Low-End Parts Make Tesla Coil With A High-End Look

November 25, 2017 by Dan Maloney 23 Comments

We all know the saying: cheap, fast, or good — pick any two. That rule seems to apply across the spectrum of hackerdom, from software projects to hardware builds. But this DIY Tesla coil build might just manage to deliver on all three.

Cheap? [Jay Bowles]’ Tesla coil is based on a handheld bug zapper that you can find for a couple of bucks, or borrow from the top of the fridge in the relatively bug-free winter months. The spark gap is just a couple of screws set into scraps of nylon cutting board — nothing fancy there. Fast? Almost everything needed to build this is stuff lying around the house, and depending on the state of your junk bin you may not even have to order the polypropylene caps [Jay] recommends. Good? That’s a relative term, of course, and if you define it as a coil capable of putting out pumpkin-slaying lightning bolts or playing “Yakkity Sax”, you’ll likely be disappointed. But there’s no denying that this Tesla coil looks good, from its Lexan base to the door-pull top load. And running off a couple of AA batteries, it’s safe to use too.

[Jay] put a lot of care into winding and dressing the secondary coil neatly, and the whole thing would look great as a desktop toy. Not into the winding part? You can always etch a PCB Tesla coil instead.

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Flip-Dot Display Brought Out Of Retirement By New Drivers

November 21, 2017 by Dan Maloney 16 Comments

LED matrix displays and flat-screen monitors have largely supplanted old-school electromechanical models for public signage. We think that’s a shame, but it’s also a boon for the tinkerer, as old displays can be had for a song these days in the online markets.

Such was the case for [John Whittington] and his flip-dot display salvaged from an old bus. He wanted to put the old sign back to work, but without a decent driver, he did what one does in these situations — he tore it down and reverse engineered the thing. Like most such displays, his Hannover Display 7 x 56-pixel flip-dot sign is electromechanically interesting; each pixel is a card straddling the poles of a small electromagnet. Pulse the magnet and the card flips over, changing the pixel from black to fluorescent green. [John] used an existing driver for the sign and a logic analyzer to determine the protocol used by the internal electronics to drive the pixels, and came up with a much-improved method of sending characters and graphics. With a Raspberry Pi and power supply now resident inside the case, a web-based GUI lets him display messages easily. The video below has lots of details, and the code is freely available.

You may recall [John] from a recent edge-lit Nixie-like display. Looks like he’s got a thing for eye-catching displays, and we’re fine with that.

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Huge 74181 Is A Classic ALU You Can Actually Understand

November 18, 2017 by Jenny List 22 Comments

You can no longer buy a brand-new 74181, they’ve been out of production for years. All is not lost though, for [Dave’s Dev Lab] have created a facsimile of one on a printed circuit board, using modern single-gate 74-series chips.

Why on earth would you want an oversized replica of an outdated logic chip from nearly five decades ago, we hear you ask? The answer lies in education. If you were to embark on learning about the internals of a microprocessor by taking a modern example such as the one that powers the device on which you are reading this, you would find it to be a daunting task. Over six decades of progress in computer technology have delivered the performance enhancements that put a supercomputer in your smartphone, but at the expense of a contemporary microprocessor being an extremely complex machine which you can’t peer into for any level of understanding.

Simple enough to work your way through the logic

The starting point for the student of microprocessor internals often lies in the past. The technology of the early 1970s holds the fundamentals from which a modern processor can be understood, but remains simple enough to grasp in its entirety as a beginner. Registers, instruction decoders, counters, and an arithmetic/logic unit, or ALU. And for decades the 74181, as an all-in-one 4-bit ALU on a chip that you might have found in a minicomputer at the turn of the 1970s, represented the most convenient way to teach the operation of these devices. Electronic engineers and computer scientists of all ages will have encountered them as they gained their qualifications.

The PCB version of the 181 faithfully follows the original, but with modern 74LVC gates laid out as they would be in the circuit diagram of the chip, and LEDs to show logic state at the different parts of the circuit. Thus when it is used to teach ALU operation it can show every part of the device in detail in a way a real 74181 would never have done.

If the 74181 has caught your interest, we’ve previously brought you [Ken Shirriff]’s reverse engineering of the device in detail using breathtaking images of the silicon.

MiSTer Upgrades Vintage Computer Recreations

November 18, 2017 by Al Williams 26 Comments

The MiST project provides an FPGA-based platform for recreating vintage computers. We recently saw an upgraded board — MiSTer — with a similar goal but with increased capability. You can see a video of the board acting like an Apple ][ playing Pac Man, below.

The board isn’t emulating the target computer. Rather, it uses an FPGA to host a hardware implementation of the target. There are cores for Apple, Atari, Commodore, Coleco, Sega, Sinclair and many other computers. There are also many arcade game cores for games like Defender, Galaga, and Frogger.

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Homebrew SNES Mini Aims For Historical Accuracy

November 15, 2017 by Tom Nardi 8 Comments

While “normies” are out fighting in the aisles of Walmart to snap up one of the official “Classic Mini” consoles that Nintendo lets slip out onto the market every once and awhile, hackers have been perfecting their own miniature versions of these classic gaming systems. The “Classic Mini” line is admittedly a very cool way to capitalize on nostalgic masses who have now found themselves at the age where they have disposable income, but the value proposition is kind of weak. Rather than being stuck with the handful of generation-limited games that Nintendo packed into the official products, these homebrew consoles can play thousands of ROMs from systems that stretch across multiple generations and manufacturers.

But for those old enough to remember playing on one of these systems when they first came out, these modern reincarnations always lack a certain something. It never feels quite right. That vaguely uncomfortable feeling is exactly what [ElBartoME] is aiming to eliminate with his very slick miniature SNES build. His 3D printed case doesn’t just nail the aesthetics of the original (PAL) console, but the system also uses real SNES controllers in addition to NFC “cartridges” to load different ROMs.

The project’s page on Thingiverse has all the wiring diagrams and kernel configuration info to get the internal Raspberry Pi 3 to read an original SNES controller via the GPIO pins. He also gives a full rundown on the hardware and software required to get the NFC-enabled cartridges working with EmulationStation to launch the appropriate game when inserted. Though he does admit this is quite a bit trickier than the controller setup.

[ElBartoME] has put a video up on YouTube that shows him inserting his mock cartridges and navigating the menus with an original SNES controller. If it wasn’t for the fact that the console is the size of a smartphone and the on-screen display is generations beyond what the SNES could pull off, you’d think he was playing on the real thing.

We’ve seen some incredibly impressive emulation boxes based on the Raspberry Pi, and builds which tried to embrace original hardware components, but this particular project may represent the best of both worlds.

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This Weekend: Vintage Computer Festival Zurich

November 14, 2017 by Brian Benchoff 14 Comments

This weekend, November 18th and 19th, the greatest vintage computer conference in Europe is going down. It’s the Vintage Computer Festival Europe, and if you’re around Zurich this weekend, we highly recommend that you check it out.

On deck for this year’s VCF Europe is an incredible amount of amazing retrotechnology. A demonstration of high-resolution graphics without using computer memory will be found in a few Tektronix storage tube terminals (their Wikipedia entry is phenomenal, by the way). There will be a few Olivetti microcomputers on display demonstrating Italy’s contribution to the computer revolution. A PDP 6 will be recreated, and a 1964 IBM 360/30 will be revived. There will be discussions on using logarithms as a basis for computers. [Oscar], creator of the PiDP-8/I will be bringing his latest project, an exquisite miniature recreation of a PDP-11/70, with a molded enclosure and purple toggle switches.

This is a retrocomputer conference where an Apple I is the least interesting computer on display, an extremely difficult feat to pull off. VCFe will be held at Rote Fabrik in Zurich, and tickets are five units of the local currency per day. You can check out the festival on Twitter, Google+, and the main website.

A Dreamcast VMU With A Secret

November 14, 2017 by Jenny List 8 Comments

Since the Raspberry Pi range of boards first appeared back in 2012, we’ve seen them cleverly integrated into a host of inventive form factors. Today we bring you the latest offering in this space, [Kite]’s Raspberry Pi Zero W installed in the case of a Sega Dreamcast VMU. The result is a particularly nicely executed build in which the Pi with a few of its more bulky components removed or replaced with low-profile alternatives sits on the opposite side of a custom PCB from a small LCD display.

The PCB contains the relevant buttons, audio, and power supply circuitry, and when installed in a VMU shell makes for a truly professional quality tiny handheld console. In a particularly nice touch the Pi’s USB connectivity is brought out alongside the SD card on the end of the Zero, under the cap that would have originally protected the VMU’s connector. Some minimal paring away of Sega plastic was required but the case is surprisingly unmodified, and there is plenty of space for a decent-sized battery.

The VMU, or Visual Memory Unit, makes an interesting choice for an enclosure, because it is a relic of one of console gaming’s dead ends. It was the memory card for Sega’s last foray into the console market, the Dreamcast, and unlike those of its competitors it formed a tiny handheld console in its own right. Small games for the VMU platform were bundled with full titles, and there was a simple multiplayer system in which VMUs could be linked together. Sadly the Dreamcast lost the console war of the late 1990s and early 2000s to Sony’s PlayStation 2, but it remains a console of note.

VMUs are not the most common of gaming survivors, but we’ve shown you one or two projects using them. There was an iPod conversion back in 2010, and much more recently some mind-blowing reverse engineering and emulation on the original VMU hardware.

Thanks [Giles Burgess] for the tip.