TechyMagThings

Well, that was fast! Last week, we reported on two apparently simultaneous hacks using the 2.4 GHz radio inside many ESP32 variants that enabled raw access to the radio samples, turning it into a listen-only software defined radio (SDR) platform. Listen only? That’s only half of the SDR story.

Last weekend, [Murmel] got started fixing that, and released an early early version of ESP32 firmware that can also transmit, and got it working with gqrx. He demos it by communicating using a Hellschrieber mode of his own devising between an S3 and a C6. And he didn’t stop there, either. He’s working on 802.15.4 modulation at the moment, which means that maybe soon your ESP32 will speak ZigBee.

This is all in the roughly 2.4 GHz band, but Espressif’s API suggests that the radios will tune down as low as 100 MHz, although we can hardly imagine that the filters are tuned to make that particularly effective. Still, it’s clear that the boundaries on the ESP-SDR are just starting to get pushed.

If the early hacks on the RTL-SDR set off a wave of hacker SDR radio experimentation, and we can only hope that this is the beginning of the ESP-SDR era. Thanks then to [Murmel] – aka [Marble] – and the original hacks coming from the Espargos team for kicking this all off!

Game consoles tend to have a weak spot or two that will take certain units out sooner than they would due to normal parts aging. In the case of the Wii U it’s the eMMC storage IC with the console’s firmware and any user data that likes to keel over, with the SK Hynix variant reportedly developing faulty cells much sooner than the Samsung and Toshiba chips. If you want to check the health of these eMMC ICs in your Wii U, you can do so easily now with the Wafel Installer project by [zer00p].

This doesn’t take much more than navigating to the wafel.xyz URL on the Wii U to launch the installer on any (unmodified) Wii U, or alternatively starting it from an SD card if you’re running a homebrew-enabled console. This can also install the Stroopwafel CFW, ISFSax and the Aroma homebrew environment, but the NAND testing option in the installer’s menu is what you want to select if you’re not into homebrew or have already cracked open the console for said sweet homebrew action.

All of this is covered in this video by [FunkyScott47], whose Wii U’s Samsung-branded eMMC is fortunately still all fine, but it shows off the variety of tests available. Unless the eMMC is already quite cooked this should take only a minute or two, so it’s pretty good for ease of mind.

With the heavily waffle, syrup and stroopwafel-coded naming scheme for these tools we can not be held responsible for a sudden case of the munchies, of course.

The variant of origami called kirigami (‘cut paper’ in Japanese) also starts off with a sheet of paper, but it allows for cutting the paper to increase the number of shapes that you can create. It is this technique that [Matthew Lim] used to create a number of three-dimensional designs that can convert between a flat configuration and some kind of functional object without any bolts, glue or similar. These include everything from a phone grip to a pretty sizeable side table.

The video starts with an interesting demonstration of how to fold an origami crane that has a smaller crane on its back. This is documented in a 1797 book on the many ways to fold a crane, with one of the first known instances where cuts are made in the single sheet of paper, which becomes the second, much smaller crane.

The same book extends that idea into making an origami grid that can fold into a grid of cranes after making a series of cuts. Later this form of origami got the name ‘kirigami’, with the video demonstrating how a few strategic cuts in an original flat shape can make it much more functional, based on scientific papers like this 2024 one by [Liu] et al. on cylindrical origami with tunable mechanical behavior.

For these functional mechanisms a laser cutter and FDM printer are used to prototype and test increasingly more advanced versions of the pop-up mechanism, before moving on to make full-sized furniture using plywood panels and 3D printed hinges. The coolest part about the resulting table is that it can be changed into different configurations, with the mechanism locking into its new position to make a relatively stable new shape.

Even if not immediately practical, these mechanisms provide interesting options for robotics and flat-pack furniture alike, as well as in applications like space exploration where every gram and cubic millimeter of space counts.

Perhaps the most famous of software-defined radios is the RTL-SDR, which is very cheap because it’s a digital TV receiver that’s been pressed into service delivering raw I and Q data streams. But the RTL-SDR is certainly not the only chipset that can do this, and today we have a new one.

The MediaTek MT7996 radio chip in the Gemtek W1700K WiFi 7 router can serve as a very competent SDR receiver, and here’s [h0m3us3r] with the code to make it stream over Ethernet to a Linux machine with a web server, through the device’s SoC.

The radio works on the 2.4, 5, and 6 GHz bands, depending upon which version of the device — and thus which radio chip — you have. These may not be entirely useful to many who use lower bands, and given that a similar hack has been found for ESP32 radios on 2.4 GHz it’s likely a demand will arise for a receive up-converter. Until then, you can look at WiFi packets in a waterfall view to your heart’s content.

Since more and more devices now incorporate a radio, we hope that more such undocumented raw streaming modes will be found, and that we’ll see some other new SDRs. Something to look forward to.

The Prusa Core One+ INDX is an interesting upgrade to the base FDM printer by Prusa, featuring eight independent extruders – hence the INDX – that in theory should allow for multi-material and multi-color printing with very little purge waste. As [Thomas Sanladerer] found out during his experiences with this printer, there are a lot of issues with this machine, including the ability – or lack thereof – to print with non-Prusa filament.

Although the premise is solid, with a claimed 0.013 grams of purge waste per color or material change along with pretty nice dual-gear Bondtech extruders, the first major hurdle that [Thomas] encountered was that the mandatory calibration sequence on starting a print is designed to only work with Prusa’s own filament and its specific material properties. This resulted in an inability to print with Voxel PLA until [Thomas] removed this sequence manually from the g-code.

This is when [Thomas] found out that the entire print sequence uses the material presets for Prusa’s filament, resulting in a failed print. The results from the manual calibration are also not saved despite the display claiming it does, making this calibration on starting a print absolutely mandatory.

Other issues found are the useless position of the camera as it’s now blocked-off by the INDX hardware, with even manual peeking into the print chamber being heavily obscured by the contraption that holds the extruders. This makes even checking that filament has loaded correctly is borderline impossible, never mind ogling the printing process.

Although there’s a lot to like about this INDX upgrade to the Core One+, the above and other issues discussed in the video make it look somewhat shaky next to competitors like the Bambu Lab H2C and Snapmaker U1, as well as Prusa’s own XL toolchanger printers. During [Thomas]’s print test comparison between the XL and the Core One+ INDX there was no contest that the XL simply works, whereas the INDX even struggles with some Prusa filaments.

Sometimes, you want to build a simple project– the minimum viable product that solves your problem and nothing else. Other times you might be feeling a little extra, and want to use oodles of machined aluminum, six steppers, two cameras, a Teensy and a PC with a GPU just to bounce a ball. That’s the mood behind [T-Kuhn]’s hexa-bouncer, a Stewart Platform on steroids.  You can read all about it on his blog or witness it in action in the video below.  Trust us, really have to see it in action.

The six stepper motors connected to planetary gearboxes each drive an arm. Ingenious linkages allow the steppers to control a ping-pong paddle in every axis of rotation and translation. A Teensy 4.0 coordinates those steppers, but the marching orders are coming from a PC where a Unity application — available on GitHub — is performing Inverse Kinematics using the two cameras to track the ball in 3D. You might imagine a GPU comes in handy there. Both the article and the video get into more detail on the IK.

As for the physical build, as stated, it’s mostly aluminum milled out on [T-Kuhn]’s CNC machine, and while the pieces aren’t actually innumerable, he has to carve out 27 chunks of aluminum for each arm– plus all the bits in the base. The total count is over 300. It’s a very impressive robot to do the very mundane job of ball bouncing, which makes it probably the most overengineered thing we’ve seen this week. Kudos to [Tobias] for that!

Most of the other hexapods we’ve seen have been upside down in comparison, but since the last metal one was a horrifying man-carrying walker, we’ll forgive their misalignment. The computer vision workflow [T-Kuhn] is using for ball tracking is one he pioneered on his octo-bounce robot, which we also covered.

Thanks to [Tobias] for the tip! If you’ve built something so amazingly over-the-top that friends and family question your sanity, bounce it into our tips line! We understand.

Retrocomputer enthusiasts have a bad rap as nerds who just want to play old video games. There’s some truth in this, but the reality is that we’re nerds who want to do all sorts of things with old hardware — everything from consoles to servers. Servers like the DEC AlphaServer 2100 [derelictelectronics] picked up at Vintage Computer Festival Midwest this year. He was kind enough to record a tour for those of us who missed seeing these early Alpha machines in their heyday.

DEC did sell these units with multiple-CPU reports from the get-go, but the [derelictronics] particular model has  a single CPU board carrying a 64-bit Alpha RISC processor. This machine from 1994 dates to near the height of the RISC wars when it seemed everyone needed to have their own high-end architecture, all of them RISC. While the machine could host up to 2GB of RAM, the example [derelictelectronics] found only has 256 MB, which was still not a small number for 1994!

He does get the machine powered on around the 20-minute mark, but doesn’t get to see an operating system. We’ve seen before that booting an Alpha machine is a bit different, but the problems he’s having appear to be power-related. Hopefully he gets it up and running with OpenVMS as promised. In the meantime, the VAX-descended OS lives on in the cloud and in the virtual machine of this operating system museum.