Новини світу мікро- та наноелектроніки

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My longstanding streak of not being infected by COVID-19 (knowingly, at least…there’s always the asymptomatic possibility) came to an end earlier this year, alas, doubly-unfortunately timed to coincide with the July 4th holiday weekend:

I’m guessing I caught one of the latest FLiRT variants, which are reportedly adept at evading vaccines (I’m fully boosted through the fall 2023 sequence). Thankfully, my discomfort was modest, at its worst lasting only a few days, and I was testing negative again within a week:

although several weeks later I still sometimes feel like I’ve got razor blades stuck in my throat.

One upside, for lack of a better word, to my health setback is that it finally prompted me to put into motion a longstanding plan to do a few pandemic-themed teardowns. Today’s victim, for example, is a pulse oximeter which I’d actually bought from an eBay seller (listed as a “FDA Finger tip Pulse Oximeter Blood Oxygen meter O2 SpO2 Heart Rate Monitor US”) a year prior to COVID-19’s surge, in late April 2019, for $11.49 as a sleep apnea monitoring aid. A year later, on the other hand…well, I’ll just quote from a writeup published by Yale Medicine in May 2020:

According to Consumer Reports, prices for pulse oximeters range from $25 to $100, if you can find one, as shortages have been reported.

This unit, a Volmate VOL60A, recently began acting wonky, sometimes not delivering definitive results at all and other times displaying data that I knew undershot reality. So, since prices have retracted to normalcy ($5 with free shipping, in this particular case, believe it or not), I’ve replaced it. Therein today’s dissection, which I’ll as-usual kick off with a series of box shots:

Let’s dive inside. The plastic tray houses our patient alongside a nifty protective case:

Underneath the tray is some literature:

The user manual is surprisingly (at least to me) quite info-thorough and informative, but I can’t find it online (the manufacturer seems to no longer be in business, judging from the “dead” website), so I’ve scanned and converted it to PDF. You can access it here. 

And there’s one more sliver of paper under the case (which also contains a lanyard):

Here’s the guest of honor, as usual alongside a 0.75″ (19.1 mm) diameter U.S. penny for size comparison purposes (the VOL60A has dimensions of 62 x 35 x 31 mm and weighs 60 g including batteries):

Before cracking the unit open, and speaking of batteries, I thought I’d pop a couple of AAAs in it so you can see it in action. Here’s the sequence-of-two powerup display cadence, initiated by a press of the grey button at the bottom:

Unless a finger is preinserted in the pulse oximeter prior to powerup, the display (and broader device) will go back to sleep after a couple of seconds. Conversely, with a finger already in place:

As you can see, it measures both oxygen saturation (SpO2), displayed at the top, and pulse rate below. Good news: my actual oxygen saturation is not as low as the displayed 75%, which had it been true would have me in the hospital if not (shortly thereafter) the morgue. Bad news: my actual resting pulse rate is not as low as 28 bpm, which if true would mean I was very fit (not to mention at lower elevation than my usual 7,500’ residence location)…or conversely, I suppose, might also have me in the hospital if not (shortly thereafter) the morgue. Like I said, this unit is now acting wonky, sometimes (like this time) displaying data that I know undershoots reality.

Let’s next flip it over on its back:

The removable battery “door” is obvious. But what I want to focus in on are the labels, particularly the diminutive bright yellow one:

Here’s what it says:

AVOID EXPOSURE

LASER RADIATION IS EMITTED FROM THIS APERTURE

LED Wavelengths

	Wavelength	Radiant Power
Red	660 ± 2nm	1.5 mW
IR	940 ± 10nm	2.0 mW

I showcase this label because it conveniently gives me an excuse to briefly detour for a quick tutorial on how pulse oximeters work. This particular unit is an example of the most common technique, known as transmissive pulse oximetry. In this approach, quoting Wikipedia:

One side of a thin part of the patient’s body, usually a fingertip or earlobe, is illuminated, and the photodetector is on the other side…other convenient sites include an infant’s foot or an unconscious patient’s cheek or tongue.

The “illumination” mentioned in the quote is dual frequency in nature, as the label suggests:

More from Wikipedia:

Absorption of light at these wavelengths differs significantly between blood loaded with oxygen and blood lacking oxygen. Oxygenated hemoglobin absorbs more infrared light and allows more red light to pass through. Deoxygenated hemoglobin allows more infrared light to pass through and absorbs more red light. The LEDs sequence through their cycle of one on, then the other, then both off about thirty times per second which allows the photodiode to respond to the red and infrared light separately and also adjust for the ambient light baseline.

Here’s what the dual-LED emitter structure looks like in action in the VOL60A; perhaps obviously, the IR transmitter isn’t visible to the naked eye (and my smartphone’s camera also unsurprisingly apparently has an IR filter ahead of the image sensor):

Note that in this design implementation, the LEDs are on the bottom half of the pulse oximeter, with their illumination shining upward through the fingertip and exiting via the fingernail to the photodetector above it. This is different than the conceptual image shown earlier from Wikipedia, which locates the LEDs at the top and the photodetector at the bottom (and ironically matches the locations shown in the conceptual image in the VOL60A user manual!).

Note, too, that the Wikipedia diagram shows a common photodetector for both LED transmitters. I’ll shortly show you the photodetector in this design, which I believe has an identical structure. That said, other conceptual diagrams, such as the one shown here:

have two photodetectors (called “sensors” in this case), one for each LED (IR and red).

In the interest of wordcount efficiency, I won’t dive deep into the background theory and implementation arithmetic that enable the pulse oximeter to ascertain both oxygen saturation and pulse rate. If you’d like to follow in my research footsteps, Google searches on terms and phrases such as pulse oximeter, pulse oximetry and pulse oximeter operation will likely prove fruitful. In addition to the earlier mentioned Wikipedia entry, two other resources I can also specifically recommend come from the University of Iowa and How Equipment Works.

What I will say a few more words about involves the inherent variability of a pulse oximeter’s results and the root causes of this inconsistency, as well as what might have gone awry with my particular unit. These root-cause variables include amount and density of both fat, muscle, skin and bone in the finger, any callouses or scarring of the fingertip, whether the user is unduly cold at the time of device operation, and the amount and composition of any fingernail polish. While, as Wikipedia notes:

Taking advantage of the pulsate flow of arterial blood, it [the pulse oximeter] measures the change in absorbance over the course of a cardiac cycle, allowing it to determine the absorbance due to arterial blood alone, excluding unchanging absorbance [due to the above variables].

Those sample-to-sample unchanging variables can still affect the baseline measurement assumptions, therefore the broader finger-to-finger, user-to-user, and test-to-test results.

And in my particular case, while I don’t think anything went wonky with the arithmetic done on the sensed data, the data itself is suspect in my mind. Note, for example, that oxygenated blood assessment is disproportionately reliant on successful passage of red visible spectrum light. If the red LED has gone dim for some reason, if its transmission frequency has wandered from its original 660 nm center point, and/or if the photosensor is no longer as sensitive to red light as it once was, the pulse oximeter would then deliver lower-than-accurate oxygen saturation results.

Tutorial over, let’s get back to tearing down. Here are left- and right-side views, both with the front and back halves of the device “closed”:

and “open”, i.e., expanded as would be the case when the finger is inserted in-between them:

What I’m about to say might shock my fellow electrical engineers reading these words, but frankly one of the most intriguing aspects of this design (maybe the most) is mechanical in nature; the robust hinge-and-spring structure at the top, supporting both linear expansion and pivot rotation, that dynamically adapts to both finger insertion and removal and various finger dimensions while still firmly clinging to the finger during measurement cycles. You can see more of its capabilities in these top views; note, too, the flex cable interconnecting the two halves:

And, last but not least, here’s a bottom-end perspective of the device:

Accessing the backside battery compartment reveals two tempting screw candidates:

You know what comes next, right?

A couple of retaining tabs also still need to be “popped”:

And voila, our first disassembly step is complete:

As you’ll see, I’ve already begun to displace the slim PCB in the center from its surroundings:

Let’s next finish the job:

This closeup showcases the two transmission LEDs, one red and the other IR and with the cluster protected from the elements by a clear plastic rectangular structure, that shine through the back-half “window” shown in the previous shot and onto the user’s fingertip underside:

Chronologically jumping ahead briefly, here’s a post-teardown re-enactment of what it looks like temporarily back in place (and this time not illuminated):

And here’s another view of that flex PCB, which (perhaps obviously) routes both power and the LEDs’ output signals to (presumably) processing circuitry in the pulse oximeter’s front half:

Speaking of which, let’s try getting inside that front half next. In previous photos, you may have already noticed two holes at the top of the device, along with one toward the top on each side. They’re for, I believe, passive ventilation purposes, to remove heat generated by internal circuitry. But there are two more, this time with visible screw heads within them, potentially providing a pathway to the front-half insides:

Yep, you guessed it:

Again, the spudger comes through in helping complete the task:

The display dominates the landscape on this half of the PCB, along with the switch at bottom:

But I bet you already saw the two screws at the bottom, on either side of the switch, right?

With them removed, we can lift the PCB away from the chassis, exposing its back for inspection:

The large IC at the top (bottom of the PCB when installed) is the STMicroelectronics-supplied system “brains”. Specifically, it’s a STM32F100C8T6B Arm Cortex-M3-based microcontroller also containing 32 KBytes of integrated flash memory. And below it, in the center, is the three-lead photosensor, surrounded by translucent plastic seemingly for both protective and lens-focusing functions. In the previous photo, you’ll see the plastic “window” in the chassis that it normally mates with. And, in closing, here’s another after-the-fact re-assembly reenactment:

Note, too, the “felt” lining this upper-half time, presumably to preclude nail polish damage? Your thoughts on this or anything else in this piece are as-always welcome in the comments!

—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.

 Related Content

• Learning and working in the era of COVID-19
• Simple pulse oximetry for wearable monitor
• Pulse oximetry basics and MCUs
• Signal processing and calibration improve blood measurements
• Pulse oximetry benefits from the latest programmable SoCs
• Teardown: Inside the art of pulse oximetry

The post Peering inside a Pulse Oximeter appeared first on EDN.

Following its recent relocation to larger premises (supporting ongoing growth and expanding operations), Sheffield University spin-off Phlux Technology —which designs and manufactures 1550nm avalanche photodiode (APD) infrared sensors — has appointed Christian Rookes as VP of marketing, Brian Williams as VP of operations, and John Fuller as director of engineering...

• Solution identifies subtle defects such as wire sag, near shorts, and stray wires for comprehensive assessment of wire bond integrity
• Advanced capacitive-based test methodology enables superior defect detection
• Test platform is high volume manufacturing ready, capable of testing 20 integrated circuits simultaneously for throughput of up to 72,000 units per hour

INDIA – Keysight Technologies, Inc. introduces the Electrical Structural Tester (EST), a wire bond inspection solution for semiconductor manufacturing that ensures the integrity and reliability of electronic components.

The semiconductor industry is faced with testing challenges due to the increasing density of chips in mission-critical applications such as medical devices and automotive systems. Current testing methodologies often fall short in detecting wire bond structural defects, which lead to costly latent failures. In addition, traditional testing approaches frequently rely on sampling techniques that do not adequately identify wire bond structural defects.

The EST addresses these testing challenges by using cutting-edge nano Vectorless Test Enhanced Performance (nVTEP) technology to create a capacitive structure between the wire bond and a sensor plate. Using this method the EST can identify subtle defects such as wire sag, near shorts, and stray wires to enable comprehensive assessment of wire bond integrity.

Key benefits of the EST include:

• Advanced defect detection – Identifies a wide range of wire bond defects, both electrical and non-electrical, by analyzing changes in capacitive coupling patterns to ensure the functionality and reliability of electronic components.
• High volume manufacturing ready – Enables throughput of up to 72,000 units per hour through the ability to test up to 20 integrated circuits simultaneously, which boosts productivity and efficiency in high-volume production environments.
• Big data analytics integration: Captures defects and enhances yield through advanced methods like marginal retry test (MaRT), dynamic part averaging test (DPAT), and real-time part averaging test (RPAT).

Carol Leh, Vice President, Electronic Industrial Solutions Group Center of Excellence, Keysight, said: “Keysight is dedicated to pioneering innovative solutions that address the most pressing challenges in the wire bonding process. The Electrical Structural Tester empowers chip manufacturers to enhance production efficiency by rapidly identifying wire bond defects, ensuring superior quality and reliability in high-volume manufacturing.”

The post Keysight Unveils Wire Bond Inspection Solution for Semiconductor Manufacturing appeared first on ELE Times.

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LED product and lighting maker Lumileds LLC of San Jose, CA, USA says that, in the past few years, it has realized significant external quantum efficiency (EQE) performance for micro-LEDs. However, for micro-LEDs, and display applications in particular, EQE on its own is not a sufficient measure of performance...

Author: STMicroelectronics

With the global spotlight on sports these days, it is almost impossible to overlook the technological innovations like the MEMS (Micro-Electro-Mechanical Systems) sensors. Embedded in wearable technology like smartwatches and fitness trackers, MEMS sensors facilitate athletic performance monitoring and enhancement. From everyday training to major sports events, these tiny yet powerful sensors help monitor progress and receive real-time feedback.

Precision in athletics and cycling

In the world of athletics, every millisecond and centimeter matters. Consider an athlete preparing for a high jump and representing their country at an international level. They are constantly seeking ways to perfect their jumping techniques. With each leap, MEMS sensors embedded in their sportswear ensure precise data capturing on jump height and distance and the real-time feedback will help athletes make immediate adjustments – optimizing form and technique.

Cyclists rely heavily on maintaining optimal cadence and power output to ensure peak performance. Thanks to MEMS sensors, they can optimize their pedaling efficiency and power distribution. The data collected by these sensors facilitates real-time adjustments, leading to not only improved performance but also providing a competitive edge.

How MEMS sensor technology works

ST is at the forefront of MEMS sensor Technology, integrating micro-electro-mechanical systems with electronic circuits and enabling the measurement of various physical parameters such as acceleration, angular velocity, orientation, pressure and more. For example, an accelerometer calculates the velocity, measures the rate of change of velocity in an object, and detects specific gestures and tracks body movements, providing athletes with precise and reliable data.

Optimizing training in swimming and racket sports

Efficient turns can make all the difference in competitive swimming. Precise depth measurements are crucial for underwater challenges and MEMS sensors have made a substantial impact in this area. For example, the ST waterproof pressure sensor can provide real-time data on turns and depth, helping swimmers optimize their performance and efficiency in the water.

Indeed, with MEMS sensors embedded in their sportswear or goggles, the swimmer can monitor their performance during training sessions. Moreover, using this data, coaches can adjust the training regimen, empowering their swimmers to perform their best, resulting in improved performance and a competitive edge in the pool or open water.

In racket sports like tennis, padel and baseball, the speed and accuracy of strokes are key. MEMS sensors embedded in rackets or bats provide detailed data on gestures and impact, helping athletes make immediate adjustments and improve their strokes. If you want to learn more about the latest advancements in performance monitoring, read the article on MEMS sensors that vastly Improve the performance-per-watt ratio.

Real-time feedback in football and adaptive training

For contact sports like football, impact monitoring is crucial for both player safety and performance, as well as tracking the ball’s speed and spin rate while in the air. High-g accelerometer MEMS sensors embedded in helmets, capture detailed impact data while meticulous smart ball tracking enhances the viewing experience for football fans.

In addition, they provide valuable insights into the force and direction of collisions that in turn help coaches and medical staff monitor the safety of the players. It also enables informed decision-making around training and gameplay. For instance, if a player experiences significant impact, the data can prompt immediate medical evaluation, thus ensuring the player’s well-being.

The versatility of MEMS sensors extends to a wide range of sports. Whether it is cyclists adjusting their cadence, swimmers refining their turns or tennis players perfecting their swing, MEMS sensors, including motion sensors such as Inertial Measurement Units (IMU) provide the real-time data needed to make immediate improvements and, over time, achieve better results and a competitive edge.

MEMS sensors embedded in wearable technology are undeniably transforming the landscape of competitive sports. They provide precise performance monitoring and optimize training routines with real-time feedback. As technology continues to advance, the role of MEMS sensors in enhancing athletic performance will only become more significant, paving the way for future generations of athletes.

The post From basic training to world-class competitions: MEMS sensors in wearable technology enhance athletic performance appeared first on ELE Times.

When we think of space exploration, the focus often gravitates toward massive rockets, sophisticated spacecrafts, and the captivating images they send back to Earth. However, the unsung heroes in these endeavors are the critical components ensuring that every part of these complex systems communicates effectively. One of the most critical components enabling this communication is connectors.

From the Artemis program’s monumental lunar missions to the revolutionary insights of the James Webb Space Telescope, the success of these missions hinges not just on the large-scale engineering feats but also on the reliability and performance of connectors. These ubiquitous components face the extreme conditions of space and are pivotal in every step, from the rigors of launch to the harsh environment of outer space.

Space Exploration Ascending

Space exploration, both by government organizations and commercial ventures, is very much in the news. One of the most extensive programs in recent space history is the Artemis program, which will see humans return to the Moon. The Space Launch System (SLS) completed its first successful test mission in December of 2022 and forms the largest component of the program. However, the latest steps in our return to the Moon are not the only exciting initiatives in space.

While these high-profile events capture the public’s imagination, they represent just a small part of the picture. Exploration and exploitation of space are everyday activities. More than 200 space launches were made in 2023 alone, carrying science missions and satellites into orbit and beyond.

The Extreme Conditions of Space

Even though spaceflight has become more common, the conditions in which these systems must perform are unlike any other. Space represents possibly the single most demanding environment known to engineering. Any equipment used in spaceflight is exposed to a range of extremes, from high and low temperatures and harsh radiation to the severities of the launch process and the vacuum of space.

The lack of atmosphere in space is incredibly unforgiving. On Earth, our atmosphere is a protective blanket that provides pressure, thermal insulation, and safety from harmful radiation. This protection is stripped away in space, exposing equipment to potential damage.

Without the atmosphere to protect it, an object in space receives the full force of the sun’s radiation. When equipment is bombarded by direct sunlight, its temperature can quickly become dangerously high. In contrast, the parts of a spacecraft that remain in shadow are very cold. These temperature extremes, must be considered when selecting the materials to use aboard space vehicles. Other radiation sources, including galactic cosmic rays, are highly ionizing and can harm delicate instruments or sophisticated electronic circuits.

Choosing the Right Materials for Spaceflight

The lack of atmospheric pressure also causes materials to behave in unique ways. Components employed for spaceflight can face an array of challenges that affect performance. Outgassing is when a gas trapped inside another material is released. This is a common problem when plastic is exposed to a vacuum during spaceflight, but it is not limited to plastics alone. Some metals, including zinc and cadmium, are also prone to sublimation in vacuum conditions, both of which are commonly used in conventional equipment design.

In both cases, the gas that is released can cause damage. It may condense onto cold surfaces such as the optics and sensors of scientific equipment, which can degrade or even negate their effectiveness and put the entire mission at risk. NASA and the European Space Agency (ESA) have recommended volume levels of outgassing for materials used in their space applications. These recommendations play a key role in selecting components for spaceflight.

Components also need to be mechanically robust, as launching satellites, probes, and spacecrafts into orbit exposes them to acceleration and vibration that can cause damage that might be undiscovered for months or years. As such, plastic components need to be manufactured using materials that exhibit high stability, even in vacuum conditions.

To provide solutions for these demanding conditions, connectors designed for spaceflight must be amongst the most advanced in the industry. Manufactured to stringent standards and tested to prove their performance even in the vacuum of space, they are the very definition of high-reliability connectors.

Engineered for Maximum Endurance

If the spaceflight environment is not challenging enough, there is one additional aspect that contributes to the difficulties of designing for spaceflight: endurance. Whether intended for commercial or scientific purposes, space missions can last for years. If a piece of equipment fails, gaining access to fix the problem is essentially impossible. In these circumstances, designers and engineers depend on the reliability of each component that makes up the equipment, no matter how small.

Endurance also plays a crucial role in power planning. A long-range probe operates on a stringent power budget, and any component that introduces unwanted electrical resistance will risk jeopardizing the mission. The electrical terminals of connectors designed for space applications are made from high-performance materials and coated with a thick layer of gold, ensuring minimal electrical resistance to reduce power loss.

Contacts with low electrical resistance provide additional benefits beyond power planning. The instruments on space probes take highly precise measurements, and the currents generated by these sensors can be extremely small. For these tiny currents, low contact resistance is crucial to maximize the likelihood of detecting critical signals.

With endurance in mind, connectors designed for spaceflight applications use materials that provide the best possible performance by reducing interference. Manufacturers must ensure that the magnetic signature of any component is minimized to prevent interference with precision scientific experiments. The connector shell also protects against electromagnetic interference (EMI). Vehicles that must traverse the vacuum of space are unprotected against solar radiation, which can interfere with scientific observations and damage sensitive instruments. This is another reason why the shells of spaceflight connectors are gold-plated, which provides the highest possible protection against EMI in these circumstances.

Mission-Critical Connector Engineering

Connectors play an often-overlooked role in spaceflight applications. Space vehicles are typically manufactured from sub-assemblies, which are brought together before launch. Connectors provide the vital interface between each system during the extensive testing regime before launch and the demanding conditions in space. Spaceflight connectors are designed according to some of the highest standards in the interconnection industry and, as a result, represent some of the most capable products available today.

David Pike

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