Kritik sah

In semiconductor technology, a base material like silicon is permanently modified to induce certain electrical behavior. In comparison a topological insulator material could be used to create temporary circuits using something like light exposure. An example of this is the Floquet topological state, which has long been theorized, but is now claimed to have been demonstrated in SnTe semiconductor material, per a paper by [F. Chassot] et al. in Nature Physics . The concept of topological insulators was first proposed in 1985, but proving their existence was hard. Recently photonic Floquet topological insulators (PFTIs) have gained interest , with experiments by [Qian Ma] et al. in 2025 as well as other teams confirming aspects of the theory. This recent publication by [Chassot] et al. would thus confirm that optical control of topological insulators is thus possible. At the core of this effect is the band inversion that results from the light pulses, with the change in conduction bei...

Reverse-engineered schematic of the IBM 604’s TR-3 module. (Credit: Ken Shirriff) Taking a break from ogling microscopic features in Intel’s semiconductor processors, [Ken Shirriff] is back to instead poking at decidedly macroscopic pluggable modules from the 1948 IBM 604 Electronic Calculator. This time around it’s one of the so-called trigger modules in the form of the TR-3 , which uses a flip-flop circuit to implement the timing signals and pulses that made the 604 work. This differs from the thyratron module that we covered previously . A thyratron is a high current switch and rectifier, which is useful more for the periphery of the computer system. These TR-3s on the other hand were used to implement the basic logic circuits, even if a flip-flop by itself seems rather boring, being just a circuit that toggles between two states. In this TR-3 module we find a 2033 dual triode design which thus increases density by having the two inverters of the flip-flop in th...

Circuit bending is a chaotic art. At its simplest, it can just involve making connections between random points on a circuit board to create weird sounds in musical hardware. Or, you can complicate things, get really specific with your hookups, and twist them with various sorts of modulation. [Simon the Magpie] has been working on something closer to the latter category, with his neat project to add MIDI to the circuit bending world.  The concept is straightforward enough. [Simon] has created a device that you place in line with your circuit bent connections, particularly those that create pitch bends with pots thanks to their variable resistance. You can then play your MIDI keyboard, and the device will vary the resistance in the circuit and bend the pitch at your command. [Simon] simply calls the device MIDI TO RESISTANCE, because that’s… precisely what it does, with the aid of a digital potentiometer. He then demonstrates it doing its thing on pitchbent toys, and it soun...

[David] has a young child who is clever enough to use a computer to play music, but he doesn’t quite want to hand over the mouse just yet. Thus, he set about building an electronic music player that could be operated in an altogether simpler fashion.  The build is based around an Arduino Nano — its job is to read RFID tags via an RC522 reader, with the tags themselves embedded in a series of small dolls belonging to [David]’s daughter. Upon reading the tag, the Arduino Nano chats over serial with a DFPlayer Mini module, which reads a playlist of MP3 files off of an SD card and plays them over a small 4 ohm speaker that [David] had laying around. It’s a simple build, with the components all neatly wrapped up in a handsome wooden case with a volume control and a skip button for if any one song becomes too annoying for a repeat listen. We’ve featured other builds in this vein before, too. There’s something satisfying about a music player with such a s...

As easy as it is to make a late 1980s-style game console using a modern microcontroller, there’s arguably more fun in doing things the traditional way. This is the challenge that [Throaty Mumbo] took upon himself when he embarked on his retro game console project, called simply the Game Console V2 . In the accompanying video the development process and other details are covered and demonstrated. Most notable perhaps are the proper cartridges with ROMs on a parallel bus rather than something like SD cards, and the absence of any modern ports including even VGA. This means only composite AV output like in the good old days of RF splitters and other assorted fun. The NTSC output signal is generated by an RP2350 MCU in the form of the PGA-shaped PGA2350 breakout board that’s wired into a 6-bit R-2R network for RGB332 output via the RCA jack, while audio is fed into a PCM5102A I2S DAC. For controllers you get 4-pin Bulgin SA2367 connectors and an N64-compatible protocol. It...

The Theremin is that classic electronic musical instrument that makes those weeee-ohhhhh noises which were so popular in mid-century science fiction movies. Mid-last-century, that is, because this century is just beginning. In any case, you could build one with old-school analog electronics, or you could go a more modern route, as [ericCycles] did. The build relies almost entirely on an ESP32 microcontroller with minimal supporting circuitry. Like any other Theremin, pitch and volume are controlled by moving hands closer or farther away from two antenna. In this case, the ESP32 uses its capacitive touch circuitry to detect effectively detect hand proximity to the two antenna in question, and uses those values to control the pitch and volume of a synthesized waveform. That waveform is then pumped out over the onboard digital-to-analog converter for playback on external speakers. If you want to build a simple Theremin-like instrument quickly and easily, it’s hard to beat the simpl...