Analog Optical Feedback Generates 4K Fractals With No Computer

August 27, 2026 by Tyler August 31 Comments

For users of a certain age, fractal patterns and computers are nearly synonymous. Typing in BASIC programs and seeing the Mandelbrot set or other fractals slowly render on screen is a key memory for some of us. Others will have generated recursive patterns mucking about: point an analog camera at the screen showing its video feed, and you’d better believe you get recursion. It’s called video feedback, and it looks a lot better than audio feedback sounds, especially in the hands of a master like [The Light Herder] who has now found a way to take this vintage art into the 4K resolution of the 21st century.

Physically this build is very similar to the “God Machine II” sculpture we covered previously, which in turn built on the first 720p version of his art piece. Getting analog video feedback in HD was hard enough — you need to be able to adjust the hue, saturation, brightness and contrast of the monitor as you go in order to have the full control of the resulting image. Most old TVs had those back in the SD era, but once HD came around it was rare; [The Light Herder] despaired of ever finding a screen that would to this in 4K.

As it turns out, the answer was to embrace digital — all the knobs on his analog control board feed into a Teensy, which is communicating via RS-232 with the LCD driver boards to alter the desired display properties. Obviously judicious selection of driver boards was required. If you watch the build video embedded below, you’ll find there’s an awful lot of tech in this analog, ‘no computer’ setup. If you want to skip the how-to and a master’s explanation of video feedback and just see pretty pictures he’s got a demo video as well. It really has to be seen to be believed.

If you want to create a colorful analog light show that isn’t quite so self-referential and a lot simpler to build, you could always try soap. Actually, we’d love to see him start the feedback with some soap-film colors. The result would likely be as was once said “totally far out, man”.

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Rebuilding An Obsolete IC To Save A Betacam SP Tapedeck

July 30, 2026 by Tyler August 8 Comments

Betacam is not the Betamax you may have had at home– it was a professional format that lived on into the 21st century, in the “SP” form. In many places, it would have been the last tape format in use. So it is perhaps understandable that [ldursw] decided to recreate an obsolete and unobtainable IC to save a Sony broadcast-grade editing Video Tape Recorder (VTR). Still mad, perhaps, but in a way we very much appreciate.

The Sony BVW-75 VTR had an odd flaw where the output lacked colour, unless paused with dynamic tracking off. Then colour would appear, but only in odd stripes. Clearly the chroma circuit was at fault. Some sluthing found that a sync separator IC– that separates the sync pulses that keep everything moving together, if the name didn’t give it away– wasn’t behaving correctly. More sluthing found that the chip in question was no longer available. Luckily, the concept of a sync separator hasn’t quite given up the ghost, and another part was available. It just didn’t fit, used a different voltage, and had an inverted output. No biggie! [ldursw] added a voltage regulator, an inverter, and a video amplifier chip, then after breadboard testing put them on a PCB with pins that match the original IC’s form-factor, making it a plug-in replacement.

That’s a GitHub link at the start of this article, by the way, so he’s open sourced the solution for anyone who needs a Toshiba TA7357P video sync separator. We don’t know who else needs this, but we’re willing to bet that whoever does, really needs it. On behalf of whoever that might be, we offer sincere thanks to [ldursw] for the hack, and for submitting it to our tips line.

This reminds us a little bit of a tape deck repair we featured previously, reviving another Sony format– D-1 tapes–to archive old media.

Pizza Eye Surgery Saves Hemispherical Projector

July 30, 2026 by Tyler August 15 Comments

If you ever make it to DNA Pizza in San Francisco, you may feel as though you’re being watched. The Eye of the Pizza is Upon You. Or, it was, until the out-of-production and now very expensive spherical projector gave up the ghost during a power outage. It’s back, though! Thanks to proprietor [Jamie Zawinski] and some cheap, absolutely-not-supposed-to-be-in-there replacement parts.

The saga started long ago, back in 2017, when [Jamie] got ahold of a Gekkin WorldEye hemispherical projector. It looks like those were meant for the educational market, to show planets and the like, but [Jamie] instead put a big eye on it, thanks in part to work by [PaintYourDragon]. It looked great, as you can see from the demo video embedded below. There it sat, staring down patrons for nine long years, until the power company did what is known in the business as “an oopsie” and turned the WorldEye into an expensive paperweight.

Not to be deterred, [Jamie] got the cheapest projector he could find and an equally-bargain-bin fisheye lens originally meant for macro photography, and mashed them into the Gekkin case without a care for such fripperies as focal length. A little surgery later, and as [Jamie] puts it, “The Eye of Pizza is, Once Again, Upon You”. In spite of the projector being 16:9, thus not quite projecting across the whole surface of the dome and the image fuzzing a touch at the edges, the result works far better than it should for the amount of engineering that went into it. [Jamie] expects further improvements can come from tweaking the image on the software side, but it looks like the current iteration is good enough for pizza parlor decor.

We’ve featured another of [Jamie]’s hacks before, when he built a Linux payphone. Weirdly enough, this isn’t the first time the WorldEye has received a projector transplant around here.

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Bad Apple On A Karaoke Machine

July 16, 2026 by Elliot Williams 6 Comments

CD+Graphics was a format that never really caught on. It let music discs pack some graphics, maybe liner notes, and mostly song lyrics into the otherwise empty space on a CD. It was never intended for displaying full-motion video, but that didn’t stop [Adam Gashlin] from getting a Bad Apple, with lyrics, running on any device that will play CD+G.

The main challenge is that CD+G gives you 300 screen commands per second, which is plenty for updating text on the 48×16 blocks as the lyrics scroll by. But if you want to send custom blocks and draw images, that’s 2.5 seconds per screen: a lousy framerate.

[Adam]’s first trick is to drop the resolution way down, which gets him into the 8 FPS range. Only update the blocks that change pushes this up to a respectable 17-20 FPS. But you can see the updates, and that’s distracting. It really needed buffering.

If you don’t know Bad Apple, it’s in black and white. And like many old graphics engines of the day, CD+G uses a dynamic palette of colors. [Adam] uses this to pack four frames into one, switching between them using palette swapping. (Absolutely check out his “rainbow” version of the video to see how the palette-swapping trick works.)

In the end, his demo has audio, triple-buffered video, and lyrics at 16.3 FPS. It’s slower than the fastest video-only version, but it looks so good, and [Adam]’s explanation of all of the graphics tricks he uses to get there is the real star of the show.

If you want to see Bad Apple running on yet more minimal hardware, how about a 16×2 LCD? Or a much more ridiculous implementation? How’s regexes in Vim for absurd? Got any Bad Apple hacks of your own? Let us know in the comments or the tips line. You can never have too many.

A Look Inside A 1997 BBC Ceefax Generator

July 11, 2026 by Maya Posch 23 Comments

Ceefax was the BBC’s broadcast teletext service that ran until 2012, providing text and rudimentary graphics that were broadcast invisibly with the TV signal. In order to get this teletext data merged into the analog TV signal, special equipment was needed, of which [Nathan Dane] has a 1997-era unit on his bench to take a gander at.

Interestingly, until this time the Ceefax signal had been generated centrally in London, meaning that regional TV broadcasts might have Ceefax issues on occasion due to retransmission glitches. This makes this Ceefax Inserter system so much more interesting, as it was one of the early examples of what these regional stations would end up installing in their racks.

At their core these units are regular PCs, running MS-DOS 6.22 on a 486-class CPU and all the typical bits and bobs that go with a PC. The speculation here is that these are essentially rebranded industrial PCs, which would make a lot of sense. As for how [Nathan] got his hands on these units, it required a deal with the company scrapping them, preventing him from showing details of the software configuration.

Following a booting demonstration, we get the teardown of a typical 1990s rackmount PC, revealing a rather interesting backplane with the mainboard being one of the cards on it. Of these, two ISA cards provide the special Ceefax sauce as well as a timing signal in the form of a PDC card featuring a Lattice CPLD or FPGA that VCRs could use to automatically start recording.

The Ceefax main event comes in the form of the inSERT Teletext Encoder card. This is pretty much its own computer system, featuring a TI TMS34010 CPU and its own RAM as well as IO. Compared to modern takes on teletext generators, this card appears to directly mix the analog signals, without any kind of conversion.

Although teletext systems have been largely shutdown now at this point due to the transition to digital TV broadcasting, there’s still a lot to be said for having such a service available for basic news and information.

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A Standalone YouTube Streaming Rig

June 27, 2026 by Jenny List 1 Comment

YouTube streaming typically involves a camera with an HDMI output, a USB3 HDMI digitiser, and a suitably beefy PC to run it all. It’s quite a process, and for [Coreymillia], more complex than it needs to be. He’s come up with something simpler, a dedicated self-contained streaming rig using a Raspberry Pi 4.

As you might expect it uses the Raspberry Pi HQ camera at the optical end, but it’s the software surrounding it that transforms it from a mere camera into a streaming rig. There’s a web based user interface, but perhaps more interesting are the companion dashboard peripherals. A Raspberry Pi or an ESP32 Cheap Yellow Display can both serve as a small in-view dashboard and controller.

We know from experience that a stream can be a difficult thing to get right even with high-end hardware, and we’re interested to see this standalone device allowing , we hope, an easier way to do it. If you’re a streamer we’re guessing you’ll be taking a closer look. Even so, this is surprisingly, not the simplest Raspberry Pi based streaming device we’ve seen.

Building A 2-Way Holographic Display

June 18, 2026 by Zoe Skyforest 6 Comments

Holographic displays sound very fancy but you can build various simple types yourself at home. [Julius Makes] whipped up a neat design that shows a different image depending on the position from which you view it.

Running the show is a Wemos D1 devboard equipped with the ESP8266 microcontroller. It’s hooked up to a pair of OLED displays over I2C. The displays are placed in a 3D printed assembly that aims each one at a beam-splitter cube. This bounces light projected into one face through 90 degrees, and out another face. By leveraging this, it’s possible to aim each display at one face and bounce it out another, such that looking at either side of the beamsplitter cube shows a different image. Since the beamsplitter cube also allows some light to be transmitted directly through as well, the image from each display appears to float in space.

[Julius] notes that this setup is being used in a puzzle box game, while wondering whether there’s any other fun ways to leverage this technique. We’ve seen some other neat holographic displays before, too, like this neat Holochess build.

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