https://www.youhere.org: "Want to know who showed up?" is the tag line. It's an app-based attendance service for teachers/coaches/band directors/conference organizers, etc. I'm a teacher and it scratches an itch I had (students not showing up to class). Been hitting the $500/month more and more often now (even after server fees).
Hi! Thanks for trying it. The "slow sway" is part of the plan! It's so the oversized first row of a qwerty keyboard can show all possible letters on the top row. If it feels too much like a game, slow it down using the main app from your home screen.
One of my favorite retro projects in this real-time TRS-80 (Model I assembler and emulator that assembles and runs Z80, literally with each key press. Mind boggling how today's CPUs can emulate and entire 8-bit computer dev-process all between key presses in a browser. https://www.teamten.com/lawrence/projects/assembly-language-...." The author even says "How about: With every keystroke in the IDE’s code editor, we assemble the whole program, reset a virtual TRS-80 to a known state, install the program, and run it??
Uni. prof here/shameless plug: I developed a general education class for college students about the 'history of navigation' which includes the science behind navigation and why clocks and (accurate) timekeeping are needed for navigation. I wrote a book about it all I use for the class, if anyone's interested: https://www.amazon.com/Longitude-Time-Navigation-Tom-Bensky-.... I was inspired by Sobel's book, but I needed more math and science in the discussions.
Also, if you can find the book by Williams called "From Sails to Satellites: The Origin and Development of Navigational Science" you'll laugh out loud at his wit about navigation throughout the book.
I work on neural nets back in the mid 1980s, so I was somewhat familiar with their structure, backpropagation, squashing functions, etc. I wanted to get back into them, so I started by rederiving all backprop formulas by hand here https://github.com/tbensky/NeuralNetworks/blob/main/Backprop....
Back during the pandemic, hardware-based contract tracers were an idea. I built one using the ESP32; see https://github.com/tbensky/npct. In a nutshell, everyone generates a (non-centralized) hash for themselves based on local entropy. This hash is set to the BLE name of the ESP32. Turn it on and throw it in your backpack as you go out. When two ESP32s pass by each other, they both log the other's BLE name (hence hash). Later on, hash logs could be inspected and uploaded to a central server so you can see who encountered who. Seems like there's still some (non-Covid) applications for this (but I can't think of any). Fun project. Learned a lot about Bluetooth.
Back in the early days of Linux (~1993) or so, I was trying to convince my workgroup in grad. school that Linux was a nice alternative for running our numerical simulations (in C). But I knew I had to get the graphics working, since no one wanted to use a text-only interface. It was a Dell PC using some graphics card; the word 'tulip' is in the fog of my memory. The graphics driver was not loading, giving some error about a reference not being found in the .o file. I didn't know what to do, so I loaded up the .o file in vi, searched for the offending reference, edited it out and saved the .o file. From then on the graphics works great!
XRF=x-ray fluorescence. You shoot X-rays into a metal, typically the gamma rays from an Am-241 source. This causes atoms in the metal to fluoresce their own gamma rays that are a (somewhat) unique signature of the atom itself. So in sum, XRF allow one to non-destructively determine the atomic constituents of a bulk material (but 'heavy' materials..heavier than Silicon for example).
Happy to see this post on HN. As a college prof, I've spend many years studying the history of 1700s navigation and taking student groups to Greenwich to see and study H1 (H2, H3 and H4). I love these clocks and all of the stories behind them. The serious enthusiast will find a lot of technical details on the Harrison's clocks in this book https://www.amazon.com/Marine-Chronometers-Greenwich-Catalog... and this one https://www.amazon.com/Marine-Chronometer-Its-History-Develo.... I've also collected all of my pedagogy on 1700s navigation into a this book: https://www.amazon.com/Longitude-Time-Navigation-Tom-Bensky-... where I dive somewhat into the innards of H1. To answer another post: H1 has been fully disassembled and reassembled with XRF done throughout.