TechyMagThings

C-3PO is one of the more famous movie robots out there. However, we don’t see a lot of replicas built, perhaps because in speech and mannerisms, he’s quite hard to replicate. Of course, that feat has become much more achievable with modern AI tech, as [Samuel Potozkin] demonstrates.

We’re not looking at a full C-3PO build here, it’s just the head—but for the project’s purposes, that’s all that was really required. The build relies on a Raspberry Pi 5 as the brains of the droid. It’s running a mic hooked up to a real time speech to text engine, and that text is then sent to a large language model for interpretation. Responses are then generated, passed through a processing layer to capture C-3PO’s general tone and vibe, and then handed off to a text-to-speech synth to imitate the iconic voice, played via speaker. The end result is a C-3PO you can actually talk to, which is something that might have knocked a few socks off when the movie first launched in 1977. In-depth materials for the build can be had via Google Drive and on Github.

This ersatz C-3PO isn’t an exact dupe of the movie ‘bot.  The protocol droid is a little slow to respond, and the patter isn’t quite on point, even if the voice synth makes a good effort at mimicking the original. Overall, it’s a little… robotic… something you wouldn’t say of the character in the movies. Still, it’s a great effort, and something we haven’t really seen much of before. If you like more classic droid replicas, though, we’ve featured those too. Video after the break.

Transistors in some circuit configurations work together and, frequently, need to be matched. This is so common that you can sometimes find ICs that are just a pair of transistors made with the same piece of silicon, so they should be matched very closely by default. But with discrete transistors, two devices of the same type are not always identical. [Learn Electronics Repair] covers the topic and explains how to match devices in the video below.

Depending on the circuit, the matching parameters may be different, but generally, the idea is that you want similar gains or matching saturation characteristics. The reason is that when you have multiple transistors working together, you don’t want one to do more work than the other device. This is inefficient and could drive the “better” component to fail.

The same idea applies in bridge circuits, where you might match resistors or capacitors to make sure that, for example, two 10% resistors are very close to the same value. A 10K resistor could be between 9K and 11K, and you might not care as long as they are both, say, 9.2K or both 10.8K.

This is different, by the way, from impedance matching, where you achieve maximum power transfer by matching a source to a load.

Once upon a time, someone set up a livestream wherein the messages from Twitch chat could control a game of Pokemon. Since then, we’ve seen Twitch control all sorts of things. If you’d like to have them play with some LEDs in your house, you might like this project from [pfeiffer3000].

The concept is simple enough. The heart of the build is an ESP32 microcontroller, which is easy to integrate with web services thanks to its onboard WiFi capability. It’s hooked upt o a string of WS2812B addressable RGB LEDs. The LEDs themselves are installed within table tennis balls to act as nice, spherical diffusers, and installed in a square frame made of PVC pipes. As for code, the rig uses the WLED library to drive the LED strings, and code from TwitchIO to interface with Twitch chat itself. It’s as simple as rigging up a bit of Python. With everything assembled, [pfeiffer3000] had an attractive LED grid that could be controlled directly by anyone watching their Twitch stream.

We’ve explored how to control things via Twitch before, too. It’s a fun way to add some interactivity to your livestream that really gets viewers involved. If you’ve been building your own audience-controlled projects, we’d love to hear about them on the tipsline!

Some people love CRTs to a degree that the uninitiated may find obsessive. We all have our thing, and for [Found Tech], it’s absolutely pointing particle accelerators at his face to play video games. He likes modern games, with modern resolutions– none of this 1080p nonsense. Today’s gamers demand 4K! Can a CRT keep up? The answer is a resounding “No, but actually, yes!”

[Found Tech] has an IBM P275 monitor, which is one of the last generation of CRTs.  Officially, the resolution maxes out at 1920 dots by 1440 lines. While one might (inaccurately) call that UHD output “2K”, you certainly cannot claim it is 4K. So, what’s the secret? Interlacing. Yes, interlacing, like old analog TV signals.

Apparently, in spite of what the manual says, getting the screen to absorb the 2880×2160 interlaced signal wasn’t the hard part, but generating it was. NVIDIA and AMD graphics cards are absolutely unable to create an interlaced signal, but Intel integrated GPUs are– if you get the right combo of chip and old driver. Sadly, the video doesn’t list exactly what he used. Of course an iGPU isn’t going to give you a very good gaming experience at this high resolution, so [Found Tech] has his games do their rendering on the discrete card before piping that over to the iGPU for display on the CRT.

Technically, you still can’t call the 2880×2160 picture “4K”, as that trademark refers to 2160p at 16:9, and this is both interlaced and 4:3. Still, close enough. In spite of the artifacting that turned us all against interlaced signals back in the day, this apparently has [Found Tech]’s eyes fooled– he says it’s as good as 2160p on his OLED, plus the extra magic that comes with glowing phosphors.

It certainly looks great in a recording, but the monitor in the recording isn’t displayed at a high enough resolution to say for sure if it’s 4K. Still, if you’re into CRT gaming, maybe give this high-res interlacing a try. If you still don’t get what’s so great about CRTs, check here, and remember it could be worse– at least we’re not going on about Plasma TVs.

The solar system is kind of hard to observe in motion all at once. Sometimes, it’s nice to have a little model to look at, so you can see the relative motions of celestial bodies play out in front of you. Such a device is called an orrery, and [illusionmanager] has built rather a nice example of their own.

The build represents all the planets in the solar system, plus the sun and our very own Moon. An ESP32 lives at the heart of the build, running an astronomical simulation to calculate the proper positions of all the celestial objects. It then drives a small stepper motor via a TMC2209 driver, turning the mechanism back and forth until all the pieces are positioned correctly, using a reed switch and magnet to detect the initial zero position. The orrery is able to be driven by a single motor in this manner thanks to an ingenious mechanism, wherein the rings interlock with each other when turned in one direction, and not in the other. The Moon is controlled by a separate geared mechanism connected to the main rotation.

It’ s a nice decoration that also serves as a great conversation piece, particularly if you like talking about the heavens. We’ve featured some fine works from [illusionmanager] before, too, like this exquisite reverse sundial. Video after the break.

Producing hot water off-grid is a surprisingly energy-intensive activity, and although it looks simple on its surface it can get quite complicated especially when used in large scale for something like providing hot water for an entire home. When using combustion to heat the water there needs to be proper venting as well as control of the fuel, and even storage of the hot water needs to be meticulous to avoid certain pathogens. [Greenhill Forge] has built an off-grid solution for heating hot water that doesn’t necessarily rely on any combustion, though, provided he can find something to spin his custom electric machine.

The machine in question is, of course, an induction heater. It works similar to any simple electric motor, generator, or transformer except in this case the eddy currents generated are exploited rather than minimized. Normally these currents, generated when a magnet passes by a metal, are wasted heat in other machines but in this induction heater it’s the goal. The machine’s stator is built from copper tube wound in a spiral which allows water to flow through and absorb heat. The tube is soldered into one electrically solid mass to maximize the eddy currents. The rotor is taken from a previous generator built by [Greenhill Forge] which holds the permanent magnets.

During the initial tests using a power drill to drive the generator, he was able to heat 1.5 liters of water from 7.9C to about 24.4 C in three minutes. The math works out to providing 575 watts of power to the heater, and with something that could spin the generator faster it might have the potential to provide around 14.5 kW. Provided that there’s a source of energy around, such as a wind or water turbine, this could be a fairly sustainable way of generating hot water in off-grid situations. Some of [Greenhill Forge]’s other projects are centered around this idea as well, like one of his builds which uses waste sawdust to heat his workshop with a custom-built stove.

You can get all kinds of fancy lenses for modern cameras, with all sorts of mechanical and electronic wizardly to make them shoot better images. But what if you paired a vintage lens with a modern camera? It would take some work, as [Mathieu] found out, but you’d also get some interesting results.

The optic in question is a 100-year old lens—a Foth 50 mm f2.5 to be precise, originally used with a folding film camera. It was sourced from a market for just 3 euros. Notably, the lens was not designed for modern cameras, and so lacks an aperture and focusing mechanism. [Mathieu] thus had to fabricate something to fit the lens to a Sony FX3. A first attempt used an aperture adapter from Amazon and an elcoid adapter, but there were vignetting problems due to the lens placement in this case. Ultimately, [Mathieu] went with a special macro adapter that allowed him to control focus and tuck in an ND filter behind the lens, which made up for the lack of an aperture.

The vintage glass isn’t the sharpest lens out there, but that’s kind of what’s fantastic about it. The center of the frame is certainly focused, but it fades out softly towards the edges of the image, giving a cinematic, dreamlike effect. The bokeh in the background are particularly charming, too. As far as 3 euro lenses go, this one was a hit.

You can slap just about any lens on anything if you get creative with how you do it. Video after the break.

[Thanks to Stephen Walters for the tip!]