Tuning an IoT MEMS Switch

Menlo Microsystems, a startup from GE, is making a MEMS-based switch fit into a broad array of systems related to Internet of Things (IoT). Already incorporated into medical systems of GE, they can tune the chip to act as a relay and power actuator for several types of industrial IoT uses, including using it as an RF switch suitable for mobile systems.

Menlo first described their electrostatic switch in 2014. They have designed it with unique metal alloys deposited on a substrate of glass. The arrangement creates a beam that a gate can pull down, making it complete a contact and allow current to flow. Compared to a solid-state switch, this electrostatic switch requires significantly less power to activate and to keep it on. This single proprietary process creates products for several vertical markets.

The low power consumption of the device allows it to handle high currents and power switching. Unlike traditional switches, the MEMS switch does not generate heat, and therefore does not require large, expensive heat sinks to keep cool.

Currently, a tiny research fab run by GE is making the switch. Menlo expects to produce it in larger quantities in mid-2018, through Silex Microsystems, a commercial fab in Sweden. According to Russ Garcia, CEO of Menlo, their biggest challenge is to get the technology qualified in a fab producing commercial items.

The device has huge opportunities as it can replace a wide variety of electromechanical and electromagnetic power switches and solid-state relays. Menlo is planning to roll out several varieties of reference boards incorporating its MEMS chips, which will be helpful in home and building automation, robotics, and industrial automation.

For instance, IoT devices such as the smart thermostat from Nest face an issue of efficiently turning on or off high power systems such as HVACs. According to Garcia, the Menlo switch can do this while drawing almost zero current. Additionally, the Menlo switch offers a two-order reduction in the size of power switches and their power consumption.

It took a 12-year research effort by GE to incubate the design of the MEMS switches. They discovered that reliability issues were related to materials MEMS used, and overcame the issues with alternate unique metal alloys for the beams and contacts of the switch including generating a novel glass substrate. This combination allows billions of on/off switches to handle kilowatts of power reliably.

The medical division of GE will be among the first users of the chip. They will use the chip to replace a complex array of pin diodes in their MRI systems. This replacement by MEMS switches can knock off $10,000 from the cost of each MRI system. This includes the payment to five PhDs who presently tune each of the machines with pin diodes. The new MEMS switch will allow an automatic programming of the system.

Although GE will be an exclusive user for the chips in their MRI systems, Menlo is discussing future uses of the chip with other MRI makers as well. According to Garcia, GE wants to create a new strategic component supplier for the chips. Menlo is also planning to use the chips for RF switches.

Thermal Protection Prevents SSR Failure

Solid State Relays (SSR) are replacing conventional electromagnetic relays for load control applications in the industry, as they hold several advantages over the latter. However, SSRs often face overheating causing them to fail. Newer designs now come with integrated thermal protection that improves longevity, efficiency, and system safety by preventing overheating and failure of SSRs.

Machinery driven by large motors requires a system to switch off the power supply to the motor on sensing higher than normal heat, thereby preventing expensive damage. Usually, this is accomplished by an electrical relay accomplishes this by interrupting the power supply to the motor. Presently, the industry uses two main types of electrical relays for the purpose—an electromagnetic relay (EMR) or a solid-state relay (SSR). Although EMRs are the tried and trusted solution for load circuit management, SSRs are now making successful inroads into their market share.

One of the major drawbacks of EMRs is their limited life span, and their susceptibility to external influences such as shock, vibration, and magnetic noise, among others. This causes wear and reduces the life cycle. On the other hand, the all-solid-state construction of the SSR, without any moving parts, makes them highly tolerant of external disturbances. As there is no wear to reduce accuracy, SSRs enjoy longer life cycles and offer predictable operation. For instance, while an EMR may work reliably for hundreds of thousands of cycles, an SSR continues to perform satisfactorily even after five million cycles of operation.

SSRs carry a several-fold entry price hike over their similarly rated electromechanical counterparts, which are priced considerably lower. Therefore, unless the application demands exclusive seclusion from positioning, vibration, shock, and/or magnetic interference, using an EMR is often more economical. SSRs are more suited to harsh operating environments, and their longer lifespan soon provides their return on investment.

Unlike EMRs, SSRs generate heat when conducting current. Unless managed by a thermal component, overheating can damage an SSR, resulting in an outage of the manufacturing system or assembly line, leading to expensive repair expenses.

To address the challenge of overheating, designers now integrate a thermostat within the SSR. This prevents the device from overheating and ensures the relay always operates within its safe operating area (SOA). Furthermore, it protects the operation of the system and components from potential outages and/or damage.

The user can set the maximum operating temperature depending on the application. If the internal temperature of the SSR crosses the set threshold, the integrated thermostat embedded within cuts off power to the input circuit. The internal power-switching device mounts a metal plate, whose temperature the thermostat constantly monitors. If the temperature of the metal plate exceeds the normal range, the power-switching device signals the SSR to turn off the power.

By providing a trip during overheating conditions, the built-in thermal protection ensures   near-absolute equipment damage. This translates into reduced maintenance expenses and production downtimes. The user can choose to turn on power automatically when the temperature has returned to normal, or opt for an inspection before switching on the power manually. The second option helps to troubleshoot design issues in the system.

What are Numerical Protection Relays?

Numerical protection relays protect power transformers and distribution systems from various types of faults. For power transformers, these faults include protection from distance, line differential, pilot wire, low-impedance busbar, high-impedance differential, frequency, voltage, failure of circuit breaker, auto reclosing, and synchronism faults. For power distribution systems, these faults include protection from overcurrent, under or overvoltage, directional overcurrent’s, and feeder manager relay faults.

Numerical protection relays are digital systems in constant communication with substation automation systems through menu-driven interfaces. They have configurable binary inputs, outputs, and programmable logic. They monitor, measure, and record electrical values, fault and disturbances, and events. Numerical protection relays feature high-speed operation and multi-functionality, offering improved selectivity and stability. As they detect faults with automatic supervision, they bring high reliability to power systems, while at the same time being compact in size and consuming very low power.

Numerical protection relays have a multiple microprocessor design. Each microprocessor within the relay performs software functions such as executing protection algorithms and scheme logic, processing signals from sensors, controlling output relays, and handling the human interface.

The relay handles several analog inputs such as phase control inputs, phase voltage inputs, and residual current inputs. Depending on the type of relay, the number of analog inputs may vary.

Internal auxiliary transformers isolate the electronics from the high voltage on the system—isolating, generating step down voltages, and conditioning the inputs from the voltage and current transformers. Analog to digital converters transform these analog signals into digital data, which the microprocessors can process further.

The front panel of a numerical protection relay is a liquid crystal display (LCD) along with pushbutton keys providing local access to the relay menu. Light emitting diodes (LEDs) on the panel visually indicate the present status of the relay.

Three types of communication ports are available on a typical numerical protection relay-an RS232C port for locally connecting to a PC, an RS485 port for connecting to a remote PC, and an IRIC-B port for connecting an external clock.

The LCD exhibits information the relay is measuring continuously and simultaneously displays the same on the local PC, and the remote PC when connected. For instance, this information shows several voltages and currents such as phase, phase-to-phase, their symmetrical components, frequency, and active and reactive power. The type of relay defines the parameters it will measure and display. Users can monitor locally as well as remotely the element output of the relay and input/out binary values.

Within the relay, the software program records several events such as tripping operations, alarms, change of relay settings, change of state of each binary input/output, and failure detected by automatic supervision. Typically, the relay stores each time-tagged event with a 1 ms resolution. The user may define additional events for the system to record.

Apart from providing a date and time for tagging of records, a numerical protection relay records faults initiated by a relay trip and logs data such as date and time of the trip operation, operating phase, protection scheme that triggered the trip, and measured current data. The relay stores the eight most recent faults, time-tagged to 1 ms resolution.

How are Transformers Protected in the Field?

For maintaining a power grid in continuous working order, power transformers play a critical part. As repair and/or replacement of components in a power grid typically has a long lead time, protection from faults has to limit the damage to a faulted transformer. Moreover, transformer faults need quick prevention, and certain protection features identify operating conditions that could cause a failure of the transformer. This includes over-excitation protection and temperature-based protection.

Classification of transformer failure is as follows:

  • Failure in windings due to short circuits—this includes turn-to-turn shorts, phase-to-phase shorts, phase-to-ground shorts, and open windings
  • Faults in the Core—this includes failure of core insulation, and lamination shorts
  • Failure of Terminals—this includes open leads, short circuits, and loose connections
  • Failures of On-Load Tap Changer—this includes electrical and mechanical failures, short circuits, and overheating

Utility and industry power distribution networks utilizing power transformers typically install protection relays for the supervision, protection, control, and measurement of different parameters of power transformers, step-up and unit transformers, and power generator-transformers as well.

Transformer relays provide a flexible protection scheme for power transformers with two windings. They limit the damage to a transformer that has a fault and may identify operating conditions that could cause a devastating transformer or grid failure. Relay protection features include thermal overload protection, differential protection, voltage protection, and automatic voltage regulation. Some relays also have configurable functionality for meeting specific requirements of various applications.

For instance, the transformer protection and control relay, RET615 from ABB, conforms to IEC standards and offers a compact and versatile solution for industrial and utility power distribution systems.

A dedicated protection and control relay, the RET615 offers supervision, protection, control, and measurement of power transformers. It offers several benefits such as a compact and versatile solution, while integrating supervision, monitoring, control, and protection is one single unit.

RET615 offers an extended range of control and protection functionality for power transformers with two windings. It provides the transformer high inrush stability, while offering fast and advanced differential protection.

Setting up and tailoring the RET615 protection and control relay is simple and easy because it has ready-made configurations that match the most commonly used vector groups. This includes swift installation and testing, thanks to its withdrawable plug-in unit.

The RET615 has a large graphical display that shows the customizable SLDs. Users have the choice of accessing the SLDs directly on the display or via a web browser human machine interface that is simple and easy to use.

Along with measurement facility, RET615 also offers voltage and differential protection. It supports several neutral earthing options, including the restricted earth-fault principles of numerical low-impedance or high-impedance. The relay offers high-speed outputs for optional arc protection.

RET615 conforms to IEC 61850 Editions 1 & 2 standards, which include PRP and HSR, and GOOSE messaging. It follows IEC 61850-9-2 LE standard for supervised communication and less wiring.

Time synchronization is highly accurate as the RET615 conforms to IEEE 1588 V2, offering maximum benefit of Ethernet communication at substation level. In addition, RET615 supports DNP3, Modbus, and IEC60870-5-103 protocols for communication.

The PiServer for the Raspberry Pi

If you were running an institution teaching computer programming to kids using Raspberry Pis (RBPis), then you would normally spend some time updating numerous RBPis with the latest Raspbian and copying over several files for the class. You can save a lot of time using the PiServer, and do away with the SD cards at the same time.

The PiServer is a new piece of software tool that can easily set up a network of client RBPis connected to a single x86-based computer acting as the server. The various RBPis connect over Ethernet, and do not need their SD cards to boot. The server can control all its clients, allowing addition and configuration of user accounts. This provides an ideal setting for the classroom, within the home, or even an industrial setting.

To recall the terminology, the server is the computer providing the boot files, the file system, and authenticates the password of the clients. The clients are several computers that communicate with the server to retrieve the boot files, and the file system from the server. Although several clients connect to one server, they share the same file system. A user, with a unique combination of a username and password, can log into a client system. Once logged in, the user can access the file system on the server. The user may log in from any client system using their credentials, but will always see the server and the same file system. As the system does not give sudo capability to any user on a client, users are unable to make significant changes to the software and its file system.

All client RBPis use the PXE or network booting, and therefore, do not require any SD card to boot. The advantages of this type of booting are a large number of clients can boot off a single server, which treats all clients as the same. Additionally, as the server runs on a regular x86 system, it offers higher performance, network speed, and disk speed.

Without the PiServer, creating such a network would involve a lot of work, setting up the required FTP and DHCP servers, and making them interact seamlessly with other components on the network. The entire network is prone to breakdown with a single error. The PiServer takes care of all the intricacies, and has automatic functionalities.

For instance, PiServer can automatically detect any RBPi trying to boot via the network, and locate its Ethernet address. PiServer also sets up a DHCP server, to act as a router to provide an IP address to each client, whether in proxy mode or in full IP mode. For the safety of the network, the DHCP server replies only to those RBPis you have specified.

The PiServer also has the task to create usernames and passwords on the server. Therefore, in the classroom, the teacher can set up all the users beforehand. This allows each user to log in individually and keep all their work separately in the central location. The PiServer uses a somewhat altered Raspbian build, which has the LDAP enabled.

Speakers: Sound From Any Surface

Although accustomed to thinking about speakers when we hear of sound reproduction, nature uses several methods of producing sound or amplifying it. For instance, a cricket makes a chirping sound by rubbing its hind legs against each other, while perching on a large leaf to amplify the sound it produces. A guitarist amplifies the sound from the wires by coupling it to the guitar’s wooden box.

Traditionally, the size of the cone and the driver of a speaker determine the frequency and range of sound it produces. That is why several small portable speakers sound tinny, as they are unable to offer the deep bass because their driver can deliver limited frequency ranges. That is also the reason high fidelity audio systems have separate speakers for reproducing extremely low frequencies through subwoofer speakers.

A new type of speaker in the market does not require a cone to reproduce sound. This speaker uses the Incisor Diffusion Technology to diffuse sound across and through any surface upon which it is resting. It uses the surface to act as its cone and the surface diffuses the sound into the surrounding area.

Created by Damson, all its products using the Incisor Diffusion Technology offer a full audio frequency range from the surfaces they are placed upon. However, as different surfaces have varying resonance properties, the audio they produce will sound somewhat different. This unique way of reproducing sound offers the hearing impaired to feel sound through vibrations—just as Beethoven did.

As Damson pushes the capabilities of sound reproduction to newer frontiers, the need for different speakers to provide bass, middle, and high frequencies is fast dissolving. A regular speaker has a coil fixed to a permanent magnet, the arrangement being known as the driver. The Incisor Diffusion Technology from Damson replaces the coil with teeth or incisors. While they act in the same way as a coil does, they also power the different frequencies pushing the through to the surface. The reaction of the Incisor Diffusion Technology with the surface transfers the sound through it. For instance, placing on of Damson speakers on a window diffuses the sound through the glass, allowing it to be heard on both its sides.

Along with the size and shape of the surface, its type also affects the sound that it delivers. For instance, a bigger surface produces more sound than a smaller surface does, as it has more area and moves a greater amount of air—just as a bigger speaker is louder than a smaller one is. Any elastic surface will work to amplify the sound through it.

That means some surfaces work better than others do when reproducing sound. For instance, you will not hear sound from surfaces made of granite or stone, thick solid wood, sand, tarmac, grass, mud, asphalt, and concrete. On the other hand, thin wood is an ideal surface for sound reproduction, as is glass such as windshields, shower screens, windows, and tables. Metals surfaces are also good for sound production, so one can use the car bonnet, hood, or the roof. Now Redux is planning to use this technology on the screen of smartphones as a replacement for tiny speakers.

Butterfly IQ – Smartphone Connected Ultrasound Scanner

Traditional ultrasound scanners are rather expensive, and rarely do people own one to use at home. However, that may be about to change, as Butterfly IQ has now obtained FDA clearance for a portable ultrasound scanner that anyone can use by connecting to their smartphones.

Connecticut-based Butterfly IQ has made an innovative ultrasound scanner that uses a semiconductor chip for generating the ultrasonic signals, rather than the piezoelectric crystal transducers that traditional ultrasound machines use. The semiconductor chip based transducer is much easier to manufacture than the piezoelectric ones are.

Using the semiconductor chip makes the device much less expensive as compared to existing ultrasonic scanners. The cost of ownership comes down further as the device can operate with a smartphone and other smartphone connected devices such as the Philips Lumify device.

According to Dr. Jonathan Rothberg, founder and chairperson of Butterfly Network, this ultrasound-on-a-chip technology opens up a low-cost window for peering into the human body, allowing anyone to access high quality diagnostic imaging. With more than two-third of the population of the world without access to proper medical imaging, this effort by Butterfly is a great beginning.

FDA has cleared the device for 13 different clinical use cases. These include pediatric, urological, gynecological, cardiac, abdominal, and fetal use cases. The scanner transfers the captured imagery directly to the user’s smartphone via a chord, and the smartphone stores the images into a HIPAA-compliant cloud.

As reported by the MIT Tech Review, the chief medical officer of Butterfly Network, Dr. John Martin, was able to detect cancerous growth in his body while testing the scanner. This is an example of the potential of the low-cost ultrasound scanner.

According to Martin, the easy-to-use, powerful, healthcare providers will be able to afford the whole-body medical imaging system for less than $2,000, and it will fit in their pockets. As the price barrier comes down, Martin expects the Butterfly device to replace the stethoscope ultimately in the daily practice of medicine. The impact this technology will provide as a low-cost diagnostic system, can be gaged from the help it will offer to hundreds of thousands of women who die in childbirth, and the millions of children who die of pneumonia each year.

After perfecting the scanner, Butterfly has plans to augment its hardware capabilities with software for artificial intelligence. This will help clinicians interpret the images that the device picks up. The company expects the products with many new features to be ready for the market by 2018. At present, the device works only with iPhones.

According to the President of Butterfly IQ, Gioel Molinari, ultrasound imaging makes a perfect combination with deep learning. With more physicians using the devices in the field, the neural network models keep improving. As physicians use the Butterfly scanner regularly, they will be able to interpret the results better. This will help improve the acquiring and interpretation of the image by the artificial intelligence, which in turn, will help less skilled users to extract life-saving insight from the images captured by the Butterfly IQ ultrasound scanner on the field.

Cloud Storage and Alternatives

Ordinarily, every computer has some local memory storage capacity. Apart from the Random Access Memory or RAM, computers have either a magnetic hard disk drive (HDD) or a solid-state disk (SSD) to store programs and data even when power is shut off—RAM cannot hold information without power. The disk drive primarily stores the Operating System that runs the computer, other application programs, and the data these programs generate. Typically, such memory is limited and tied to a specific computer, meaning other computers cannot share it.

A user has two choices for adding more memory to a computer—he/she can either buy a bigger drive or add to the existing one, or he can use cloud storage. Various service providers offer remote memory storage, and the user has to pay a nominal rental amount for using a specific amount of cloud memory.

There are several advantages of using such remote memory. Most cloud storage services offer desktop folders where users can drag and drop files from their local storage to the cloud and vice versa. As accessing the cloud services requires Internet connection, the user can avail the cloud facilities from anywhere, while sharing it between several computers and users.

The user can use the cloud service as a back up for storing a second copy of their important information. In the event an emergency strikes and the user loses all or part of their data on their computer, accessing the cloud storage through the Internet can help to restore the stored information on the cloud. Therefore, cloud storage can act as a disaster recovery mechanism.

Compared to local memory storage, cloud services are much cheaper. Therefore, users can reduce their annual operating costs by using cloud services. Additionally, the user saves on power expenses, as cloud storage does not require the user to supply power that local memory storage would need.

However, cloud storage has its disadvantages. Dragging and dropping files to and from the cloud storage takes finite time on the Internet. This is because cloud storage services usually limit the bandwidth the user can avail for a specific rental charge. Power interruptions and or bad Internet connection during the transfer process can lead to corruption of data. Moreover, the user cannot access his/her data on the cloud storage unless there is an Internet connection available.

Storing data remotely also brings up the concerns of safety and privacy. As the remote memory is likely to be shared by other organizations, there is a possibility of data comingling.

Therefore, people prefer using private cloud services, which are more expensive, rather than using cheaper public cloud services. Private cloud services may also offer alternative payment plans, and these may be more convenient for users. Usually, the private cloud services have better software for running their services, and offer users greater confidence.

Another option private cloud services often offer is of encrypting the stored data. That means only the actual user can make use of their data, and others, even if they can access it, will see only garbage.

What is a wireless router?

Most of the electronic gadgets we use today are wireless. When they have to connect to the Internet, they do so through a device called a router, which may be a wired or a wireless one. Although wired routers were very common a few years back, wireless routers have overtaken them.

Routers, as their name suggests, direct a stream of data from one point to another or to multiple points. Usually, the source of data is the transmitting tower belonging to the broadband dealer. The connection from the tower to the router may be through a cable, a wire, or wireless. To redirect the traffic, the router may have a network of multiple Ethernet ports to which users may connect their PCs, or, as in the latest versions, it may transmit the data wirelessly. The only wire a truly wireless router will probably have is a cable to charge its internal battery.

Technically speaking, the wireless router is actually a two-way radio, receiving the signals from the tower and retransmitting them for other devices to receive. A SIM card inside the router identifies the device to the broadband company, helping it to keep track of the routers statistics. Modern wireless routers follow international wireless communication standards—the 802.11n being the latest, although there are several of the type 802.11b/g/n, meaning they conform to the earlier standards as well. Another differentiation between various routers is their operating speed, and the band on which they operate.

The international wireless communication standards define the speed at which routers operate. For instance, wireless routers of the type 802.11b are the slowest, with speeds reaching up to 11 Mbps. While those with the g suffix can deliver a maximum speed of 54 Mbps, those based on the 802.11n standard are the fastest, reaching up to 300 Mbps. However, a router can deliver data only as fast as the Internet connection allows. Therefore, even if it has a rating of n or 300 Mbps, it will perform at speeds of 100 Mbps at the most. Nonetheless, a fast wireless router can increase the speed of your network, and this allows PCs to interact faster, making them more productive.

International standards allow wireless communication on two bands—2.4 GHz and 5.0 GHz. Most wireless routers based on the 802.11b, g, and n standards use the 2.4 GHz band. These are the single band routers. However, the 802.11n standard allows wireless devices to operate on the 2.4 GHz or the 5.0 GHz band also. These are the dual-band routers, which can transmit in either of the two bands via a selection switch, or in some devices, they can operate in both frequencies at the same time.

A newer standard, 802.11a, allows wireless networking on the 5.0 GHz band, while also transmitting on the 2.4 GHz band used by the 802.11b, g, and n standards. These are also dual band wireless routers with two different types of radios that support connections on both 2.4 GHz and 5.0 GHz bands. The 5.0 GHz band offers better performance, lower interference, and more coverage.

Blinkt! is Compatible with the Raspberry Pi

If you are interested in learning how to control RGB LEDs with the Raspberry Pi (RBPi) single board computer, Blinkt! provides a simple way to interface. Blinkt! is a strip of eight superbright RGB LED lights that you can connect to the RBPi without wires, so it is an easy way to start. Blinkt! Has a female connector that matches the male GPIO connector on the RBPi, and that allows the tiny LED board to sit atop the RBPi.

The RBPi can individually control each of the eight APA102 RGB LEDs on the Blinkt! board individually, so you can consider them as matrix of 1×8 pixels. The footprint of the board is tiny enough to allow it sit directly on top of the RBPi and the pair fits inside most of the Pi cases. Although the RBPi controls the eight LEDs with PWM, it does not interfere with the SBC’s PWM audio. Blinkt! comes fully assembled and is compatible with RBPi models 3, 2, B+, A+, Z, and ZW. Pimoroni, the manufacturers of Blinkt!, also provide a Python library for the users.

Combining Python programming and Blinkt! with the RBPi is a great way of understanding how RGB LEDs work and how a computer program controls their operation.

If you are using the RBPi3 for this project, it will already have the male GPIO on the board. However, the RBPiZ and RBPiZW may not have the connector, which means you may need to solder the connector to the board. You need to be careful when plugging the Blinkt! board onto the RBPi taking care to orient it in the right way. The Blinkt! board has rounded corners on one of its side, and this side should face the outside of the RBPi. Once you align the boards properly, push the Blinkt! board in and it should fit snugly on the RBPi.

To make the RBPi control the LEDs on the Blinkt!, it will need to have the right code. The best way to begin is to update the Operating System of the RBPi to the latest Raspbian. Once you have done this, and the RBPi is running, connect it up to the Internet and open the terminal on the RBPi screen.

Typing the code “curl https://get.pimoroni.com/blinkt | bash” without the quotes, should allow the RBPi to download the necessary Python libraries from the Pimoroni website. Now you can use the Python 3 IDLE code editor to use the library to write the Python program and control the LEDs.

While writing the Python program, you will need to begin by importing the Blinkt! library you had downloaded in the first step. Each LED is termed as a pixel so the parameter “set_pixel” allows you to address a specific LED, while “set_brightness” allows setting its brightness. The command “show” turns on the specific LED, and “clear” turns it off.

Even though the LEDs are numbered as 1 to 8 on the board, the program addresses them as 0 through 7. Therefore, the program can pick a light and tell it the color it needs to be, its brightness, and whether it should turn it on or off.