMI port, which means you need to log in through SSH. The board also does not have an audio port, but you can get audio out if you solder the 0.1-inch edge connector.

On the software side, you will need to get an ARMBIAN, especially for this board, and a specific version of the legacy Jessie installation from the Armbian site. If you flash the Armbian code into a 16 GB SD card, you can boot up the NanoPi NEO board.

Initially, you should see a dim green LED coming on, and it will brighten up after a few seconds. About 30 seconds later, you should see a blue LED start to flash regularly, along with the green. About a minute after you have plugged the board into the local net via Ethernet, you should be able to see the NanoPi NEO board in its address range.

At this stage, you should be able to log in through Putty or SSH, with login credentials as root and password as 1234, and effect an initial password change.
Although it uses the same Allwinner processor, as does the RBPiZW, the NanoPi NEO runs a lot hotter. That is why the makers are supplying a heat sink along with the case for the NAS kit.

The NanoPi NEO is a marvelous and cute little board. Another version of the board does away with the Ethernet port, but adds Wi-Fi and two USBs.