The GREMLIN sensor suite contains several sensing modalities to detect, track, characterize and identify UAP in areas of interest. (Credit: US AARO)

US’s UFO-Hunting Aerial Surveillance System Detailed In Report

November 17, 2024 by 16 Comments

Formerly known as Unidentified Flying Objects, Unidentified Anomalous Phenomena (UAP) is a category of observations that are exactly what the UAP label suggests. This topic concerns the US military very much, as a big part of national security involves knowing everything that appears in the skies. This is the reason for the development of a new sensor suite by the Pentagon called GREMLIN. Recently, a new report has provided more details about what this system actually does.

Managed by the All-domain Anomaly Resolution Office (AARO) within the DoD, GREMLIN blends many different sensors, ranging from radar to ADS-B and RF monitors, together to establish a baseline and capture any anomalies within the 90-day monitoring period to characterize them.

UAPs were a popular topic even before the 1950s when people began to see them everywhere. Usually taking the form of lights or fast-moving objects in the sky, most UAP reports can be readily classified as weather balloons, satellites like Starlink, airplanes, the Northern Lights, the ISS, or planets like Mars and Venus. There are also curious phenomena such as the Hessdalen lights, which appear to be a geological, piezoelectric phenomenon, though our understanding of such natural lighting phenomena remains limited.

But it is never aliens, that’s one thing we know for sure. Not that UFO’s don’t exist. Really.

Schooling ChatGPT On Antenna Theory Misconceptions

November 17, 2024 by 39 Comments

We’re not very far into the AI revolution at this point, but we’re far enough to know not to trust AI implicitly. If you accept what ChatGPT or any of the other AI chatbots have to say at face value, you might just embarrass yourself. Or worse, you might make a mistake designing your next antenna.

We’ll explain. [Gregg Messenger (VE6WO)] asked a seemingly simple question about antenna theory: Does an impedance mismatch between the antenna and a coaxial feedline result in common-mode current on the coax shield? It’s an important practical matter, as any ham who has had the painful experience of “RF in the shack” can tell you. They also will likely tell you that common-mode current on the shield is caused by an unbalanced antenna system, not an impedance mismatch. But when [Gregg] asked Google Gemini and ChatGPT that question, the answer came back that impedance mismatch can cause current flow on the shield. So who’s right?

In the first video below, [Gregg] built a simulated ham shack using a 100-MHz signal generator and a length of coaxial feedline. Using a toroidal ferrite core with a couple of turns of magnet wire and a capacitor as a current probe for his oscilloscope, he was unable to find a trace of the signal on the shield even if the feedline was unterminated, which produces the impedance mismatch that the chatbots thought would spell doom. To bring the point home, [Gregg] created another test setup in the second video, this time using a pair of telescoping whip antennas to stand in for a dipole antenna. With the coax connected directly to the dipole, which creates an unbalanced system, he measured a current on the feedline, which got worse when he further unbalanced the system by removing one of the legs. Adding a balun between the feedline and the antenna, which shifts the phase on each leg of the antenna 180° apart, cured the problem.

We found these demonstrations quite useful. It’s always good to see someone taking a chatbot to task over myths and common misperceptions. We look into baluns now and again. Or even ununs.

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ESP32 Hosts A USB Keyboard In This Typewriter

November 17, 2024 by 14 Comments

Did you know the ESP32 can be a USB host? Well it can, and [Volos] uses host mode to build this fun little word processor.

The venerable ESP32 has a well-known USB device mode. Anyone who has programmed one has used it. A bit less known is the microcontroller’s ability to host USB devices. These days, operating as a USB device is relatively simple. But acting as a host is a much more complex task. The ESP32 has a software host that works — but only for Human Interface Devices (HID).  Human interface devices generally are keyboards, mice, trackballs, and similar devices that handle data relatively slowly, forming the interface with us simple humans.

[Volos] uses the EspUsbHost Arduino library for this project. The library makes USB host mode simple to use. Another piece of the puzzle is the LCD board [Volos] picked. It has a dual-role USB Type-C port, meaning the hardware to switch roles is baked in. Other boards may require some modifications or special cables to make things work.

The software is the best part of this build. [Volos] implemented a simple word processor. It can save and load files from a microSD card and, of course, edit text — all controlled by a USB keyboard. He had to use a 4-bit palette to save memory. This gives the device a retro charm that reminds us of Don Lancaster’s TV Typewriter. The source for this and all of [Volos] projects can be found on GitHub. Now, all we need is a spell check that can fit in the memory constraints of the ESP32! We have to admit the chip has a lot of potential USB tricks.

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A Handheld Gaming PC With Steam Deck Vibes

November 17, 2024 by 9 Comments

Since its inception, the Steam Deck has been a bit of a game changer in the PC gaming world. The goal of the handheld console was to make PC gaming as easy and straightforward as a walled-garden proprietary console like a Switch or Playstation but still allow for the more open gaming experience of a PC. At its core, though, it’s essentially a standard PC with the parts reorganized into handheld form, and there’s no reason any other small-form-factor PC can’t be made into a similar system. [CNCDan] has the skills and tools needed to do this and shows us how it’s done.

The build is based around a NUC, a small form factor computer that typically uses the same low-power mobile processors and graphics cards found in laptops but without the built-in battery or screen. This one has an AMD Ryzen 7 processor with Radeon graphics, making it reasonably high-performing for its size. After measuring out the dimensions of the small computer and preparing for other components like the battery, joysticks, buttons, and even a trackpad, it was time to create the case. Instead of turning to a 3D printer, this one is instead milled on a CNC machine. Something tells us that [CNCDan] prefers subtractive manufacturing in general.

With all the parts assembled in the case, the build turns into a faithful Steam Deck replica with a few bonuses, like an exposed Ethernet port and the knowledge that everything can easily be fixed since it was built from the ground up in the first place. The other great thing about builds like these is they don’t need an obscure NUC for the hardware; you can always grab your old Framework mainboard for handheld gaming instead. Reminded us of the NucDeck.

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Classic LED Bubble Displays Ride Again

November 17, 2024 by 17 Comments

Hewlett-Packard used to make some pretty cool LED displays, many of which appeared in their iconic pocket calculators back in the 1970s and 1980s. [Upir] tracked down some of these classic bubble displays and used them with a microcontroller. We love the results!

The displays featured here, the HPDL-1414, aren’t quite what would have been found in an HP-35, of course. These displays have 16 segments for reasonably legible approximations of most of the ASCII character set. Also, these aren’t just the displays; rather, a pair of the bubble-topped displays, each with four characters, is mounted to a module that provides a serial interface. [Upir] found these modules online, but despite the HP logo on the PCB silkscreen, it’s not really clear who made them. The documentation was a bit thin, to say the least, but with a little translation help from Google, he figured out the serial parameters and the character encoding. The video below shows him putting these modules through their paces.

Unusually for [upir], who has made a name for himself hacking displays to do things they weren’t designed to do, he stuck with the stock character set baked into this module. We think it would be fun to get one of these modules and hack the firmware to provide alternative character sets or even get a few of the naked displays and build a custom interface. Sounds like a fun rainy-day project.

This reminded us of another HP display project we saw a while back. Or, roll your own displays.

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Close-up of a CPU

Register Renaming: The Art Of Parallel Processing

November 16, 2024 by 12 Comments

In the quest for faster computing, modern CPUs have turned to innovative techniques to optimize instruction execution. One such technique, register renaming, is a crucial component that helps us achieve the impressive multi-tasking abilities of modern processors. If you’re keen on hacking or tinkering with how CPUs manage tasks, this is one concept you’ll want to understand. Here’s a breakdown of how it works and you can watch the video, below.

In a nutshell, register renaming allows CPUs to bypass the restrictions imposed by a limited number of registers. Consider a scenario where two operations need to access the same register at once: without renaming, the CPU would be stuck, having to wait for one task to complete before starting another. Enter the renaming trick—registers are reassigned on the fly, so different tasks can use the same logical register but physically reside in different slots. This drastically reduces idle time and boosts parallel tasking. Of course, you also have to ensure that the register you are using has the correct contents at the time you are using it, but there are many ways to solve that problem. The basic technique dates back to some IBM System/360 computers and other high-performance mainframes.

Register renaming isn’t the only way to solve this problem. There’s a lot that goes into a superscalar CPU.

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Open Source Universal ROM Programmer Grows Up

November 16, 2024 by 18 Comments

When we first looked at [Anders Nielsen’s] EEPROM programmer project, it was nice but needed some software and manual intervention and had some limitations on the parts you could program. But through the magic of Open-Source collaboration, revision 2 of the project overcomes all of these limitations and—as you can see in the video below—looks very polished.

If you recall, the programmer is in a “shield” format that can plug into an Arduino or — if you prefer a retrocomputer — a 6502uno. Along with hardware improvements from the community, [Henrik Olsson] wrote Python software to handle the programming (see the second video below).

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