1. Inside a $1 radar motion sensor
Total comment counts : 15
Summary
The article discusses the author’s exploration of the RCWL-0516 microwave motion sensor and their attempt to understand its functioning. The author explains that the sensor uses the BISS0001 infrared motion sensor chip and works by detecting millivolt-level changes in the low frequency IF signal created when a moving object reflects the transmitted carrier signal. The article provides a detailed analysis of the sensor’s components and oscillators. The author also notes that the sensor’s performance is inconsistent, working well indoors but often failing outdoors where there are no static returns to amplify the signal. The author mentions attempting to modify the sensor by removing a component but does not provide further details.
Top 1 Comment Summary
The article discusses the ability to use through-wall 2.4Ghz Wi-Fi CSI radar to detect human activity with $20 ESP32 boards. Espressif claims that the radar can capture subtle movements caused by breathing and chewing in a static environment. The technology works with ESP32 series microcontrollers and does not require any changes to the hardware. The article also mentions that AI/NPU laptops with Wi-Fi 7 from Intel and Qualcomm can combine RF radar and on-device inference to identify human activity. Several related links are provided, including a DIY radio telescope project, the use of Wi-Fi devices as object sensors, and information on automotive radar and Wi-Fi sensing of movement.
Top 2 Comment Summary
The article discusses a teardown of a Doppler radar module called HB100. It mentions that the module contains an IC, which makes it more soothing. However, the author admits to not fully understanding how the IC works. The article also refers to a similar teardown of HB100. You can find the full article at the provided link.
2. Python toolkit for quantitative finance
Total comment counts : 19
Summary
The article is about GS Quant, a Python toolkit for quantitative finance developed by Goldman Sachs. It is built on a risk transfer platform and is designed to assist in the development of trading strategies and risk management solutions. It can be used for derivative structuring, trading, risk management, and data analytics applications. The toolkit is maintained by quantitative developers at Goldman Sachs and examples, guides, and tutorials can be found on the Goldman Sachs Developer website. Contributions are also encouraged, and readers are invited to reach out with any questions or feedback to gs-quant@gs.com.
Top 1 Comment Summary
The article discusses OpenBB, a well-known project in the financial data category. It mentions that most data vendors require a free API key in order to access their data and may try to upsell users over time. Alternatively, users can access “free data” through projects that scrape financial data from websites, although this may require frequent updates from the main maintainer. The author of the article claims to be the main creator behind the OpenBB project on GitHub.
Top 2 Comment Summary
The article states that the only purpose of the content provided is to study the design. To access any useful information, users need to utilize GS specific data APIs through a specific website.
3. Show HN: I am building an open-source Confluence and Notion alternative
Total comment counts : 42
Summary
The article discusses an open-source collaborative documentation and wiki software called Docmost. It is described as an alternative to platforms like Confluence and Notions. The article mentions that the software is currently in beta and invites readers to provide feedback. The article also provides links to the website and documentation for further information.
Top 1 Comment Summary
The article claims that both Notion and Confluence have very poor accessibility. The author highlights the importance of companies adopting accessible tools, especially considering the ADA in the US and the upcoming EAA in the EU. The author offers to review a product called Docmost and mentions their background as a native screen reader user, blind person, developer, and accessibility auditor.
Top 2 Comment Summary
The author of the feedback expresses interest in trying the website but was put off by the installation page. They were expecting simpler instructions for installing and configuring the website, specifically using Docker. The author suggests that the prerequisites should be made clearer or presented in a different way to avoid confusion. They also mention that developers and tech-savvy people tend to skip over unnecessary information and directly look for terminal commands or code. Overall, they provide constructive criticism and acknowledge that the website seems well-designed.
4. The Operational Wargame Series: The best game not in stores now (2021)
Total comment counts : 13
Summary
The article discusses a tabletop game called Assassin’s Mace, which is part of the Operational Wargame Series (OWS). OWS allows players to simulate combat between 2025 and 2050, focusing on the operational level of warfare and incorporating military capabilities across different domains. The game was developed by Retired Col Tim Barrick and a team of designers at the USMC Warfighting Lab. It uses a “hex and counter” format and features large counters representing military units. The game mechanics involve the use of dice to determine outcomes, with different dice sizes depending on unit status and environmental factors. The game requires players to plan their turns and involves air, naval, and ground combat. The article also mentions a mega test of the OWS system at the USMC War College, where students played the game to learn and have fun.
Top 1 Comment Summary
The article discusses a type of game that involves simulating historic battles. These games often follow a scripted structure and can take a long time to play, sometimes even days or weeks. The author initially questions why these games are not played on a computer, but realizes that the ability to spread out a physical map and see everything at once has advantages that current display technologies cannot replicate. However, the author believes that the advent of cheap, high-resolution, networked AR/VR headsets could change this, making digital versions of these games more feasible and eliminating some of the drawbacks.
Top 2 Comment Summary
The article discusses the use of war games in military training and the rarity of these games being available to the general public. It mentions Volko Ruhnke, a game designer who has created games for training the CIA. The article includes links to more information about Kriegspiel, a historical war game, and a book on the topic of wargaming.
5. Show HN: Conway’s Game of Life, but as a div full of Braille characters
Total comment counts : 5
Summary
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Top 1 Comment Summary
The author recounts their experience in art school, where they were assigned a typography project that required creating art pieces using “found typography” - lettering from photographs, rather than computer fonts. The author incorporated Braille discovered in an elevator into their design, but their typography professor rejected it, leading to a class discussion about whether Braille counts as typography. The author still believes they were right, and their design featuring Braille remains one of their favorite pieces.
Top 2 Comment Summary
The author, a blind person, states that braille does not convey any specific meaning. They suggest it would be interesting to add hidden messages in braille that spell out words.
6. Trilobites killed by volcanic ash
Total comment counts : 5
Summary
The article discusses the discovery of well-preserved trilobite fossils that provide new details about the extinct arthropod. The fossils, which were buried in volcanic ash more than 500 million years ago, show previously unseen features, such as the clustering of leg pairs around the mouth. It was also discovered that trilobites had four pairs of head appendages rather than the previously believed three pairs. The fossils were found in rock composed of volcanic ash and were quickly fossilized after being smothered by the ash. High-resolution X-ray micro-tomography was used to study the fossils and reveal their anatomy in three dimensions. The study highlights the potential of volcanic ash deposits as a source of exceptionally preserved fossils. Trilobites are extinct arthropods and one of the most abundant lifeforms in fossil deposits from the Palaeozoic Era.
Top 1 Comment Summary
Trilobites are ancient arthropods that existed over 500 million years ago. There are more than 20,000 species of trilobites, with sizes ranging from less than two millimeters to over 90 centimeters. The website trilobites.info provides numerous drawings of these diverse trilobite species.
Top 2 Comment Summary
The article discusses a research study that reveals multicellular organisms are older than previously believed, at least 2.1 billion years ago. The study was conducted by a researcher who was previously featured on the cover of Nature in 2010. For more information, refer to the link provided.
7. Weekend projects: getting silly with C
Total comment counts : 15
Summary
The article discusses the quirks and lesser-known features of the C programming language. It highlights the expressive simplicity of C, its influence on other programming languages, and its potential for code obfuscation. The article specifically focuses on the switch statement, explaining how it can be used without curly brackets, how it functions similarly to a goto statement, and how case labels can appear anywhere in the block. The author also mentions alternative techniques, such as using the && operator and labels to replace switch and for loops. Overall, the article explores the unusual aspects of C programming while emphasizing that code can still be readable despite its complexity.
Top 1 Comment Summary
This article discusses the concept of undefined behavior in C programming. It explains that using an uninitialized variable does not necessarily mean that it will have a random value. Instead, it is undefined behavior, and the compiler can handle it in different ways. For example, the compiler could initialize the variable to a specific value, remove the instructions altogether, optimize away subsequent instructions, or even crash the program.
Top 2 Comment Summary
The article discusses a programming construct called “brkcase” that can be used in a switch statement. This construct eliminates the need for explicitly writing “break” at the end of each case clause. The article suggests that while compilers may not like this control flow, they are likely to optimize and remove it effectively.
8. Neo Geo Architecture: A practical analysis
Total comment counts : 12
Summary
This article discusses the Neo Geo, a gaming console that was designed for both arcade and home use. The console had a dual-processor configuration, with a Motorola 68000 CPU for executing the main program and a Zilog Z80 CPU for sound management. The Neo Geo’s motherboard included integrated controllers that expanded the capabilities of the CPUs. The article also mentions the use of a vectorized interrupt table, which improved the handling of I/O communication. Overall, the Neo Geo was a high-end console that aimed to please both arcade owners and wealthy households.
Top 1 Comment Summary
The article discusses the Z80 interrupt system and its capabilities, specifically focusing on the powerful IM2 interrupt mode. IM2 supports an interrupt vector table with up to 128 entry points in memory and can handle any number of prioritized interrupt sources. However, this mode was not properly supported in Western home computers like the Speccy, CPC, and MSX, while East German home computers like Z1013, Z9001, and KC85/2 to 4 fully supported it. The reason for this is that IM2 requires interrupt sources to implement a complex “daisy chain protocol” for prioritization. Western home computers did not have the necessary support chips to implement this protocol, while East German computers using TTL logic and Z80 family chips could fully utilize the IM2 interrupt capabilities.
Top 2 Comment Summary
The article discusses the MiSTerFPGA project, which uses a Terasic DE10 Nano FPGA evaluation board to recreate older consoles, computers, and arcade systems in hardware. The system has a good MiSTerFPGA core that supports Neo Geo AES, MVS, and CD systems. It is mentioned that the cost for entry into MiSTerFPGA will soon decrease significantly with the availability of clone boards for the DE10 and expansion memory boards. The article suggests that with these affordable options, users will be able to run consoles up to PS1/Saturn/N64 level, and if they want to experience higher-level consoles, they can either use software emulation or wait for the next round of FPGA-based retro-consoles. The article includes links to additional information and videos for reference.
9. A buried ancient Egyptian port reveals connections between distant civilizations
Total comment counts : 17
Summary
Archaeologists have made remarkable discoveries at the site of Berenike, an ancient port city along the Red Sea. Excavations have revealed two harbors, houses, shops, and shrines, as well as artifacts such as letters, receipts, and imported treasures from regions like eastern Africa, southern Arabia, and India. These findings are shedding light on the significant ocean trade that sustained the Roman Empire and may have been more economically important than the Silk Road. Among the discoveries are inscribed stones, including one with Sanskrit script and a dedication to the welfare of all beings, which challenges previously-held ideas about Rome’s connections to the Eastern world.
Top 1 Comment Summary
The article discusses the existence of a large trade link between India and Egypt via the Red Sea, which was known at least a year ago. The author, William Dalrymple, has written a book on the topic, which goes into more detail. The article suggests that there is a renewed interest among Indian scholars in discovering and exploring ancient Indian history, which has been largely forgotten over time.
Top 2 Comment Summary
The article is praised for living up to its catchy title and includes a mix of anecdotes, facts, and images. The author highlights the lack of recognition for instances where different civilizations and religions coexisted and collaborated. The Isis temple mentioned in the article is described as a noteworthy sight.
10. Coffee helped the Union in the Civil War
Total comment counts : 12
Summary
During the Civil War, the Union faced a shortage of coffee, which was considered essential for energy and morale. Imports from Brazil had been disrupted due to the Union blockade of Southern ports. To find a new source of coffee, Stephen Allen Benson, the president of Liberia, offered to export coffee from the country to the North. Benson, a former coffee farmer in Liberia, hoped that the young Republic of Liberia could support the Union in its fight against slavery. An early alliance between Northern abolitionists and the Liberian people had already introduced small amounts of Liberian coffee to the North prior to the war. This partnership between Benson and abolitionist George W. Taylor helped supply the growing demand for coffee from consumers who sought slavery-free alternatives. Liberian coffee became attractive to the American Free Produce movement, which aimed to use ethical commerce to undermine the global slave trade. Despite the absence of formal trade treaties, a shipment of Liberian coffee in 1862 became vital for the Union’s victory.
Top 1 Comment Summary
This article mentions the existence of stimulants such as tea, tobacco, and yaupon (black drink) in the South, in addition to discussing a Liberian farmer entrepreneur.
Top 2 Comment Summary
This article discusses the author’s experience with caffeine and their decision to stop consuming it for a period of three months. They highlight how caffeine can provide a sense of relief and help cope with daily pressures and work-related challenges. However, the author also acknowledges the downside of relying on caffeine, such as poor sleep quality and the need to consume more caffeine to counteract its effects. Despite their attempt to abstain from caffeine, the author eventually succumbs to the pressure and resumes its consumption. They encourage others to examine their own relationship with caffeine and express astonishment at how addicted the population was to the drug in the 1800s.