Category Archives: Guides

Selecting Universal Motor Controls

Inside the home, one will find a number of gadgets with the universal motor dominating. Mostly, these are used in high speed, low-cost motor applications, such as in power tools, vacuum cleaner, and countertop blenders. However, not all gadgets perform equally. For example, a bargain-basement blender may make a lot of noise when working. Others may be relatively quieter. While some products have a tendency to overheat, others run cool even if you load them over. Actually, the motor itself has little to do with the wide variation in performance. Mostly, the lifespan and performance of the universal motor depends on its drive circuitry.

If speed control is not necessary, gadgets have their universal motors simply connected to the AC mains or to the DC rail, as this is the most cost-effective method for driving the motor and letting it spin. However, the speed of the universal motor depends largely upon the voltage applied, and connecting it directly to the voltage source allows it to spin at its maximum speed at minimum load.

While connecting directly to the voltage source for maximum speed might suit power tools or a vacuum cleaner, other applications may require the speed of the shaft to vary. Designers accomplish these using subtractive measures, mostly by reducing the motor voltage. This helps to reduce the speed to a fraction of the maximum RPM.

One can power universal motors through either alternating voltage or direct voltage, with each approach having its own advantages and disadvantages. While DC control circuits tend to be more expensive than their AC counterparts are, the DC controls have the advantage of prolonging the motor life, and offer noticeably quieter operations, with improved efficiency.

Running a universal motor on alternating voltage and implementing a lowest-cost speed control entails feeding the motor varying amounts of the AC half-cycle. The cheapest open-loop method employs two semiconductor devices, a Triac triggered by a Diac, with a series RC network controlling the phase at which the Diac fires.

Closed-loop controls replace the Diac with a low-cost 8-bit micro-controller. Apart from offering improved control of the Triac, use of the micro-controller results in a closed-loop speed control, more sophisticated user interface, and a proprietary software-based design. By digitally monitoring the motor voltage and current under load, most applications are able to forego the use of a tachometer on the motor shaft for feedback.

Although the above makes for a very economical drive, the downside to using this approach results in a high current ripple, making the operation run fairly noisy. Dissipations in the Triac reduces the efficiency of the approach, with the thermal strain on the brushes ultimately reduces their life.

DC drives, on the other hand, take a different approach. Regulated DC power to the motor is pulse-width modulated, with the rate of rotation of the shaft being directly proportional to the duty cycle of the PWM waveform. When the energy supplied to the motor is low, it spins slower.

The DC drive has the advantage of higher efficiency, reduced noise, highly responsive speed regulation, prolonging the motor life. Overall, the application may use a smaller motor.

How Are Industrial Lasers Cooled?

There are several varieties of industrial lasers. Some lasers, such as fiber lasers, have specific arrangements that enable spreading the heat they generate over a larger surface area. This arrangement gives fiber lasers better cooling characteristics over other media. Other lasers need extra cooling arrangements to remove the heat they generate. For example, ion lasers generate extreme heat when active and need elaborate cooling methods. Other lasers, emitting energy in the microwave and far-infrared region of the spectrum such as carbon dioxide lasers are immensely powerful, and cut hard material such as steel. The laser essentially melts through the material it focuses on. The problem is these industrial lasers have a limited surface area from where to exchange heat.

Although people traditionally use thermoelectric modules as heat exchangers, their efficiency has always limited their application. Now, thermoelectric modules are available which exhibit high heat flux density and are able to achieve higher heat pumping capacity compared to standard thermoelectric modules.

For instance, the UltraTEC series of thermoelectric modules from Laird has heat-pumping capacity of up to 340 Watts, which is fully adequate to cool applications such as industrial lasers that offer only a limited surface for heat exchange.

Industrial laser applications are numerous, including drilling, additive manufacturing, micro machining, welding, and cutting. Irrespective of the application, industrial lasers generate tremendous amounts of heat, which needs to be quickly and effectively removed to allow the laser to perform long-term and properly. Cooling lasers efficiently has always been a significant challenge for the industry.

Typical methods of cooling include transferring the excess heat by conduction or convection. Air may be used to remove the heat directly, or the heat could be transferred to a coolant, usually circulating water. The water carrying the heat is then circulated through a chiller or any heat transfer system. However, these arrangements depend on the system size and configuration, and can be expensive, complex, and noisy.

The UltraTEC series of thermoelectric modules offers excellent heat pump density, and allows precise temperature control. In fact, under steady state conditions, temperatures can remain within ±0.01°C. As these thermoelectric modules offer solid-state operation, these cooling solutions do not produce noise or vibrations. Moreover, they are available in multiple configurations, making them simple to implement.

Any laser system needs to be accurate and repeatable. Stability of the laser system is highly dependent on balanced, controlled cooling. The advantage of using UltraTEC thermoelectric modules for cooling is they can deliver highly reliable cooling solutions under conditions where the laser is in continuous use and even when cycling at high powers.

Laird assembles UltraTEC thermoelectric modules from Bismuth Telluride semiconductor materials. They use aluminum oxide ceramics, which are thermally conductive. This makes the UltraTEC thermoelectric modules capable of carrying high currents that are necessary for large heat-pumping applications. For instance, with Qmax rating of 340.6 W at 25°C, these thermoelectric modules can operate continuously up to 80°. This adequately ensures that the laser system will never overheat when being cooled by the high heat pump density UltraTEC series of thermoelectric modules. These modules are RoHS compliant and DC operated.

Heat Pipes for Electronic Applications

Electronic applications such as mobile, embedded computing, and servers often use intermediate level heat pipes to cool systems dissipating 15-150 Watts. Usually, such heat pipes use copper tubes and sintered copper wicks with water as the working fluid.

System designers incorporate heat pipes when the thermal design has limitations of space and/or weight and other materials such as solid aluminum or copper heat sinks cannot achieve the desired cooling. However, heat pipes for electronic applications require several considerations.

Manufacturers often publish thermal conductivity of heat pipes as ranging from 10,000 to 100,000 W/mK, which is nearly 500 times that of solid aluminum, and 250 times that of solid copper. However, unlike solid metal, the effective thermal conductivity of copper heat pipes varies extensively with their length and other factors affect this figure as well, although to a lesser extent.

For instance, a sample heat pipe could reach its published thermal conductivity of 100,000 W/mK when its length was 100 mm, when transporting heat from a 75 W power source. However, on increasing the length of the same heat pipe to 200 mm, its thermal conductivity fell to less than one-third the published figure.

Moreover, customization for a specific electronic application can severely limit the operational and performance characteristics of a heat pipe. This is much like the type of transformation a vehicle requires when fitting it out for a specific activity such as track racing or off-roading.

An engineer often has to customize the heat pipe when navigating the crowded route from the heat source to the evaporator or condenser. They do this by flattening or bending the heat pipe. For a lower thermal resistance, the designer may have to machine a heat pipe assembly to create a flat surface capable of direct contact with the heat source. This may require elimination of the solid metal base plate and the extra TIM layer. To keep the entire fitment small enough, the heat pipe may have to use a diameter that is different at one end from the other.

Drastic changes to customize the heat pipe to the electronic application often results in the heat pipe unable to meet the power handling requirements. To make it suit the application, the engineer may have to make changes to the internal structure of the heat pipe design.

This often requires changing the porosity and thickness of the wick, allowing the engineer to tune the heat pipe to meet specific operating parameters and performance characteristics. For instance, the heat pipe may have to operate at higher power loads or against gravity, requiring a larger pore radius or an increase in the capillary pressure of the wick.

However, a larger pore radius works against gravity, and therefore, in place of increasing the pore radius, increasing the wick thickness may make it more effective. Alternately, the engineer may increase both the wick thickness and porosity along the length of the tube. Some suppliers specialize in custom heat pipes and use unique mandrels and/or custom formulated copper powder to fabricate them. The outward physical characteristics also affect the performance of a heat pipe.

Using the Raspberry Pi to Secure IoT

The popular single board computer, the Raspberry Pi (RBPi), can effectively secure systems that traditional protection mechanisms often cannot. Industrial control system networks and Internet of Things fall under this category. You can use the RBPi2B and later models as an adequate medium for running the various security tools.

For this project, you need a Micro SD card of at least 8 GB size, and the bigger it is the better, as you can use the extra space to store a longer log data history, for instance, for logging data from Bro IDS. A case for the RBPi is preferable, and you can use one suitable to your individual taste and style. Although optional, a small form factor wireless keyboard is more helpful to configure the device on the fly, rather than using a full size keyboard.

Once you have configured the RBPi for networking, enable SSH and allow configurations from an SSH client. The hardware you will need includes an RBPi2B or later, an 8+ GB Micro SD card, a case for the RBPi, a Micro USB power cord, and an optional mini wireless keyboard.

Use the RBPi website to follow their getting started guide and install the Raspbian operating system using the New Out of the Box Software (NOOBS). Those familiar with the installation system can also use the traditional method of installing the Raspbian OS directly without the NOOBS, and it should work fine. Other OS distributions for the RBPi may also work, but you will need to try them out.

As the RBPi security solution places great reliance on lightweight open-source software, and the device monitors all traffic, you need to install software that inspects the traffic to learn what is going on. This requires installation on an Intrusion Detection System or IDS. Among the several free products available in the market, the one most suitable for the RBPi is the Bro IDS. The Bro inspects traffic at all OSI layers, and adds additional scripting that increases attack detection.

Bro IDS has some prerequisites before it can install on the RBPi. Install the prerequisites via apt-get, and after completing, download the latest source code for the Bro. Now, setup the environment to build, and to install the build—use configure, make, and make install. This allows you to manually control Bro, or use Broccoli to control it automatically.

Although the Bro IDS comes with an extensive signature base that can detect a number of common attacks, you can enhance its signature with Threat Intelligence. Another advantage in using the Bro IDS is the availability of Critical Stack, and you can integrate the threat intelligence with the Bro.

You can use Critical Stack, a threat intelligence feed, as a free aggregator. It functions as a simple point-n-click integration as it pulls data, such as addresses for Tor Exit Mode IP, known phishing domains and/or other malicious IPs. After pulling the data for threat intelligence, the Critical Stack agent formats it into a scripting language that Bro understands. The Bro IDS can pick up the new script automatically.

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.