Monthly Archives: January 2024

Ultrasonic Sensors in IoT

For sensing, it has been a standard practice to employ ultrasonic sensors. This is mainly due to their exceptional capabilities, low cost, and flexibility. With IoT or the Internet of Things now virtually entering most industries and markets, one can now find ultrasonic sensors in newer applications in healthcare, industrial, and smart offices and homes.

As their name suggests, ultrasonic sensors function using sound waves, especially those beyond the hearing capability of humans. These sensors typically send out chirps or small bursts of sound in the range of 23 kHz to 40 kHz. As these chirps bounce back from nearby objects, the sensor detects them. It keeps track of the time taken by the chirp for a round trip and thereby calculates the distance to the object based on the speed of sound.

There are several benefits from using ultrasonic sensors, the major one being very accurate detection of the object. The effect of material is also minimal—the sensor uses sound waves and not electromagnetic waves—the transparency or color of the object has minimum effect on the readings. Additionally, this also means that apart from detecting solid objects, ultrasonic sensors are equally good at detecting gases and liquid levels.

As ultrasonic sensors do not depend on or produce light during their operation, they are well-suited for applications that use variable light conditions. With their relatively small footprints, low cost, and high refresh rates, ultrasonic sensors are well-established over other technologies, like inductive, laser, and photoelectric sensors.

According to a recent study, the smart-office market will likely reach US$90 billion by 2030. This is mainly due to a surging demand for sensor-based networks, brought about by the need for safety and advancements in technology. Ultrasonic sensors will be playing an expanded role due to industry and local regulations supporting increased energy efficiency for automating different processes around the office.

A prime example of this is lighting and HVAC control in offices. Ultrasonic sensors are adept at detecting populated rooms in offices all through the day. This data is useful in programming HVAC systems, for keeping rooms hot or cool when populated, and turning the system off at the end of the day, kicking back on at first arrival.

Similarly, as people enter or leave rooms or areas of the office, ultrasonic sensors can control the lights automatically. Although the process looks simple, the energy savings from cutting back on lighting and HVAC can be huge. This is especially so for large office buildings that can have many unoccupied office spaces. For sensing objects across large areas, ultrasonic sensors offer ideal solutions, with detecting ranges of 15+ meters and detecting beam angles of >80°.

Additionally, smart offices can also have other smart applications like hygiene and touchless building entry devices. Touchless devices include automatic door entries and touchless hygiene products include faucets, soap dispensers, paper towel dispensers, and automatically lifting waste bin lids. During the COVID-19 pandemic, people’s awareness of these common applications has increased as public health and safety became critical for local offices and businesses.

Electric Motor Sans Magnets

Although there are electric motor designs that do not use permanent magnets, they typically work with an AC or alternating current supply. As such, these induction motors, as is their popular name, are not suitable for EVs or electric vehicles running on batteries, and are therefore, DC or direct current systems. Magnets in EV motors are permanent types, typically made of rare-earth elements like ferrite, samarium-cobalt, or neodymium-boron-iron, and are heavy and expensive.

The extra weight of the PM or permanent magnet EV motors tends to reduce the efficiency of the drive system, and it would be advantageous if the weight of the EV motor could be reduced somehow. One of the ways this can be done is to use motors that did not use heavy magnets.

A Stuttgart-based automotive parts manufacturer has done just that. MAHLE has developed a highly efficient magnet-free induction motor that works on DC systems. They claim the new motor is environmentally friendly and cheaper to manufacture as compared to others. Moreover, they claim it is maintenance-free as well.

According to a press statement from MAHLE, the new type of electric motor developed by them does not require any rare earth elements. They claim to have combined the strength of various concepts of electric motors into their new product and to have achieved an above 95% efficiency level.

The new motor generates torque via a system of contactless power transmission. Its fine-tuned design not only makes it highly efficient at high speeds but also wear-free.

When working, a wireless transmitter injects an alternating current into the receiving electrodes of the rotor. This current, in turn, charges wound copper coils, and they produce a rotating electromagnetic field much like that inside a regular three-phase induction motor. The rotating electromagnetic field helps to spin the rotor, thereby generating torque.

The magnetic coils take the place of permanent magnets in regular motors. MAHLE typically leaves an air gap between the rotating parts of the motor to prevent wear and tear. According to the manufacturer, it is possible to use the new concept in many applications, including subcompact and commercial vehicles.

MAHLE claims to have used the latest simulation processes to adjust and combine various parameters from different motor designs to reach an optimal solution for their new product. Not using rare earth element magnets allowed them to make lighter motors and has gained them a tremendous advantage from a geopolitical perspective as well.

Electric vehicles, and therefore PM electric motors, have seen a recent boom. But PM electric motors require rare earth metals, and mining these metals is not environmentally friendly. Moreover, with the major supply of these PM electric motors coming from China, automakers outside of China, are understandably, uncomfortable.

Although MAHLE used the latest simulation processes to design their new motor, the original concept is that of induction motors, invented by Nikola Tesla, in the 19th century. Other automakers have also developed EV motors sans permanent magnets, the MAHLE design has a rather utilitarian approach, making it more sustainable as compared to others

Battery-Free Metal Sensor IoT Device

Many industrial, supply chain and logistics applications require advanced monitoring of temperature, strain, and other parameters during goods transfer. One of the impediments of such requirements is a battery-powered device, typically involving its cost and maintenance overheads. A global leader in digital security and identification in the IoT or Internet of Things, Identiv, Inc., has developed a sensory TOM or Tag on Metal label, collaborating with Asygn, a sensor and IC specialist from France. The advantage of this sensory label is it operates without batteries.

The new sensor label is based on the next-generation IC platform of Asygn, the AS321X. They can capture strain and temperature data near metallic objects. The AS321X series of UHF or ultra-high frequency RFID or radio-frequency identification chips is suitable for sensing applications and can operate without batteries. Identiv has partnered with Asygn to expand its portfolio of products. It now includes the new sensor-based UHF inlays compliant with RAIN RFID standards, enabling the identification of long-range products and monitoring their condition.

According to Identiv, their advanced RFID engineering solutions, combined with Asygn’s sensing IC platform, have created a unique product in the industry. Taking advantage of their production expertise, and the latest sensor capabilities of Asygn, these new on-metal labels from Identiv offer the first exclusive, on-metal, battery less sensing solution in the market.

Using their connected IoT ecosystems, Identiv can create digital identities for every physical object by embedding RFID-enabled IoT devices, labels, and inlays into them. Such everyday objects include medical devices, products from industries like pharmaceuticals, specialty retail, luxury brands, athletic apparel, smart packaging, toys, library media, wine and spirits, cold chain items, mobile devices, and perishables.

RFID and IoT are playing an increasing role in the complex and dynamic supply chain industry. The integration of RFID with IoT is developing automated sensing, and promoting seamless, interoperable, and highly secure systems by connecting many devices through the internet. The evolution of RFID-IoT has had a significant impact on revolutionizing the SCM or Supply Chain Management.

The adoption of these technologies is improving the operational processes and reducing SCM costs with their information transparency, product traceability, flexibility, scalability, and compatibility. RFID-IoT is now making it possible to interconnect each stage in the SCM to ensure the delivery of the right process and product at the right quantity and to the right place. Such information sharing is essential for improving coordination between organizations in the supply chain and improving their efficiency.

Combining RFID and IoT makes it easier to identify physical objects on a network. The system transmits raw data about an item’s location, status, movement, temperature, and process. IoT provides the item with an identification ID for tracking its physical status in real-time.

Such smart passive sensors typically power themselves through energy harvesting, specifically RF power. Each sensor is battery-free and has an antenna for wireless communication. As an RF reader interrogates a sensor, it uses the energy from the signal to transmit an accurate and fast reading. Many sensors form a hub that collects their data while communicating with other connected devices.

Shape-Changing Robot Travels Large Distances

The world of robotics is developing at a tremendous pace. We have biped robots that walk like humans do, fish robots that can swim underwater, and now we have a gliding robot that can travel large distances.

This unique and innovative robot that the engineers at the University of Washington have developed, is, in fact, a technical solution for collecting environmental data. Additionally, it is helpful in conducting atmospheric surveys as well. The astonishing part of this lightweight robotic device is that it is capable of gliding in midair without batteries.

The gliding robots cannot fly up by themselves. They ride on drones that carry them high up in the air. The drones then release them about 130 ft above the ground and they glide downwards. The design of these gliding robots is inspired by Origami, the Japanese art of folding paper to make various designs.

The highly efficient design of these gliding robots or micro-fliers as their designers call them can change shape when they are floating above the ground. As these robots or micro-fliers weigh only 400 milligrams, they are only about half the weight of a small nail.

According to their designers, the micro-fliers are very useful for environmental monitoring, as it is possible to deploy them in large numbers as wireless sensor networks monitoring the surrounding area.

To these micro-fliers, engineers have added an actuator that can operate without batteries and a controller that can initiate the alterations in its shape. They have also added a system for harvesting solar power.

When dropped from drones, the solar-powered micro-fliers change their shape dynamically as they glide down, spreading themselves as a leaf as they descend. The electromagnetic actuators built into these robots control their shape, changing them from a flat surface to a creased one.

According to their designers, using an origami shape allows the micro-fliers to change their shape, thereby opening up a new space for the design. Inspired by the geometric pattern in leaves, they have combined the Miura-ori fold of origami, with power-harvesting and miniature actuators. This has allowed the designers to make the micro-fliers mimic the flight of a leaf in midair.

As it starts to glide down, the micro-flier is in its unfolded flat state. It tumbles about like an elm leaf, moving chaotically in the wind. As it catches the sun’s rays, its actuators fold the robot, changing its airflow and allowing it to follow a more stable descent path, just like a maple leaf does. The design is highly energy efficient, there is no need for a battery, and the energy from the sun is enough.

Being lightweight, the micro-flier can travel large distances under light breeze conditions, covering distances about the size of a football field. The team showcased the functioning of the newly developed micro-flier prototypes by releasing them from drones at an altitude of about 40 meters above the ground.

During the testing, the released micro-fliers traveled nearly 98 meters after they changed their shapes dynamically. Moreover, they could successfully transmit data to Bluetooth devices that were about 60 meters away.

Are Lithium Iron Phosphate Batteries Better?

According to the latest news from developments in batteries, the LFP or Lithium Iron Phosphate battery technology is going to pose a serious challenge to that of the omnipresent Lithium-ion type.

As far as e-mobility is concerned, Lithium-ion batteries have some serious disadvantages. These include higher cost and lower safety as compared to other chemistries. On the other hand, recent advancements in battery pack technology have led to an enhancement in the energy density of LFP batteries so that they are now viable for all kinds of applications related to e-mobility—not only in vehicles but also in shipping, such as in battery tankers.

In their early years of development, LFP cells had a lower energy density as compared to those of Lithium-ion cells. Improved packaging technology had bumped up the energy density to about 160 Wh/kg, but this was still not enough for use in e-mobility applications.

With further improvements in technology, LFP batteries now operate better at low temperatures, charge faster, and have a longer cycle life. These features are making them more appealing for many applications, including their use in electric cars and in battery tankers.

However, LFP batteries still continue to face several challenges, especially in applications involving high power. This is mainly due to the unique crystal structure of LFP, which reduces its electronic conductivity. Scientists have been experimenting with different approaches, such as reducing the directional crystal growth or particle size, using different conductive layer coatings, and element doping. These have not only helped to improve the electronic conductivity but have increased the thermal stability of the batteries as well.

Comparing LFP batteries with the Lithium-ion types shows them to have individual advantages in different key characteristics. For instance, Lithium-ion batteries offer higher cell voltages, higher power density, and better specific capacity. These characteristics lead to Lithium-ion batteries offering higher volumetric energy density suitable for achieving longer driving ranges.

In contrast, LFP batteries offer a longer cycle life, better safety, and better rate capability. As the risk of thermal runaway, in case of mechanical damage to a cell, is also much lower, these batteries are now popularly used for commercial vehicles with frequent access to charging, such as scooters, forklifts, and buses.

It is also possible to fully charge LFP batteries in each cycle, in contrast to having to stop at 80% to avoid overcharging some type of Lithium-ion batteries. Although this does allow simplification of the battery management algorithm, it adds other complexities for Battery Management Systems managing LFP cells.

Another key advantage of LFP batteries is they do not require the use of cobalt and nickel in their anodes. The industry fears that in the coming years, sourcing these metals will be more difficult. Even with mining projections of both elements doubling by 2030, they may not meet the increase in demand.

All the above is making the LFP batteries look increasingly interesting for e-mobility applications, with more car manufacturers planning to adapt them in their future cars.

What are Flash SSDs?

Earlier we used traditional hard disk drives in our computers. These were mechanically spinning magnetic disks with read-write heads. Nowadays, we use SSD or Solid-State Drives that have no moving parts. SSDs can retain data once it is saved without power, as they use NAND flash memory. To increase the data density, the NAND chips are multilayered. That means they can hold upwards of one bit of information per cell. SSDs using multilayered chips are named single-, multi-, triple-, quad-, and penta-level SSDs, according to the number of bits each cell can hold.

Multilayered SSDs have their own advantages and shortcomings and can range from speed to price to reliability. For instance, SLC or Single Level Cells have a lifespan measured in program/erase cycles of about 50,000 to 100,000 and can withstand high-intensity write operations.

MLCs or multi-level cells with two bits per cell can expect a lifespan of about 10,000 cycles and are mostly suitable for enterprise data centers.

TLCs or triple-level cells with three bits per cell can expect a lifespan of about 3,000 cycles and are useful for digital consumer products.

QLCs or quad-level cells with four bits per cell can expect a lifespan of about 2,000 cycles and are suitable for read-heavy operations, streaming media, and content delivery applications.

No data is available for the lifespan of PLCs or penta-level cells with five bits per cell. These SSDs are suitable for long-term storage of data such as in data archives.

Flash SSDs have revolutionized the storage of enterprise data in all its forms. They have enabled faster boot times and the application starts on PCs and mobile devices. They have facilitated the blistering performance of storage arrays in workloads like business analytics. In most performance metrics, flash SSDs have far outshone the older hard disk drives.

Speed aside, flash SSDs offer additional benefits. They are far more durable while being less susceptible to damage from abrupt physical shocks and movements, as compared to the traditional HDDs. Additionally, they use much less power to operate. Even though they cost more than the HDDs per gigabyte, the improved performance of SSDs overcomes their higher expense for most applications.

Flash SSDs store data in their memory cells using a technique called FGT or Floating Gate Metal Oxide Field Effect Transistors that can store a binary 0 or 1. With two gates, each FGT behaves like an electrical switch with current flowing between two points. NAND flash is named so as it uses NOT-AND logic gates. Power is not necessary to retain data in the flash cells, as, in the absence of power, the FGT provides the electrical charge for maintaining the data intact in the memory cells.

Flash SSDs are solid state, meaning they have no mechanical part to wear out. However, SSDs can nonetheless fail. One measure of SSDs is the lifespan or the number of program/erase cycles that a drive can complete before its degradation and failure. This is overcome by using wear-leveling technology, whereby the life of the SSD is prolonged by evenly distributing the program/erase cycle across the total NAND cells in the drive.

New Circuit Protection Technologies

A wide variety of vehicle models is entering the EV market these days. The demand is for decreased charging times and increased range. This is heightening not only the challenges towards electrical system performance but also towards better circuit protection.

For instance, decreasing the charging times requires systems using higher voltages and higher currents. This has necessitated the shift from the 400 V system to the 800 V, bringing with it major challenges to the design of circuit protection, especially on the battery side. That is because manufacturers must now consider increased fault currents that the protection components must handle.

With motor currents and power ramping up, circuit protection and switching devices also face higher stresses. They now need to withstand not only the higher operating currents but also the higher cycling requirements. Increased range means higher fault currents.

Therefore, circuit protection requirements are moving in several directions simultaneously. SiC MOSFET switches, acting as solid-state resettable transistor switches, address the high-voltage, low-current subsystems.

The power distribution box in the vehicle is still using the conventional system architecture of a coordinated fuse and contactor. Coordination between the two is necessary to ensure they cover the full range of possible faults from a range of underlying causes including different states of charge of the battery.

Another circuit protection technique is the pyrotechnic approach. This comes into play in events of a catastrophic nature, such as in crashes, when it is necessary to physically cut the busbar. These systems are mostly triggered by circuits that deploy the airbag and work to quickly isolate the battery from the rest of the vehicle. This helps to protect the driver, the passengers, and the first responders from fire and explosion from short circuits through the body of the vehicle.

The above are leading to the development of newer types of protection, such as with breaktors, fully coordinating circuit protection, and switching. Its design allows the breaktor to trigger passively or it can actively interrupt in case of power loss, thereby improving the functional safety of critical protection systems. Moreover, it has the ability to reset itself.

Another is an automotive precision bidirectional eFuse, which is increasingly becoming a common device in a vehicle. Traditional automotive fuses can be low in accuracy and slow to react. This can be a safety issue, as the safety of the system is indirectly proportional to the response time of a fuse. An eFuse not only has high accuracy but also a low response time, which increases the safety of the system.

However, there is a durability issue related to fuses and contactors that vehicle manufacturers use. The solution for this is the pyrotechnical switch. This is a protection device based on a trigger-able circuit similar to the functioning of an airbag. It produces a controlled explosion to sever a conducting busbar. Pyrotechnical switches, while solving the challenge of coordination, must rely on accurate triggering rather than on the passive reaction of fuses. Additional components are necessary to ensure a reliable triggering.

All the above protection systems require a trade-off between speed and durability. While a big fuse can be slow to operate, a smaller one may be faster but may suffer from a fatigue risk.