Feed aggregator

Electric traction has become a critical part of a growing number of systems that need efficient motion and position control. Motors do not just provide the driving force for vehicles, from e-bikes to cars to industrial and agricultural machinery. They also enable a new generation of robots, whether they use wheels, propellers or legs for motion.

The other common thread for many of these systems lies in the way they are expected to operate in a highly connected environment. For instance, wireless connectivity has enabled novel business models for e-bike rental and delivers positioning and other vital data to robots as they move around.

But the same connections to the Internet open avenues of attack in ways that previous generations of motion-control systems have not had to deal with. It complicates the tasks of designing, certifying, and maintaining systems that ensure safe operation.

To guarantee the actuators do not cause injury, designers must implement safeguards for their control systems to prevent them being bypassed and creating unsafe situations. They also need to ensure that corruption by hackers does not disrupt the system’s behavior. Security, therefore, now plays a major role in the design of the motor-control subsystems.

Figure 1 Connectivity in warehouse robots also opens vulnerabilities in motor control systems. Source: EnSilica

Algorithmic demands drive architectural change

Complexity in the motor control also arises from the novel algorithms that designers are using to improve energy efficiency and to deliver more precise positioning. The drive algorithms have moved away from simple strategies such as analog controllers that simply relate power delivered to the motor windings to the motors rotational speed.

They now employ far more sophisticated techniques such as field-oriented control (FOC) that are better able to deliver precise changes in torque and rotor position. With FOC, a mathematical model predicts with high precision when power transistors should activate to supply power to each of the stator windings in order to control rotor torque.

The maximum torque results when the electric and magnetic fields are offset by 90°, delivering highly efficient motion control. It also ensures high positioning accuracy with no need for expensive sensors or encoders. Instead, the mathematical model uses voltage and current inputs from the motor winding to provide the data needed to estimate position and state accurately.

Figure 2 The use of techniques like FOC delivers highly efficient motion control, which ensures greater positioning accuracy without expensive sensors or encoders. Source: EnSilica

In robotics, these algorithms are being supplemented by techniques such as reinforcement learning. Using machine learning to augment motion control has proven highly effective at delivering precise traction control for both wheeled vehicles and legged robots. Dusty or slippery surfaces can be problematic for any automated traction control systems. Training the system to cope with these difficult surfaces delivers greater stability than conventional model-based techniques.

Such control strategies often call for the use of extensive software-based algorithms running on digital signal processors (DSPs) and other accelerators alongside high-performance microprocessors in a layered architecture because of the different time horizons of each of the components.

An AI model trained using a reinforcement learning model, for example, will typically operate with a longer cycle time than the FOC algorithms and the pulse-width modulation (PWM) control signals below them that ensure the motors follow the response needed. As a result, DSP-based models with long time horizons will be supported by algorithms and peripherals that use hardware assistance to operate and meet the deadlines required for real-time operation.

The case for custom hardware

The hard real-time functions are those that have direct control over the power transistors that deliver power to the motor windings, usually implemented in an “inverter” comprising a half-bridge circuit for each of the motor phases. Traditionally, such half-bridge controllers have focused on the implementation of timing loops for PWM.

The switching frequencies are often too high to be supported reliably by software running even on a dedicated microprocessor without needing the processor to be clocked at excessive frequencies. The state machines used to implement PWM switching also take care of functions such as dead-time insertion, which is used to ensure that each transistor doesn’t turn on before its counterpart transistor in the half-bridge inverter is turned off.

The timing gap prevents the shoot-through of current that would result if both transistors were active at the same time. The excess current can damage the motor windings and the drive circuit board. These subsystems are so important that they are often provided as standard building blocks for industrial microcontrollers.

However, in the context of increased threats from hackers and the need to support advanced algorithms, the inverter controller can become a vital component in supporting overall system resilience. By customising the inverter controller, implementors can more easily guarantee safety and security, as well as protect core traction-control IP. Partitioning of the inverter and the rest of the drive subsystem need not just support all three aims, which can also reduce the cost of implementation and verification.

A major advantage of hardware in terms of security is its relative immutability compared to software code. Attackers cannot replace important parts of the hardware algorithm if they gain access. This simplifies some aspects of security certification in addition. Techniques such as formal verification can determine whether the circuitry can ever enter a particular state. Future updates to the system will not directly affect that circuitry.

It’s possible for code changes to alter the interactions between the microcontroller-based subsystems and the lower-level hardware. However, this relationship provides opportunities for the designer to improve their ability to guarantee safe operation, even under the worst-case conditions where a hacker has gained access and replaced the firmware.

Hardware-based lockout mechanisms and security checks can ensure that if the upper-level software of the system is compromised, the system will place itself into a safe state. The lockouts can include support for mechanisms such as secure boot. This ensures that only the software that passes the ASIC’s own checks can activate the motor.

Using hardware for safety and security protection can help reduce the cost of software assurance, which is now subject to legislation such as the European Union’s Cybersecurity Resilience Act (CRA). The new law demands that manufacturers and service operators issue software updates for critically compromised systems.

By moving key elements of the system design into hardware and minimizing the implications of a hack, the designer can reduce the need for frequent updates if new vulnerabilities are found in upper-level software. Similarly, moving interlocks into hardware simplifies the task of demonstrating safe operation for standards such as ISO 26262 compared with purely software-based implementations.

Physical attacks can often involve power interruptions, which provides a way to design an ASIC that protects against such tampering. For example, if power monitoring circuitry detects a brownout, it can reset the microprocessor and place the rest of the system in a safe, quiescent state.

Hardware choices that support compliance and control

Alongside the additional functions, an ASIC inverter controller can host more extensive parts of the motor-control subsystem and reduce the cost of the microprocessor components. For example, FOC relies on trigonometric and other computationally expensive transforms.

Moving these into a coprocessor block in the ASIC can streamline the design. This combination can also reduce control latency by connecting inputs from current and voltage sensors to the low-level DSP functions.

The functions need not all be fixed. Modern ASICs may include configurable blocks such as programmable filters, gain stages, and parameterizable logic to offer a level of adaptability. The use of programmable functions can let a single ASIC design control various motor configurations across an entire product range.

The programming of these elements illustrates one of the many safety and security trade-offs that design teams can make. Incorporating non-volatile memory into the ASIC can provide the greatest security. Putting the programmable elements into an ASIC that can be locked by blowing fuses after manufacturing is more secure than a design where a host microcontroller writes configuration values during the boot process.

The MCU-based control chips require a silicon process suitable for storing the firmware code, normally based on flash memory. This implies some additional processing masks, which increase the cost of the final product, a factor especially sensitive if the production volume is high.

If the design calls for the high-voltage capability offered by Bipolar-CMOS-DMOS (BCD) processes for the motor-drive circuitry, a second die may be needed for non-volatile memory. But the flash CMOS process will normally support a higher logic density than the BCD-based parts, which allows the overall cost to be optimized.

Thanks to its ability to support deterministic control loops and support verification techniques that can ease security and safety certification, the use of hardware is becoming increasingly important to e-mobility and robotics designs.

Through careful architecture selection, such hardware can enable the use of software for flexibility and its own ability to support novel control strategies as they evolve. The result is an environment where ASIC use can offer the best of both worlds to design teams.

David Tester, chief engineer at EnSilica, has 30+ years of experience in the development of analogue, digital and mixed-signal ICs across a wide range of semiconductor products.

Related Content

• Learning the Basics of Motor Control
• Optimizing motor control for energy efficiency
• Five trends to watch in automotive motor control
• MCUs specialize in motor control and power conversion systems
• High-Performance Motor Control Chip with Multi-Core Architecture

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Перемога КПІшниць у кіберзмаганнях! kpi пт, 09/05/2025 - 10:45

Designed for Automotive, Energy, and Industrial Applications, AEC-Q200 Qualified Device Withstands Grade III THB Testing

Vishay Intertechnology, Inc. introduced a new AEC-Q200 qualified DC-Link metallized polypropylene film capacitor designed for the harsh conditions of automotive, energy, and industrial applications. Offering high temperature operation up to +125 °C, the Vishay Roederstein MKP1848e delivers ripple current up to 44.5 A and withstands temperature humidity bias (THB) in accordance with Grade III of IEC60384-16 ed.3 – 60 °C / 93 % R.H for 1344 hours at rated voltage.

With its high temperature operation and resistance to high humidity, the Automotive Grade capacitor released, is ideal for automotive power conversion applications such as on-board chargers (OBC), power trains, HVAC systems, e-compressors, and DC/DC converters. This next-generation DC-Link capacitor also addresses the stringent needs for energy and industrial power conversion applications such as fast chargers, solar inverters, rectifiers for hydrogen electrolyzers, battery storage systems, motor drives, and UPS.

The MKP1848e offers rated capacitance from 1 µF to 140 µF and low ESR down to 1.0 mΩ, in rated voltages from 500 VDC to 1300 VDC. The devices provide 25 % higher ripple current density than previous-generation solutions with the same volume, while its compact footprint and pitch options down to 22.5 mm enable volume reductions up to 40 % and 15 %, respectively, at 500 VDC and 900 VDC.

To meet the standard high voltage levels of electric (EV) and plug-in hybrid electric vehicles (PHEV), the MKP1848e withstands operating voltages from 250 VDC to 800 VDC at +125 °C for a limited time. It also features high thermal shock capabilities — withstanding 1000 temperature cycles from -40 °C to +125 °C, with a 30-minute dwell time for each temperature extreme.

The post Vishay Intertechnology Automotive Grade MKP1848e DC Link Film Capacitor Delivers High Temp. Operation Up to +125 °C and High Robustness Under High Humidity appeared first on ELE Times.

In the backdrop of Semicon India 2025, Kaynes Semicon announces a strategic partnership with Emeron’s NI Semiconductor Test Systems (STS). Under the strategic partnership, Kaynes will deploy Emerson’s NI STS as the preferred platform across its expanding semiconductor test facilities. 

“We have partnered in the sense that we have invested in those testers, and those would be a part of our ecosystem that we build,” says Mr Raghu Panicker, CEO of Kaynes Semicon Private Limited, in an exclusive conversation with ELE Times. “They have already given us their best possible prices for the testers, and we will deploy them in the products that we will assemble and test in Sanand, Gujarat,” he adds. 

Scope of Work

The collaboration will unify test infrastructure across Kaynes’ analog, mixed-signal, RF, power, and MEMS devices—enhancing production speed, ensuring test flexibility, and shortening time-to-market. This move reinforces Emerson’s vision of establishing itself as a trusted Test-as-a-Service partner for the semiconductor industry.

Emergence of Partnerships 

Underlining the need for partnerships as India strives to achieve its semiconductor ambitions, Shitendra Bhattacharya, Country Head and Director, India, Emerson Test and Measurement Buseiness Group says, “ The great value add that we were able to offer and where we see a synergy is the fact that our hardware and software capabilities have come together in modular, flexible, and scalable system” in an exclusive conversation with ELE Times at Semicon India 2025. 

Adding to the business aspect of securing investments, he says, “NI Testers are the most preferred because of the modularity, flexibility, and scalability. These platforms can evolve into different kinds of chips that they will be testing in the future.” 

About the systems 

The NI STS is a PXI-based test solution offering compact form factor, reconfigurable architecture, and software integration through LabVIEW and TestStand, enabling reuse of instruments and multi-site execution. This helps manufacturers like Kaynes to reduce equipment redundancy, streamline workflow, and respond quickly to changing test requirements.

The partnership is supported by Emerson’s strong India presence, including field engineers, application support, and training resources, ensuring seamless implementation and long-term success for Kaynes’ test operations.

As India ramps up semiconductor manufacturing, Emerson’s NI test platforms are well-positioned to support emerging OSATs and fabs with high-speed, mixed-signal testing. With up to 10x faster test speeds, these systems help reduce capital costs and enable scalable, efficient production—making them ideal for the country’s growing semiconductor ecosystem.

The post Exclusive Insights: Kaynes Semicon & Emerson India to Deploy NI Test Systems at Sanand OSAT, Confirmed at Semicon India 2025 appeared first on ELE Times.

submitted by /u/DenkJu [link] [comments]

The new Akida Cloud is developed for instant access to the company's innovations and reduced development cycles.

Харчова безпека та доступ до їжі в КПІ ім. Ігоря Сікорського kpi пт, 09/05/2025 - 00:26

Nexperia has introduced two programmable USB Type-C power delivery controllers and new ESD protection diodes for high-speed applications exceeding 10 GHz.

After the introduction of its first-generation (Gen 1) D3GaN 650V devices, followed by Gen 1+, and now second-generation (Gen 2) products, VisIC Technologies Ltd of Ness Ziona, Israel – a fabless supplier of power conversion devices based on gallium nitride (GaN) transistors – says that it has created a roadmap for achieving maximum energy efficiency through optimized RDS(ON) performance...

Series 600 high-voltage reed relays from Pickering Electronics offer over 2500 combinations of rating and connection options. They are customizable from 3.5 kV to 12.5 kV, with standoff voltages from 5 kV to 20 kV and switching power up to 200 W. Switch-to-coil isolation reaches 25 kV, safely separating control circuitry from high-voltage paths even in demanding environments.

Built with vacuum-sealed, instrumentation-grade reed switches, the relays are available with 1 Form A (NO), 1 Form B (NC), and 1 Form C (Changeover) contacts and 5-V, 12-V, or 24-V coils. An optional diode or Zener-diode combination suppresses back EMF, while mu-metal screening reduces magnetic interference. Insulation resistance exceeds 1013 Ω, ensuring minimal leakage and maximum isolation.

A variety of case sizes, connection types (turrets, flying leads, PCB pins), and potting materials helps engineers meet thermal, mechanical, and environmental requirements. Series 600 relays support many high-voltage test and switching applications, including EV BMS and charge-point testing, inverter or insulation-resistance testing in solar systems, and isolation in medical equipment.

Request free pre-production samples, access the datasheet, or try the configuration tool via the product page link below.

Series 600 product page 

Pickering Electronics 

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Quectel has announced the KCMCA6S series of Wireless M‑Bus (WM‑Bus) modules, capable of sub-1 GHz operation for smart metering. Based on Silicon Labs’ EFR32FG23 wireless SoC, featuring a 73‑MHz Arm Cortex‑M33 processor, the modules operate in the 868‑MHz, 433‑MHz, and 169‑MHz bands.

The devices comply with EN 13757‑4, the European standard for wireless metering, and support the WM‑Bus protocol and other proprietary sub‑GHz protocols. Their built-in software stack and flexible configuration modes eliminate the need for third-party protocol integration.

Modules include an optional integrated SAW filter to limit interference from cellular signals, an important factor for devices combining WM-Bus with cellular technologies such as NB-IoT or LTE Cat 1. They feature 32 KB of RAM and 256 KB of flash memory.

Availability for the KCMCA6S series was not provided at the time of this announcement.

KCMCA6S product page

Quectel Wireless Solutions 

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Three 650-V SiC MOSFETs from Toshiba come in compact surface-mount TOLL packages, boosting both power density and efficiency. The 9.9×11.68×2.3-mm package shrinks volume by more than 80% compared to through-hole TO-247 and TO-247-4L(X) types.

TOLL also provides lower parasitic impedance, reducing switching losses. As a 4-terminal package, it enables a Kelvin source connection for the gate drive, minimizing the impact of package inductance and supporting high-speed switching. For the TW048U65C 650-V SiC MOSFET, turn-on and turn-off losses are about 55% and 25% lower, respectively, than the same Toshiba products in the TO-247 package without Kelvin connection.

The third-generation MOSFETs in this launch target switch-mode power supplies in servers, communication gear, and data centers. They are also suited for EV charging stations, photovoltaic inverters, and UPS equipment.

Datasheets and device availability are accessible via the product page links below.

TW027U65C product page 

TW048U65C product page 

TW083U65C product page 

Toshiba Electronic Devices & Storage 

The post TOLL-packaged SiC MOSFETs cut size, losses appeared first on EDN.

Keysight physical-layer test software provides compliance and performance validation for HDMI 2.2 transmitters and Cat 4 cables. The D9021HDMC electrical performance and compliance software and the N5992HPCD cable eye test software help engineers address the demands of UHD video and HDR content. Together, they improve signal integrity and support HDMI Forum compliance.

The recent release of the HDMI 2.2 test specification introduces more stringent compliance requirements for transmitters and cables, exposing gaps in conventional test coverage. As the HDMI ecosystem evolves to support higher resolutions, faster refresh rates, and greater bandwidth, the Keysight software provides a unified platform for automated electrical testing as defined by the specification. 

Keysight’s platform combines high-bandwidth measurement hardware with automated compliance workflows to manage complex test scenarios across transmitters and cables. Its modular architecture enables flexible test configurations, and built-in diagnostics help identify the root causes of signal degradation. This allows design teams to verify compliance and optimize performance early in development.

D9021HDMC product page 

N5992HPCD product page 

Keysight Technologies 

The post Software verifies HDMI 2.2 electrical compliance appeared first on EDN.

Microchip’s GNSS-disciplined oscillator (GNSSDO) modules integrate positioning, navigation, and timing (PNT) for mission-critical aerospace and defense applications. Built with the company’s chip-scale atomic clock, miniature atomic clock, and OCXOs, the compact modules are well-suited for systems that operate in GNSS-denied environments.

The modules process reference signals from a GNSS or an alternative clock source to discipline the onboard oscillator, ensuring precise timing, stability, and holdover operation. They can function as a PNT subsystem within a larger system or as a stand-alone unit.

All modules output 1-PPS TTL and 10-MHz sine wave signals, with distinct features for different use cases:

• MD-013 ULTRA CLEAN – Highest-performance design with multi-constellation GNSS support, ultra-low phase noise, and short-term stability; optional dual-band receiver upgrades.
• MD-300 – Rugged 1.5×2.5-in. module with MEMS OCXO or TCXO for low g-sensitivity, shock/vibration tolerance, and low thermal response; suited for drones and manpacks.
• LM-010 – PPS-disciplined module for LEO requiring radiation tolerance, stability, and holdover; built with a digitally corrected OCXO or low-power CSAC.

The GNSSDO modules are available in production quantities.

GNSSDO module product page 

Microchip Technology 

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Lumentum Holdings Inc of San Jose, CA, USA (which designs and makes optical and photonic products for optical networks and lasers for industrial and consumer markets) has announced the pricing of $1.1bn worth of convertible senior notes (due 2032) in a private placement to qualified institutional buyers (pursuant to Rule 144A under the Securities Act of 1933, as amended). The firm has also granted the initial purchasers a 13-day option to purchase up to an additional $165m of the notes...

The battery in my two-year-old first-gen Pixel Watch generally—unless I use GPS and/or LTE data services heavily—lasts 24 hours-plus until it hits the 15%-left Battery Saver threshold. And because sleep quality tracking is particularly important to me, I’ve more or less gotten in the habit of tossing it on the charger right before dinner, for maximum likelihood it’ll then robustly make it through the night. Inevitably, however, once (or more) every week or so, I forget about the charger-at-dinner bit and then, right when I’m planning on hitting the sack, find myself staring at a depleted watch that won’t make it until morning. First world problem. I know. Still…

Therein lies one (of several) of the key motivations behind my recent interest in the rapidly maturing smart ring product category. Such devices typically tout ~1 week (or more) of between-charges operating life, and they also recharge rapidly, courtesy of their diminutive integrated cells. A smart ring also affords flexibility regarding what watches (including traditional ones) I can then variously put on my wrist. And, as noted within my 2025 CES coverage:

This wearable health product category is admittedly more intriguing to me because unlike glasses (or watches, for that matter), rings are less obvious to others, therefore it’s less critical (IMHO, at least) for the wearer to perfectly match them with the rest of the ensemble…plus you have 10 options of where to wear one (that said, does anyone put a ring on their thumb?).

I’ve spent the last few months acquiring and testing smart rings from three leading companies: Oura (the Gen3 Horizon), Ultrahuman (the Ring AIR), and RingConn (the Gen 2). They’re left-to-right on my left-hand index finger in the following photo: that’s my wedding band on the ring finger . The results have been interesting, to say the least. I’ll save per-manufacturer and per-product specifics for follow-up write-ups to appear here in the coming months. For now, in the following sections, I’ll share some general comparisons that span multiple-to-all of them.

Judicial Jockeying

An important upfront note: back in April, I learned that Finland-based Oura (the product category’s volume shipment originator, and the current worldwide market leader) had successfully obtained a preliminary ruling from the United States ITC (International Trade Commission) that both China-based RingConn and India-based Ultrahuman had infringed on its patent portfolio. The final ITC judgement, released on Friday, August 22 (three days ago as I write these words) affirmed that earlier ruling, blocking (in coordination with U.S. Customs and Border Protection enforcement) further shipments of both RingConn and Ultrahuman products into the country and, more generally, further sales by either company after a further 60 day review period ending on October 21. There’s one qualifier, apparently: retailers are allowed to continue selling past that point until their warehouse inventories are depleted.

I haven’t seen a formal response yet from RingConn, but Ultrahuman clearly hasn’t given up the fight. It’s already countersued Oura in its home country, also reporting that the disputed patent, which it claims combines existing components in an obvious way that renders it invalid, is being reviewed by the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board.

We welcome the ITC’s recognition of consumer-protective exemptions and its rejection of attempts to block the access of U.S. consumers. Customers can continue purchasing and importing Ring AIR directly from us through October 21, 2025, and at retailers beyond this date.

What’s more, our software application and charging accessories remain fully available, after the Commission rejected Oura’s request to restrict them.

While we respectfully disagree with the Commission’s ruling on U.S. Patent No. 11,868,178, its validity is already under review by the USPTO’s Patent Trial and Appeal Board (PTAB) on the grounds of obviousness.

 Public reporting has raised questions about Oura’s business practices, and its reliance on litigation to limit competition.

We are moving forward with confidence — doubling down on compliance while accelerating development of a next-generation ring built on a fundamentally new architecture. As many observers recognize, restricting competition risks fewer choices, higher prices, and slower innovation.

Ultrahuman remains energized by the road ahead, committed to championing consumer choice and pushing the frontier of health technology.

One perhaps-obvious note: the ITC’s actions only affect sales in the United States, not elsewhere. This also isn’t the first time that the ITC has gotten involved in a wearables dispute. Apple Watch owners, for example, may be familiar with the multi-year, ongoing litigation between Apple and Masimo regarding blood oxygen monitoring. Also, more specific to today’s topic, Samsung pre-emptively filed a lawsuit against Oura prior to entering the market with its Galaxy Ring in mid-2024, citing Oura’s claimed litigious history and striving to ensure that Samsung’s product launch wouldn’t be jeopardized by patent infringement lawsuits from Oura.

The lawsuit was eventually dismissed in March, with the judge noting a lack of evidence that Oura ever intended to sue Samsung, but Samsung is now appealing that ruling. And as I noted in recent Google product launch event coverage, this same litigious environment may at least partly explain why both Google/Fitbit and Apple haven’t entered the market…yet, at least.

Sizing prep is essential

Before you buy a smart ring, whatever company’s device you end up selecting, I strongly advise you to first purchase a sizing kit and figure out what size you need on whatever finger you plan to wear it. Sizing varies finger-to-finger and hand-to-hand for every person, first and foremost. Not to mention that if the ring enhances your fitness, leading to weight loss, you’ll probably need to buy a smaller replacement ring eventually—the battery and embedded circuitry preclude the resizing that a jeweler historically would do—hold that thought.

Smart ring sizing can also vary not only from traditional ring measurements’ results, but also from company to company and model to model. My Oura and RingConn rings are both size 11, for example, whereas the Ultrahuman one is a size 10. Sizing kits are inexpensive…usually less than $10, with the purchase price often then applicable as credit against the subsequent smart ring price. And in the RingConn case, the kits are free from the manufacturer’s online store. A sizing kit is upfront money well spent, regardless of the modest-at-worst cost.

Charging options and sometimes-case enhancements

One key differentiator between manufacturers you’ll immediately run into involves charging schemes. Oura and Ultrahuman’s rings leverage close-proximity wireless inductive charging. Both the battery and the entirety of its charging circuitry, including the charging coil, are fully embedded within the ring. RingConn’s approach, conversely, involves magnetized (for proper auto-alignment)-connection contacts both on the ring itself and on the associated charger.

(Ultrahuman inductive charging)

(RingConn conventional contacts-based charging)

I’ve yet to come across any published pros-and-cons positioning on the two approaches, but I have theories. Charging speed doesn’t seem to be one of the factors. Second-gen-and-beyond Google Pixel Watches with physical contacts reportedly recharge faster than my wireless-based predecessor, especially after its firmware update-induced intentional slowdown. Conversely, I didn’t notice any statistically significant charge-speed variance between any of the smart rings I tested. Perhaps their diminutive battery capacities minimize any otherwise evident variances?

What about fluid-intrusion resistance? I could imagine that, in line with its usage with rechargeable electric toothbrushes operated in water exposure-prone environments:

inductive charging might make it possible, or at a minimum, easier from a design standpoint, to achieve higher IP (ingress protection) ratings for smart rings. Conversely, however, there’s a consumer cost-and-convenience factor that favors RingConn’s more traditional approach. I’ve acquired two chargers per smart ring I tested—one for upstairs at my desk, the other in the bathroom—the latter so I can give the ring a quick charge boost while I’m in the shower.

Were I to go down or (heaven forbid) up a size-or-few with an Oura or UltraHuman ring, my existing charger suite would also be rendered useless, since inductive charging requires a size-specific “mount”. RingConn’s approach, on the other hand (bad pun intended), is ring size-agnostic.

Speaking of RingConn, let’s talk about charging cases (and their absence in some cases). The company’s $199 Gen 2 “Air” model comes with the conventional charging dock shown earlier. Conversely, one of the added benefits (along with sleep apnea monitoring) of the $299 Gen 2 version is a battery-inclusive charging case, akin to those used by Bluetooth earbuds:

It’s particularly handy when traveling, since you don’t need to also pack a power cord and wall wart (conventional charger docks can also be purchased separately). Oura-compatible charging cases are, currently at least, only available from (unsanctioned-by-Oura, so use at your own risk) third parties and require a separate Oura-sourced dock.

And as for Ultrahuman, at least as far as I’ve found, there are only docks.

Internal and external form factors

In addition to the aforementioned charging circuitry, there is other integrated-electronics commonality between the various manufacturers’ offerings (leading to the aforementioned patent infringement claim—if you’re Oura—or “obviousness” claim—if you’re Ultrahuman). You’ll find multi-color status LEDs, for example, along with Bluetooth and/or NFC connectivity, accelerometers, body temperature monitoring, and pulse rate (green) and oximetry (red) plus infrared photoplethysmography sensors.

The finger is the preferable location for blood-related monitoring vs the wrist, actually (theoretically at least), thanks to higher comparative aggregate blood flow density. That said, however, sensor placement is particularly critical on the finger, as well as particularly difficult to achieve, due to the ring’s circular and easily rotated form factor.

Most smart rings are more or less round, for style reasons and akin to traditional non-electronic forebears, with some including flatter regions to guide the wearer in achieving ideal on-finger placement alignment. One extreme example is the Heritage version of the Oura Gen3 ring:

with a style-driven flatter frontside compared to its Gen3 Horizon sibling:

Interestingly, at least to me, Oura’s newest Ring 4 only comes in a fully round style:

as well as in an expanded suite of both color and size options, all specifically targeting a growing female audience, which Ultrahuman’s Rare line is also more obviously pursuing (I hadn’t realized this until my recent research, but the smart ring market was initially male-dominated):

The Ring 4 also touts new Smart Sensing technology with 18 optical signal paths (vs 8 in the Gen3) and a broader sensor array. I’m guessing that this enhancement was made in part to counterbalance the degraded-results effects of non-ideal finger placement. To wit, look at the ring interior and you’ll encounter another means by which manufacturers (Oura with the Gen3, as well as RingConn, shown here) include physical prompting to achieve and maintain proper placement: sensor-inclusive “bump” guides on both sides of the backside inside:

Some people apparently find them annoying, judging from Reddit commentary and reviews I’ve read, along with the fact that Ultrahuman rings’ interiors are smooth, as well as the comparable sensor retraction done by Oura on the Ring 4. The bumps don’t bother me (and others); in contrast, in fact, I appreciate their ongoing optimal-placement physical-guidance assistance.

Accuracy, or lack thereof

How did I test all these rings? Thanks for asking. At any point in time, I had one on each index finger, along with my Pixel Watch on my wrist (my middle fingers were also available, along with my right ring finger, but their narrower diameters led to loose fits that I feared would unfairly throw off measurement results).

I rotated through my three-ring inventory both intra- and inter-day, also repeatedly altering which hand’s index finger might have a given manufacturer’s device on it. And I kept ongoing data-point notes to supplement my oft-imperfect memory.

The good news? Cardio- and pulmonary-related data measurements, including sleep-cycle interpretations (which I realize also factor in the accelerometer; keep reading), seemed solid. In the absence of professional medical equipment to compare against, I have no way of knowing whether any of the output data sets (which needed to be viewed on the associated mobile apps, since unlike watches, these widgets don’t have built-in displays…duh…) were accurate. But the fact that they all at least roughly matched each other was reassuring in and of itself.

Step counting was a different matter, however. Two general trends became increasingly apparent as my testing and data collection continued:

• Smart ring step counts closely matched both each other and the Pixel Watch on weekends, but grossly overshot the smart watch’s numbers on weekdays, and
• During the week, whatever ring I had on my right hand’s index finger overshot the step-count numbers accumulated by its left-hand counterpart…consistently.

Before reading on, can you figure out what was going on? Don’t feel bad if you’re stumped; I thank my wife’s intellect (which, I might add, immediately discerned the root cause), not mine (sloth-like and, standalone, unsuccessful), for sorting out the situation. On the weekends, I do a better job of staying away from my computer keyboard; during the week, the smart rings’ accelerometers were counting key presses as steps. And I’m right-handed, therefore leading to additional right-hand movement (and phantom step counts) each time I accessed the trackpad.

By the way, each manufacturer’s app, with varying breadth, depth, and emphasis, not only reports raw data but also interpretations of stress level and the like by combining and analyzing multiple sensors’ outputs. To date, I’ve generally overlooked these additional results nuances, no matter that I’m sure I’d find the machinations of the underlying algorithms fascinating. More to come in the future; for now, with three rings tested, the raw data was overwhelming enough.

Battery life and broader reliability

As I dove into the smart ring product category, I kept coming across mentions of claimed differentiation between their “health” tracking and other wearables’ “fitness” tracking. It turns out that, as documented in at least some cases, smart rings aren’t continuously measuring and logging data coming from a portion of their sensor suites. I haven’t been able to find any info on this from RingConn, whose literature is in general comparatively deficient; I’d welcome reader direction toward published info to bolster my understanding here. That said, the company’s ring was the clear leader of the three, dropping only ~5% of charge per day (impressively translating to nearly 3 weeks of between-charges operating life until the battery is drained).

Oura’s rings only discern heart rate variability (HRV) during sleep (albeit logging the base heart rate more frequently), “to avoid the daytime ‘noise’ that can affect your data and make it harder to interpret”. Blood oxygen (SpO2) sensing also only happens while asleep (I took this photo right after waking up, right before the watch figured out I’d done so and shut off):

Selective, versus continuous, data measurement has likely obvious benefits when it comes to battery life. That said, my Oura ring’s (which, like its RingConn counterpart, I bought already lightly used; keep reading) battery level dropped by an average of ~15% per day.

And Ultrahuman? The first ring I acquired only lasted ~12 hours until drained, and took nearly a day to return to “full”, the apparent result of a firmware update gone awry (unrecoverable in this case, alas). To its credit, the company sent me a replacement ring (and told me to just keep the existing one; stay tuned for a future teardown!). At about that same time, Ultrahuman also added another Oura-reminiscent and battery life-extending operating mode called “Chill” to the app and ring settings, which it also made the default versus the prior-sole “Turbo”:

Chill Mode is designed to intelligently manage power while preserving the accuracy of your health data. It extends your Ring AIR battery life by up to 35% by tracking only what matters, when it matters. Chill Mode uses motion and context-based intelligence to track heart rate and temperature primarily during sleep and rest.

More generally, keep in mind that none of these devices are particularly inexpensive; the RingConn Gen 2 Air is most economical at $199, with the Oura Ring 4 the priciest mainstream option at between $349 and $499, depending on color (and discounting the up-to-$2,200 Ultrahuman Rare…ahem…). A smart ring that lasts a few years while retaining reasonable battery life across inevitable cycle-induced cell degradation is one thing. One that becomes essentially unusable after a few months is conversely problematic from a reputation standpoint.

Total cost, and other factors to consider

Keep in mind, too, that ongoing usage costs may significantly affect the total price you end up paying over a smart ring’s operating life. Ironically, RingConn is not only the least expensive option from an entry-cost standpoint but also over time; although the company offers optional extended warranty coverage for damage, theft, or loss, lifetime support of all health metrics is included at no extra charge.

On the other end of the spectrum is Oura; unless you pay $5.99/month or $69.99/year for a membership (first month free), “you’ll only be able to see your three daily Oura scores (Readiness, Activity, and Sleep), ring battery, basic profile information, app settings, and the Explore content.” Between these spectrum endpoints is Ultrahuman. Like RingConn, it offers extended warranties, this time including (to earlier comments) 2-year “Weight loss insurance”:

Achieved your weight loss goals? We’ll make resizing easy with a free Ultrahuman Ring AIR replacement, redeemable once during your UltrahumanX coverage period.

And, again, as with RingConn, although baseline data collection and reporting are lifetime-included, it also sells a suite of additional-function software plug-ins it calls PowerPlugs.

One final factor to consider, which I continue to find both surprising and baffling, is the fact that none of the three manufacturers I’ve mentioned here seems to support having more than one ring actively associated with an account, therefore, cloud-logging and archiving data, at the same time. To press a second ring into service, you need to manually delete the first one from your account first. The lack of multi-ring support is a frequent cause of complaints on Reddit on elsewhere, from folks who want to accessorize multiple smart rings just as they do with normal rings, varying color and style to match outfits and occasions. And the fiscal benefit to the manufacturers of such support is intuitively obvious, yes?

Looking back, having just crossed through 3,000 words, I’m sure glad I decided to split what was originally envisioned as a single write-up into a multi-post series I’ll try to get the RingConn and Ultrahuman pieces published ahead of that October 21 deadline, for U.S. readers that might want to take the purchase plunge before inventory disappears. And until then, I welcome your thoughts in the comments on what I’ve written thus far!

—Brian Dipert is the Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.

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The post The Smart Ring: Passing fad, or the next big health-monitoring thing? appeared first on EDN.

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Curious about how respiratory belt transducers work—or how to design one yourself? This quick guide walks you through the essentials, from sensing principles to circuit basics. Whether you are a hobbyist, student, or engineer exploring wearable health technology, you will find practical insights to kickstart your own design.

Belly breathing, also known as diaphragmatic or abdominal breathing, involves deep inhalation that expands the stomach and allows the lungs to fully inflate. This technique engages the diaphragm—a dome-shaped muscle at the base of the lungs—which contracts downward during inhalation to create space for lung expansion and relaxes upward during exhalation to push air out.

In contrast, chest breathing (also called thoracic or shallow breathing) relies on upper chest muscles and produces shorter, less efficient breaths, limiting oxygen intake and often contributing to stress and tension. Belly breathing has been shown to lower heart rate and blood pressure, promote relaxation, and improve overall respiratory efficiency.

What if you could measure your breathing motion, capture it in real time, and receive meaningful feedback? A respiratory belt transducer offers a simple and effective solution. It detects changes in chest or abdominal diameter during breathing and converts that movement into a voltage signal, which can be recorded and analyzed to assess breathing patterns, rate, and depth.

First off, note that while piezoelectric, inductive, capacitive, and strain gauge sensors are commonly used in respiratory monitoring, this post highlights more accessible alternatives, namely conductive rubber cords and stretch sensors. These materials offer a low-cost, flexible solution for detecting abdominal or chest expansion, making them ideal for DIY builds, classroom experiments, and basic biofeedback systems.

Figure 1 A generic 2-mm diameter conductive rubber cord stretch sensor kit that makes breathing belt assembly easier. Source: Author

As observed, the standard 2-mm conductive rubber cord commonly available in the hobby electronics market exhibits a resistance of approximately 140 to 160 ohms per centimeter. This capability makes it suitable for constructing a respiratory belt that generates a voltage in response to changes in thoracic or abdominal circumference during breathing.

Next, fabricate the transducer by securely bonding the flexible sensing element—the conductive rubber cord—to the inner surface of a suitably sized fabric belt. It should then be placed around the body at the level of maximum respiratory expansion.

A quick hint on design math: in its relaxed state, the conductive rubber cord (carbon-black impregnated) exhibits a resistance of approximately 140 ohms per centimeter. When stretched, the conductive particles disperse, increasing the resistance proportionally.

Once the force is removed, the rubber gradually returns to its original length, but not instantly. Full recovery may take a minute or two, depending on the material and conditions. You can typically stretch the cord to about 50–70% beyond its original length, but it must stay within that range to avoid damage. For example, a 15-cm piece should not be stretched beyond 25–26 cm.

Keep in mind, this conductive rubber cord stretch sensor does not behave in a perfectly linear way. Its resistance can change from one batch to another, so it’s best used to sense stretching motion in a general way, not for exact measurements.

To ensure accurate signal interpretation, a custom electronic circuitry with a sensible response to changes in cord length is essential; otherwise, the data will not hold water. The output connector on the adapter electronics should provide a directly proportional voltage to the extent of stretch in the sensing element.

Frankly, this post doesn’t delve into the mechanical construction of the respiratory belt transducer, although conductive rubber cords are relatively easy to use in a circuit. However, they can be a bit tricky to attach to things, both mechanically and electrically.

The following diagram illustrates the proposed front-end electronics for the resistive stretch sensor (definitely not the final look). Optimized through voltage scaling and linearization, the setup yields an analog output suitable for most microcontroller ADCs.

Figure 2 The proposed sensor front-end circuitry reveals a simplistic analog approach. Source: Author

So, now you have the blueprint for a respiratory belt transducer, commonly known as a breathing belt. It incorporates a resistive stretch sensor to detect changes in chest or abdominal expansion during breathing. As the belt stretches, the system produces an analog output voltage that varies within a defined range. This voltage is approximately proportional to the amount of stretch, providing a continuous signal that mirrors the breathing pattern.

Quick detour: A ratiometric output refers to a sensor output voltage that varies in proportion to its supply voltage. In other words, the output signal scales with the supply itself, so any change in supply voltage results in a corresponding change in output. This behavior is common in unamplified sensors, where the output is typically expressed as a percentage of the supply voltage.

Before wrapping up, I just came across another resistive change type strain sensor worth mentioning: GummiStra from Yamaha. It’s a rubber-like, stretchable sensor capable of detecting a wide range of small to large strains (up to twice in length), both statically and dynamically. You can explore its capabilities in detail through Yamaha’s technology page.

Figure 3 GummiStra unlocks new use cases for resistive stretch sensing across wearables, robotics, and structural health monitoring. Source: Yamaha

We will leave it there for the moment. Got your own twist on respiratory belt transducer design? Share your ideas or questions in the comments.

T. K. Hareendran is a self-taught electronics enthusiast with a strong passion for innovative circuit design and hands-on technology. He develops both experimental and practical electronic projects, documenting and sharing his work to support fellow tinkerers and learners. Beyond the workbench, he dedicates time to technical writing and hardware evaluations to contribute meaningfully to the maker community.

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The post A design guide for respiratory belt transducers appeared first on EDN.

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