Ringing In The Holidays With Self-Playing Chimes

December 24, 2020 by Adam Zeloof 4 Comments

The holiday season is here, and along with it comes Christmas music. Love them or hate them, Yuletide tunes are a simple fact of life each December. This year, [Derek Anderson] put a modern spin on a few classic melodies and listened to them via his set of self-playing chimes.

Inspired by [Derek]’s childhood Ye Merry Minstrel Caroling Christmas Bells (video), these chimes really bring the old-school Christmas decoration into the 21st century. Each chime is struck by a dedicated electromagnetically-actuated mallet, which is in turn controlled by an ESP32 running MicroPython.

The chimes play MIDI files, so you could, of course, play music unrelated to Christmas if you wanted to. And they even feature an OLED screen that displays what song is being played. For added flair, the entire thing is beautifully framed in black walnut, not to mention the custom-wound solenoids.

This project incorporated mechanical and electrical design, woodworking, 3D printing, programming, and song arrangement. It’s a wonder that [Derek] was able to create the entire product in the 40-80 hour time frame he estimated. (Though it looks like he had a bit of help.)

We always love to see projects like this, ones in which several disciplines get rolled together to create a beautiful finished piece.

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Real Hackers Videoconference In Terminal

December 15, 2020 by Adam Zeloof 18 Comments

At some point or another, many of us have tried to see how much of our digital lives could be accessed from the comfort of a terminal. We’ve tried Alpine for email, W3M for web browsing, and even watched Star Wars via telnet. But, in the increasingly socially-distant world we find ourselves in today, we find ourselves asking: what about video calling?

Okay, we weren’t asking that. But thankfully [Andy Kong] was, and saw fit to implement it when he and a friend created AsciiZOOM, a “secure, text-based videoconferencing app, accessible from the safety of your terminal.”

As you may have guessed, [Andy]’s solution replaces the conventional video stream we’re all used to with realtime animated ASCII art. The system works by capturing a video stream from a webcam, “compressing” each pixel by converting it into an ASCII character, and stuffing the entire frame into a TCP packet. Each client is connected to a server (meeting room?) which coordinates the packets, sending them back and forth appropriately.

As impressive as it is impractical, the only area in which the project lacks is in audio. [Andy] suggests using Discord to solve that, but here’s hoping we see subtitles in version 2! Will AsciiZOOM be replacing our favorite videoconferencing suite any time soon? No. Are we glad it exists? You betcha.

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How To Get Into Lost Wax Casting (with A Dash Of 3D Printing)

December 7, 2020 by Adam Zeloof 24 Comments

I’ve always thought that there are three things you can do with metal: cut it, bend it, and join it. Sure, I knew you could melt it, but that was always something that happened in big foundries- you design something and ship it off to be cast in some large angular building churning out smoke. After all, melting most metals is hard. Silver melts at 1,763 °F. Copper at 1,983 °F. Not only do you need to create an environment that can hit those temperatures, but you need to build it from materials that can withstand them.

Turns out, melting metal is not so bad. Surprisingly, I’ve found that the hardest part of the process for an engineer like myself at least, is creating the pattern to be replicated in metal. That part is pure art, but thankfully I learned that we can use technology to cheat a bit.

When I decided to take up casting earlier this year, I knew pretty much nothing about it. Before we dive into the details here, let’s go through a quick rundown to save you the first day I spent researching the process. At it’s core, here are the steps involved in lost wax, or investment, casting:

Make a pattern: a wax or plastic replica of the part you’d like to create in metal
Make a mold: pour plaster around the pattern, then burn out the wax to leave a hollow cavity
Pour the metal: melt some metal and pour it into the cavity

I had been kicking around the idea of trying this since last fall, but didn’t really know where to begin. There seemed to be a lot of equipment involved, and I’m no sculptor, so I knew that making patterns would be a challenge. I had heard that you could 3D-print wax patterns instead of carving them by hand, but the best machine for the job is an SLA printer which is prohibitively expensive, or so I thought. Continue reading “How To Get Into Lost Wax Casting (with A Dash Of 3D Printing)” →

Teensy Controller For Powerful CNCs

November 11, 2020 by Adam Zeloof 44 Comments

It seems like every year, it gets a bit easier to build your own CNC. From the Enhanced Machine Controller (EMC) project of the early 1990s to Arduinos running Grbl in the late 2000s, the open source community has moved ahead in leaps and bounds. Grbl is at its core firmware that interprets G-code and commands stepper motors, usually to move a tool head in such a way as to make something. Tons of systems have been built around it, including early Makerbot printers.

Its also spawned a plethora of other projects (the Grbl GitHib repo has 2,400 forks!), including a 32-bit flavor called grblHAL. This version is at the heart of a fantastic CNC controller board developed by [Phill Barrett]. Ditching the Arduino for a more powerful Teensy 4.1, [Phil]’s controller supports full five-axis control, variable frequency drive spindles, dust extractor control, and flood and mist coolant control. It can run at blazing stepping rates of up to 160 kHz (standard Grbl on an Arduino hits 30 kHz) and can be assembled with either a USB or Ethernet interface.

There’s no shortage of interesting Grbl-based machines out there — including a revamped Atari plotter and a three-axis rotary CNC (shameless plug for the author’s own project) but it’s always exciting to see new hardware developed that will undoubtedly find its way into the next generation of a family of projects. We can’t wait to see what comes next!

Visualizing Magnetic Memory With Core 64

November 11, 2020 by Adam Zeloof 17 Comments

For the vast majority of us, computer memory is a somewhat abstract idea. Whether you’re declaring a variable in Python or setting a register in Verilog, the data goes — somewhere — and the rest really isn’t your problem. You may have deliberately chosen the exact address to write to, but its not like you can glance at a stick of RAM and see the data. And you almost certainly can’t rewrite it by hand. (If you can do either of those things, let us know.)

These limitations must have bothered [Andy Geppert], because he set out to bring computer memory into the tangible (or at least, visible) world with his interactive memory badge Core 64. [Andy] has gone through a few different iterations, but essentially Core 64 is an 8×8 grid of woven core memory, which stores each bit via magnetic polarization, with a field of LEDs behind it that allow you to visualize what’s stored. The real beauty of this setup is that it it can be used to display 64 pixel graphics. Better yet — a bit can be rewritten by introducing a magnetic field at the wire junction. In other words, throw a magnet on a stick into the mix and you have yourself a tiny drawing tablet!

This isn’t the first time we’ve seen cool experiments with core memory, and not even the first time we’ve seen [Andy] use it to make something awesome, but it really illuminates how the technology works. Being able to not only see memory being written but to manually write to it makes it all so much realer, somehow.

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Rockin’ Out In LTSpice: Simulating Classic Guitar Pedals

October 29, 2020 by Adam Zeloof 9 Comments

Musicians have a fantastic language to describe signals. A sound can be fat, dark, crunchy, punchy — the list goes on. These aren’t very technical terms, but they get the job done. After all, it’s much easier to ask to guitarist for a crisper sound than to ask them to sharpen the edges of the waveform, while amplifying the high-frequency components and attenuating the low-frequency components. Of course, it’s fun to look at signals this way as well, especially when you can correlate shifts in sound quality to changes in the waveform and, ideally, the circuit that produces it.

To undergo such an investigation, [Nash Reilly] has been simulating guitar effects pedals in LTSpice. Able to find most of the schematics he needs online, [Nash] breaks down the function of each part of the circuit and builds a simulation of the entire system. His write-up clearly explains, and often demonstrates, what’s going on inside the box. On the surface, it’s an interesting tour of the inner workings of your favorite effects pedals. Beyond that, it’s an excellent survey of analog design that is well-worth the read for anybody interested in audio, electronics, or audio electronics.

For those interested in taking the physical route rather than the simulated one, we’ve taken a look at pedal design before. Anybody who wants to try their hand at creating simulations can grab a copy of LTSpice, or check out a package called LiveSpice, which lets you simulate circuits in realtime and use them to process live audio — pretty useful for prototyping guitar effects.

Radio Remote Control Via HTML5

October 24, 2020 by Adam Zeloof 36 Comments

It’s a common scene: a dedicated radio amateur wakes up early in the morning, ambles over to their shack, and sits in the glow of vacuum tubes as they call CQ DX, trying to contact hams in time zones across the world. It’s also a common scene for the same ham to sit in the comfort of their living room, sipping hot chocolate and remote-controlling their rig from a laptop. As you can imagine, this essentially involves a server running on a computer hooked up to the radio, which is connected via the internet to a client running on the laptop. [Olivier/ F4HTB] saw a way to improve the process by eliminating the client software and controlling the rig from a web browser.

[Oliver]’s software, aptly named Universal HamRadio Remote, runs a web server that hosts an HTML5 dashboard for controlling the radio. It also pipes audio back and forth (radio control wouldn’t be very useful if you couldn’t talk!), and can be run on a Raspberry Pi. Not only does this make setup easier, as there is no need to configure the client machine, but it also makes the radio accessible from nearly any modern device.

We’ve seen a similar (albeit expensive and closed-source) solution, the MFJ-1234, before, but it’s always refreshing to see the open-source community tackle a problem and make it their own. We can’t wait to see where the project goes next!