For most of us the abbreviation “CRT” brings to mind a monitor or TV. But at its core it’s about the special vacuum tube that makes the images appear.
Regardless of whether it’s just a simple monochrome CRT in an oscilloscope or a full RGB CRT, the basic steps to make it work in a device remain the same. In a recent video by [Void Electronics] these steps are worked through, including the biasing at the end that is necessary to get a stable image.
A big part of installing a CRT and driving it is knowing how to read its datasheet. Much like other vacuum tube types, there are heaters, control grids and a range of voltages to get right and keep happy. Even then you can still have a situation where you must troubleshoot problems, which is also touched upon in the video. All of this is demonstrated using an RFT B6S1 CRT as the subject, including how to build your own bias circuit.
Despite calling it an “obsolete skill”, there is still a lot of demand for CRTs in vintage lab equipment, arcade restorations and far more obscure fields that still have new CRTs produced for them. Not to mention that even today CRTs have characteristics that make them competitive with flat-screen technologies.
With the advent of affordable 2.5 Gbit, 5 Gbit, and 10 Gbit consumer networking gear, more and more people are taking advantage of these higher networking speeds, with [This Does Not Compute] having used 10 Gbit SFP+ modules over regular Cat-5e copper to connect to a NAS in the next room. Only problem was that after a while these SFP+ modules began to start dropping frames. On taking a closer look at these modules, he found that they were running pretty hot: 40°C while idle. A teardown of one of these modules showed severe discoloration due to heat.
Side view of the SFP+ module’s PCB. (Credit: This Does Not Compute, YouTube)
Inside these 10Gbit modules is the Marvell-branded Alaska X 88X3310/40P PHY, which despite the ‘low-power’ claims have a metal heatsink glued onto the actual IC and thermally coupled to the module’s metal enclosure. The other side of the PCB was quite discolored, further indicating how hot these modules run in operation. Some digging revealed that this can go up to around 2.5 watts.
Perhaps the most fascinating part of this teardown is the discovery of an 8051-based MCU that’s responsible for telling the switch the module is put into that it is a 30-meter multi-mode fiber module, presumably for compatibility purposes. It’s definitely an interesting feature of these FS-branded SFP+ modules.
These old modules were replaced with Wiitek-branded modules that are supposed to use only up to around 1.5 watts in operation courtesy of a newer chipset, in the hope that these wouldn’t fry themselves. At idle these do however still run at 30 °C. As noted in the comments, it might be a good idea to have active airflow over high-speed networking gear like this, as they generally can get pretty hot and sometimes crispy.
The final solution for the video’s networking problem was to just run single-mode fiber to the room and use appropriate SFP+ modules for that, also because these run noticeably cooler. If you still have room in your cable ducts, that would seem to be the optimal solution.
One of the stun gun modules with battery pack. (Credit: Dani Cruster DiWHY, YouTube)
Few things are more satisfying during a Summer night than hearing the crackle and pop of another mosquito hurling itself against a bug zapper and knowing that it won’t be trying to suck your blood any more. The only problem with those bug zappers, whether the mounted or hand-held type is that you cannot get every single attacking mosquito. Unless you were to put the bug zapper on yourself, of course. This is basically what [Dani Cruster] of the aptly named ‘DiWHY’ channel decided would be the right course of action.
The video is apparently dubbed over from the original Russian – with the team claimed to be based in Moldova – which probably explains a lot of the reasoning behind this engineering. At the core of the whole-body bug zapper is galvanized mesh, with a big question being how close you can get it to the body before said body gets zapped too. With about a millimeter of clearance between both layers of mesh required at 1 kV, this was another design consideration.
Ultimately the guts of stun guns were used, which output around 10 kV and thus require a 1 cm gap between the mesh layers. PVC plates were used to create the structural elements of the walking bug zapper suit, using a heatgun to form it into a body-appropriate shape. That’s when human testing started, to try and not make it zap the wearer.
The final suit of bug zapping armor uses six stun gun modules, each powered by a 3 V power source created from two 1.5 V alkaline cells that are good for an hour of zapping. One issue found during a human trial run was that the zip ties used turned out to actually cause arcing, which had to be addressed first before heading to the mosquito-infested woods. In the video these are said to be near Tarkov in what appears to be the national park in Russia’s Tver Oblast and clearly a prime mosquito breeding ground.
During the real-life test run many mosquitoes and apparently even some ticks find their electrifying demise, before for some reason they seem to clear out after an hour or so. Overall it seems to work well, even if it’s not that ergonomic and things get spicy when it starts to rain.
In the quest to make every wearable device ‘smart’, a lot of electronics along have to be crammed in very small spaces, along with ways to make them resistant to environments that our bodies do not mind, like getting hit by a rainstorm or simply washing our hands. These two factors combined make especially devices like smart rings an interesting case study for repairability, with [iFixit] recently taking apart a modern Oura smart ring to assess its e-waste factor after the built-in battery dies.
The tiny 10.5 mAh Lipo cell in the Oura Ring 5. (Credit: iFixit)
The subject of the teardown video is the Oura Ring 5, a $400 smart ring that’s designed to track your vitals much like a wrist-worn fitness tracker — just in a much smaller package. This metal-and-epoxy sandwich can definitely survive a good rain shower and washing of hands, but to get to the internals rather forceful methods were needed, unlike previous Oura and Samsung smart rings where some applied heat was enough.
In the Ring 5’s case even more heat was needed to make the inner ring start to slide out, but by that point the Li-ion battery inside had already popped from the heat. The inner ring then got stuck and more violence was required to continue the disassembly and get to the super-tiny, 10.5 mAh battery. Of course, at this point the smart ring really won’t be getting back together, never mind still work or be waterproof, which is a central issue with these smart rings.
With the EU’s February 2027 deadline for user-replaceable batteries looming on the horizon, it’ll be interesting to see whether devices like this can squeeze into an exception category, or whether manufacturers will have to massively redesign or stop selling these devices to this rather large market. So far this particular regulation has already forced Nintendo to make a special Switch 2 console for the EU.
One of the most hilarious things you can do with an LLM-based chatbot is to ask it to do calculations. If it’s a well-written chatbot frontend, it can detect requests for arithmetic – like summing 1 and 1 – and pass it on to a dedicated calculator application, even if still cannot correctly count the ‘r’s in ‘strawberry’. This is where [Alvaro Videla] asks the question whether it is at all possible to perform arithmetic with a language model.
Since an LLM at its core is nothing but a vector space of probabilities that a matrix-based inference process uses to create a probabilistic output of tokens you’d not expect a lot of deterministic behavior. How can you do arithmetic without grounding it in some kind of deterministic process?
This is where [Alvaro]’s Rune project comes into play, which is ‘a mechanism-aware JIT compilation project for language-model arithmetic’. Although it is statistically impossible for an LLM to ever correctly perform any random series of arithmetic calculations, you can monitor the internal state of the model and interfere once the parameters of an arithmetic calculation have been identified. By putting the correct result back into the inference process and letting it continue you did not need to rely on external tools.
Ultimately this attempt sort-of worked, but was deemed a failure. It would seem that a language model is the wrong tool after all for replacing the humble calculator.
Generally the idea with photopolymers as used with resin 3D printing is that the process only works in a single direction as with all thermosets: after polymerization under influence of UV light they become an inert lump of plastic. Being able to turn these lumps back into resin would of course be ideal, as it would make recycling incredibly easy. Here depolymerizable resin turns out to be a thing, with 3Dresyn being one company that sells additives and resin which enable this (found via Fabbaloo).
Irreversible (thermoset), partial and full depolymerization. (Credit: Machado et al., Nature, 2024)
These additives and resins come in essentially two flavors based on which temperature they depolymerize at, which can be at either 80°C or 150°C. This comes at a cost, of course, with the ready-to-use resin coming in at an eyewatering €833.00 for a 1 kg bottle, a factor only slightly helped by the reusability aspect.
From a more technical perspective this depolymerization feature is fascinating, as it addresses the one aspect of thermosets (like SLA and epoxy resins) that thermoplastics have as advantage, especially from a recycling view. This type of circular photopolymer appears to be quite novel, with an article by [Machado] et al. from 2024 claiming to have demonstrated the first resin that can be photopolymerized, depolymerized and subsequently again photopolymerized in a closed loop.
In the demonstration by [Machado] et al. the depolymerization is achieved using dynamic disulfide bonds, with the pulverized printed samples put into a 2-methyl-tetrahydrofuran (MeTHF) solvent. After heating at 80°C for 3 hours with an inert atmosphere, most of the photopolymerized material had returned to its original, pre-printing state. In a more recent 2025 study by [Bo Yang] et al. an approach using catalytic thermal dissociation of dithioacetal bonds was explored.
Based on the available information by 3Dresyns it would seem that their product is closer to this latter approach, with depolymerization requiring putting the part into an oven at the target temperature for up to an hour, presumably in some kind of suitable container. This is said to target elements like sacrificial molds, reusable tooling and jigs that would otherwise be discarded, or need to melt like a thermoplastic instead of acting like a thermoset. Whether a solvent like MeTHF is required as in the two cited studies is sadly unclear based on a quick scan of the site.
For some time now [Tobi Friedly] has been tinkering away at porting the original Super Mario 64 from the Nintendo 64 to just about any device imaginable. One of these being the Nintendo DS, with the code and build instructions now up on GitHub, along with the demonstration video below that shows off the added multiplayer functionality.
We previously covered this project and the challenges involved. The main problem that kept him from just taking the existing Nintendo DSi port by [Hydr8gon] and running it on the original DS is that the latter doesn’t have enough RAM to load the entire game ROM into memory. The integration of NitroFS for asset streaming took some time, along with addressing sound support and overall stability. Meanwhile it appears that multiplayer support was also added along the way.
This multiplayer involves two DS systems, each running its own copy of the game. This can be nice for co-op playing of the game, as well as just for goofing around in a 120 star fully finished game with a buddy.
For most of us the abbreviation “CRT” brings to mind a monitor or TV. But at its core it’s about the special vacuum tube that makes the images appear.
