TechyMagThings

A pacemaker is implanted to send signals that regulate a patient’s heartbeat, and to do that, you need power. That means they require battery changes, and when the device in question happens to be inside your chest, that means surgery. Sometimes as often as every five years. [Alex Music] writing in Spectrum notes that researchers have a new paper discussing a possible alternative: a tiny patch stuck to the outside of the chest that uses ultrasound to pace the heart rhythm.

Rats, pigs, and human heart cell samples have all responded to the system. You might wonder how ultrasound could make your heart beat, but the new pacemaker relies on gene therapy to sensitize your heart cells to the high-frequency waves. The therapy is delivered by a simple injection.

In addition to the chest patch, the patient would need a data and power module that they could keep in their pocket. The gene therapy doesn’t alter your DNA but introduces RNA to make heart cells produce a sound-sensitive protein in the cell’s ion channels. When stimulated, the ion channels admit calcium, which causes the heart to beat.

Pacemakers are nothing less than a modern technological marvel. Maybe if this catches on, cheap junked pacemakers will show up on the surplus market. They could be useful.

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 are fans of macro pads and especially homebrew ones. The Apna Dost project by [np_vishwakarma] ticks most of our boxes. In addition to a few buttons, there’s an encoder, an OLED display, and it runs QMK firmware. Plus, it looks good, too.

We like that the system uses an RP2040. It is possible you have everything you need to put one of these together right now. We would wish for a few more keys, but it wouldn’t be hard to add them, either.

Perhaps we would have laid it out so the OLED could more easily label the macro keys, but — again — you could do that easily if you wanted to build your own. We did like that encoder could serve multiple purposes.

It always ticks us off when cheap macro pads you buy don’t use QMK or some other reasonable firmware. This one does, though, so it should be very easy to modify and customize.

We converted an old conference badge to a QMK macro pad of sorts. If you want a real deep dive on a much larger macro pad, that’s out there, too.

When you think of a computer, you probably don’t think of a tube full of motors and mechanics. However, as [Our Own Devices] shows, the Bendix AN5841 API Computer, an air position indicator computer, is exactly that. Using mechanical integrators and data from other analog systems on an airplane to provide key flight data to a pilot. You can see the video below.

These devices were made for military aircraft, including the B-29. It is odd that speed data can be derived from a pump that balances pressures using a fan. The video does a good job of explaining exactly how that works.

The way engineers used mechanics to convert physical measurements into analog computations is nothing short of amazing. You have to wonder how you dream up this kind of stuff. Perhaps mechanical engineers wonder the same thing about electronics. But we sort of doubt it.

We are glad our computer doesn’t have any flexible shafts or rotating disks to do math. But we do love looking at ones that did. Some analog computers used voltages instead of mechanics. This video made us think of the M13A1 ballistic computer and, of course, the Norden.

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.