Arc from a flyback transformer power supply

A Cornucopia Of High Voltage Sources

May 26, 2016 by Steven Dufresne 39 Comments

Having hacked away with high voltage for many years I’ve ended up using a large number of very different high voltage sources. I say sources and not power supplies because I’ve even powered a corona motor by rubbing a PVC pipe with a cotton cloth, making use of the triboelectric effect. But while the voltage from that is high, the current is too low for producing the necessary ion wind to make a lifter fly up off a tabletop. For that I use a flyback transformer and Cockcroft-Walton voltage multiplier power supply that’s plugged into a wall socket.

So yes, I have an unorthodox skillset when it comes to sourcing high voltage. It’s time I sat down and listed most of the power sources I’ve used over the years, including a bit about how they work, what their output is like and what they can be used for, as well as some idea of cost or ease of making. The order is from least powerful to most powerful so keep reading for the ones that really bite.

Triboelectric Effect

You’ve no doubt encountered this effect. It’s how your body is charged when you rub your feet on carpet and then get a shock from touching a door knob. When you rub two specific materials together there’s a transfer of electrons from one to the other. Not just any two materials will work. To find out which materials are good to use, have a look at a triboelectric series table.

Materials that are on the positive end of the table will become positively charged when rubbed against materials on the negative end of the table. Those materials will become negatively charged. The further apart they are in the table, the stronger the charging.

Powering corona motor with triboelectricity

An example of where I’ve used this is to power the corona motor shown here. I vigorously rub a PVC pipe with a cotton cloth, and as the pipe emerges from the cloth, a sharp wire a few millimeters away takes the charge from the pipe. You can see this corona motor being powered by other power sources in the video here.

This would be considered an electrostatic power source because charge is accumulated on surfaces. Being insulating materials, that charge can’t move around.

Continue reading “A Cornucopia Of High Voltage Sources” →

Flame Triodes Don’t Need Any Vacuum

May 26, 2016 by Jenny List 37 Comments

There is a rich history surrounding the improvisation of electronic components. From cats-whisker foxhole radio detectors using razor blades through radio amateurs trying antique quartz lenses as crystal resonators and 1950s experimenters making their own point-contact transistors, whenever desirable components have been unavailable the ingenuity of hackers and makers has always sought to provide.

In an age when any component you might wish for is only a web browser and a courier package away, you might think there would be no need for such experiments. But it is in our curious nature to push the boundaries of what can be made without a factory at our disposal, so there are still plenty of ingenious home-made components under construction.

One such experiment came our way recently. It’s a few years old, but it’s a good one. [Nyle Steiner, K7NS] made a working triode without any form of vacuum, instead its medium is a flame. He’s demonstrated it as a rectifier, amplifier, and oscillator, and while it might not be the best triode ever it’s certainly one of the simplest.

In a traditional vacuum triode the current flows as electrons released from a hot cathode and are able to cross the space because there are no gas molecules for them to collide with. The flame triode has an abundance of gas, but the gasses within it and its immediate surroundings are also strongly ionized, and thus electrically conductive. Flame ionization detectors have exploited this phenomenon in scientific instruments for a very long time.

A roaring flame might not be the most practical thing to keep in your electronic equipment, but [Nyle]’s experiment is nonetheless an impressive one. He’s posted a video showing it in action, which you can see below the break.

Continue reading “Flame Triodes Don’t Need Any Vacuum” →

A Modern But Classic Enigma Machine

May 24, 2016 by Moritz Walter 31 Comments

Hacking has always brought more good to the world than not hacking. The successful efforts of the Allies during World War II in deciphering the Enigma machine output still reminds us of that. Today, the machine is a classic example of cryptography and bare-metal computing.

We have covered quite a few DIY Enigma machines in the past, yet 14 years old [Andy] really impressed us with his high school science fair project, a scratch built, retro-modern Enigma machine.

Continue reading “A Modern But Classic Enigma Machine” →

The Man Who Didn’t Invent The Personal Computer

May 23, 2016 by Brian Benchoff 45 Comments

[John Blankenbaker] did not invent the personal computer. Museums, computer historians, and authors have other realities in mind when they say [John]’s invention, the KENBAK-1, was the first electronic, commercially available computer that was not a kit, and available to the general population.

In a way, it’s almost to the KENBAK’s detriment that it is labelled the first personal computer. It was, after all, a computer from before the age of the microprocessor. It is possibly the simplest machine ever sold and an architecturally unique machine that has more in common with the ENIAC than any other machine built in the last thirty years..

The story of the creation of this ancient computer has never been told until now. [John], a surprisingly spry octogenarian, told the story of his career and the development of the first personal computer at the Vintage Computer Festival East last month. This is his story of not inventing the personal computer.

Continue reading “The Man Who Didn’t Invent The Personal Computer” →

A Minitel Terminal As A USB Linux Terminal

May 22, 2016 by Jenny List 20 Comments

If you paid a visit to France in the 1980s the chances are you’d have been surprised to see a little brown screen and keyboard sitting next to the telephones wherever you went. At the time, it was another reason apart from the food, wine, and super-fast trains to envy our Gallic cousins. This was Minitel, their take on the cutting-edge of online data services of the day.

Minitel stood apart from similar services of the day in most other countries, because of its business model. Unlike the UK’s Prestel or West Germany’s BTX for which you had to spend significant money on a terminal, the French Minitel terminals were free. Thus in the early 1980s everybody in France was busy using videotext while most of the rest of Europe was still excited by chipping bits of flint into arrow heads. Or at least, that’s how it seemed at the time to those of us who didn’t have Minitel.

The Minitel service was finally shuttered in 2012, but the terminals can still be found. [Tony Pigram] bought one, an Alcatel Minitel 1, and made it into something useful by turning it into a USB serial terminal for his Raspberry Pi. Surprisingly the physical interface between the Minitel and the USB port is a relatively simple level shifter, but the configuration of both the Minitel and the Pi was anything but.

The problem was that Minitel terminals were meant to work with Minitel, and [Tony]’s difficulties were increased by his machine being an earlier model without the handy function key to access settings found on later terminals. A lot of research paid dividends though, and he now has what must be one of the most compact and stylish CRT serial terminals available. We can’t help noticing it has a QWERTY keyboard and English menus, it would be interesting to know which non-French market it was made for.

We’ve featured an RS-232 integration into a Minitel terminal before here at Hackaday, but if you are really interested in Gallic retro-tech take a look at our discussion of their 8-bit scene.

Build A Replica Apple ///

May 21, 2016 by Gerrit Coetzee 15 Comments

[Mr. Name Required] pointed us to a great video on the modeling of a replica Apple /// to the small scale needed to contain a Raspberry Pi by [Charles Mangin].

[Mr. Name] pointed out that the video was a great example of the use of reference photos for modeling. [Charles] starts by finding the references he needs for the model. Google image search and some Apple history websites supplied him with the required images.

He modeled the Apple /// in Autodesk 123. It has sketch tools, but he chose to craft the paths in iDraw and import them into the software. This is most likely due to the better support for boolean combination tools in vector editing software. Otherwise he’d have to spend hours messing with the trim tool.

Later in the video he shows how to change the perspective in photographs to get a more orthographic view of an object. Then it’s time for some heavy modeling. He really pushes 123 to its limit.

The model is sent off for professional 3D printing to capture all the detail. Then it’s some finishing work and his miniature Apple /// is done. Video after the break.

Continue reading “Build A Replica Apple ///” →

A Dis-Integrated 6502

May 16, 2016 by Brian Benchoff 57 Comments

The 6502 is the classic CPU. This chip is found in the original Apple, Apple II, PET, Commodore 64, BBC Micro, Atari 2600, and 800, the original Nintendo Entertainment System, Tamagotchis, and Bender Bending Rodriguez. This was the chip that started the microcomputer revolution, and holds a special place in the heart of every nerd and technophile. The 6502 is also possibly the most studied processor, with die shots of polysilicon and metal found in VLSI textbooks and numerous simulators available online.

The only thing we haven’t seen, until now, is a version of the 6502 built out of discrete transistors. That’s what [Eric Schlaepfer] has been working on over the past year. It’s huge – 12 inches by 15 inches – has over four thousand individual components, and so far, this thing works. It’s not completely tested, but the preliminary results look good.

The MOnSter 6502 began as a thought experiment between [Eric] and [Windell Oskay], the guy behind Evil Mad Scientist and creator of the discrete 555 and dis-integrated 741 kits. After realizing that a few thousand transistors could fit on a single panel, [Eric] grabbed the netlist of the 6502 from Visual6502.org. With the help of several scripts, and placing 4,304 components into a board design, the 6502 was made dis-integrated. If you’re building a CPU made out of discrete components, it only makes sense to add a bunch of LEDs, so [Eric] threw a few of these on the data and address lines.

This is the NMOS version of the 6502, not the later, improved CMOS version. As such, this version of the 6502 doesn’t have all the instructions some programs would expect. The NMOS version is slower, more prone to noise, and is not a static CPU.

So far, the CPU is not completely tested and [eric] doesn’t expect it to run faster than a few hundred kilohertz, anyway. That means this gigantic CPU can’t be dropped into an Apple II or commodore; these computers need a CPU to run at a specific speed. It will, however, work in a custom development board.

Will the gigantic 6502 ever be for sale? That’s undetermined, but given the interest this project will receive it’s a foregone conclusion.

Correction: [Eric] designed the 555 and 741 kits