TechyMagThings

After previously putting a very basic version of Minecraft on the Game Boy Color, [Tobi] decided to have some fun and port that version also to the Super Nintendo (SNES), just to see what would happen with its more powerful hardware. Even without using an add-on chip like the Super FX 3D chip that made games like Star Fox and Doom possible with its 3D-rendered geometry, the basic SNES hardware can already provide a serviceable Minecraft experience.

You can download the SFC file here, featuring a starting world in which you can do all the usual Minecraft-ing shenanigans, like world destruction and construction. Unsurprisingly the game’s resolution is much higher than on the GBC, though the brief glimpse [Tobi] shows of Minecraft on the Game Boy Advance (GBA) with its proper 3D-rendering hardware are leaps ahead of what the basic SNES can do.

This of course raises the question of what Minecraft on the SNES could look like once you add the Super FX or similar 3D accelerator chips for the SNES into the mix. Rather than just being limited to sprite-based graphics and transformations, suddenly you can use real polygons.

A time-honored tradition in the electronics repair business is to make many into one, specifically a stack of broken devices into one that works. So too with a triplet of heavily corroded and bug-infested WiiMote controllers that [eWastelander] dug out of a box of e-waste. After suffering abuse like leaving in leaky alkaline cells, bugs and general corrosion the task was to see whether at least one working WiiMote could be assembled from these three. (Video, embedded below.)

Adding to the fun was that the PCBs in these WiiMotes spanned at least two hardware revisions, and on one board the battery corrosion had caused an IC to fall off. After an initial assessment, neutralizing the battery acid and a deep clean of all the disassembled parts, it was time to give it a shot at reassembly into something resembling a Wii controller you could use and even want to touch without washing your hands afterwards.

Ultimately at least one working WiiMote was put together, with still an open question whether the remaining two  units in much worse conditions could be revived in some way. An interesting idea here is to use the WiiMote shells for a custom OpenMote board, which replaces the guts with an ESP32-S3-based system for more general non-Wii things around the house.

Over recent years there have been a range of classic 16-bit consoles coaxed into running familiar operating systems, with -nommu Linux being a favourite. But the 16-bit era had its own operating systems of note, and [1d4r3k] has brought one of them to a console that fit very much into a different 16-bit camp. It’s Atari’s TOS, on a Sega Mega CD.

We should in all fairness start by saying it’s not “real” TOS, but EmuTOS, an open-source drop-in replacement. So far it supports a serial keyboard device, a printer, and sound, and it mounts the CD or cartridge it booted from, a RAMdisk, internal backup RAM, and cartridge save RAM. We’re told in the tip email that there’s also been some work porting GEOS to the platform, and thus the GEOS software suite may be ported to it.

Sadly there are no images, so we can’t see it working, but trying it looks to be as straightforward as burning aan ISO or flashing a cartridge if you have the original hardware. We have no idea as to whether it would be any use given the specs of the Sega, but given that TOS ran on Ataris without a lot of RAM we suspect it might be. Meanwhile, here’s a Megadrive/Genesis running Linux.

Header: 軍事用懐中電灯, CC BY-SA 4.0.

Drone control links are, from a radio signals perspective, nothing short of amazing: using a transmitter capable of transmitting, at most, one watt, a protocol such as ExpressLRS (ELRS) can control a drone over 100 kilometers away. [Stan], who has been building a drone electronics stack from scratch, recently designed four ELRS receivers and went over the principles behind their incredible range.

Up to a certain point, the simplest way to increase a radio’s range is to lower the frequency; lower radio frequencies penetrate better through most materials and don’t attenuate as quickly with distance. However, although ELRS can use 900 MHz bands, [Stan]’s receivers primarily use 2.4 GHz. The major improvement is in modulation: unlike other control protocols, which mostly use frequency modulation, or Wi-Fi, which uses phase and amplitude modulation, ELRS uses Chirp Spread Spectrum modulation. This has a low data rate, but it’s very reliable; every bit is transmitted as a chirp – a linearly rising radio tone – and the data is encoded in the chirp’s starting frequency. To decode this, the receiver multiplies it with an inverse chirp, then takes a fast Fourier transform, revealing the starting frequency. This process has an equivalent gain of 24 dB, which is enough to let it decode signals even below the receiver’s noise floor.

The hardware [Stan] designed to implement this was comparatively simple, just an ESP32 microcontroller, an SX1281 radio chip, and a few peripherals. All four receivers worked in 2.4 GHz, but two had additional 900 MHz antennas. Against RF design convention, one of the receivers used a via to connect the antenna. This would normally cause a significant impedance mismatch, but since there were enough ground-plane vias nearby, the current return path was barely affected; the receiver’s performance hardly changed. In one test, all four receivers maintained a connection at more than five kilometers, despite a forest blocking the signal’s path.

We previously covered ExpressLRS when it was still an emerging technology. To get this kind of range, it builds on LoRa technology, which has reached some impressive distance records.

Thanks to [Keith Olson] for the tip!

Making a film camera is a project within the reach of almost anyone, from the experimenter with cardboard and sticky tape, to the machinist with an aluminium billet. But 3D printing has opened up the world of cameras to whole new set of experimenters, and we’ve seen some very impressive builds here as a result. For all that, there’s always been a particularly tricky aspect to a home made camera: the shutter. In particular, making one with variable speed has proved almost impossible. Now [Camera Things] has given it a very good shot, with a sliding 3D printed design.

To cock it, both the strips are pulled across, before the blind strip is pushed back, and the shutter operates by sliding back under the influence of a rubber band. The clever part in this case is that the blind strip can be partially pushed back to affect the size of the shutter opening. The effect is then of a variable width strip of light passing over the film, which is equivalent to varying the speed of a conventional shutter.

Due to space constraints he’s only able to make it a half frame shutter, so he’s abandoning this design in favour of a more complicated set of vertical leaves. Sadly he’s not made the files available, but we thing proficient CAD users should be able to make their own version. The video is below the break.

It’s not the first printable shutter we’ve seen, but it remains the first variable one.

A fun way to think about a national electrical grid is as a massively upscaled electrical circuit, one in which you have multiple power supplies injecting AC power, with various bits and bobs involving resistors, inductors and capacitors in between working to synchronize and clean-up this power before it gets to the end users. Recently [Jordan Taylor], also known as [The Electric Brit] took a look at the grid’s harmonic filters that do a lot of this sinewave scrubbing after the HVDC to AC conversion.

Using a UK-based line-commutated converter (LCC) HVDC converter station as a physical example [Jordan] takes us through the elements of this harmonic filter, what it is, what it does and why it’s a necessity. The design considerations with components at this immense scale are also covered, along with the types of filters possible.

The Cliff’s Notes version is that following the conversion step from said HVDC there are harmonics introduced in the AC, not unlike in a much lower-voltage converter. This results in a noisy sinewave that can potentially cause harm to AC-powered devices, not to mention cause heating and other losses along the way. The answer is naturally to add an LC-filter, just on a slightly larger scale than for consumer electronics.

Also noted by [Jordan] is the nice synergy of these harmonic filters when it comes to absorbing and generating reactive power on the AC grid, due to their massive capacitors and inductors. This helps to dampen oscillations on the grid and thus further contributing to its stability.

The Hammond organ is an early form of electronic– or perhaps electromechanical– musical instrument. It solved the very real problem of organs normally being the sort of thing you built into a cathedral, allowing a similar sound to fit into a piano-like form factor. Their workings are a so simple that it’s hard to wrap your head around it actually working– which is why [Uri Tuchman] built one on YouTube. Also for a gift exchange, but we’re not Santa, here– we’re here to learn, and [Uri] does not disappoint.

[Uri]’s organ is a bit smaller than what the Hammond corporation was putting out back in the day, just one hand-cranked octave– and it lacks the distinct spinning speaker in favour of plugging into any old guitar amp. It’s enough to get the idea across. Each of the twelve keys acts as a simple switch, wired to a pickup made from a coil of wire around a steel rod– much like a magnetic pickup on an electric guitar. The pickup faces the tone wheel, which is the part that feels like magic: the tonewheel spinning past the pickup acts exactly like the steel string vibrating in an electric guitar, its ferroelectric motions inducing a tiny current. The tonewheels smooth teeth are spaced to create sine waves at the frequencies corresponding to each key, so it has to be exact. That’s why while the rest of the brass-and-wood build is [Uri]’s beautiful craftsmanship, the iron tonewheels are CNC’d.

Aside from the amp it is plugged into, there are no electronics here. There’s nothing to double or otherwise alter the frequencies: one key means one tonewheel– twelve for this build– and if the RPMs are off everything is out of tune. Good thing [Uri] made it hand-cranked! Well, it is for a gift exchange. Maybe it’s a white elephant sort of thing, because we can only imagine that making it much harder to play. On the other hand, [Uri] demonstrates some neat effects by varying the RPM at the end of the video, so perhaps that’s a feature.

As nice as [Uri]’s work is, Hammond Organ Company filmed the construction themselves, back in the day if you want to see the true quill. Alternatively, you can get more of [Uri]’s craftsmanship with this square guitar.