TechyMagThings

In this wonderful world of MEMS technology, sensor technology has been downsized and reduced in cost to the point where you can buy a car tire pressure sensor for less than $3 USD on a site like AliExpress. Recently [electronupdate] got his mittens on one of these items to take a look inside, and compare it against his trusty old mechanical tire pressure gauge.

Perhaps unsurprisingly, there isn’t a whole lot inside these devices once you pop them open to reveal the PCB. The MEMS device is a tiny device at the top, which has the pressurized air from the tire guided to it. The small hole inside the metal can leads to the internals that consist of a thin diaphragm with four piezoresistors that enable measurements on said diaphragm from which pressure can be determined.

Handling these measurements and displaying results on the small zebra connector-connected LCD is an 8-bit MCU manufactured by Chinese company SDIC. Although the part number on the die doesn’t lead to any specific part on the SDIC site, similar SDIC parts have about 256 bytes of SRAM and a few kB of one-time programmable ROM.

This MCU also integrates the clock oscillator, thus requiring virtually no external parts to work. Finally, its sigma-delta ADC interacts with the MEMS device, rounding out a very simple device that’s nevertheless more than accurate enough for a spot check as well as quite portable.

Today, fireplaces, their cozy glow once a household staple, are mostly a thing of the past. In fact, a decent amount of old fireplaces are completely blocked up! [David Capper] brings back the atmosphere without the actual flames, with his RP2040-based fireplace glow simulator.

It’s not just a string of LEDs with some PWM brightness control, either. No, [David] goes into detail about the black body radiation that gives these fires their colors. He then uses the theory of black-body radiation to determine the colors that the LEDs glow to simulate the colors of a real fire.

But the colors alone don’t make for a good simulated fire, so [David] adds the heat equation. It starts with a grid wherein each cell has a temperature. Over time, cells are randomly selected to have heat added to them (increasing the cell’s temperature), then he applies the heat equation to diffuse and decay the heat within the grid for a nice simulated crackling fire. Add in a custom PCB and a nice little 3D-printed case and you’re ready for a cozy hacker time.

Before there was pressure-treated wood, before modern paints, there was pine tar. Everything from tool handles to wagons to ships were made of wood preserved with pine tar, once upon a time, and [woodbrew] wants to show you how to make it, how to use it, and why you might put it on your skin.

It starts with, you guessed it, pine! In the first part of the video, [woodbrew] creates a skin salve with pine resin and food-safe oil. The pine resin–which is the sticky goop that dries around wounds on evergreen trees–is highly antiseptic and has been used in wound salves since the stone age. The process is easy: melt it in a double boiler, then mix with equal parts oil. [woodbrew] also adds a touch of beeswax to firm it up, an a little eucalyptus extract for extra germ-killing power, and a nice smell to boot.

That’ll preserve your hands, but what about preserving wood?  That starts at about 9 minutes in, and for that you’re going to need a lot more resin, so picking it off wounded trees like he does at the start of the video won’t work. [woodbrew] suggests starting with dead-or-dying pines, and harvesting the crooks of their branches for “fatwood” — wood with the highest resin content. He also suggests the center of stumps, again of trees that died or were severely injured before being cut down. Then it’s a matter of cooking those fine organic molecules out. This is where we burn the wood to save the wood. Well, to save other wood. Wood we didn’t burn, obviously.

The distillation process [woodbrew] uses it fairly traditional, and consists of a couple of buckets. One bucket is buried and collects the pine tar; the other, with holes in the bottom to allow the tar to drip out, is filled with fatwood and covered tightly before being surrounded by firewood which is set alight. You could use an alternate source of heat here, but if you just cut down a pine tree for its fatwood, well, you’d have the rest of the tree to work with. Inside the fatwood bucket, the heat of the fire cooks off the volatile compounds that make pine tar, while the lack of oxygen from being closed up keeps it from burning. Burying the collection bucket keeps it from getting so hot the volatiles all boil off.

If this sounds like the process for making charcoal or woodgas, that’s because it is! He’s letting the gas fraction flare off here, but you could probably capture it– though a true gasifier brakes the tar down into gaseous compounds as well. The charcoal of course stays in the bucket as a bonus.

To make it usable as a wood finish, [woodbrew] mixes his homemade pine tar 50:50 with linseed oil, thining it to a spreadable consistency that helps it penetrate deep into the wood. By filling the voids in the wood, this mixture will help keep moisture out, and the antiseptic properties of the organic soup that is pine tar will help keep fungi at bay for potentially decades to come.

Thanks to [Keith Olson] for the tip!

The Sinclair ZX81 was hardly the most accomplished of 1980s 8-bit microcomputers, but its ultra-low-budget hardware was certainly pressed into service for some impressive work. Perhaps the most legendary piece of commercial software in this vein was 1K Chess, which packed an entire chess engine into the user-available bytes in the unexpanded 1K ZX’s memory map. [MarquisdeGeek] has taken this vintage piece of code in 2026 and subjected it to a thorough analysis, finding all the tricks along the way.

Though hackers have since found ways to trick the ’81 into displaying bitmap graphics, using it as intended is text-only with some limited block graphics. The chess board then is text-only, and its illusion of “thinking” about moves comes courtesy of the on-screen board doubling as the play area memory. In the GitHub repository you can find decompiled and annotated versions as well as the original ZX binary, with as a bonus a screen capture of the game as it appears as BASIC with the ZX’s odd means of storing Z80 code in REM statements.

If that wasn’t enough, in his note giving us the tip he reveals that much of the work was done in a ZX emulator running in a Dragon emulator, and gives us a fun glimpse of the game running in an emulator on a Cheap Yellow Display inside 1K Chess cassette box. We like it, a lot!

If you need a greater ZX81 fix, take a look at how this machine chased the beam to make TV graphics on the cheap.

Over the years there have been many designs for pan-and-tilt camera mounts suitable for single board computer cameras. Often they mount small servos for the movement, but those in turn present problems when the device finds its way outdoors. [GOAT Industries] is here with a novel solution to this problem, instead of trying to cover up the servos on the mount itself, the whole thing is remotely controlled by linear actuators through Bowden cables.

Testing was performed using Mole-Grips instead of actuators, and revealed a few design quirks. There are hefty springs to provide tension, and since they work against 3D printed assemblies those in turn have to be reinforced. The layout of the Bowden cable run is also important, as it has a bearing on the amount of springinesss in the system. But it provides a versatile pan-and-tilt mount for a Pi camera mounted in an IP-rated box, which is the object of the exercise.

For anyone wishing to build one the files can be found in a GitHub repository, and there’s a video below showing the device in action. Meanwhile it’s by no means the first pan-and-tilt head we’ve seen here at Hackaday, however many others are by necessity much more substantial affairs.

Although easily dismissed by some as another cruel April Fools joke, Raspberry Pi’s announcement of a new 3 GB model of the Raspberry Pi 4 along with (more) price increases for other models was no joke. Courtesy of the ongoing RAMpocalypse, supplies of LPDDR4 and LPDDR5 are massively affected, leading to this new RPi 4 model with two 1.5 GB LPDDR4 chips, as these are apparently cheaper to source.

Affected in this latest price increase across RP’s product range are RPi 4 and 5 models with 4 or more GB of RAM, with price bumps ranging from $25 on the low end to $150 for the Raspberry Pi 500+. If you wanted a Raspberry Pi 5 with 16 GB of RAM, you’re now paying $300 for the privilege.

Obviously, this news has got people like [Jeff Geerling] rather down in the dumps, essentially stating that using SBCs like the RPi is now beyond the means of many hobbyists. While you can still use SBCs that use e.g. LPDDR2 RAM, such as the older RPi Zero, 2 and 3 models, [Jeff] himself is now moving more towards wrangling with snakes on MCUs, as these boards are so far not significantly affected in terms of price.

With current projections in the RAM market being that this year will still see more price increases, it remains hard to tell exactly how ‘temporary’ this situation will be. That said, using readily available, powerful and cheap MCUs like the ESP32 variants for projects isn’t a bad idea if you really don’t need to be running more than perhaps FreeRTOS.

If you’ve never heard of the threadless ball screw, which was invented over sixty years ago, [Angus] of Maker’s Muse has a video demonstrating the whole thing, covering its history and showcasing both its strengths and weaknesses. If you like seeing mechanical assemblies in action, give it a watch.

The device — consisting of little more than a smooth rod and three angled ball bearings — is a way to turn rotational motion into linear motion. Not a single belt, thread, or complex mechanical assembly in sight. While a simple nut on a threaded rod can turn rotation into linear motion, those come with their own issues. The threadless ball screw was one effort at finding a better way.

Threadless ball screws never really took off, although they were given some consideration for use in 3D printers back in the RepRap days. Today one can purchase quality CNC components without leaving one’s web browser, but back in the early 2000s things like lead screws and ball screws were rather more specialized, less accessible, and more expensive than they are today. RepRap folks had to make their own solutions. But while the threadless ball screw is a very DIY-friendly design, it was ultimately lacking in performance.

The main problem is they’re just not precise enough for anything like CNC work. [Angus] does some back-and-forth tests with a 3D printed unit that shows serious drift after only a few minutes. Now, he knows perfectly well that his 3D-printed test unit is far from ideal, but the rapidity at which it drifted was still a surprise. Making a carriage with two threadless ball screws — one at each end — performed a lot better, but was ultimately still flawed.

It’s not all bad. There’s zero backlash. They are mechanically simple, remarkably smooth, and utterly quiet. Also, [Angus] discovered that the maximum force this setup can be made to apply is surprisingly significant, and is directly related to the tension on the bearings. That means one can trivially adjust how easily the carriage slips  (or doesn’t) just by tightening or loosening the screw holding each bearing.

Sure, they’re not precise. But maybe you don’t need precision. Maybe you just need to move something back and forth in a strong & silent sort of way that can still slip gracefully (and quietly) if something goes awry, like bottoming out an axis. 3D printing makes it pretty easy to whip one up, so maybe there’s still a place for the threadless ball screw.