lcamtuf’s thing

lcamtuf’s thing explores the intricacies of modern and traditional electronics, challenges and insights from moving to a rural area, the basics and applications of electronic components, the impact of AI in understanding technology, the philosophy of effective altruism, and reflections on corporate life and technology's evolution. It blends technical tutorials with personal experiences and broader technological discussions.

Electronics Rural Living and Challenges Electronic Components and Circuits AI and Technology Effective Altruism Corporate Life Technology Evolution

Top posts of the year

And their main takeaways

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.

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.

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.

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.
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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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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 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.