Category Archives: Newsworthy

Linear Position Sensor for Embedded Use

The launch of ME-7 Series Linear Position Sensors by the Alliance Sensors Group (Moorestown, NJ) facilitates a wide range of multiple applications. These sensors have been designed for embedded use suitable for measuring the ram position in hydraulic and pneumatic cylinders, in subsea, mobile or industrial applications. The ME-7 series is designed to be a functional replacement for embedded type magnetostrictive sensors with a drop-in form and fit for use. They can also be used as a replacement for embedded resistive potentiometers. Not only does the ME-7 series provide optimum accuracy, there is no wear-out involved. The design offers a number of unique features.

The ME-7 Series offers measurements ranging from four to 36 inches, which translates as 100 to 900 mm while operating at pressures of 5000 psi as well as at depths of 10,000 feet or 3,000 meters. The sensors are available with aluminum or stainless steel housing, both of which are categorized under IEC IP-67. The operating temperature is typically 85°C, but the series is also being offered with an operational temperature of 105°C as an optional feature. The analog output is in DC volts or current and these inductive sensors have been designed with the requirements of multiple applications in mind.

Although the Alliance Sensors Group has designed the ME-7 series to be highly robust, at the same time they have maintained the cost to a level that makes it affordable to the user. The technology used for ME-7 series is proprietary and known as contactless inductive sensing technology. It uses a 7 mm diameter solid probe requiring only a simple conductive tube target. This can be a simple gun drill ID of the cylinder rod that the operation is utilizing. This is considered better than a magnet or a special target type typically used by other sensors. The ME-7 series can replace an existing magnetostrictive sensor.

These sensors can be embedded at the same location that is configured for accepting magnetostrictive sensors. It is vital to note that the magnet from the magnetostrictive sensor need not be removed from its current place. The performance of ME-7 is not affected due to the presence of the magnet. Additionally, since the ME-7 series sensors are contactless, there is no wear and tear and the output signal is free from any deterioration. With the use of inductive coil in place of wires and the use of “time of flight” technology, the ME-7 series sensors are able to withstand shocks and vibrations in a more sustained manner.

The Alliance Sensors Group can justifiably claim that ME-7 series sensors have a very robust construction, are able to adapt to existing cylinder designs, offer higher resolutions as well as offer options for multiple analog outputs. There is no need for a target rod or magnet and the sensors have an infinite life, as they are free from any contact. It is expected that almost all users will be able to benefit from the ME-7 series in more than one way.

MCUs: Interesting things happen within smart phones and tablets

Cell phones and tablets have several interesting things within them such as touch-screens, cameras, gesture sensors, USB interfacing, battery charge monitoring, and many others. Most of these individual functions need tiny components called micro-controller units or MCUs. Of course, additional components are also required such as ADC or Analog to Digital Converters, PWM or Pulse Width Modulators, LCDs or Liquid Crystal Displays and capacitive touch screen interfaces.

The role of MCUs in modern cell phones and tablets can be appreciated by the different functions they handle. MCUs communicate with several analog sensors that in turn, take in analog signals and convert these into digital values. For example, high-end products may have temperature sensors such as RTDs, thermistors and humidity sensors. Others may have accelerometers for measuring 2- or 3-axis movement and convert this input into a digital signal for the MCU to handle.

Smartphones use several types of sensors that require handling by MCUs. ALS or Ambient Light Sensors allow automatic control of the display backlight brightness. This happens over a wide range of illumination conditions ranging from a dark room to direct sunlight. Magnetic sensors gauge the magnetic field intensity for indicating the North. Cameras and proximity sensors offer face and hand movement detection. This is useful for the MCU to switch on the keypad when the user’s hand comes near. IR proximity sensors in conjunction with the camera allow the MCU to switch on the touch screen by detecting the closeness of the user’s face, ear or head. Not only does this eliminate false touches on the touch screen, it reduced battery drain by shutting down unnecessary functions.

MCUs in smartphones dynamically regulate the transmission power when a human is near. In tablets, this is dependent on the Specific Absorption Rate or SAR. SAR is the rate at which the human body absorbs electromagnetic energy when exposed to radio frequencies.

Low-cost cell phones use a mechanical keypad, and an MCU decodes the user inputs. Another MCU handles the Lithium-ion battery charging and its optimal charge life. High-end cell phones have a touch screen and an MCU provides the interface. It uses Haptics or tactile feedback technology for detecting touch, force, vibration or motion of the human body parts near the screen.

USB interface is another very useful function provided by an MCU. It connects several external peripherals to the application processor within the smartphone in a host and slave mode for transferring data from the peripherals at high speeds.

Designers and manufacturers are now combining MCUs with programmable logic and high-performance analog-to-digital conversion capabilities. These are called the programmable system on chip or PSoC. They also have memory integrated into them.

By design, PSoC devices consume negligible amounts of power when in standby mode, making them eminently suitable for use in cellphones. Further design and operation complexity is reduced by having internal op-amps, comparators and ADCs within the PSoC. Sample and hold capability allows sensing and monitoring of slowly varying inputs such as from the battery or a temperature-measuring device. With the use of PSoC, manufacturers have been able to minimize PCB size for cell phone applications largely.

Power Your Smartphone by Your Sweat

Anyone can power a smartphone by manually running a small electric generator. Without a doubt, some will sweat in the process. However, this technology is somewhat different. Here, a small tattoo will detect whether you are sweating (for whatever reasons) and generate power directly from your sweat.

Researchers at the University of California in San Diego have developed a sensor to monitor a person’s progress when he or she is exercising. Although this is not something new, but the sensor is in the form of a temporary tattoo and it also doubles as a bio-battery. It can detect when the person is perspiring and produce power from it.

According to one of the researchers, Wenzhao Jia, when a person sweats, one of the naturally occurring chemicals is lactate. The sensor detects and responds to lactate, which is a very important indicator of how the person is progressing with the exercise. That is because with more intense exercise, the body produces increasing amounts of lactate. With strenuous physical activity, the body activates a process called glycosis, which produces energy and lactate.

Professional athletes test their performance by monitoring the levels of lactate they produce. This is one of the ways they evaluate their training program and their fitness. Moreover, some conditions cause abnormally high lactate levels in the body such as lung or heart diseases. Doctors measure the lactate levels during exercise testing of their patients. However, lactate testing is intrusive because it needs blood samples of the person to be collected at different times during exercising and then analyzed. Therefore, the current process is inconvenient.

The team led by Joseph Wang, of which Jia is a member, has developed a faster, easier and more comfortable way of measuring lactate during exercise. They imprinted the biosensor onto a temporary tattoo paper. The sensor has an enzyme that strips electrons from the lactate produced during the workout and generates a weak electrical current.

In practice, the tattoo is applied to the upper arm of the person exercising. When the person exercises on a stationary bicycle, it is easy to monitor the performance against increasing resistance levels. The researchers were able to monitor 10 health volunteers for 30 minutes and checked the lactate levels in their sweat over time and with changes in intensity of their exercise.

One of the startling discoveries from the research was that different people produced different amounts of electricity. Surprisingly, people who exercised less than once per week and hence were less fit produced more power as compared to moderately fit people who exercised between one and three times per week. Those who were the most fit, working out more than three times per week, produced the least amount of power.

According to the researchers, less-fit people become fatigued sooner and glycosis kicks in earlier for them. Therefore, they produce more lactate because of their increased fatigue. In the low-fitness group, the maximum amount of energy produced by a person was 70μW for every square cm of skin. Although the power generated is not very high, the researchers are confident of eventually increasing it to power small gadgets.

e-whisker: how about a hairy robot?

No matter how quietly you approach a cat from behind, it is sure to detect your presence almost always. It is not its acute sense of hearing or smell that helps the cat, but its whiskers. They can sense the tiniest air turbulence caused by your movements. In fact, such tactile feedback gathered by most animals and insects with their whiskers and antennae makes it very efficient to coordinate their movements at striking speeds.

Such high-speed reflexes are possible because the feedback from the sensors is directly coupled to the insects’ locomotive actions and does not have to pass through much processing. Actually, there is absolutely no central processing or environmental data analytics to impede the information from multiple data sources.

Several insects and certain mammals use their antennae and whiskers – the hair-like tactile sensors – to monitor wind turbulences and for navigating around obstacles in tight spaces. Researchers at Berkeley Lab found this a new source of inspiration and they came up with e-whiskers or electronic whiskers. These e-whiskers are based on flexible polymer fibers with high aspect ratio, coated with a mixture of silver nano-particles and carbon nanotubes.

According to the lead researcher Ali Javed of the Materials Sciences Division of Berkley Lab, tests of these whiskers show they are ten times more sensitive compared to all previously reported resistive or capacitive pressure sensors. In addition, by changing the composition of the whiskers, researchers could manipulate their characteristics.

For example, a change the ratio of the nanoparticles and the nanotubes resulted in a change in resistance from a minimal 10% to around 260% with the application of a 2.4% strain on the whiskers. Scientists monitored the resistivity change by hooking up the e-whiskers arrays to a computer. The carbon nanotubes give the e-whiskers their excellent bendability with their conductive network matrix. On the other hand, the silver nanoparticles contribute to the conductivity of the coated fibers giving them the high mechanical strain sensitivity. That makes the e-whiskers so sensitive to pressures as low as 1Pa, representing 8%.

When scientists increased the weight content of the silver nanoparticles, the strain sensitivity of the e-whiskers was enhanced. This can be explained as the change in the distance between the silver nanoparticles in the film directly affecting the probability of electrons tunneling through neighboring conductive nanoparticles. As compressive and tensile stresses cause the gaps between the nanoparticles to become smaller and larger compared with the relaxed state, the e-whisker is able to detect the direction of bending.

Scientists at Berkley Lab built the e-whisker by patterning it with a micro-etched silicon mold with trenches which were 15mm long, 250µm wide, and 250µm deep. They then coated the fiber with the carbon nanotube and silver nanoparticle composite and cured it. The researchers claim that the whiskers can be made smaller still – they would have to use the MEMS processes for that.

With this e-whisker array of seven vertically placed fibers, scientists demonstrated mapping a weak wind flow (1m/s) in three dimensions as a proof-of-concept. More applications are planned for the future.

What is stretchable electronics?

Imagine carrying your solar panel rolled up like a grapefruit while going camping and stretching it to the size of a room on the spot. It will not break, since it is made from fracture-proof electronics that is super compliant. Well, for the moment, that is the dream of Professor Darren Lipomi, department of Nano engineering, University of California at San Diego.

Darren has a vision of self-repairing skins for sensors. A special super-thin layer of organic material will make up the stretchable skin, very similar to a thin layer of plastic. As this will be as pliable as foil, it will allow the semiconductor to conform to the object and stretch with movement. Such a new phase of bendable materials will influence change in the supply chain by turning flexible electronics into a layer similar to skin. Not only will this give a new meaning to the current phrase – mobile technology, to accommodate to the transition, OEMs will have to alter their manufacturing processes.

Darren is exploring different materials and types of electronics that have molecular structures for allowing conductive materials to function even when deformed or contorted in any direction for long durations. Of importance here, is the molecular level structural details of organic semiconductors. According to the scientists at the University of California, the super-thin film-like material, sometimes as thin as 100 nanometers, could be made to stretch without any loss in its electronic functions. Display light emitters need only be about one hundred billionth of a meter thick, according to Darren.

The professor is interested in solar panels, which he plans on making in the form of a thin, stretchable film on any object such as a piece of clothing or a tent. He describes this as an extremely large solar module that is fracture proof while generating electricity. He also envisions flexible commercial displays used in wearable devices such clothing and watches from Microsoft, Samsung, LG, Google, Apple and many others.

The professor’s research has identified several types of electronic materials that can stretch. However, he feels the major challenge here is to understand the way in which the molecular structure of the flexible materials influences the mechanical and electrical properties. This is especially true when moving from the laboratory material to a commercial product. Depending on the acceptance of the industry towards development of new processes and technology, Darren expects stretchable organic materials will find use in about 10-20 years.

The research is proceeding in two directions. One way is trying to obtain working electronic properties from films of highly amorphous nature. The other is trying to prepare stretchable fabrics or nanowires from processing solutions or by electro spinning. According to the researchers, the latter path forms the middle ground between molecular and composite approaches to elastic semiconductors.

This presents a challenge of representing high-performance molecular semiconductors that have predictable mechanical properties. A tight collaboration will be required from materials scientists, device engineers, synthetic chemists along with theorists – specializing in both the mechanical behavior of soft materials and the electronic structure calculations.

Will UEFI replace BIOS?

BIOS or the Basic Input Output System, designed by IBM for its Personal Computers has been with us for more than thirty years now. Whenever a computer is switched on, it conducts a self-check to see if it has a keyboard, a display and memories. Then it proceeds to look for a suitable Operating System. A small program, the BIOS, resident on a flash memory on the motherboard accomplishes all the above tasks. Once it has found a satisfactory operating system, it hands over the control of the computer. Those who are into programming of micro-controllers will recognize BIOS as the Monitor program.

However, the humble PC has come a long way in these thirty years. From a paltry 4/8 bit system with hardly 256bytes of RAM, PCs now work typically at 64 bits and 8/16GBytes of RAM. The evolution of Operating Systems and external threats to PCs has led to a demand for an overhauling of the BIOS. Introduction of Intel’s Itanium processors in 1998 put the final nail in the coffin of BIOS and a new Intel Boot Initiative was born. This initiative went on to become the EFI, or the Extensible Firmware Interface. In 2005, a new forum was born, UEFI, a consortium of AMD, IBM, Apple, Microsoft, Intel, and so on.

UEFI, or the Unified Extensible Firmware Interface, is a complete re-imaging of the computer’s boot environment and has almost no similarities to the BIOS that it replaces. While BIOS is basically a solid piece of firmware, UEFI is more or a programmable software interface that sits on top of the BIOS. This BIOS is shorn off most of its boot code, and the UEFI handles that while sitting in a part of the non-volatile memory, either on the motherboard, on the hard drive or possibly on a network share.

In essence, UEFI resembles more of a lightweight operating system. When switched on, the computer boots into UEFI, carries out a set of arbitrary actions and then triggers the loading of an operating system. As part of its specifications, the UEFI defines the boot and runtime services, device drivers, protocols for communication between services and extensions. There is even an EFI shell that allows execution of EFI applications.

As UEFI is a pseudo-operating system, it is able to access all the hardware on the computer, allowing you to surf the internet from the UEFI interface or backup you hard drive. There is even a full, mouse-driven GUI. With the boot data now stored on NAND flash or on a hard drive, a lot more space is available for language localization, boot-time diagnostics and various utilities.

UEFI enables secure boot in that it can sense if a malware is trying to take over your computer even before it has had a chance to boot into its OS. This no-compromise approach to security offers unparalleled capabilities to the customers while at the same time offering full and complete control over the PC. UEFI can validate firmware images before allowing them to execute, based on the PKI process. This secure boot helps to reduce the risk of boot loader attacks.

How to Measure Large DC Currents Accurately

The market has several instruments for accurately measuring small DC currents, say up to 3A. You can also find some devices that can measure DC currents that extend beyond 50A with good accuracy. Large currents are common in photovoltaic renewable energy installations, grid energy storage, electric vehicles, to name a few. Usually, it is a common necessity for such systems to be able to predict accurately the state of charge or SOC of the associated energy storage batteries.

Usually, systems for current or charge measurements are designed to include built-in data acquisition modules such as ADCs or analog to digital converters, filters and suitable amplifiers. The arrangement is typically that of a current sensor followed by a filter/amplifier and finally an ADC. The current sensor senses the current a circuit for converting the output into a usable form such as voltage, typically follows it. The signal requires filtering to reduce the radio frequency and electromagnetic interferences. The cleaned signal may have to be amplified before being digitized. Current data samples multiplied by the appropriate time interval are accumulated for charge values.

Two sensor technologies are commonly used for measurement of large currents. The first of these techniques measures the voltage drop across a resistor (also called a current shunt) that carries the current to be measured. The voltage drop follows Ohm’s law and equals the product of the current times the resistance.

Large DC currents may cause power bus bars and cables to dissipate significant amounts of heat. As a thumb rule, designers of power installations strive to achieve less than 1% power loss from the wiring, including bus bars and heavy cables. For example, an offline storage system of batteries with output of 1KV and 1KA supplies power at 1MW. Although the dissipation of a 50W shunt is insignificant at 0.005%, the power cables and bus bars may dissipate heat upwards of several KW.

To put things in perspective, designers go by 1W per µOhm at 1KA, therefore, for a shunt with 10 µOhm resistance, a continuous current of 1KA passing through it will heat it up to 10W. Alternately, copper wire, with a diameter of one-inch, will be dissipating 12-14W of heat at 1KA for each foot, since the resistance of the wire is about 10 µOhm per foot, after correcting for resistance increase due to heating.

The second technology senses the magnetic field encircling the current carrying conductor. The device for sensing the current is generally known as the Hall-Effect current sensor. Usually, the magnetic field around the current carrying conductor is concentrated in a magnetic core, which has a thin slot and the Hall element resides here. The magnetic field is thus perpendicular to the plane of the Hall element, while the magnetic core makes it nearly uniform. Energizing the Hall element with an exciting current makes it produce a voltage proportional to the magnetic field in the core and the exciting current. This voltage, suitably amplified and filtered, is presented to the ADC.

One advantage of the second technique using Hall elements is the isolation between the current carrying conductor and the measuring electronics. Since the coupling is only magnetic, the current carrying conductor may have very high voltage potentials, which do not affect the current measuring elements.

What Is The Future Of The Internet?

Brazil and NET1 organized a major conference called NETmundial on April 23-24, 2014. Representatives of the tech community, civil society and governments convened to discuss the future of the Internet. Their focus was on how the Internet should be governed.

The necessity for the event was multiple revelations, such as from Edward Snowden, about mass surveillance of digital communications by state agencies. As the President of Brazil stated at the 68th UN General Assembly, the absence of right to privacy takes away the true freedom of expression and opinion, destroying effective democracy.

That set the ball rolling for the Internet governance institutions, which include ICANN or the Internet Corporation for Assigned Names and Numbers, IRTF or the Internet Engineering Task Force and the W3C or the World Wide Web Consortium. Together, they released a joint statement renouncing activities of mass surveillance. They referred to the recent revelations of pervasive surveillance and monitoring, expressing strong concerns over the undermining of the confidence and trust of Internet users globally. They identified the need to keep up the efforts for addressing Internet Governance challenges, while agreeing to support community-wide efforts actively towards the development of a global multi-stakeholder Internet cooperation.

In reality, the Internet runs as an MSM or a multi-stakeholder model. Here, the tech community, civil society groups, governments and the private sector all have their say. However, it is old news that different parties want to have a greater power over the Internet. In this respect, the US, which has a historically grown role of dominance in Internet governance, is envied not only by other nations, but also by the Internet libertarians.

Every few years or so, the battle over Internet governance raises its head. The last time this happened was in the 2012 conference of the UN International Telecommunication Union. Although many non-western nations attempted to delegate more influence to governments, the US and its European allies successfully warded off the demands for Internet governance changes.

However, this time, because of the NSA scandal, the US has lost much of its legitimacy of dominance over Internet governance. Moreover, most of those who allied with the US in 2012 now have their own reasons in demanding globalization of Internet governance.

The Global Multi-stakeholder Conference or NETmundial has two goals to achieve. The first is to produce universal principals that will govern the Internet. The second is to generate a roadmap that will lead to the globalization of Internet governance institutions such as ICANN.

The conference will generate an outcome document to bring forth the conclusions and decision made on the summit. The draft outcome document disseminated prior to the start of the summit, allowed those gathered at the summit to propose changes to the document, aiming to create the final version that all have agreed on.

However, the first day of the summit saw civil society organizations issue a press release expressing their concern over the weaknesses in the draft document. Organizations such as the Free Press, World Wide Web Foundation and Article 19 are proposing a number of amendments, which include:

• Interception and surveillance must be done in accordance with international human rights law
• The right to privacy must be reinforced by stronger actions
• The globalization of ICANN should follow a clear roadmap and be completed by September 2015.

The latest in wireless charging technology

Although battery technology has improved many times over, mobile devices remain always hungry for power, thanks to the demands from always-on wireless, GPS, hi-performance audio and video along with the ever-increasing applications and nearly constant use of the mobile devices. People are looking for more convenient and accessible ways of charging their mobile gadgets. That has led to the availability of wireless charging systems, where one needs only to place the mobile device on the charging pad for an effective charging. The demand can be estimated from the fact that more than five million wireless charging devices were shipped in 2012, with a forecast of more than 100 million more to ship by 2015. Apart from smartphones, these numbers include MP3 players, digital cameras and other mobile devices.

Foremost among wireless charging technologies is the technique offered by Qi (pronounced as “Chee”). Using a wireless charging pad and a properly equipped mobile device, the intention is to create an international standard for interoperability. A conglomerate of nearly 200 organizations including phone manufacturers, semiconductor suppliers and wireless service providers came together to form the Wireless Power Consortium. They released the Qi open standard in 2009. Since then the market has over 350 types of Qi-compliant devices. Among them are the Samsung Galaxy S3 and S4, which can be equipped with after-market receiver sleeves suitable for Qi wireless charging. The Qi wireless charging pads are available off the shelf at eBay and Amazon. Other manufacturers who are directly integrating Qi into their devices include Google Nexus 4, Nokia Lumia 920, LG Optimus LTE2 and phones from Panasonic Eluga.

A Qi wireless charging system is available as a single-position, guided placement or a single-position, free placement. For those who want to charge more than one device at a time, there is the Qi three-position charging pad. The single-position guided placement is the cheapest type where the user can charge only a single mobile that he has to set in a specific position. The single-position, free placement is a little more expensive, as the user does not have to lock the mobile to the charger in any particular position. The Qi charging sleeve is very inexpensive and can be fitted to several models of mobiles.

The wireless charging standard makes it simpler for the consumer because of the ease of interoperability. Only a single wireless charger is enough for all devices in the household. Imagine that you are visiting the local coffee shop that has a Qi wireless charger. While enjoying your coffee, not only can you sample their free Wi-Fi, but make use of their wireless charging, without any concern about the compatibility of your device.

Qi works on the principles of magnetic induction between two coils. The charging pad holds one of the coils, which acts as the transmitter. The other coil is positioned inside the mobile device, usually just under the battery cover. Maximum power transfer requires one transmitter for each receiver, less than 4 cms of separation between the coils and a specific positioning of the mobile in relation to the transmitter. Qi chargers overcome the last limitation by providing more number of transmitter coils.

Pulse Ranging Technology Sensors Can Now Measure Distance

Radar measures the distance of an object by bouncing bursts of high frequency waves from the surface of the object and sensing the time it takes the echo to return. Pulse Ranging Technology or PRT sensors use a similar technique, but instead of using radio waves, they use bursts of light. The sensor emits bursts of light that travel to the object, bounce off its surface and return to the sensor. A processor in the sensor measures the time of flight of the light pulse and calculates the distance to the object.

PRT sensors emit light pulses of high-intensity at rates of 250 thousand pulses every second. The delay between the emission of light and its recapture increases with distance. Distances can also be measured by sensing the difference in phase shift of the reflected light from other types of photoelectric time of fight sensors that emit continuous light beams. The returning beam of light undergoes a change of phase because of reflection, and the difference in phase is a measure of the distance travelled by the light beam. However, a PRT sensor is superior in performance to other types of sensors.

Since a PRT sensor uses a pulsed laser diode, higher currents can be pumped into the laser source, resulting in light of higher intensity as compared to sources emitting continuous light. Light from a PRT sensor can be up to a thousand times more intense than that from other sources, which means they can easily detect objects further than 300 m.

High intensity light pulses from PRT sensors are not harmful to eyes. Although the light is intense, PRT sensors are off for longer periods that they are on. Therefore, in reality, PRT sensors emit very low power at any time compared to sensors sending out continuous light beams. In the market there are several PRT sensors certified as Class 1 laser products or “eye-safe.”

As pulsed light is easy to differentiate, PRT sensors are immune to other nearby photoelectric sensors, lighting and even sunlight. While sensing pulsed light, the PRT sensors can eliminate interference and crosstalk. On the other hand, sensors that use continuous light beams find light from stray sources often interfering with their readings.

PRT sensors are very useful in measuring continuously changing positions of the target. For example, they can monitor the stack height of metals; check if a container has been filled up to a specified height; and position a load or a product properly. They are good in preventing collisions of cranes, gantry and conveyors. Some PRT sensors can convert the distance measurement to streams of binary digits via Profibus, Ethernet or IO-Link, while some can output analog signals as well.

PRT sensors are useful not only for distance measurements, but also for detecting the presence/absence of objects. For example, they can verify rack occupancy in warehouses, detect stacks or panels within a defined window, tell when spools or rolls are either empty or full and check the height of a forklift truck. Moreover, designers can set the range at which the sensor will start detecting objects.