Moon moving from inside a large glass sphere into screens of two vintage television sets

Blending Pepper’s Ghost, Synths, And Vintage TVs

We were recently tipped off to the work of [Joshua Ellingson], and digging in, we found an extensive collection of art and ongoing experiments, with synthesizers deforming and driving old black-and-white clips played on vintage television sets, objects jumping from screens into the real world and back, and cathode ray tube oscilloscopes drawing graphics in the air (loud sound!) (nitter). It’s recommended that you check out the short showcase videos we embedded below before you continue reading, because transcribing these visuals into words won’t do them justice.

In case you’re not up for a video, however, we shall try transcribing them anyway. Animals, shapes and figures appear in the real world, bound by glass spheres and containers, using the technique known as Pepper’s Ghost. A variety of screens used for creating that illusion – sometimes it’s a tablet, and sometimes it’s an old television set rested upside down on top of a glass aquarium. Vintage television sets are involved quite often in [Ellingson]’s experiments, typically found playing movie scenes and clips from their appropriate eras, or even used as one of the locations that a Pepper’s Ghost-enchanted object could move into — firmly a part of the same imaginary world turned real.

It’s not always that things move from a TV screen into their glass boundary, gaining an extra dimension in the process, but when it happens, the synchronization is impeccable. All of that is backed by — and usually controlled by — Moog synthesizer sounds, knob turns driving video distortions or aspects of an object movement. Not all of his clips have synthesizers, old TVs, or Pepper’s Ghost illusion in them, but every experiment of his contains at least two out of these three, working in unison to create impressions. And as much as the art value is undeniable, [Ellingson] also adds a whole lot of hacker value for us to take away!

[Ellingson] understands what goes into building optical illusions like Pepper’s Ghost — using a variety of different glassware, from Erlenmeyer flasks to teapots, producing a consistent and ongoing stream of new ideas with unique spins on them. His aim is to share and create beyond what his art can achieve, which is why he encourages us to try it out ourselves — with this one minute video of a quick Pepper’s Ghost build, using nothing but a generic tablet, an emptied-out plastic snow globe and a piece of cheap transparency film used for school projectors. If you want to go beyond, he’s made an extensive tutorial on illusions of the kind he does, their simplicities and complexities, and all the different ways you can build one.

We all benefit when an artist finds a technology and starts playing with it, closing the divide between technology and art – and by extension, the divide between technology and nature. Sometimes, it’s flowing light art installations where you are a boulder in route of plankton’s movement, other times, it’s through-hole component-packed printed circuit birds that sing not unlike the non-printed-circuit ones, or manipulation of CRT displays with function generator-driven coils to offset the beam and turn the image into a pattern of lines.

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Wearable Electronics Takes The 3D Printing Route

There was a time when a cheap 3D printer was almost certain to mean an awful kit of parts, usually a so-called “Prusa i3”, which was of course as far away in quality from the machines supplied by [Josef Průša] himself as it’s possible to get. But as Chinese manufacturers such as Creality have brought machines with some quality and relaibility into the budget space these abominations have largely been crowded out. There are still cheap 3D printers to be found though, and it’s one of these that [3D Printing Professor] has mounted on his wrist (Nitter) for the ultimate in portable manufacturing.

The Easythreed K7 is a novel take on a 3D printer that positions the device more as a child’s toy than a desktop manufacturing solution. It’s somewhat limited in its capabilities by its tiny size but by all accounts it’s a usable machine, and at around $100 USD it’s about the cheapest 3D printer for sale on the likes of AliExpress. The wearable mount is probably best described as a forearm mount rather than a wrist mount, but has provision for a battery pack and a small roll of filament. And this contraption is claimed to work, but we maybe would think before committing to a day-long print with it.

This may be the smallest wearable 3D printer we’ve shown you so far, but it’s not the first. That achievement goes to Shenzhen maker [Naomi Wu], who strapped one on her back way back in 2017.

Thanks [J. Peterson] for the tip!

A vacuum tube computer next to a part of its schematic

This Colossal Vacuum Tube Computer Plays A Mean Game Of Pong

It doesn’t happen often that we report on new vacuum tube based computer designs. Today however, we’re pleased to introduce to you the Fast Reliable Electronic Digital Dot Computer, or Fred.Computer for short. It’s the brainchild of [Mike] who also brought us ENA, which we featured earlier.

Fred is a new design that reuses the parts that made up ENA. It has an 8-bit CPU, 16 bytes of RAM, 256 bytes of NVRAM, and runs at a clock speed of 11.3 kHz. With its 560 tubes drawing a total supply current of about 200 A it also provides a fair bit of heating to [Mike]’s study. The main logic is implemented through NOR gates, built from 6N3P dual-triode tubes sourced from Eastern Europe. These NOR gates are combined into more complex structures like latches, registers and even a complete ALU. A total of sixteen machine code instructions can be used to write programs; clever design allows Fred to perform 16, 32 or even 64-bit calculations with its 8-bit ALU.

A PCB with many reed relays
Need some RAM? There’s sixteen bytes right here.

An interesting addition is a new RAM design based on reed relays. [Mike] realised that relays are actually very similar to digital transmission gates and can therefore be used to make a simple static RAM cell. If you thought relays were too slow for RAM cells, think again: these reed relays can toggle at a mind-boggling 700 Hz, making them more than fast enough for Fred.

The main I/O device is a console that contains several pushbuttons as well as a 12 x 8 LED display. All of this makes Fred a fully-functional general-purpose computer that’s even capable of playing Pong (video, embedded below). [Mike]’s website is full of interesting detail on all aspects of vacuum tube computer design, and makes delightful reading for anyone tempted by the idea of building their own.

Can’t get enough of vacuum tube computers? Have a look at this 1-bit MC14500 implementation, marvel at this modern interpretation of an adding machine, or find out how IBM designed its logic in the 1950s.

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The Deadliest Project On The Internet?

Before deciding whether the headline of this article is clickbait, please take a moment to watch the excellent video by [BigClive] below the break. And then, go to your local search engine and search the phrase “fractal burning death”. We’ll wait.

With that out of the way, we have to admit that when we saw the subject “The most deadly project on the Internet” on [bigclivedotcom]’s YouTube channel, we were a bit skeptical. It’s a big claim. But then we watched the video and did some googling. Sadly, there are over 30 documented cases of this project killing people, and more cases of permanent grievous injury.

The results of Fractal Wood Burning with High Voltage

Fractal Burning is a hobby where wood is burned by slathering wood in a conductive slurry and then applying high voltage to either side of the wood, usually using something not rated for high voltage, such as jumper cables. The High Voltage is supplied by an unmodified Microwave Oven Transformer. Other projects using MOT’s typically rip out the high voltage secondary windings and re-wind them as low voltage, high amperage transformers, and are using in Spot Welders and even arc welders.

As laid out by [BigClive], the voltages coming from an unmodified MOT, ranging from 2-3 KV (That’s between two and three thousand Volts) at a very low impedance are right up there in the “Don’t go near it!” territory.

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The TinyPICO board and the rocker switch soldered together showing a complete device, shown being held in the air by a crocodile clip

Simple Hardware Switch For OS Dualbooting, Thanks To RP2040

Dualbooting your computer can be a chore, the more switching between OSes you have to do – which is why virtualization or having separate computers are the go-to for many. Failing that, we have no choice but to smooth over our dualbooting experience with various workarounds and helpers. [William Somsky] shares one such helper tool with us – an elegant device made with a RP2040-sporting TinyPICO board and a three-way rocker switch, directing GRUB to boot into either Windows or Linux automatically, or leave us with the usual boot menu. This way, you can just flip the switch, hit “reboot” and walk away, coming back to your PC booted into OS of your choice, instead of timing your presence just so that you can catch the boot menu on time.

All you need to do is to solder a rocker switch to your RP2040 board of choice, then flash the RP2040 with code that detects the state of the switch, and creates a mass storage device hosting a file setting a Grub variable to either one of the 0, 1 or 2. [William] describes his journey, fighting mysterious caching problems, but tells us he got it working in the end. Sadly, [William] hasn’t shared the RP2040-side code with us, but he has at least put the Grub’s custom.cfg file in the ‘Files’ section of the Hackaday.io project.

Readily accessible microcontrollers with mass storage functions sure help make such hacks simple – earlier, we’ve seen dualboot switching like this done by modifying assembly code of the MBR. Dualbooting is a hacker’s rite of passage, and certain OSes of late can make it harder than other ones. Even if you don’t want to dualboot your PC, however, you sure can dualboot an Arduino!

A boy looking at a small wind turbine

Hackaday Prize 2022: A 3D Printed Portable Wind Turbine For Hikers

If you’re out in the wilderness and off the grid, but still need to charge your phone, the most obvious way to do that is by using a solar panel. Light, flat and without moving parts, they’re easy to store and carry on a hike. But they obviously don’t work in the dark, so what’s a hiker to do if they want to charge their devices at night? If you happen to be in a windy place, then [adriancubas] has the solution for you: a portable wind turbine that folds up to the size of a 2 L soda bottle.

[adrian] designed the turbine to be light and compact enough to take with him on multi-day camping trips. Nearly all parts are 3D printed in PLA, and although ABS or PETG would have been stronger, the current design seems to hold up well in a moderate breeze. The generator core is made from a stepper motor with a bridge rectifier and a capacitor to create a DC output. [adrian] estimates the maximum power output to be around 12 W, which should be more than enough to charge a few beefy power banks overnight.

All parts are available as STL files on [adrian]’s project page, so if you’re looking for some wind power to charge your gadgets on your next camping trip you can go ahead and build one yourself. While we’ve seen large 3D printed wind turbines before, and portable ones for hikers, [adrian]’s clever folding design is a neat step up towards making wind power almost as easy to use as solar power.

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Screenshot of a logic analyzer software, showing the SDA channel being split into three separate traces

I2C Tap Helps Assign Blame For SDA Conflicts

If you’ve ever debugged a misbehaving I2C circuit, you probably know how frustrating it can be. Thankfully [Jim] over at Hackaday.io, has a proto-boardable circuit that can help!

Inter-integrated circuit bus (aka I2C) uses open collector outputs on a two wire interface. Open collector means a device connected to the I2C bus can only pull the bus down to ground. Chips never drive a logic “HIGH” on the wires. When nothing is driving the lines low, a weak resistor pulls the lines up to VCC. This is a good thing, because I2C is also a multidrop bus — meaning many devices can be connected to the bus at the time. Without open collector outputs, one chip could drive a high, while another drives a low – which would create a short circuit, possibly damaging both devices.

Even with all this protection, there can be problems. The SCL and SDA lines in the I2C communication protocol are bidirectional, which means either a controller or a peripheral can pull it low. Sometimes, when tracing I2C communications you’ll need to figure out which part is holding the line low. With many devices sharing the same bus, that can become nigh-impossible. Some folks have tricks with resistors and analog sampling, but the tried and true method of de-soldering and physically lifting chip pins off the bus often comes into play.

[Jim’s] circuit splits SDA signal into controller-side and peripheral-side, helping you make it clear who is to blame for hiccups and stray noise. To do that, he’s using 6N137 optoisolators and LMV393 comparators. [Jim] shared a NapkinCAD schematic with us, meant to be replicate-able in times of dire need. With this design, you can split your I2C bus into four separate channels – controller-side SDA, peripheral-side SDA, combined SDA and SCL. 4 Channels might be a lot for a scope, but this is no problem for today’s cheap logic analyzers.

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