Quetzal-1 Satellite Goes Open Source

July 4, 2023 by 30 Comments

Back in 2020, students from Universidad Del Valle De Guatemala (UVG) pulled off a really impressive feat, designing and building a CubeSat that lasted a whopping 211 days in orbit. In addition to telemetry and radio equipment, it carried a black-and-white camera payload.

But it turns out space is hard. The first pictures were solid black or white, with the automatic exposure process failing pretty badly. A pair of good pictures were taken by waiting until the satellite was passing over Guatemala during sunrise or sunset. A hung I2C bus led to battery drain, and the team tried a system reset to clear the hung state. Sadly the craft never came back to life after the reset, likely because of one of the Lithium-Ion battery cells failed completely in the low charge state.

That was 2020, so why are we covering it now? Because the project just released a massive trove of open source design documents, the software that ran on the satellite and ground station, and all the captured telemetry from the flight. It’s the ultimate bootstrap for anyone else designing a CubeSat, and hopefully provides enough clues to avoid some of the same issues.

Even though the mission had problems, it did achieve a lot of milestones, including the first picture of Earth taken by a Central American satellite. Even coming online and making radio contact from orbit to an earthbound station is quite a feat. The team is already looking forward to Quetzal-2, so stay tuned for more!

And if you want the details on the Quetzal-1 design, and what went wrong with the electrical system, both PDF papers have been released. Seeing more open source in space is an encouraging development, and one that should continue to grow as the cost of payloads to orbit continues to fall. We’ve covered the UPSat satellite, the PyCubed framework, and even the RTL-SDR for listening to satellite radio traffic.

Windows 10 The Hard Way: On A Phone

July 4, 2023 by 19 Comments

Sure, there are — or were — Windows phones. But [neozed] wanted something different. An earlier project ran Windows 10 on the Raspberry Pi 4 with some tricks, but those are sometimes hard to come by lately, so the next project was to put one on a Xiaomi PocoPhone F1.

The choice of phone wasn’t an accident. There was enough support and information on the Snapdragon 845 to pull the trick off, and this is one of the phones that looked like it should work. They were pretty inexpensive on eBay and have 128 GB of flash and 6 GB of RAM.

After a few false starts, the phone yielded to fastboot mode. Loading UEFI firmware allows you to re-partition the disks using a PC. With the partitions set up, you must find an ARM Windows 10 image to load. Sounds simple, but as you’ll see in the post, the devil is always in the details. Combined with a USB dock, the end result is a tiny Windows computer. However, it does seem like a lot of work. Even the original poster says: “TL;DR don’t do it… get a used Surface X instead.”

We’ve seen old phones repurposed before, of course. Or, go the other way: start from scratch and build a new phone. We won’t judge, either way.

There’s Always Room For Another Cycle Accurate PC Emulator

July 3, 2023 by 17 Comments

While many Hackaday readers will have their own pieces of classic hardware lovingly preserved, it still remains that most of us get our fix of retro goodness through emulation. And while there are emulators aplenty for almost every platform imaginable, the world of emulation is never complete. Thus we’re happy to encounter a new player in the form of MartyPC, a cycle-accurate 8088 PC emulator written in Rust.

It’s a project that started only in April 2022, but alongside such in-depth processor support it has the full range of PC and XT peripherals including CGA and VGA cards to the extent that it will run even the most hardware-demanding demos. Below the break you can see it running the fiendishly hardware-specific PC demo Area 5150 — thought to be the first time an emulator has managed this task.

If there’s a snag it’s that the releases are so far Windows-only, though it’s claimed that it should also compile on other major platforms. There’s also a WebAssembly version, though sadly the link to it doesn’t work. We look forward to this emulator maturing, because we’re sure it will become a PC standby. After all, not everyone managed to snag one of the recent batch of new hardware.

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Pratt Parsing For Algebraic Expressions

July 3, 2023 by 10 Comments

Parsing algebraic expressions is always a pain. If you need to compute, say, 2+4*2, the answer should be the same as (2 + (4 *2)), not ((2 + 4) * 2) — in other words, the right answer is 10, not 12. The classic way to do this is to use two stacks and a table of precedences for the operators. However, [Martin Janiczek] prefers to use Pratt Parsers and wants to show you how they work.

The parser is named after [Vaughn Pratt]. The algorithm works with a table of precedence where operators with higher precedence have higher numbers. It then builds a left and right portion of a string, using recursion. So if you consider 2+4*2, you wind up, on the first pass, with (2+ parse(4*2)). The second parse returns a full expression to produce: (2+(4*2)).

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Cooling Paint You Can Actually Make

July 3, 2023 by 59 Comments

[NightHawkInLight] has been working on radiative sky paint. (Video, embedded below.) That’s a coating that radiates heat in the infrared spectrum at a wavelength that isn’t readily absorbed or reflected by the atmosphere. The result is a passive system that keeps materials a few degrees cooler in direct sunlight than an untreated piece in the shade. That sounds a bit like magic, but apparently the math checks out.

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Adding Smart Watch Features To Vintage Casio

July 3, 2023 by 16 Comments

[Matteo] has been a fan of the Casio F-91W wristwatch virtually since its release in 1989. And not without good reason, either. The watch boasts reliable timekeeping and extremely long battery life thanks to a modern quartz crystal and has just about every feature needed in a watch such as an alarm and a timer. And, since it’s been in use since the 80s, it’s also a device built to last. The only thing that’s really missing from it, at least as far as [Matteo] was concerned, was a contactless payment ability.

Contactless systems use near-field communication (NFC) to remotely power a small chip via a radio antenna when in close proximity. All that’s really required for a system like this is to figure out a way to get a chip and an antenna and to place them inside a new device. [Matteo] scavenges the chip from a payment card, but then builds a new antenna by hand in order to ensure that it fits into the smaller watch face. Using a NanoVNA as an antenna analyzer he is able to recreate the performance of the original antenna setup in the smaller form factor and verify everything works before sealing it all up in a 3D-printed enclosure that sandwiches the watch.

There are a few reasons why using a contactless payment system with a watch like this, instead of relying on a smartwatch, might be preferential. For one, [Matteo] hopes to explore the idea that one of the physical buttons on the watch could be used to physically disable the device to reduce pickpocketing risk if needed. It’s also good to not have to buy the latest high-dollar tech gadget just for conveniences like this too, but we’ve seen in the past that it’s not too hard just to get these systems out of their cards in the first place.

The Chess Computer From 1912

July 3, 2023 by 12 Comments

Who was [Leonardo Torres Quevedo]? Not exactly a household name, but as [IEEE Spectrum] points out, he invented a chess automaton in 1920 that would foreshadow the next century’s obsession with computers playing chess.

Don’t confuse this with the infamous Mechanical Turk, which appeared to be a chess computer but was really a guy hiding inside a fake chess computer. The Spanish engineer’s machine really did play a modified end game. The chessboard was vertical, and pegs represented pieces. There were mechanical arms to move the pegs. The device actually dates back to 1912, with a public demonstration in Paris in 1914. Given [Quevedo’s] native language, the machine was called El Ajedrecista.

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