Mysterious Files PH

We have seen a number of self-playing chess boards over the years, but the general theme has been standard chess pieces moved by either an internal electromagnet or an external robotic arm. This is, of course, a reasonable choice, as it reduces complexity, and sometimes you can even use standard chess pieces on a regular board. But what if each piece could move by itself? That seems cooler, so that’s what [3DprintedLife] did with 3D-printed chess pieces that are also tiny robots.

Although technically not the first, as you can buy the commercial Chessnut Move offering, this being an open hardware and source project makes it a lot more interesting, also because the general design is generic enough to be usable for applications other than just playing chess.

The MiniBots, as the individual pieces are called, are built around a custom PCB with an ESP32-C3 module, two PMO8-2 miniature stepper motors with requisite drivers, a magnetometer, and are powered by a 170 mAh LiPo battery. Communication with the central hub is done using ESP-NOW, with each MiniBot using its own dedicated channel.

This hub’s mainboard also runs on an ESP32-C3 for the wireless interface, while the processing is handled via a serial link with a Raspberry Pi SBC that runs the main Python-based software. Localizing the individual pieces on the board is done by scanning electromagnets embedded in the board and using the readings from the individual magnetometers to triangulate the positions.

Although at the end of the video a basic prototype sort of works, the ESP32-C3, being a single-core MCU, tripped up the firmware, necessitating some changes that should be in the next update, along with power saving and easier recharging being issues to address.

If you want to see a more conventional chess robot, we’ve seen plenty.

If you have a Bambu Labs printer and aren’t keen to send your files to Bambu’s servers with each print job, then check out Bambuddy, an open-source, self-hosted, cloud-free central command that offers a local alternative for managing Bambu Labs printers. It acts as a replacement for the official cloud services, allowing you to slice, print, and monitor with full local control and zero reliance on Bambu Labs’ servers.

To use it, one installs Bambuddy, then puts their printer(s) into LAN-only mode. Doing this disables cloud functionality, including remote access. Then one enables Developer Mode, which allows external software to control printer functions via a machine API. Once that’s done, the printers can be added to Bambuddy.

Bambuddy then acts as a full-featured control panel and management center for anywhere from one to forty printers. It runs on Linux, macOS, or Windows, and a Raspberry Pi is a common install target.

Bambu Labs makes indisputably high-quality printers, and using their software and official app is certainly convenient. But the fact that every print job goes through Bambu’s servers, and a software architecture that frustrates home-grown solutions? Not so much. Add AGPLv3 violations and some heavy-handed legal behavior to the mix, and it’s easy to understand the motivation for an alternative to the factory software.

Bambuddy has a huge number of features — including an integrated slicer and proxy mode for remote access — and it may look a little intimidating at first. Fortunately, the project’s website offers a live sandbox demo with simulated printers, which should be right up the alley of those who prefer to learn by clicking around in a consequence-free environment.

Although both a SEM and a TEM are electron microscopes, their working principles and images are very different. Whereas an SEM uses secondary electrons ejected after bombarding a sample’s surface with primary electrons, a TEM works more like an X-ray machine, with a sensor placed behind the sample to record primary electrons after they pass through said sample. It is, however, possible to turn a SEM into a TEM with some creativity, as [ProjectsInFlight] recently did with his SEM.

We previously covered how the SEM in the video was saved from being scrapped and subsequently revived, and now it is getting a pretty nice upgrade. That said, this SEM to TEM change isn’t anything new, with so-called STEM imaging having been possible for ages using a rather simple reflecting adapter. The problem here is that such adapters cost enough to make you dread filing a budget request, yet they are simple enough that you might be able to DIY one.

The main concern with the DIY adapter was clearance between the sample holder and the fragile components inside the chamber. This turned out to be a hair under 14 mm (0.55″), giving not a lot of space to work with, but that was relative to the standard bulky sample holder. With a thinner sample plate machined out of aluminum, significantly more space became available, including for the primary electron mirror and shield for the secondary electrons.

Some more lathe, milling, and tapping work later, the entire sample holder came together. During testing a hack was implemented to enable adjusting the mirror angle while in the evacuated vacuum chamber so that the adapter could be dialed-in. Subsequently, a first sample was imagined in the form of gold nanoparticles, which revealed a leaky secondary electron shield due to bypassing.

Further testing revealed that the shield needed to extend much higher to meaningfully block secondary electrons, after which the TEM image massively improved. Subsequently, a previously expired mosquito graciously donated its wings to science, with TEM imaging clearly revealing the delicate structures within these wonders of evolutionary design.

The next challenge will be to TEM image biological cells, which require substantial preparation.

This isn’t the first STEM converter we’ve seen. The SEM has a long checkered history that we’ve talked about before, too.

We were excited to see [Z0hn]’s project about 3D printing a custom watch from scratch — both because it was an exciting idea, and because the pictures looked great. While we still liked the project, we quickly realized it wasn’t really printing a watch so much as it was printing a case that holds an off-the-shelf movement. But it still looked great.

Many homebrew watches are cool and fine to wear to your next hackerspace board meeting. But this watch wouldn’t raise an eyebrow out among the normal public. Conventional watches use press-fit backs, tiny screws, or make the back screw into the housing. None of those are great for 3D printing, so this watch uses a bayonet connector, which is easy to create, robust, and reliable.

The watch looks easy to modify, so if you don’t like, for example, the unusual crown placement, you can change it. The movement is a Miyota 8N24 and, of course, the crystal is off-the-shelf, too.

While not exactly a printed watch, it was still pretty cool, and there are lessons to be learned here if you want to pull off the same feat. Or just go full on hacker. You could, too, try your hand with an open source movement.

Although in our imagination those scale models of cars certainly can drive and steer just like their full-scale counterparts, there’s something incredibly satisfying about watching them truly come to life. Here [diorama111] is an absolute master at the craft, with the most recent conversion of a 1:150 Toyota Probox car model once again demonstrating these skills with casual ease.

We previously covered such conversions, with another recent one in 2024 involving another 1:150 scale model. That particular one demonstrated driving around on scale model roads, which shows a good practical use of this conversion if you want to have e.g. a scale model town with cars that actually drive around.

In the video you can see how first the base of the scale model has a tiny 25 mAh Li-polymer battery installed, along with two motors, one for steering and one for driving using a rod-linkage system and a lead screw.

The tiny gears used were salvaged from mechanical watches, with photoreflectors keeping track of the driving and steering positions. Remote control is done by infrared, with a tiny SMD IR receiver module in the car, while charging and programming of the MCU is done via terminals installed on the bottom.

In the final part of the video the car is demonstrated driving around, with working head- and rear lights, as well as blinkers and stop lights, including the top rear one. In the video description links are provided to the various schematics and software on Google Drive for those who are feeling like a fun Sunday afternoon project.

Sometimes it’s useful to add extra mass to a 3D print, and [Joe Fedewa] shared a simple and effective technique that uses plaster of Paris. Rather than pause the print and insert hardware or weighted bits inside, he designed the base as hollow. Not in the sense of zero infill, but in the sense of modeling a cavity into the open bottom of the object.

After the print is complete, he mixes the dry plaster with water until it creates a thick but pourable mixture. Then the object gets turned upside-down and the cavity filled. In about an hour, it will have set up enough to be handled and worked.

Plaster of Paris has a good heft to it, but more importantly it can be made perfectly presentable thanks to being very friendly to post-processing. Any rough spots can be easily sanded and the whole bottom smoothed, so one doesn’t even need to cap it off. Completely cured plaster can be sealed with a clear coat for a more durable finish, if desired.

This basic concept has been used in other ways, such as reinforcing prints with concrete to yield parts solid enough to make tools out of. But using plaster of Paris not just to add mass, but specifically to create a presentable surface that doesn’t need covering up is a neat and highly economical adaptation of the idea.

Other methods of adding mass to a 3D print include inserting metal balls or chunky nuts, bolts, or other hardware, but this method doesn’t require pausing prints to insert things. Nor does it require sealing off or capping the print, messing with goopy epoxies or resins, or spending a lot of money — making it a good one to keep in mind in case it comes in handy someday.

Last week, Elliot got his foot stepped on by a 1.5 metric ton draft horse, and boy is he glad to be back to the relative safety of podcasting! Joining him today is Jenny List, no stranger to farm life, who has been trodden by a cow. It’s going to be one of those podcasts, folks.

Another thing the two hosts have in common is a love for the mystery of the numbers station. But did you know that GPS satellites, for the last 20 years, have broadcast literally millions of secret messages to everyone on the earth with a receiver? After that bombshell, we have an ATtiny85 emulating an 8080, a primer on how to embed magnets in 3D prints, definitive proof that more than one cassette mechanism is still being manufactured, and a look at what makes home automation enthusiasts tick.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download in DRM-free MP3 and play it in space.

Episode 373 Show Notes:

News:

• No news is good news.  No Mailbag, on the other hand, is no fun!  Write or mail in a question to mailbag@hackaday.com.

What’s That Sound:

• Jenny came in with a sound this week. Have a guess at it!

Interesting Hacks of the Week:

• • Spy Tech: The GPS Numbers Station
    • New address for GNSS data and products – GFZ GNSS Observatory
    • Investigation into September 2020 GPS SVN 74 Performance Anomaly
  • Secret Radio Stations By The Numbers
    • Numbers Station Simulator, Right In Your Browser
  • An Unlikely Host For An 8080 Emulator
    • Because You Can: Linux On An Arduino Uno
  • Ways To Embed Magnets In 3D Prints And Not Ruin Printers
  • As It Turns Out, There’s More Than One Cassette Mechanism Being Made After All
    • Know Audio: Mixtapes, Tape Loops, And Razor Blades
  • Vintage Turntable Gets Brain Transplant And Home Assistant Integration
  • Connecting Your Car To Home Assistant
  • Print Your Own Robby The Robot
    • 3D Printing Computer Space

Quick Hacks:

• • • Elliot’s Picks:
      • The Winners Of The 2025 Obfuscated C Code Contest
      • If You Want To Hack Me, Come In Through The Speaker
      • Pico-Driven Ultrasound Enables Scaled Acoustic Model Of Home Stereo
      • Optimizing Pancakes From Chemical Principles
    • Jenny’s Picks:
      • Re-Enable All Compute Units On The PS5-like BC-250 Cryptomining Card
      • Less Than 10 Years? Commonwealth Fusion Systems Applies To Plug Into Grid In 2030s
      • A New Life For A Rare Console

Can’t-Miss Articles:

• • • Questions Remain About Tense Moment Aboard ISS
    • NASA Announces Artemis III Crew And Ambitious Goals
    • 10 Years Ago: EVA 23 – How A High Visibility Close Call Cut Short a Spacewalk – NASA
    • Remember When Flash Drives Were Going To Make Your PC Faster?