How Wearable Optical Sensors Measure Heart Rate and SpO₂
Why wearables use green light for pulse tracking and red and infrared light for oxygen-saturation estimates—and what the photodiode actually measures.
Technical insights on optical sensing, power electronics, EMC, astronomy instrumentation, and product verification.
Why wearables use green light for pulse tracking and red and infrared light for oxygen-saturation estimates—and what the photodiode actually measures.
How near-infrared light can help estimate fruit quality without cutting the fruit open—and why wavelength selection, calibration and signal quality matter in the field.
Why many small conductive cells can preserve airflow while improving electromagnetic shielding performance.
Anyone working in the field of power electronics will eventually encounter terms such as Qg, QGD, Ciss, Crss, Miller Plateau, dv/dt, and Gate Drivers. Although these parameters are included in almost...
When we look at images captured by large telescopes, the universe often appears to be filled with almost mythical colors. Red nebulae, blue clouds of gas, golden star clusters, and galaxies billions...
Recently, while observing the night sky with my amateur telescope, I noticed something interesting.
The starting point of this article was actually a rather ordinary problem.
A simulation-based comparison of active peak detectors, examining pulse tracking, hold-capacitor reset, amplitude error, and the limits of conventional and modified LTC6244-based circuits.
In mixed-signal PCB design, the coexistence of analog and digital circuits on the same board presents significant challenges related to electromagnetic interference (EMI). Analog circuits typically...
When we look at the sky, stars appear merely as bright points. However, in astronomy, the fundamental objective is not simply to see these points, but to resolve their physical structure.
This article is a continuation of the Optical Sensing System Design – Optical Elements – Prisms series. Retroreflectors based on prism geometry are optical components that redirect incident light...
This article is part of the Optical Sensing System Design – Optical Elements series and focuses on prisms that guide and separate light. In optics, separation is a well-defined and necessary process...
I initially planned this article under the title Optical Sensing System Design – Optical Elements, aiming to cover all optical elements within a single framework. As the writing progressed, it became...
The first article in the expanded Optical Elements section, covering lens terminology, lens types, aberrations, and collimation.
At the beginning of 2026, I am starting with a topic that I have wanted to write about for a long time. In order to maintain continuity in the subject, it will be beneficial to review my articles...
In shielded cables, the conductors are surrounded by a braided and/or foil layer. This layer:
What made the 300 Spartans powerful at Thermopylae was not individual courage, but the perfect continuity of shields raised side by side. There was also Ephialtes in the story; his body was hunched...
Learn how Directive 2014/35/EU defines electrical safety, how harmonised standards work, and how manufacturers demonstrate LVD conformity.
This article is the second part of our three-part series: “Preparing a Product for the Market: CE, EMC and LVD Testing & Certification Guide.”
When you step into the world of optical sensing, you are greeted by an infinite universe of colors and wavelengths. In the previous section, we embarked on a long journey through this universe...
The foundations of optical sensing, from light–matter interactions to wavelength selection, and the updated reading order for the series.
A practical engineering roadmap for identifying EU product legislation, selecting standards, planning tests, building technical documentation, and applying the CE marking.
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