Watching The Watchers

Although it used to be a much more rare event, now almost any time at dawn or dusk, provided clear weather, a human observer can walk outside, look up, and spot an artificial satellite passing overhead. This has caused some consternation among astronomers who have another source of pollution to deal with in their data, but has benefited society in other ways such as more reliable internet and better weather predictions. To keep an eye on what exactly is passing overhead, take a look at this tool built by [Armaan].

The browser-based satellite tracker uses simplified perturbations models (SGP4) to model the passes of every satellite that has passed a given location on Earth in the past seven days. The modeling is all done locally within the user’s browser, and can even be self-hosted through a fairly simple method that involves forking the project with a tool called Vercel. Not only does this tool find the satellite passes for that given location, though, but it also automatically downloads any imagery that those satellites sent back down to Earth.

The project itself is open source, so users can engage with the code without using Vercel if they choose. Beyond just checking out what happened to fly overhead in the last few days and checking out weather data without needing your own satellite dish to download the data yourself, this could also be useful for radio operators looking to make contacts with satellite repeaters or those wanting to keep tabs on crewed satellites like the International Space Station while it still remains in orbit.

The Goat Emoji Is 100% Valid Machine Code, And It Doesn’t Stop There

Did you know emojis can be executables? Well, they are if you treat them like Intel 8088 or 8086 machine code, anyway. [GloriousCow] shared this clever revelation, demonstrating that executable programs could be created entirely from emojis. To really appreciate why, it’s necessary to take a small step back.

It all started when [GloriousCow] happened to notice, entirely by chance, that 🐐 (the goat emoji) was F0 9F 90 90. Anyone familiar with x86 assembly language probably recognizes 90h as nop,  or null operation, or “spend a cycle doing nothing”. What about F0 and 9F? Together they are lock lahf (assert the bus lock signal then copy some status flags into register AH) which, on an 8088 and 8086, essentially does nothing.

This means the goat emoji (F0 9F 90 90) is 100% technically valid machine code. It doesn’t do anything, but here’s where it gets even more interesting.

A short string of emojis is machine code that writes HELLO (lower right) by writing directly to video memory.

There are loads of emojis, and many of them start with F0 9F followed by two more bytes, and many of those other two-byte combinations are surely also valid machine code. Could one create a meaningful executable program consisting entirely of emojis? The answer is yes, and [GloriousCow] crafted a simple Hello World program to demonstrate.

The simple program looks like this: 🐸☺️🐰🐎♐🗃️🧯🧯🧯🐮💗🦮🪏♐🐰🐹🗃️🧯🧯🧯🧯💗🪗🧯😗🧮🫪😗🧮😗🐮😪😔⭐. Save that string of emojis to a file, give it a .com extension, and run it in DOSBox with CPU type set to 8086. It’ll print HELLO at the bottom-right of the screen by writing directly to video memory.

There are loads more details on the original blog post, including plenty of resources and tips for writing your own executables with emojis. There’s also a much more involved VGA demo program made from emojis, so give it a look.

Some of you may be aware that ASCII characters can also be used in a similar way (and more flexibly, since they are not four-byte combinations like emojis). This was used in BASIC programs as a way to cleverly embed machine code in things like REM statements, creating odd-looking code that did things in BASIC that shouldn’t have been possible.

A Tiny OS For A Tiny Board

As microntrollers have become ever more powerful, we have started to see an increasing number of operating systems written to take advantage of this extra power. Usually they’re aimed at handheld or other similar devices with support for screens and input devices, but just what can be done if a developer eschews those niceties? KoaOS is a small OS for the ESP32-S3 on the Heltec WiFi LoRa 32 V4, and it’s headless. You can only talk to it via a serial terminal on its USB port.

What it provides is a UNIX-like shell, with editor, GPS, weather and APRS apps ready to run. It’s not just limited to those, there’s an SDK of sorts to create new apps and compile them from C. These .esp files can be installed and uninstalled at will over the network.

There are a few limitations, for example it’s only for the Heltec V4 due to a large requirement for PSRAM. We are guessing that another similar spec board could probably be made to perform, however it’s clear that hasn’t yet been done. Despite that we think this OS is interesting for concentrating on the OS rather than the interface, and we hope to see it develop further.

Several takes on an ESP32 OS have appeared in recent times, including this JavaScript one.

FloppoScope Is A Disk Image Analyzer

If you’re a big retro tech fan, you might still have a floppy drive on hand, or even some sort of high-end disk imaging solution. If you’re a little less committed, you may still have plenty of disk images on your hard drive for various reasons. Either way, you might find [0ldStaph]’s latest project to be useful for examining any disk images you have on hand.

FloppoScope is a browser-based tool for analyzing floppy disk images. Despite being browser-based, everything runs locally, so you’re not actually risking any sensitive data by using the tool—though we can’t imagine you’ve got too much Top Secret intel stored as floppy disk images, anyway.

The tool will draw you a nicely color-coded map of the disk layout and shows all the pertinent data for the filesystem of the image. It will even let you preview common file types if you need. The tool can also convert images between various formats, and spit out reports on things like bad sectors or corrupted files that have been detected. FloppoScope can handle everything from PC and Apple format disks, to Amiga, Atari DOS, and BBC Micro stuff. Oddities like various Sharp MZ machines and the NeXTSTEP format are included too. It works with both image and flux files, as well, so whichever way you captured your disks, it should work here.

We’ve looked at the importance of imaging remaining floppy disks quite recently. If you’ve got unpreserved disks sitting in your bedroom, shed, or study, consider getting on that as a matter of priority at this point!

Learn To Edit STL Files In Just A Few Minutes

Sometimes an STL file needs a bit of editing, but if one doesn’t already know how to use a mesh editor it’s unlikely that one has the time to sit down and learn it in the middle of a project. Happily, that’s where [Prusa]’s five-minute guide to editing STL files directly will come in handy.

The editor of choice is Blender, a fantastic piece of open source software that can be intimidating because it’s got one of those interfaces in which clicking around with an explorer’s heart just isn’t going to get you very far. Most guides start at learning Blender from scratch, assuming one will be using it to create new 3D models. This guide instead focuses on importing and modifying existing models rather than trying to teach the entire interface. For all the apparent complexity, Blender’s underlying functions are actually quite straightforward and simple to use once one knows the right approach.

Having to make changes to an STL file is something most folks have grimaced inwardly about at least once when 3D printing. Certainly, STL files can be imported into CAD programs like FreeCAD, but editing them that way is always a bit of a square peg in a round hole.

A guide like this is a valuable reference for the next time an STL file needs some changes, but the time has not yet come to sit down with a gallon of coffee and learn Blender from scratch.

An Attempt At A Useful Desktop OS For Microcontrollers

We’re living at an interesting time here in 2026, when microcontrollers are becoming powerful enough to surpass the capabilities of “real” computers from a time when those real computers were starting to become useful. We’ve seen plenty of microcontrollers emulating machines from the 1990s, but what if instead they were giving all their power to the OS? It’s a question [Thomas] is trying to answer with SylphideOS, a general purpose GUI operating system aimed at multiple microcontroller platforms.

On the surface it has a GUI that appears to owe a lot to the early Macintosh machines, but underneath it has the FreeRTOS kernel, something that has been around for quite a while. You can argue among yourselves as to whether this make it an OS in its own right or a FreeRTOS distro. Aside from driving a screen through a framebuffer it also has the hardware interfaces you’d expect, for keyboard and storage. There’s support for RP2350 and selected ESP32 platforms so far, as well as an emulator.

We have already seen a few operating systems for microcontrollers that provide a user interface for a binary bootloader rather than persisting under whatever programs are running, so this marks an interesting departure. Only time will tell if it becomes a success, but perhaps it’s one to watch.

Emulate The 486 In Your Browser

You might fondly remember the days of the Intel 486, but you probably don’t have one on your desk anymore. If you’d like to emulate that classic hardware, you can now do it in your browser, thanks to [Jan de Jager].

What [Jan] has built is a 100% browser-based emulator for an Intel 80486DX2-66 PC. Obviously, it’s not just a CPU that’s being emulated here—[Jan] has gone so far as to throw in the motherboard and ISA/VLB adapter card emulation necessary to make this a real and functioning computer that runs inside a solitary browser tab.

It’s all written in ES6 JavaScript. It will happily run SeaBIOS, VGA BIOS, FreeDOS 1.3, and a whole bunch of classic games, like Wolfenstein 3D, Duke Nukem, and DOOM. There’s even a control panel where you can configure the PC how you like, from storage to expansion cards and all the rest.

Once upon a time an emulator was an application you had to download and run, hoping all the while that your new machine had enough grunt to emulate the classic hardware of your desires. These days, we have endless piles of CPU cycles to throw at everything and you can do it all within a browser. Or even on a tiny microcontroller, if you feel like it!