2026-02-13 20:00:01
Pneumatics are a common way to add some motion to soft robotic actuators, but adding it to a robot can be somewhat of a chore. A method demonstrated by [Jackson K. Wilt] et al. (press release, preprint) involves using a 3D printing to extrude two materials: one elastomeric material and a fugitive ink that is used to create pneumatic channels which are dissolved after printing, leaving the empty channels to be filled with air.
By printing these materials with a rational, multi-material (RM-3DP) custom nozzle it’s possible to create various channel patterns, controlling the effect of compressed air on the elastomeric material. This way structures like hinges and muscles can be created, which can then be combined into more complex designs. One demonstrated design involves a human-like hand with digits that can move and grasp, for example.
In the demonstration the elastomeric material is photopolymerizable polyurethane-acrylate resin, with the fugitive ink being 30 wt% Pluronic F-127 in water. The desired pattern is determined beforehand with a simulation, followed by the printing and UV curing of the elastomeric resin.
As is typical of soft robotics implementations, the resulting robots are more about a soft touch than a lot of force, but could make for interesting artificial muscle designs due to how customizable the printing process is.
2026-02-13 17:00:59
The classic design of a mechanical clock generally consists of a display, a way to store energy, a way to release that energy at regular intervals, and a mechanism to transmit it where it needs to go. Most of us might be imagining a pendulum or a balance wheel, but there have been many other ways to maintain a reliable time standard with a physical object beyond these two common methods. This clock, for example, uses a rolling ball bearing as its time standard and [Tommy Jobson] discusses its operation in depth during a restoration.
The restoration of this clock, which [Tommy] theorizes was an amateur horological project even when it was new, starts by dismantling the clock nearly completely. The clock was quite dirty, so in addition to being thoroughly cleaned it also needed a bit of repair especially involving a few bent pins that stop the table’s rotation. These pins were replaced with stronger ones, and then everything in the clock’s movement was put back together. The tray carrying the ball bearing needed to be cleaned as well, and [Tommy] also added a lacquer to help preserve the original finish as long as possible. From there it was time to start calibrating the clock.
The ball bearing itself rolls back and forth along an inclined plane on a series of tracks. When it gets to the end it hits a lever which lets a bit of energy out of the movement, tilting the table back in the other direction to repeat the process. This is a much more involved process for getting an accurate time interval than a pendulum, so [Tommy] had a lot of work to do here. But in the end he was able to bring it back to life with an accuracy fairly close to a pendulum clock.
Ball bearings are a pretty popular medium for clock builds even in the modern era. This one uses them in a unique display, and a more recent version goes even further by using marbles to display digits directly.
Thanks to [Keith] for the tip!
2026-02-13 14:00:29
The Raspberry Pi Compute Module form factor is a tantalizing core for a potential laptop, with a CM5 module containing a fairly beefy SoC and RAM, with depending on the exact module also eMMC storage and WiFi. To turn this into a laptop you need a PCB to put the CM5 module on and slide it into a laptop shell. This is in effect what [Argon40] did with their crowdfunded ONE UP laptop, which [Jeff Geerling] has been tinkering with for a few weeks now, with some thoughts on how practical the concept of a CM5-based laptop is.
Most practical is probably the DIY option that [Jeff] opted for with the ‘Shell’ version that he bought, as that meant that he could pop in one of the CM5s that he had lying around. The resulting device is totally functional as a laptop, with all the Raspberry Pi 5 levels of performance you’d expect and with the repair-friendliness of a Framework laptop.
If you’re buying the Core version with the 8 GB CM5 module and 256 GB NVMe SSD included, you’re looking at €475 before shipping or the equivalent in your local currency. This puts it unfortunately in the territory of budget x86 laptops and used Apple MacBooks, even before taking into account the current AI-induced RAMpocalypse that’d push [Jeff]’s configuration to $600 if purchased new, with prices likely to only go up.
Even if this price isn’t a concern, and you just want to have a CM5-based laptop, [Jeff]’s experience got soured on poor customer support from [Argon40] and above all the Raspberry Pi’s arch nemesis: the inability to do sleep mode. With the lid closed it runs at 3.3 W idle, but that’ll run down the battery from 100% to flat in about 17 hours. Perhaps if Raspberry Pi added sleep states to their systems would it make for a good laptop core, as well as for a smartphone.
2026-02-13 11:00:12
[The Signal Path] shows us how to recreate a classic science experiment to measure the weight of an electron. Things are easier for us, because unlike [J. J. Thomson] in 1897, we have ready sources of electrons and measuring equipment. Check it out in the video below.
The main idea is to trap an electron using a magnetic field into a circular path. You can then compute the forces required to keep it in that circle, along with some other equations, and combine them. The result lets you compute the charge to mass ratio using parameters you can either control or measure, like the radius of the circular path and the electric field.
Helmholtz coils create the magnetic field, and a cold cathode tube provides the electrons. Honestly, the equipment looks a bit like something out of an old monster movie.
Of course, the result is the charge to mass ratio, which means to get the mass, you need to know the charge of the electron. Today, you can look that up, but in 1897, no one knew what it was. [Robert Millikan] would conduct another experiment using oil drops about a decade later to determine that number, and then the world could know the mass of a single electron.
The resulting ratio was very close to the accepted value. It would be fun to see someone replicate the oil drop experiment, too. You could spend a lot of time recreating classic science experiments. Some of the experiments are easy with today’s gear.
2026-02-13 08:00:01
For as long as small, hidden radio transmitters have existed, people have wanted a technology to detect them. One of the more effective ways to find hidden electronics is the nonlinear junction detector, which illuminates the area under investigation with high-frequency radio waves. Any P-N semiconductor junctions in the area will emit radio waves at harmonic frequencies of the original wave, due to their non-linear electronic response. If, however, you suspect that the electronics might be connected to a dangerous device, you’ll want a way to detect them from a distance. One solution is harmonic radar (also known as nonlinear radar), such as this phased-array system, which detects and localizes the harmonic response to a radio wave.
One basic problem is that semiconductor devices are very rarely connected to antennas optimized for the transmission of whatever harmonic you’re looking for, so the amount of electromagnetic radiation they emit is extremely low. To generate a detectable signal, a high-power transmitter and a very high-gain receiver are necessary. Since semiconductor junctions emit stronger lower harmonics, this system transmits in the 3-3.2 GHz range and only receives the 6-6.4 GHz second harmonic; to avoid false positives, the transmitter provides 28.8 decibels of self-generated harmonic suppression. To localize a stronger illumination signal to a particular point, both the transmit and receive channels use beam-steering antenna arrays.
In testing, the system was able to easily detect several cameras, an infrared sensor, a drone, a walkie-talkie, and a touch sensor, all while they were completely unpowered, at a range up to about ten meters. Concealing the devices in a desk drawer increased the ranging error, but only by about ten percent. Even in the worst-case scenario, when the system was detecting multiple devices in the same scene, the ranging error never got worse than about 0.7 meters, and the angular error was never worse than about one degree.
For a refresher on the principles of the technology, we’ve covered nonlinear junction detectors before. While the complexity of this system seems to put it beyond the reach of amateurs, we’ve seen some equally impressive homemade radar systems before.
2026-02-13 05:00:47
Ham radio operators may be familiar with slow-scan television (SSTV) where an image is sent out over the airwaves to be received, decoded, and displayed on a computer monitor by other radio operators. It’s a niche mode that isn’t as popular as modern digital modes like FT8, but it still has its proponents. SSTV isn’t only confined to the radio, though. [BLANCHARD Jordan] used this encoding method to store digital images on a cassette tape in a custom-built tape deck for future playback and viewing.
The self-contained device first uses an ESP32 and its associated camera module to take a picture, with a screen that shows the current view of the camera as the picture is being taken. In this way it’s fairly similar to any semi-modern digital camera. From there, though, it starts to diverge from a typical digital camera. The digital image is converted first to analog and then stored as audio on a standard cassette tape, which is included in the module in lieu of something like an SD card.
To view the saved images, the tape is played back and the audio signal captured by an RP2040. It employs a number of methods to ensure that the reconstructed image is faithful to the original, but the final image displays the classic SSTV look that these images tend to have as a result of the analog media. As a bonus feature, the camera can use a serial connection to another computer to offload this final processing step.
We’ve been seeing a number of digital-to-analog projects lately, and whether that’s as a result of nostalgia for the 80s and 90s, as pushback against an increasingly invasive digital world, or simply an ongoing trend in the maker space, we’re here for it. Some of our favorites are this tape deck that streams from a Bluetooth source, applying that classic cassette sound, and this musical instrument which uses a cassette tape to generate all of its sounds.
