A drone is shown, carrying underneath it a white plastic box. On the side of the box are two patch antennas. A camera extends from one end of the box, and a large GPS antenna from the other end.

Synthetic Aperture Radar Drone Gets Interferometric Imaging

September 28, 2026 by No comments

It’s been more than a year since [Henrik Forstén] built the first iteration of his synthetic-aperture radar (SAR) imaging drone, and he’s certainly been productive in the meantime. Not only did he develop a much more powerful autofocus algorithm to clean up the radar images, but he also extended the software to create high-resolution interferometric images.

The main limitation of the original radar system was the GPS, which only had a resolution of about one meter; the autofocus algorithm owed much of its improved clarity to an improved estimation of the drone’s position. A simpler, though more expensive, solution was to add an RTK-capable GPS receiver. RTK (Real-Time Kinematic) receivers use a fixed ground station to constantly transmit a correction signal, letting them reach a couple centimeters of accuracy. Since the drone doesn’t actually need to know its position in real time, it can also use PPK (Post-Processing Kinematic) positioning, which compares recorded GPS signals after the flight to obtain similarly accurate positions.

[Henrik] also implemented a few other hardware improvements, including stabilizing the phase-locked loop used to generate the radar’s frequency sweep. The controller FPGA’s SD card interface had too low a bandwidth to record data in real time, so [Henrik] also implemented a simple, fast compression algorithm to speed that up. Most significantly, he also developed a program for interferometric imaging. The drone flies the same path twice at different altitudes; by comparing phase information from different passes, it’s possible to detect a target’s elevation. Normally, the radar program assumes constant elevation, making tall objects seem to lean toward the radar source; an interferogram, on the other hand, allowed [Henrik] to generate a detailed elevation map.

[Henrik] is no stranger to synthetic aperture radar; we’ve previously covered a bike-mounted iteration and a budget SAR system. If the concepts behind this are still a bit fuzzy, we’ve also covered a guide to making your own SAR setup.

Places To Visit: Landschaftspark Duisburg-Nord

September 28, 2026 by 8 Comments

There are many benefits to spending time in the park, but perhaps few of them have a Hackaday angle. There’s a park in Germany you might want to make an exception for, and it lies in the Ruhrpott city of Duisburg.

I was lucky enough last month to join a friend as she toured Germany for the first time with a caravan. It’s a large country with many beautiful places, so her choice might seem unexpected at first sight. The Ruhrpott, or Ruhr area, is a loose conurbation of industrial cities that loosely follows the river Ruhr on its trip to the Rhine on the western edge of the country. It’s close to  deposits of coal and iron ore, so just like similar areas in other countries, it became a centre for heavy industry. Today that continues, but as you might expect it’s also dotted with the remains of former industries. It’s one of those which is our subject for today, and it offers a very unusual opportunity.

A view out over a wooded post industrial landscape against a grey cloudy sky. In the foreground is a hiuge traverser crane.
Looking out over the former ore bunkers shows just how huge this site is.

Landschaftspark Duisburg-Nord is a forest park on the northern side of the city of Duisburg. But of course that’s not the whole story, because until 1985 it was the site of the Thyssen ironworks. In rehabilitating the site they chose to keep the main structures of the ironworks intact as they reclaimed the surrounding polluted industrial land, so today it may be one of the few places in the world where you can free of charge get up-close and personal with a fully-intact and preserved blast furnace. The site has three of them remaining along with their associated ore and gas processing plants, and the largest and newest, blast furnace number 5, is a structure you can climb to its top. If you’ve ever been curious about iron smelting, this is the place to come. Continue reading “Places To Visit: Landschaftspark Duisburg-Nord” →

Jet Megatextures Demo For ESP32-S3

September 28, 2026 by 1 Comment

Mipmapping is a good way to add a lot more detail to a 3D scene without overburdening the rendering hardware with detail that won’t be seen by the user. This level-of-detail rendering technique was demonstrated on the N64 console hardware a few years ago by [James Lambert] with [Michael Biggins], also known as [PhonicUK], now demonstrating it on the ESP32-S3 using his own Jet rendering engine.

Although level-of-detail rendering really speeds things up, it does also require far larger texture sizes, with [James]’s N64 demo taking up 40 MB of a 64 MB cartridge. To fit it on an ESP32-S3 with 16 MB of PSRAM and no SD card expansion or such the textures were further compressed to use 8-bit indexing, resulting in a mere 5.01 MB of textures.

There’s a demonstration video over on the associated Reddit thread, which shows the camera moving through the scene. Even if not as exciting as the Wipeout port by [Michael] that we previously covered, it does make clear that even without a proper 3D GPU the ESP32-S3 is already a pretty capable gaming machine that can go toe-to-toe with some 1990s consoles.

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The FPGA Chronicles: Exploring The Tang Nano 20K

September 28, 2026 by 13 Comments

FPGAs used to be mysterious, expensive devices, but these days you can buy surprisingly capable boards for very little money. Some years ago, I did an FPGA Bootcamp over on Hackaday.io. Much of that material still applies, but the hardware is dated. So I decided it was time to update it, using the inexpensive Tang Nano 20K and its GOWIN GW2AR-18 FPGA as the main platform, with perhaps a few excursions into other FPGAs.

History and Motivation

Once upon a time, if you wanted to have a custom IC, you went with a wheelbarrow full of money to a semiconductor company. However, some smart person at a semiconductor fab eventually realized they could make a chip with a lot of uncommitted blocks on it and then, for a custom chip, only design the wiring that connected them together. This still required a wheelbarrow full of money, but it was a smaller wheelbarrow.

Then one day, someone realized they could do the same thing but make the electrical connections between the blocks configurable. Maybe have fuses you can blow, or use EEPROM or RAM cells to remember which blocks are connected to which. It is complicated, sure, but then you can make many of these chips and sell them to people who could, in theory, make their own custom chips without your help.

When do you need an FPGA? A classic classroom exercise for an FPGA, for example, is a traffic light because it shows off how to do state machines, which are important for some kinds of FPGA designs. But other than as a learning example, why would you do this? Even a simple 8-bit CPU can handle a traffic light.

Suppose instead that you have hundreds of digital sensors on a rocket, and any one of them must raise an alarm within a few microseconds. A processor has to sample inputs in groups, service interrupts, or rely on extra hardware. An FPGA can simply implement the equivalent of one enormous OR gate. It watches every input continuously, and unrelated logic elsewhere in the FPGA does not steal execution time from it. Can you do it with a microcontroller? Probably, but not easily. For some classes of problems, an FPGA is the better answer.

Of course, you can also build a CPU on your FPGA and some FPGAs have CPUs in the same package. This is often a sweet spot because then things that are easy to do in software, you do in software. Things that are easier to do in hardware, you do in the FPGA.

Continue reading “The FPGA Chronicles: Exploring The Tang Nano 20K” →

Using The SNES Super FX Chip To Run Super Mario 64

September 28, 2026 by 7 Comments

Although the Nintendo 64 was the first to bring real 3D graphics to the table in 1996, the Super Nintendo had an ace up its sleeve in the form of the Super FX chip. One major advantage of using cartridge-based games is that you have the option to add wild features such as a 3D graphics chip to your SNES, something that got used to make games like Star Fox, and as [Tobi] demonstrates in a recent video, can also totally run Super Mario 64 if you squint a lot.

While there’s a rumor that Nintendo was looking to release a ‘Super Mario FX’ game for the SNES, there’s no evidence for such a project. Fortunately these days we got hobbyists prepared to give it a shake to see what a determined group of SNES game developers could have accomplished back then.

The pleasant surprise here is that although a new engine was needed, the SM64 assets could be used with this ‘SMFX’ game and it runs fairly well. There is still room for performance improvement, and the 2 MB memory limit is a problem that may require some culling of parts of levels.

Frames are painted back to front since there’s no advanced Z-culling or similar features, but it shows just how capable the Super FX chip is. [Tobi] has said that he’ll look at releasing the project in some form once he’s happy with how it works and runs, which is definitely something that we’ll look forward to.

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An IR Blaster Project, In A Nutshell

September 28, 2026 by 22 Comments

The speed that computers have gotten smaller is a bit mind-bending. Most of us now walk around with computers in our pockets that would have rivaled the supercomputers from a few decades ago. And, although it seems like the speed at which things are getting smaller and faster has slowed a bit compared to the rapid pace of the 90s and 00s, some truly minuscule computers are accessible nowadays. So much so that it’s possible to do useful computing inside a walnut shell.

The first step in this build is to crack into a walnut. Most have a natural seam that separates two hemispheres, so splitting it open, enjoying a small snack, and then adding some small neodymium magnets on the inside of that seam to close up the shell is not too difficult. From there, some LEDs were installed at various points in the shell, with an ESP32-C3 installed in the middle to control everything and oriented so that its USB port is still accessible.

Although putting a small microcontroller in a nutshell might seem like a novelty, [JSK-koubou] is actually using the LEDs to perform a useful task. The walnut sits in his living room and connects to a home automation system through the ESP32, and when it receives a command it uses the LEDs to send infrared signals to non-connected devices. Hiding projects in unexpected places is a fun pastime, like this Meshtastic node hidden in a landscape light.

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Hackaday Links: September 27, 2026

September 27, 2026 by 2 Comments

It isn’t quite hailing frequencies open, but researchers from Harvard claim they’ve picked up a radio signal directly from a nearby exoplanet. Before you get too excited, planets in our solar system also emit RF, so no one credible is claiming these are extraterrestrial reruns of their version of I Love Lucy, but it is the first time they’ve localized a radio signal to an exoplanet, in this case, Beta Pictoris B.

Speaking of space, the asteroid formerly known as 1981 EC26 is now sporting a new moniker: (14331) Alyankovic. If you think that sounds like (Weird) Al Yankovic, you aren’t wrong. The Tucson Star reports that, thanks to the efforts of several planetary scientists who are also Weird Al fans, the International Astronomical Union made the name official. Apparently, another asteroid now bears a name in honor of Weird Al’s predecessor, Tom Lehrer.

The postmarketOS — er — Nura logo.

If you follow open mobile phone software, you probably know the name postmarketOS, a Linux distribution based on Alpine aimed at mobile phones and tablets. Well, now you can forget it. The project announced a name change, so we’re now talking about Nura. Why Nura? According to the team, it is a shortened form of Nuraghe, some granite structures in Sardinia that are over 5,000 years old. The FAQ mentions that postmarketOS was hard to remember. We aren’t sure Nura is that much more memorable. Perhaps they should have pivoted to Phonz OS.

Continue reading “Hackaday Links: September 27, 2026” →