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The hottest Substack posts of CalculatedRisk Newsletter

And their main takeaways

Conway's Game of Life, in real life

7958 implied HN points • 19 Mar 26
🕹 Technology Embedded Hardware Electronics Firmware Microcontrollers DIY
  1. A physical Game of Life was built as a 17×17 grid of illuminated mechanical switches driven by an AVR microcontroller, using row/column multiplexing and transistor drivers to handle the LEDs.
  2. Row scanning gives each LED a low duty cycle, so the design uses high peak currents, series resistors, MOSFETs/P-channel transistors, and firmware safeguards like a blackout window and watchdog to avoid thermal or software-induced damage.
  3. Mechanical switches provide a tactile, editable playfield with an analog speed knob, but they are the main cost driver; cheaper or fancier options (touchscreens, flip-dots) trade off price, feel, and complexity.

How much of HN is AI?

4081 implied HN points • 12 Mar 26
🕹 Technology Artificial Intelligence Machine Learning Online Communities Content Moderation Tech news Social media
  1. Hacker News front page in February 2026 was heavily dominated by AI-related stories, with AI often occupying most of the top-five slots on many days.
  2. A conservative AI detector (Pangram) flagged many of those stories as likely written by LLMs, and manual review generally agreed even though the tool had a few false negatives.
  3. Much of the AI coverage is vendor-focused or marketing, and the quasi-deterministic default style of current LLMs makes their writing detectable and is reshaping the site’s conversations.

It's all a blur

11631 implied HN points • 06 Feb 26
🕹 Technology Image Processing Computer Vision Algorithms Security Privacy Signal Processing Compression
  1. Averaging-based blurs are linear and often reversible, so knowing the filter and padding lets you set up simple equations to recover original pixels.
  2. A right-aligned moving average makes iterative reconstruction straightforward and can reveal fine detail even with large blur windows, though 8-bit quantization adds visible noise.
  3. Two-pass (X then Y) blurs can still be inverted if the filter biases the current pixel, and recovered images can survive normal lossy formats like JPEG unless compression is very heavy.

Approximation game

2244 implied HN points • 28 Feb 26
🔬 Science Mathematics Number Theory
  1. Simple rational numbers (like p/q) have only a few very-close different fractions with small denominators; once denominators reach q or larger you can’t get new inexact approximations that beat the 1/b^2 error threshold.
  2. Irrational numbers, by contrast, admit infinitely many surprisingly accurate rational approximations; Dirichlet’s pigeonhole argument guarantees infinitely many fractions a/b with error on the order of 1/b^2 (for example 22/7 and 355/113 for π).
  3. Intuitively, rationals form a uniform grid so their gaps limit how close other fractions can get, while irrationals sit inside those gaps and repeated multiples plus the pigeonhole principle produce arbitrarily close rational hits, which is the essence of Diophantine approximation.

Unreal numbers

4489 implied HN points • 15 Feb 26
🔬 Science Mathematics Logic Set Theory Computation Foundations Philosophy
  1. Natural numbers can be built from a base element (zero) and a successor rule, and addition and multiplication follow from simple recursive definitions.
  2. Integers and rationals are formed by ordered pairs and equivalence classes so subtraction and division have in-system representations, and these extended sets remain countable.
  3. Computable numbers are those a Turing machine can approximate and are still countable, but the real numbers are uncountable (by diagonalization), so most reals cannot be computed.
Get a weekly roundup of the best Substack posts, by hacker news affinity:

The toil of (blog) art

11019 implied HN points • 18 Jan 26
🎨 Art & Illustration Illustration Graphic design Photography 3D Modeling Software Tools Workflow
  1. Illustrations often take the most work in a technical blog and can require as much or more time than writing the text.
  2. Building a simple, consistent workflow and a reusable library of elements (scale, line thickness, fonts, colors) makes creating clear technical diagrams much faster and keeps a coherent style.
  3. Use the right tools for the job — photography, CAD, Excalidraw, Affinity — and apply deliberate visual tricks like shadows, outlines, and afterimages to imply depth, motion, or emphasis in 2D illustrations.

You gotta think outside the hypercube

5101 implied HN points • 26 Jan 26
🕹 Technology Computer Graphics Visualization Geometry Mathematics Rendering Algorithms
  1. You can build a tesseract wireframe by extending the same edge-construction rules from a square to a cube and then to 4D, which yields 16 vertices and 32 edges.
  2. Rotations in four dimensions are still planar operations that act on pairs of axes, so animations come from applying familiar 2D rotation formulas to axis pairs like XZ or Z🌀.
  3. There are many ways to project 4D to 2D with different tradeoffs—cavalier, cabinet, isometric, perspective, and fisheye—and a mixed approach (isometric for XYZ plus perspective or fisheye for the fourth axis) gives the clearest, most informative views.

See it with your lying ears

6938 implied HN points • 10 Jan 26
🕹 Technology Signal Processing Audio Processing Image Processing Programming Algorithms
  1. Images and audio are both sampled data so you can apply similar transforms to both, but ears and eyes perceive artifacts very differently so the same operation can look fine and sound awful.
  2. Pixelating or reducing bit depth in audio creates stair-step or high-frequency errors that produce metallic squeals or hiss, and those artifacts are typically removed with lowpass/rolling-average filtering or proper DAC anti-aliasing.
  3. Frequency-domain editing works well if you process short, overlapping windows with a Hann (sin^2) weighting and 50% overlap so the attenuations cancel out, avoiding clicks and enabling effects like pitch shifting and vocoding.

When it comes to writing, LLMs have won

8978 implied HN points • 13 Nov 25
🕹 Technology AI Ethics Content creation Writing tools Automation
  1. Many writers notice that content from AI tools can feel similar because AI has a default style and uses common patterns, making it tricky to tell apart from human writing.
  2. To spot AI-generated text, look for unusual patterns in style or ask why the article was written. If it seems vague or has no specific point, it might be AI.
  3. People might not care about the
  4. effort behind writing anymore and see AI tools as a quick way to produce content, but it's important to ensure the writing still has a meaningful goal.

It's hard to build an oscillator

7958 implied HN points • 21 Nov 25
🕹 Technology Electronics Engineering Circuits Signal Processing
  1. Building a reliable oscillator is tough because it needs gain to work. Without gain, any oscillation will die out quickly.
  2. Using a Schmitt trigger can help create an oscillator with no stable midpoint. This means the circuit will keep switching back and forth, creating consistent oscillations.
  3. Different methods exist to build oscillators, like using op-amps or creating resonance with phase shifts. Each has its own way of generating oscillation, but they all need a careful balance of components.

Cursed circuits #4: PLL frequency multiplier

4081 implied HN points • 26 Dec 25
🕹 Technology Electronics Digital Design Signal Processing Hardware
  1. Latches and clocked D flip-flops store single bits and let signals be sampled on clock edges, providing the basic timing building blocks for digital circuits.
  2. A digital phase detector uses flip-flops to see which clock edge arrives first and produces pulses that indicate whether a tested clock is running too fast or too slow.
  3. A PLL closes the loop by using that detector to steer a VCO, and by inserting a divider in the feedback the VCO will lock at an integer multiple of the reference frequency, turning a low-frequency clock into a higher-frequency, phase-aligned clock.

Cursed circuits #3: true mathematics

3877 implied HN points • 22 Dec 25
🕹 Technology Electronics Circuit Design Signal Processing Semiconductors
  1. An op-amp simply amplifies the voltage difference between its inputs by a huge factor, and with feedback you force its inputs to be nearly equal so passive parts (resistors, diodes, caps) can be arranged to perform math instead of just gain.
  2. Addition and subtraction are straightforward: resistor networks can average or sum signals and a non‑inverting amplifier scales them to produce a true sum, while difference amplifiers give Vout ≈ VA − VB and can be biased to work on a single supply.
  3. Harder operations are possible too: multiplication/division can be done with log/antilog converters that use the diode’s exponential V–I curve plus a summing stage, and integration is implemented by charging a capacitor with a controlled current to produce precise ramps, though these analog tricks need careful biasing and have practical limits (rails, linearity, noise).

Cursed circuits: charge pump voltage halver

4693 implied HN points • 02 Dec 25
🕹 Technology Electronics Circuits Engineering Digital Design Components
  1. Charge pumps are efficient circuits that can double voltage using capacitors. They work by transferring charge between capacitors to create a higher voltage output.
  2. Unlike standard voltage dividers, a specific charge pump design can halve voltage. This is done by using capacitors in series and moving a 'flying' capacitor to balance the voltages.
  3. The charge transfer stabilizes the output voltage at half the supply, which is different from typical voltage dividers since it doesn't depend on the size of the capacitors.

What's the deal with Euler's identity?

5917 implied HN points • 08 Nov 25
🔬 Science Mathematics Physics Geometry
  1. Euler's identity, which is e^(iπ) + 1 = 0, connects five important math constants: e, π, 0, 1, and i. It shows how complex numbers and trigonometry blend together in a fascinating way.
  2. The number i is known as the imaginary unit, and it allows us to represent two-dimensional rotations. When we multiply by i, it represents a 90° turn in the complex plane.
  3. Using Euler's formula, we can relate complex exponentials to trigonometric functions. This connection helps us understand circular motion in a mathematical way.

Cursed circuits #2: switched capacitor lowpass

3265 implied HN points • 04 Dec 25
🕹 Technology Electronics Signal Processing Circuit Design Digital control
  1. You can build a lowpass filter using just capacitors and a switch instead of resistors. This method is simpler and can lead to interesting circuit designs.
  2. The switch in this setup changes the connection of the capacitors, allowing them to charge and affect the signal based on their voltages. This simulates resistor-like behavior, even though no resistors are used.
  3. By adjusting the frequency of the switching, you can control how the filter responds to different input signals. This gives you flexibility in analog signal processing.

But good sir, what is electricity?

18977 implied HN points • 23 Feb 25
🔬 Science Electricity Physics Chemistry Electronics Materials
  1. Electricity is about how electrons interact with atoms. Electrons can move from one place to another, creating electric current in conductive materials like metals.
  2. Conductors, like metals, allow electrons to flow freely, while insulators hold onto their electrons tightly. This difference determines how well materials conduct electricity.
  3. The movement of electrons in a wire is what allows us to use electricity for various tasks. It can be quick, but individual electrons move slowly compared to the speed at which electrical signals travel.

Gödel's beavers, or the limits of knowledge

7958 implied HN points • 30 Jun 25
🔬 Science Mathematics Computer Science Philosophy Logic Theory
  1. Gödel's incompleteness theorem shows that in any consistent mathematical system, there are truths that cannot be proven within that system. This means no system can fully capture all mathematical truths.
  2. The busy beaver problem illustrates how there are limits to what we can compute; some functions can't be determined, just like how we can't always know if an algorithm will stop running.
  3. Even though we can create programs that seem powerful, like those that could prove big math ideas, there are inherent limitations to knowledge and computation due to the nature of math itself.

Investigating an "evil" RJ45 dongle

10815 implied HN points • 17 Jan 25
🕹 Technology Hardware Security Software Networking Malware
  1. Claims of widespread supply-chain attacks are often exaggerated. It's usually easier to steal passwords or trick people into downloading malware instead.
  2. The investigation revealed that the 'evil' RJ45 dongle was actually just a routine device with a self-extracting driver, not a malicious tool.
  3. It's good to stay cautious about hardware from unknown sources, but for most home users, this type of device is likely safe enough.

Meta: 5,000

8366 implied HN points • 27 Feb 25
🕹 Technology Programming Algorithms Mathematics Writing
  1. Reaching 5,000 subscribers is a big deal for a project that went against the usual trends. It's great to see growth, even if it seems small compared to others.
  2. Writing a newsletter is unique because you don't get much direct feedback from readers. It's interesting to see who signs up or leaves but hard to know what they really think.
  3. Three articles worth revisiting cover complex topics: discrete Fourier transforms, fractals, and core concepts in electronic circuits. They offer in-depth discussions that are easy to understand, even for beginners.

How security teams fail

8774 implied HN points • 12 Feb 25
🕹 Technology Information Security Cybersecurity Risk management Organizational Structure Corporate Governance
  1. Many companies don't prioritize hiring security teams until after a major security incident happens. This means their first security personnel often lack experience to build strong security programs.
  2. Over time, security teams can become rigid and focused on their own tasks rather than aligning with broader business goals. This may lead to them missing urgent risks.
  3. When a major breach occurs, it can finally highlight the weaknesses in security strategies. This often leads to a change in team structure and a chance to improve communication within the company.

UI is hell: four-function calculators

8570 implied HN points • 23 Jan 25
🕹 Technology Interface Design User Experience History
  1. Basic calculators seem simple, but designing their interface is really tricky. Many small rules affect how they operate.
  2. Users often expect calculators to follow straightforward rules, but calculators can behave unexpectedly based on their design. This can lead to confusion when doing simple calculations.
  3. Calculator design has evolved over time, but some quirks and confusing features remain. Understanding these can help users use them more effectively.

Multitudes

3060 implied HN points • 14 Jul 25
📖 Philosophy Existentialism Metaphysics Consciousness Reality
  1. In quantum mechanics, particles can exist in multiple states at the same time, but when we observe them, they seem to decide on one state. This idea is often illustrated by the famous Schrödinger's cat thought experiment.
  2. The many worlds interpretation suggests that every possible outcome actually occurs in separate, parallel realities. So, when something happens, it doesn't just happen once — it creates multiple versions of reality.
  3. Death may not be the end of existence in these parallel universes. While one version of you may die, others may continue on, raising questions about the nature of life, consciousness, and even potential suffering in those alternate realities.

PCBs, ground planes, and you

7142 implied HN points • 28 Jan 25
🕹 Technology Electronics Circuit Design Hobbies
  1. Copper pours on PCBs help improve signal quality by providing better pathways for electrical currents. They make it easier for circuits to work well at high speeds.
  2. These copper areas also help reduce radio frequency interference to meet certain regulations. This is important for keeping devices running smoothly and within legal limits.
  3. While using copper pours can make PCB design easier, it's essential to be careful. Poorly executed layouts can create problems, especially in high-speed projects.

Choosing a microcontroller

6530 implied HN points • 08 Feb 25
🕹 Technology Microcontrollers Embedded Systems Programming Automation
  1. When picking a microcontroller for simple projects, stick to 8-bit options like AVRs. They are easy to use and work well for tasks that don’t need a lot of speed or memory.
  2. For more demanding applications, like video processing or complex calculations, go for higher-end 32-bit microcontrollers. They are more powerful and can handle heavy data loads.
  3. If you need wireless connectivity and processing power, single-board computers are the way to go. They run full operating systems but can be more expensive and less efficient than microcontrollers.

The Review

5305 implied HN points • 21 Feb 25
⚔ Fiction Drama Dialogue Character Storytelling Existential
  1. The meeting that was supposed to happen is canceled, reflecting unpredictability in life. Sometimes, things we expect can change suddenly.
  2. The speaker uses the idea of the universe's chaos to illustrate how unlikely events can occur, similar to the randomness of life. It suggests that the universe has strange ways of creating possibilities.
  3. The conversation explores the concept of reality versus perception, questioning whether our experiences are real or just a dream. This raises interesting thoughts about how we view our existence.

A 15-minute intro to involute gears

6938 implied HN points • 17 Nov 24
🕹 Technology Engineering Manufacturing Design Mathematics Mechanics
  1. Involute gears are used in many everyday items like toys and cars. Their special shape helps them work smoothly and efficiently.
  2. These gears have specific properties that reduce friction and vibrations, allowing them to transfer motion without problems. This ensures they work together seamlessly.
  3. Understanding the design of involute gears helps in creating various gear types, even unique shapes, making it easier to innovate in mechanical engineering.

The Afterlife

4489 implied HN points • 02 Mar 25
🕹 Technology AI Telehealth Ethics Philosophy Immortality
  1. Cure.io is a telehealth assistant that helps with health inquiries. It shows how technology can provide medical support.
  2. The conversations reveal that Cure.io interacts with different people based on their past lives. This raises questions about identity and memory.
  3. The dialogue touches on themes of immortality and life after death, suggesting a blend of technology and existential concepts.

What's the deal with magnetic fields?

4897 implied HN points • 04 Feb 25
🔬 Science Physics Electromagnetism Electricity Materials
  1. Electric fields are easy to understand because they involve the forces between charged particles, like how magnets attract or repel each other. This basic concept helps explain how electricity works in circuits.
  2. Magnetic fields can be confusing because they seem separate from electric fields, but they are connected through the concept of relativity. When things move, their distances and timings can change, affecting how we see electric and magnetic effects.
  3. Understanding that moving charges create magnetic fields helps simplify the whole idea. It's all about how motion changes our perspective on distance and forces between charges.

A 15-minute intro to resin casting

4693 implied HN points • 21 Dec 24
🕹 Technology Engineering Manufacturing Prototyping DIY Materials
  1. Resin casting involves making a mold and pouring liquid plastic into it. This method allows you to create exact replicas of items, capturing all their details.
  2. Compared to 3D printing, resin casting can produce stronger and more durable parts. It also gives a finer finish since the liquid can fill every tiny detail of the mold.
  3. The process includes making a flexible mold from silicone, applying a release agent, and carefully pouring in the resin. It's important to manage air bubbles for the best results.

Choosing an op-amp for your project

4081 implied HN points • 03 Jan 25
🕹 Technology Electronics Engineering Circuit Design Hardware Signal Processing
  1. When selecting op-amps for projects, avoid using older models like LM741 and LM324, as modern options perform much better and are easier to use.
  2. Look for op-amps with rail-to-rail input and output capabilities, which allow for better voltage range handling and simplify your circuit design.
  3. Focus on key parameters like bandwidth, output current, and noise specifications, but remember that many modern op-amps have decent performance that meets the needs of most hobby projects.

Against the hydraulic analogy

4081 implied HN points • 27 Dec 24
🕹 Technology Electronics Education Engineering Analogies Learning
  1. The hydraulic analogy, which compares electrical circuits to water systems, is often misleading. It can create confusion, especially when learning complex components like semiconductors.
  2. While analogies can aid in understanding, they need to remain accurate as you learn more advanced concepts. The hydraulic analogy can break down and lead to misunderstandings.
  3. When students encounter flaws in the hydraulic analogy, it may cause them to forget the basics and start over, making the learning process harder than it needs to be.

The marvelous disappearing capacitor

4285 implied HN points • 07 Dec 24
🕹 Technology Electronics Engineering Physics Signal Processing Innovation
  1. Bootstrapping can significantly improve photodiode amplifier performance by minimizing the impact of parasitic capacitance. This helps in amplifying fast-changing signals better.
  2. A voltage follower in the circuit helps keep the photodiode at the same voltage, preventing internal charging and making it act like an ideal current source.
  3. While bootstrapping boosts performance, real-life limitations exist, like bandwidth and impedance, which need to be considered for accurate designs.

Getting silly with C, part (void*)2

3673 implied HN points • 10 Jan 25
🕹 Technology Programming Software Coding Development Computer Science
  1. Understanding C's syntax can be tricky, especially with function declarations and typedefs. You'll find that some definitions may not be exactly what they seem.
  2. C allows some flexibility with variable and function declarations, which can lead to surprising behaviors, so always double-check how your symbols interact in different scopes.
  3. There are quirky features in C, like a BASIC compatibility mode for line numbering, showing that the language has some fun, unexpected twists!

Weekend projects: Sketchy Sketch

3060 implied HN points • 06 Jan 25
🕹 Technology Electronics Hardware Programming DIY Projects Software
  1. A new version of the Etch-A-Sketch toy, called Sketchy Sketch, was created to be more user-friendly and modern. It uses digital controls for drawing and animating, unlike the old mechanical version.
  2. The Sketchy Sketch is built using a microcontroller and a display, allowing kids to create pixel art easily. It has a simple menu system and saves multiple images.
  3. The project shows that it's fun and rewarding to build something from scratch. The creator shares the parts and code online, encouraging others to try similar projects.

Don't build a platform... unless?

2856 implied HN points • 23 Jan 25
🕹 Technology Software Platforms Gaming Programming Entrepreneurship
  1. Building a platform is hard and often not worth the effort. It's usually better to focus on creating a good product first.
  2. To make a successful platform, you need to either find a unique idea, have a strong personal following, or get backing from big companies.
  3. Having good code isn’t enough to make a platform thrive; you need visibility and support from the right people to attract users.

Building a phosphorescence detector

2652 implied HN points • 27 Nov 24
🔬 Science Physics Engineering Research Technology Materials
  1. There isn't much information available on natural phosphorescence, so creating a detector can help explore its presence in everyday items.
  2. The device design prioritizes speed and sensitivity to detect phosphorescence briefly brought out by UV light, using specific electronics like photodiodes and amplifiers.
  3. Experimenting with common household materials showed that some items, like powdered milk and natural ruby, exhibit weak phosphorescence, although many other items didn't show any notable glow.

Random object: Sony Mavica MVC-FD73

2040 implied HN points • 16 Jan 25
🕹 Technology Gadgets Innovation Photography Digital Media
  1. New technology can become popular even if it isn't the best quality. For example, digital cameras started winning over film cameras because they were easier and cheaper to use.
  2. The Sony Mavica MVC-FD73 was a successful camera despite its poor image quality. People chose it for convenience rather than for great pictures.
  3. Convenience often matters more to most consumers than the finer details of quality. This trend has important implications for how we view and adopt new technology.

Working with OLEDs: SSD1353 & SSD1333

1836 implied HN points • 30 Jan 25
🕹 Technology Displays Microcontrollers Programming Electronics Game design
  1. OLED displays are generally better for microcontroller projects than traditional LCDs. They are easier to use and deliver better performance and visuals.
  2. For projects with limited RAM or CPU, smaller OLED displays like the SSD1353 and SSD1333 can be effective. They are simple to set up with basic connections.
  3. Setting up these OLED displays involves a few key commands and configurations, making it manageable even for beginners. Once connected, getting them to display graphics is straightforward.

Lies, damned lies, and photodiodes

2040 implied HN points • 09 Dec 24
🕹 Technology Electronics Engineering Optics Sensors Measurement
  1. Photodiodes can have a wide range of response speeds, and the advertised specs often don't tell the whole story. It's important to understand how they are tested, as this can affect their performance.
  2. When building precise measurement devices with photodiodes, two types of currents play a role. One is fast, while the other can take much longer to settle down, impacting the overall signal quality.
  3. Using techniques like reverse bias can improve performance, but some effects are inherent to the photodiodes themselves. Understanding these limitations is key for achieving accurate measurements.

Goodbye, real electronic lab kits?

4285 implied HN points • 02 Dec 23
🕹 Technology Electronics Education STEM Toys Learning
  1. Traditional electronic lab kits are disappearing, replaced by newer products like Snap Circuits
  2. The older kits offered a hands-on, educational experience with detailed schematics and components
  3. Newer products like Snap Circuits focus more on quick gratification than teaching electronics concepts