Making A 1940s Radio Digital With Nixies

March 17, 2019 by 10 Comments

Classix Philly One Oh Seven Nine is your home for Philly soul right at the top of the dial. That phrase, ‘top of the dial’ doesn’t mean much these days because we all have radios with a digital display and seek buttons. There was a time when radios actually had dials, but [glasslinger] is in a class all by himself. He’s adding a digital display to a 1940s radio, and he’s doing it with Nixie tubes.

The circuitry for the digital display for this AM radio requires getting the frequency the radio is tuned to. This is done by counting the oscillator frequency, then subtracting the IF. [glasslinger] is doing this with an Arduino (hey, it’s a legitimate engineering choice) and a 4040 12-bit binary counter as a pre-scaler. The Arduino does the math and then drives a few 74141 Nixie drivers, which then display the frequency of the receiver in beautiful glass tubes. Add in a single neon bulb for the thousands digit, and you have a four-digit display that will tell you the frequency you’re tuned to on an old AM radio.

The rest of the build consists of fixing up an old radio and gluing the veneer down again with modern glues that will last another seventy years. The finished cabinet was sanded, a bezel for the display was added, and since [glasslinger] has the equipment, he made a new, long neon tube to light up with the volume of the radio. And you thought a cat’s eye detector was cool.

This build is a tour de force, and something that is so incredibly modern but at the same time built on vintage technology. If you’ve got an hour and a half, we highly recommend checking out the build video below.

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Building A Magnetic Loop Antenna

March 17, 2019 by 21 Comments

Antennas come in many shapes and sizes, with a variety of characteristics making them more or less suitable for various applications. The average hacker with only a middling exposure to RF may be familiar with trace antennas, yagis and dipoles, but there’s a whole load more out there. [Eric Sorensen] is going down the path less travelled, undertaking the build of a self-tuning magnetic loop antenna. 

[Eric]’s build is designed to operate at 100W on the 20 meter band, and this influences the specifications of the antenna. Particularly critical in the magnetic loop design is the voltage across the tuning capacitor; in this design, it comes out at approximately 4 kilovolts. This necessitates the careful choice of parts that can handle these voltages. In this case, a vacuum variable capacitor is used, rated to a peak current of 57 amps and a peak voltage of 5 kilovolts.

The magnetic loop design leads to antenna which is tuned to a very narrow frequency range, giving good selectivity. However, it also requires retuning quite often in order to stay on-band. [Eric] is implementing a self-tuning system to solve this, with a controller using a motor to actuate the tuning capacitor to maintain the antenna at its proper operating point.

If you’re unfamiliar with magnetic loop builds, [Eric]’s project serves as a great introduction to both the electrical and mechanical considerations inherent in such a design. We’ve seen even more obscure designs though – like these antennas applied with advanced spray techniques.

 

A Lasercut ATX Case For Your Next Desktop Rig

March 17, 2019 by 36 Comments

Case modding exploded in the late 1990s, as computer enthusiasts the world over grew tired of the beige box and took matters into their own hands. The movement began with custom paints and finishes on existing cases, with competitions and bragging rights then taking over to further push the state of the art. It’s one thing to mod a case, however, and another to build one entirely from scratch. [Wesley]’s lasercut case build is an excellent example of the latter.

The build is designed for the ATX form factor, making it suitable for regular desktop computer parts. There are provisions for 3.5 and 2.5 inch drives, as well as a standard ATX PSU and provisions for case fans. The large lasercut panels are supplemented by some 3D printed parts, and the usual metric M3 hardware used with the ATX standard.

It’s a tidy build you can replicate yourself, with the parts available on Thingiverse for your making pleasure. [Wesley]’s build is resplendent in orange, but we’d also love to see an all-transparent build with blinding LED light effects. If you build it, you know where to send it.

Of course, if you’re looking for something more compact, you could always build the whole computer inside the power supply. 

Alma The Talking Dog Might Win Some Bar Bets

March 16, 2019 by 17 Comments

Students at the University of Illinois at Urbana-Champaign have a brain-computer interface that can measure brainwaves. What did they do with it? They gave it to Alma, a golden labrador, as you can see in the video below. The code and enough info to duplicate the electronics are on GitHub.

Of course, the dog doesn’t directly generate speech. Instead, the circuit watches her brainwaves via an Arduino and feeds the raw data to a Raspberry Pi. A machine learning algorithm determines Alma’s brainwave state and plays prerecorded audio expressing Alma’s thoughts.

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The MiniITX Retro System

March 16, 2019 by 12 Comments

There are hundreds of modern, retrocomputing projects out there that put ancient CPUs and chips in a modern context. The Neon816 from [Lenore] is perhaps one of the most impressive projects like this we’ve seen. It’s a classic system in a modern form factor, with modern video output, mashed together into a MiniITX motherboard.

The powerhouse of this computer is the Western Design Center W65C816 CPU. This is the second generation of the venerable 6502 CPU, the same chip found in everything from the Commodore 64 to the Apple II to the Nintendo Entertainment System. The 65816 is a 6502 at start-up until you flip a bit in a register, at which time the signalling on the address bus becomes much weirder. We’ve seen some single board computers based on the 65816 before and The 8-Bit Guy has a few ideas to build a computer around this CPU, but for the foreseeable future work on that will be trapped in development hell.

Of note, the Neon816 will feature DVI output (I guess technically you can just run the analog signals through the connector), a PS/2 Joystick input, two Atari / Sega joystick ports, MIDI in and out, a PC-style floppy disc connector, and a Commodore serial bus. It’s a hodge-podge of classic retrotainment, all in a single MiniITX motherboard.

The key other feature of the Neon816 is an FPGA, specifically a Lattice XP2 8000 LUT chip that is used for video and audio. This is combined with 1MB of main RAM (looks like a simple SRAM) and 128k of Flash storage for the ROM. There’s also an SD card in there for storage.

Right now, [Lenore] is populating the first prototype board, and we can’t wait to see some video generated with this impressive little system.

The Enlightenment Turns Light And Noise Into Sound

March 16, 2019 by 24 Comments

We’re all familiar with the subtle sounds of electrical equipment present in daily life. There’s the high-pitched whine of a CRT, the mains hum of a poorly isolated audio amplifier, and the wailing screams of inductors. Typically these sounds go unnoticed unless something is malfunctioning or otherwise wrong. However, Quiet Ensemble decided to capture these noises and turned them into a performance they call The Enlightenment.

The basic setup consists of a series of lights, most of which are theatrical in nature. There are spotlights, a series of neons, and even a few bright strobes. Copper coils are used to pick up the stray electrical noises generated by these lights in operation. These noises are then fed to mixers, amplifiers, and other audio equipment to allow the performers to control the audio as they wish.

The end result is a mechanical, and at times, brutal soundscape that wouldn’t sound out of place on the Homeworld soundtrack. Flashing strobes contribute rhythm while the rest of the lights lend their droning and whining to fill out the ensemble.

If it’s a little too niche for your tastes, the Triforium may be more to your liking. Video after the break.

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Printable Filament Spool Hub Skips The Bearings

March 16, 2019 by 32 Comments

When you really start fine-tuning your 3D printer, you might start to notice that even the smallest things can have a noticeable impact on your prints. An open window can cause enough of a draft to make your print peel up from the bed, and the slightly askew diameter of that bargain basement filament can mess up your extrusion rate. It can be a deep rabbit hole to fall down if you’re not careful.

One element that’s often overlooked is the filament spool; if it’s not rotating smoothly, the drag it puts on both the extruder and movement of the print head can cause difficult to diagnose issues. For his custom built printer, [Marius Taciuc] developed a very clever printable gadget that helps the filament roll spin using nothing but the properties of the PLA itself. While the design might need a bit of tweaking to work on your own printer, the files he’s shared should get you most of the way there.

All you need to do is print out the hubs which fit your particular filament spools (naturally, they aren’t all a standard size), and snap them on. The four “claws” of the hub lightly contact a piece of 8 mm rod enough to support the spool while limiting the surface area as much as possible. The natural elasticity of PLA helps dampen the moment that would result if you just hung the hub-less spool on the rod.

The STL files [Marius] has provided for his low-friction hubs should work fine for anyone who’s interested in trying out his design, but you’ll need to come up with your own method of mounting the 8 mm rod in a convenient place. The arms he’s included are specifically designed for his customized Prusa Mendel, which is pretty far removed from contemporary desktop 3D printer design. Something to consider might be a piece of 8 mm rod suspended over the printer, with enough space that you could put a couple spools on for quick access to different colors or materials.

Hackers have been trying to solve the spool friction issue for years, and as you might expect we’ve seen some very clever designs in the past. But we especially like how simple [Marius] has made this design, and the fact that you don’t need to source bearings to build it. If you’re thinking of giving this new design a shot, be sure to leave a comment so we know how it worked out for you.

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