Maya Posch writes about the LC harmonic filters at HVDC converter stations, which scrub the noisy AC sinewave produced after line-commutated HVDC-to-AC conversion. Drawing on a video by Jordan Taylor (The Electric Brit), the piece walks through a UK-based converter station to explain what these filters are, how they work, and why their design at grid scale is a distinct engineering challenge.
- The distortion introduced by HVDC-to-AC conversion is directly analogous to the harmonics in a much lower-voltage power supply, making the fix (an LC filter) conceptually the same, just orders of magnitude larger.
- The same massive inductors and capacitors that form the filter also absorb and generate reactive power on the AC grid, damping oscillations and adding a secondary layer of stability.
- The distortion introduced by HVDC-to-AC conversion is directly analogous to the harmonics in a much lower-voltage power supply, making the fix (an LC filter) conceptually the same, just orders of magnitude larger.
- The same massive inductors and capacitors that form the filter also absorb and generate reactive power on the AC grid, damping oscillations and adding a secondary layer of stability.
Bryan Cockfield writes about the Kiwix open-source project, which started as an offline backup for Wikipedia and now includes other sites like StackExchange.To preserve and serve information from personal hardware, ensuring survival through internet outages and website disappearances, Kiwix is available on Linux (Docker compatible), Windows, Android, and Apple platforms.
- A separate tool called Zimit is required to generate the .zim archive files that Kiwix serves.
The Kiwix organization hosts pre-downloaded .zim files of common sites, sparing users from crawling Wikipedia themselves, a task that could take months on limited consumer hardware.
- The article points to a prior piece on building an "armageddon-proof" Raspberry Pi briefcase as suggested hosting hardware.
- A separate tool called Zimit is required to generate the .zim archive files that Kiwix serves.
The Kiwix organization hosts pre-downloaded .zim files of common sites, sparing users from crawling Wikipedia themselves, a task that could take months on limited consumer hardware.
- The article points to a prior piece on building an "armageddon-proof" Raspberry Pi briefcase as suggested hosting hardware.
Fenix Guthrie writes that Chris Staecker restored a remarkably well-preserved Digi-Comp 1, the 1963 programmable educational toy computer introduced by E.S.R. The device uses mechanical logic gates programmed with soda-straw-like tubes on sliding rails and spring-loaded levers actuated by a clock switch to compute simple binary functions as a non-Turing-complete state machine reflective of early 1960s computing.
- E.S.R. originally intended to make actual computers before becoming a premier educational toy company in the 1960s
- Staecker'''s restoration used rubber bands and 3D-printed parts to return the toy to working condition
- The machine has 88 states, equivalent to 16,777,216 possible configurations
- Article references successor Digi-Comp II and other vintage ''"sort of''" computers like Geniac
- E.S.R. originally intended to make actual computers before becoming a premier educational toy company in the 1960s
- Staecker'''s restoration used rubber bands and 3D-printed parts to return the toy to working condition
- The machine has 88 states, equivalent to 16,777,216 possible configurations
- Article references successor Digi-Comp II and other vintage ''"sort of''" computers like Geniac
Tyler August writes that The Masked Bear's open-source wifisense-pi project uses an ESP32-S3 sampling the 2.4 GHz WiFi channel 100 times per second with a Raspberry Pi 4 for signal processing to detect subtle body motions via WiFi disturbances, effectively sensing breathing or presence through walls without dedicated hardware.
- Can detect a perfectly still human by breathing, but presence can be hidden by holding breath
- Single sensor provides no position information and cannot reliably distinguish one vs multiple people
- Works by sniffing existing 2.4 GHz signals and functions through walls
- Not the first WiFi-based presence project; prior work includes ESP32 person sensors and millimeter-wave alternatives
- Can detect a perfectly still human by breathing, but presence can be hidden by holding breath
- Single sensor provides no position information and cannot reliably distinguish one vs multiple people
- Works by sniffing existing 2.4 GHz signals and functions through walls
- Not the first WiFi-based presence project; prior work includes ESP32 person sensors and millimeter-wave alternatives
The author is undertaking a project to develop "Bridgetris," a game for the vintage 1985 BBC Bridge Companion console originally intended to teach bridge via television. To achieve this, the creator must master Z80 assembly language, reverse-engineer the system BIOS to allow custom code execution from cartridges, and perform hardware modifications like composite video integration.
- The device uses the TMS9129 VDP which features 16kB of VRAM.
- Original retail price was approximately £200 in 1985.
- Hardware was originally designed by a company named Heber Ltd.
- A composite video mod was implemented to improve visual quality on modern displays compared to the original RF output.
- The device uses the TMS9129 VDP which features 16kB of VRAM.
- Original retail price was approximately £200 in 1985.
- Hardware was originally designed by a company named Heber Ltd.
- A composite video mod was implemented to improve visual quality on modern displays compared to the original RF output.
Zoe Skyforest writes about Kek, an emulator developed by vanheusden to bring the influential 16-bit PDP-11/70 minicomputer back to life on modern hardware. The software supports a variety of platforms including Linux, Windows, and microcontrollers like the ESP32 or Teensy 4.1.
- Emulates classic disk drives such as RK05, RL02, RP06, and RP07.
- Supports KW11-L line time clocks and DC-11 serial interfaces.
- Capable of running Unix versions from version 5 through version 7 in multi-user mode.
- Emulates classic disk drives such as RK05, RL02, RP06, and RP07.
- Supports KW11-L line time clocks and DC-11 serial interfaces.
- Capable of running Unix versions from version 5 through version 7 in multi-user mode.
Al Williams writes that International Reply Coupons (IRCs) are nearing their end as the Universal Postal Union prepares to phase them out by December 31, 2026. Once essential for radio hobbyists and international mailers, these coupons allowed individuals to pay postage in one country that could be exchanged for local stamps in another, but modern digital communication has rendered such physical vouchers nearly obsolete.
- Radio enthusiasts used the system primarily to receive QSL cards from foreign stations without requiring senders to cover international shipping costs.
- The Universal Postal Union consists of an association of post offices across 192 countries.
- Charles Ponzi's original scheme involved exploiting price discrepancies for these coupons between different nations.
- Radio enthusiasts used the system primarily to receive QSL cards from foreign stations without requiring senders to cover international shipping costs.
- The Universal Postal Union consists of an association of post offices across 192 countries.
- Charles Ponzi's original scheme involved exploiting price discrepancies for these coupons between different nations.
Timothy Giles has developed a 3D-printed optical cavity designed to detect minute shifts in space and wavelength. By arranging two semi-transparent mirrors—one on a printed mount and the other attached to a speaker diaphragm—the setup uses light interference to measure displacement at a nanometer scale. A webcam monitors an emitted beam pattern for alignment, while the speaker acts as a linear actuator to vary cavity length. This experiment also demonstrates how thermal shifts in a laser diode can cause wavelength instability through changing interference patterns.
- 3D printing construction of optical cavities
- Measuring displacement via light interference
- Utilizing a speaker diaphragm as an actuator
- Observing temperature-induced laser wavelength fluctuations
- 3D printing construction of optical cavities
- Measuring displacement via light interference
- Utilizing a speaker diaphragm as an actuator
- Observing temperature-induced laser wavelength fluctuations
The community-led open-source hosting site Codeberg has announced bans on two types of projects: cryptocurrency-related projects and those whose code is substantially or entirely generated by Large Language Models (LLMs) such as Claude or OpenAI Codex. Following a community vote, the ban on LLM-generated code passed with 358 votes in favor to 144 against. The reasoning for these decisions includes concerns over "license whitewashing," the massive increase in hardware and energy costs caused by AI datacenter scaling, and the potential negative impact of generative AI tools on the Open Source Software (OSS) community.
The comments reflect a deep division within the tech community regarding this decision:
* **Supporters** argue that current LLM practices are unethical because they undermine software rights, increase environmental strain, and create massive amounts of "junk" code that is difficult to maintain or scale.
* **Critics/Skeptics** suggest the ban is a "Luddite" reaction to an unstoppable trend (comparing it to people refusing cell phones). They argue that LLMs are already integrated into most workflows ("the toothpaste is out of the tube") and that banning them might be impossible or impractical.
* **Nuanced Perspectives** emerge from users who distinguish between using LLMs as a "reasoning tool" for scientific/mathematical scaffolding versus pure "vibe coding." Some argue that while full generation creates maintenance risks, LLM tools are essential assets for hobbyists and professionals alike to solve problems efficiently.
The comments reflect a deep division within the tech community regarding this decision:
* **Supporters** argue that current LLM practices are unethical because they undermine software rights, increase environmental strain, and create massive amounts of "junk" code that is difficult to maintain or scale.
* **Critics/Skeptics** suggest the ban is a "Luddite" reaction to an unstoppable trend (comparing it to people refusing cell phones). They argue that LLMs are already integrated into most workflows ("the toothpaste is out of the tube") and that banning them might be impossible or impractical.
* **Nuanced Perspectives** emerge from users who distinguish between using LLMs as a "reasoning tool" for scientific/mathematical scaffolding versus pure "vibe coding." Some argue that while full generation creates maintenance risks, LLM tools are essential assets for hobbyists and professionals alike to solve problems efficiently.
The Kindalive project by Drew Smith uses a simulated dot-matrix face to express emotions through the modeling of eight key neurochemicals like dopamine and cortisol. Rather than using discrete sentiment labels via LLMs, this approach simulates the organic decay and interplay between chemicals to create fluid mood changes. These emotional states are visually represented through twelve facial movements based on the Facial Action Coding System (FACS).
- Models short-term and long-term moods through neurochemical simulation
- Uses nonverbal communication to increase robot relatability
- Employs 12 elements of the Facial Action Coding System for expression
- Models short-term and long-term moods through neurochemical simulation
- Uses nonverbal communication to increase robot relatability
- Employs 12 elements of the Facial Action Coding System for expression
