Monthly Archives: December 2016

What are Light-Emitting Capacitors good for?

HLEC, or Hyper-elastic Light-Emitting Capacitors are good for making electroluminescent skin for robotics, and you can do a lot with them. That is according to Dr. Rob Shepard of Cornell University and his team of graduate students, who have published a paper on the electroluminescent skin they have developed recently.

The team was inspired to develop the electroluminescent skin by observing several cephalopods such as the Octopus. According to the team, their material can change its color, just as an octopus can, including changing its size to fit into areas that structures that are more rigid cannot. For instance, the skin continues to emit light even when it has been stretched to about six times its original size.

Layers of transparent hydrogel electrodes separated with elastomer sheets as dielectric make up these HLEC or Hyper-elastic Light-Emitting Capacitors. Panels of these capacitors, integrated into robotic systems, and outfitted with sensors act as ideal health-based sensor applications for wearables. The team at Cornell has fabricated one robotic system from three panels and it is capable or crawling. With each panel consisting of six layers, the robot crawls along with worm-like movements, using two pneumatic actuators that alternately inflate and then deflate. You can see the stretchable skin and its crawling action in the video here.

Although the team is in raptures over how well the HLEC panels function, their next step is convert the material into practical devices with applications – find a reason to use it, as they say.

The team expects the development of uses for these new panels to lead to some innovative applications. Although at present, the speculated devices range primarily from health care to industries related to transportation, there is a significant interest in future robotic application as well. The latter is based on the interest in advancing the way robots interact with humans.

For instance, the robot Atlas, from Boston Dynamics, looks formidable enough to crush you were you to give it a hug accidentally. Humans prefer soft and puffy robots, and in the future, robots may even be able to change color based on the mood of the person in front. People generally grow an innate fear of robots after having watched T-800 in movies such as ‘The Terminator’. However, future robots such as Baymax should help make a difference in their thinking. According to Professor Shephard, HLEC panels can be part of the break-through.

It is important to get the human-robot interactions right. Simple things such as the ability to change their color can let robots make emotional connections with humans. This could be in response to the tone of the room or the mood of the humans in it.

This new electroluminescent skin has a huge potential for all kinds of new devices. However, it needs the assistance of other engineers as well to discover new applications and make use of this technology. Primarily, the material scientists who developed this skin are planning to use this for life-saving wearable health monitors. However, it could easily be used as a robot that fits into tight areas. Once the HLEC panels are commercially available, surely, there will be many people to think of additional innovative applications.

Advanced Applications Need Alternate Switch Technologies

Although conventional reed switches have been in use for their excellent properties, their large size makes them difficult to integrate in advanced applications. Most equipment now use miniature components and manufacturers have found a way to reduce the size of reed switches to match. They now use HARM MEMS or High Aspect Ratio Microfabrication MEMS technology to make miniature reed switches, keeping all their desirable properties intact.

Reed switches are popular because they do not require power to operate, they offer milliohms of ON resistance, and tera-ohms of insulation when OFF. They are immune to ESD or electrostatic discharge. Moreover, they require very little additional circuitry to operate and hence, take up very little real estate on the printed circuit board. Some advanced applications where the alternate HARM MEMS reed switches are useful are as follows.

Small Portable Hearing Aids

The baby-boomer market is increasingly in need of small portable medical devices such as hearing aids or hearing assistance devices. HARM MEMS switches are ideal for the control functions in these devices. As the user preference for small, almost unnoticeable hearing aids grows, the ever-shrinking devices are making increasing use of the tiny magnetically operated switches for functions such as Telecoil operation and program switching. As these switches need no power to operate, the once bulky behind-the-ear hearing aids are disappearing into the ear canal itself. Since batteries have also shrunk, the zero power operation of the microfabrication reed switches is a boon for the user.

Endoscopes the Size of Capsules

No one forgets the trauma of getting an endoscope done to know what is wrong within his or her gastrointestinal tract. However, that might soon be outdated, as HARM MEMS can shrink the endoscope down to the size of a capsule, which the patient swallows. As the pill shaped endoscope passes down the gastrointestinal tract, its one or more video cameras capture images lit by its white LED headlamps, also a part of the pill.

As the device is small enough to be swallowed easily, the capsule endoscope has electronic circuitry that is highly miniaturized, so that it can reach where conventional endoscopes or colonoscopes cannot. The tiny pill requires a mechanism to allow it to start functioning just before it is swallowed. In addition, there must be no drain from the tiny batteries when the device is in storage. Active switches are not helpful here, as they draw current even when inactive and hence reduce the shelf life. HARM MEMS switches are the best fit here because of their tiny size and zero power consumption.

Insulin Delivery Pumps

All over the world, diabetes is increasingly affecting people of all ages. In the most severe form of this disease, insulin must be administered multiple times daily to the body. There are two ways to do this – either by multiple daily syringe injections or via insulin pumps. The pumps generally contain a disposable insulin reservoir. The pump unit must reliably detect this reservoir. Modern insulin pumps are small credit card sized and contain a HARM MEMS reed switch, which is activated by a magnet attached to the reservoir.

How Can I Protect My Raspberry Pi?

By connecting the Single Board Computer to the Internet, you actually run the risk of compromising your Raspberry Pi or RBPi to different types of attacks from malicious persons. However, as several advantages of an Internet connection far outweigh such risks from attackers, there is merit in looking for ways to mitigate them. Spain Hardware from Madrid is venturing on a Kick Starter project to enable hardware protection for the RBPi.

When your RBPi requires secure communication, you can rely on the PiSec module, from Spain Hardware, to provide the necessary assistance. PiSec, being a protecting module, uses its own hardware to protect and encrypt all the inputs and outputs on the RBPi. PiSec protects the RBPi from all angles – SD card, USB, and Ethernet, offering a strong hardware base security that includes Elliptic curves and AES-256 XTS.

PiSec, based on a True Random Number Generator, works by generating safe and strong encryption keys and certificates. Internally, PiSec uses a protected file system that it protects with an internal certificate making it impervious to unauthorized access. The processor on board the PiSec module makes use of Elliptic Curve Cryptography to reduce its own overhead and speed up the process of verification.

PiSec provides protection complying with certificates such as the AES 256-bit XTS Military Grade Encryption and X.509. Repeated attempts after a predefined number of unsuccessful attempts to gain access to the RBPi results in the PiSec automatically blocking access. This helps in preventing DoS or Denial-of-Service and brute force attacks.

Typically, you can use your RBPi right out of its box, including its Ethernet connection, the USB ports, and its SD card. You can use the SBC to collect, store, and transfer data, but the RBPi handles all this using clear text, which anyone can intercept and read. You can use your tiny but powerful computer in several ways, for instance, as a standalone PC as a storage system, data logger, and standalone server, a device to control complex systems/machines, or used with licensed software. In all these cases, it will certainly hurt your business if your data is exposed and someone sniffs the actuator or the sensor communication lines and steals your telemetry.

There are several ways to achieve security through software generated keys and certificates. However, relying on a hardware solution is a far better solution, as most of such software solutions do not use a true random generated number. PiSec offers this strong protection security to the entire RBPi, including all devices on its SPI bus, without overloading the processor of the RBPi, nor collapsing its OS. Being a hardware solution, it is simple enough to plug the PiSec on your RBPi, without any necessity of a learning curve or any previous experience on security.

Features of the PiSec include a TRNG or true random number generator. It obtains the random seed from on-board white noise generators that are FIPS and AIS 31 compliant, and with a very high entropy level. TRNG is crucial to creating strong secure keys and certificates.

Integrating Piezoelectric Flexure Actuators

The familiar reed switch comes with a unique set of properties. These include ON resistance of the order of milliohms, OFF resistance of the order of tera-ohms, total immunity to ESD or electrostatic discharge, hot switching capability of about one watt, and almost zero power operation. However, as all electronic components are shrinking to surface mount sizes of 0402, 0201 and even to 01005 (0.4 x 0.2 mm), the large size of the reed switch is anachronistic. Since 70 years of its invention, the conventional reed switch has been steadily shrinking. What began with a 50 mm long glass tube in 1938 has come down to about 5 mm today.

However, even after a sort of following Moore’s law of ever-shrinking transistor size on integrated circuits, reed switches have now reached a brick wall. The fundamental limitations of physics and manufacturing are preventing the conventional reed switches from going below the 5 mm size. Now, a new technology promises to break this barrier of 5 mm size, while retaining all the desirable properties of the reed switch. Manufacturers are using HARM, or High-Aspect Ratio Microfabrication MEMS technology. For instance, reed switches such as the RedRock RS-A-2515 piezoelectric flexure actuators from Coto Technology is based on this technology.

Alternatives to reed switches also exist. For instance, there are Hall Effect switches, AMR or Anisotropic MagnetoResistive switches, and GMR or Giant MagnetoResistive switches in the market. However, all the above are active switches, requiring a power supply to operate them. This is a disadvantage related to these active switches, as they add to circuit complexity and take up PCB real estate. Active switches require three electrical connections instead of two – one for supply power, one for the return ground and the third for the sensor signal.

Active switches have further disadvantages in that they require external circuit elements such as bypass capacitors or pull-up resistors. This increases the cost and effective size of these multi-component switching systems. There is additional complexity as these can only switch milliamp-level currents, and extra buffer circuitry is necessary for switching higher currents. Active switches are also susceptible to damage from ESD. In contrast, reed switches made from the HARM MEMS technology has none of the above disadvantages.

Switches made from the HARM MEMS technology offer very small size, high-current hot-switching capability, and zero-power operation. This performance makes the technology suitable for a wide range of applications including automotive and medical. For instance, HARM MEMS technology allows making endoscopes the size of a pill that patients simply swallow, nearly invisible and tunable hearing aids, convenient insulin delivery systems, and some exciting new automotive switching applications.

Although motor vehicles are large systems with enough battery power, conventional affordable reed switches have been widely used for a variety of functions such as ABS systems, gear lever position sensing, and door lock control. Smaller reed switches are also necessary in vehicles for sensing various fluids, for instance, brake fluids. Usually, a single reed switch, triggered by a float magnet in the fluid reservoir indicates a binary position – there is either enough fluid, or there is none.

Tractor Beams are a Possibility Now

For some time now, science fiction has been predicting the tractor beam, the strange column of energy that can transport everything from living beings to inanimate objects through space. Now this long-envisioned chunk of technology from science fiction is en-route to becoming science fact. At the Public University of Navarre in Spain, scientists are successfully manipulating tiny objects in midair. They are doing this with what they claim are acoustic holograms.

Ordinarily, holograms are three-dimensional optical structures, that is, they are made from light. More specifically, they are made by photons diffracting through interference patterns on a holographic plate. Although not popularly known, sound waves can do this as well. Sound waves, when interfering constructively and destructively with ultrasonic waves, can generate 3-D structures. That allows the sound waves to exert force on objects and behave in the same way a tractor beam does.

For instance, scientists have earlier demonstrated acoustic levitation techniques. These can suspend particles within the standing ultrasonic wave created by a single array aimed at a reflector, or between a pair of ultrasound emitter arrays. By varying the phase of the ultrasound, the nodes can move, thereby transporting the particles along a single axis. However, the acoustic levitation technique is fundamentally limited because the design relies on a fixed enclosure. Acoustic holograms are a step forward since they accomplish the same with only a single acoustic emitter and do not require any special enclosure.

These 3-D structures, made of sound or acoustic holograms, are actually bridging the gap between optical and acoustical trapping – shaped in the form of bottles, twisters, or tweezers. Scientists produce them typically from 400 numbers of 10 mm ultrasonic transducers arranged in an array of 20 x 20. Each transducer generates 40 kHz waves of ultrasonic sound using programmable relative phase modulation.

Within each transducer, there are two elements – one to determine the shape of the ensuing structure, and another, a holographic lens generated when the sound waves emitted phase-coincide at the structure’s nodal point. When the rapidly oscillating sound waves of the transducer array combine with the holographic lens, they are able to suspend small particles of about 3 mm in diameter in midair. In addition, they also grant control over the position and orientation of the particles.

Brüel and Kjær have done further research on the subject of STSF, Spatial Transformation of Sound Fields or acoustic holography. They have combined acoustic holography with transitory calculations. This allows defining any sound field signifier such as particle velocity, sound intensity, or sound pressure as a function of position and time. They have demonstrated through animated maps the control over a specific property change as a function of time.

Scientists at the Public University of Navarre in Spain have published their findings in Nature Communications. They have successfully levitated, rotated, and otherwise manipulated a tiny ball in midair using a grid of Ultrasonic transducers that send out high intensity sound to create a kind of force field around the object. They moved the tiny ball around the grid as though human fingers were doing the work.