January 08, 2019 Volume 15 Issue 01

Electrical/Electronic News & Products

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Mini LVDTs offer position feedback for UAVs

Unmanned drones require a variety of sensors to monitor different critical measurements to control flight and maintain aircraft stability. Miniature Linear Position Sensors from NewTek Sensor Solutions provide reliable position feedback for monitoring the fin/rudder position and rotor angle of unmanned aerial vehicles (UAVs) with quick response times, so drones can make adjustments to accurately control flight.
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Cobham introduces spacecraft, satellite electronics

Cobham Advanced Electronic Solutions, a leading provider of electronics technology and services for space and other high-reliability applications, recently released the new LeanREL product family designed to meet the needs of small satellite and non-traditional spacecraft manufacturers. The LeanREL product family, comprised of microprocessors, microcontrollers, as well as memory and interface integrated circuits (ICs), leverages Cobham's 30+ years of radiation-hardened, QML-level reliability, and innovative space systems design expertise and offers an unmatched combination of user benefits.
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Touch panels require 50 percent less input force

Fujitsu Components America has just released a series of customizable, flush-surface, resistive touch panels with less than half the input force of conventional resistive panels, nearly identical to that of projected capacitive panels. The new series (FID-1300 4-wire and FID-1520 5-wire) offers OEMs a cost-efficient alternative to projected capacitive touch panels with a comparable user experience, while maintaining resistive technology's reliable input capability and unlimited choice of input sources. Target applications include industrial automation and HMI machine control, medical equipment, and vehicle navigation systems.
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Automatic vision system with max throughput

The new AV450 Automatic Vision System from L.S. Starrett Company is a versatile, accurate, fast, and American-made 3-axis vision system that allows users to achieve high throughput in their inspection process cost effectively. This heavy-duty CNC video-based measurement system is ideal for both repetitive, larger part-run applications and routine quality assurance in inspection labs, manufacturing, assembly, and research facilities.
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Application Note:
Quadcopter propeller torque/thrust testing

The quadcopter's four propellers are designed to work in conjunction with each other to ensure that there are no torque imbalances that could send the vehicle spinning out of control. But just how would a professional developer or hobbyist perform accurate propeller torque and thrust testing? Advanced sensor specialist FUTEK has the answer.
Read the full article.


Engineer's Toolbox: How to choose the right relay

Relays come in a variety of form factors, styles, and technologies. Depending on your application, only one relay type may be suitable. In other cases, multiple relay types may be appropriate. By understanding the strengths and weaknesses of the different relays, you should be able to pick the one that is best suited for the job at hand. National Instruments lays out the options.
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Cool Tools: New Raspberry Pi 3 Model A+

Fans of the extremely popular credit card-sized computer called Raspberry Pi have something new to celebrate. The line of highly customizable base units has expanded with the third-gen A+ board, which brings the latest features and capabilities to a more compact form factor and lower price point -- only 25 bucks (and we have seen this on sale for under 20)!
Read the full article.


Vandal-resistant sealed switches

C&K has just launched its ATP19 and ATP22 series anti-vandal sealed pushbutton switches. The new high-strength, lightweight switches are IP67/IK10 rated, ensuring their suitability for operation in harsh conditions and ability to withstand potential malicious damage. The switches are also corrosion resistant and offer the industry-standard ring-illuminated version in 19-mm and 22-mm diameters.
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New inductive-technology position sensors

Novotechnik's TF1 Series touchless linear position sensors overcome issues with legacy magnetostrictive technology. They are unaffected by strong magnetic fields and metal flakes or filings present in a user's environment. The TF1 Series consists of an inductively coupled position marker attached to a moving rod/piece of the user's application that requires a position measurement and the sensor with operational and programming status LEDs. While operating, LEDs indicate whether the sensor is operating and the marker within measuring range or out of range, as well as indicating results of internal diagnostics for valid output from the sensor. Can also measure speed and temperature.
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Sensor development kit for power-optimized IoT applications

The RSL10 Sensor Development Kit from ON Semiconductor is designed to provide engineering teams with a comprehensive platform for developing IoT applications with cutting-edge smart sensor technology, enabled by the industry's lowest power Bluetooth Low Energy radio. The kit brings together the highly integrated RSL10 System-in-Package (RSL10 SIP) with a range of advanced low-power sensors from Bosch Sensortec. The development platform provides nine degrees of freedom (DoF) detection and environmental monitoring, including ambient light, volatile organic compounds (VOC), pressure, relative humidity, and temperature. An ultra-low noise digital microphone is also included, along with a user-programmable RGB LED, three programmable push-button switches, and 64 kb of EEPROM. Using the RSL10 Sense and Control mobile application, developers can connect to the RSL10 Sensor Development Kit to monitor sensors and to evaluate the kit's features. The app also supports multiple commercial cloud platforms for uploading sensor data.
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EC fans offer spark-proof IP68-ATEX protection for harsh AC applications

Orion Fans has expanded its family of Electronically Commutated (EC) fans to include spark-proof IP68-ATEX-rated versions for applications involving explosive atmospheres or flammable gases. Implementing IP68-ATEX fans into a design decreases the possibility of an explosion or fire. Available in a range of sizes including 60 mm, 120 mm, and 172 mm, the EC IP68-ATEX fans are ideal for a broad range of applications including appliances, commercial and process control, refrigeration, HVAC, electronic enclosures, and cabinets. By maintaining the same interface between the fan and equipment, EC fans can be used as drop-in replacements for equivalent-sized AC fans. The AC input fans utilize a brushless DC motor and incorporate voltage transformation within the motor for significantly lower power consumption. This equates to power savings of up to 50 percent.
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Cable assemblies for demanding microwave and RF applications

Intelliconnect has expanded its cable assembly offering for high-frequency and mission-critical applications. Comprised of high-quality cables, connectors, and terminations, the highly reliable RF cable assembly product offering now includes Low Loss, Semi-Rigid, Semi-Flex, and Conformable versions. The microwave and RF cable assembly line is designed for a wide range of applications including marine, medical, mil/aero, microwave communications, oil and gas, rail traction, test and measurement, and more. Available in a variety of sizes and performance specs, these assemblies operate up to 70 GHz and beyond and can be armored internally or externally. Phase matching is also available. Assemblies can be specified as matched sets or built to a specified phase length.
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How electronic flow sensors help spread road salt

Salt spreading trucks use a pre-wetting system when ice needs to be removed from roads and the temperatures are too low for direct salt spreading to work. The system sprays salt water onto the road salt as it is being spread to "jump start" the melting process. But how do you monitor the amount of pre-wet salt used?
Read this short, informative blog from Gems Sensors & Controls.


Bend the rules of lighting design: Cut and form LED sheets

VCC is bending the rules of lighting design with its new VentoFlex tiles. The VentoFlex modular lighting system opens up countless ways for architects and lighting designers to make an impact. Available in 12-in. x 12-in. sheets, these innovative LED tiles can be cut and formed around any design element, including rounded corners and tight spaces, without taking up much room at all -- just 0.15 in. (3.81 mm). A pair of scissors is the only tool required to cut VentoFlex tiles to the size and shape you desire. Ten or 15 tiles can be linked together to one driver and dimmer to create thousands of square inches of versatile lighting power!
Learn more about this new and exciting lighting technology.


Slip rings improve Ethernet transmission

The Kuebler Group offers contact and contactless slip rings for reliable Ethernet transmission, achieving higher data rates and greater cycle synchronicity in demanding industrial environments. Application examples include industrial automation, bottling plants, labeling machines, rotary tables, and other processes requiring high transmission rates. The standard Slip Ring SR120 features an innovative three-chamber system and shield to enable parallel, interference-free Ethernet transmission up to 100 Mbps. It boasts a long service life up to 500 million revolutions and a rugged, modular structure that can be expanded up to 20 channels. Another model, the Slip Ring SR160 with integrated Sendix Encoder, provides position information in addition to contactless Ethernet transmission -- either two channels at 100 Mbps multiplexed or one channel at 1 Gbps.
Learn more.


New way to do solar power: Researchers boost efficiency and stability of optical rectennas

Georgia Tech researchers have developed a new higher efficiency rectenna design. Here, the device's ability to convert blue light to electricity is tested. [Credit: Christopher Moore, Georgia Tech]

 

 

By John Toon, Georgia Tech

The research team that announced the first optical rectenna in 2015 is now reporting a two-fold efficiency improvement in the devices -- and a switch to air-stable diode materials. The improvements could allow the rectennas, which convert electromagnetic fields at optical frequencies directly to electrical current, to operate low-power devices such as temperature sensors.

Ultimately, the researchers believe their device design, which is a combination of a carbon nanotube antenna and diode rectifier, could compete with conventional photovoltaic technologies for producing electricity from sunlight and other sources. The same technology used in the rectennas could also directly convert thermal energy to electricity.

"This work takes a significant leap forward in both fundamental understanding and practical efficiency for the optical rectenna device," said Baratunde Cola, an associate professor in the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology. "It opens up this technology to many more researchers who can join forces with us to advance the optical rectenna technology to help power a range of applications, including space flight."

The research was reported January 26 in the journal Advanced Electronic Materials. The work has been supported by the U.S. Army Research Office under the Young Investigator Program, and by the National Science Foundation.

Optical rectennas operate by coupling the light's electromagnetic field to an antenna, in this case an array of multiwall carbon nanotubes whose ends have been opened. The electromagnetic field creates an oscillation in the antenna, producing an alternating flow of electrons. When the electron flow reaches a peak at one end of the antenna, the diode closes, trapping the electrons, then re-opens to capture the next oscillation, creating a current flow.

Optical rectenna schematic: This schematic shows the components of the optical rectenna developed at the Georgia Institute of Technology. [Credit: Thomas Bougher, Georgia Tech]

 

 

The switching must occur at terahertz frequencies to match the light. The junction between the antenna and diode must provide minimal resistance to electrons flowing through it while open, yet prevent leakage while closed.

"The name of the game is maximizing the number of electrons that get excited in the carbon nanotube, and then having a switch that is fast enough to capture them at their peak," Cola explained. "The faster you switch, the more electrons you can catch on one side of the oscillation."

To provide a low work function (ease of electron flow), the researchers initially used calcium as the metal in their oxide insulator/metal diode junction. But calcium breaks down rapidly in air, meaning the device had to be encapsulated during operation -- and fabricated in a glovebox. That made the optical rectenna both impractical for most applications and difficult to fabricate.

So Cola, NSF Graduate Research Fellow Erik Anderson, and Research Engineer Thomas Bougher replaced the calcium with aluminum and tried a variety of oxide materials on the carbon nanotubes before settling on a bilayer material composed of alumina (Al2O3) and hafnium dioxide (HfO2). The combination coating for the carbon nanotube junction, created through an atomic deposition process, provides the quantum mechanical electron tunneling properties required by engineering the oxide electronic properties instead of the metals, which allows air stable metals with higher work functions than calcium to be used.

Rectennas fabricated with the new combination have remained functional for as long as a year. Other metal oxides could also be used, Cola said.

The researchers also engineered the slope of the hill down which the electrons fall in the tunneling process. That also helped increase the efficiency, and allows the use of a variety of oxide materials. The new design also increased the asymmetry of the diodes, which boosted efficiency.

"By working with the oxide electron affinity, we were able to increase the asymmetry by more than ten-fold, making this diode design more attractive," said Cola. "That's really where we got the efficiency gain in this new version of the device."

Optical rectennas could theoretically compete with photovoltaic materials for converting sunlight into electricity. PV materials operate using a different principle, in which photons knock electrons from the atoms of certain materials. The electrons are collected into electrical current.

In September 2015 in the journal Nature Nanotechnology, Cola and Bougher reported the first optical rectenna -- a device that had been proposed theoretically for more than 40 years, but never demonstrated.

The early version reported in the journal produced power at microvolt levels. The rectenna now produces power in the millivolt range, and conversion efficiency has gone from 10-5 to 10-3 -- still very low, but a significant gain.

"Though there still is room for significant improvement, this puts the voltage in the range where you could see optical rectennas operating low-power sensors," Cola said. "There are a lot of device geometry steps you could take to do something useful with the optical rectenna today in voltage-driven devices that don't require significant current."

Cola believes the rectennas could be useful for powering internet of things devices, especially if they can be used to produce electricity from scavenged thermal energy. For converting heat to electricity, the principle is the same as for light-capturing oscillations in a field with the broadband carbon nanotube antenna.

"People have been excited about thermoelectric generators, but there are many limitations on getting a system that works effectively," he said. "We believe that the rectenna technology will be the best approach for harvesting heat economically."

In future work, the research team hopes to optimize the antenna operation and improve their theoretical understanding of how the rectenna works, allowing further optimization. One day, Cola hopes the devices will help accelerate space travel, producing power for electric thrusters that will boost spacecraft.

"Our end game is to see carbon nanotube optical rectennas working on Mars and in the spacecraft that takes us to Mars," he said.

This work was supported by the Army Research Office under the Young Investigator Program agreement W911NF-13-1-0491 and the National Science Foundation Graduate Research Fellowship program under grant DGE-1650044.

Published March 2018

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