A 50W Speaker Made Of Light Bulbs

June 8, 2020 by 27 Comments

When we think of a speaker, we are likely to imagine a paper cone with a coil of wire somewhere at the bottom of it suspended in a magnetic field. It’s a hundred-plus-year-old technology that has been nearly perfected. The moving coil is not however the only means of turning an electrical current into a sound. A number of components will make a sound when exposed to audio, including to the surprise of [Eric], the humble incandescent light bulb. He discovered when making an addressable driver for them that he could hear the PWM frequency when they lit up, so he set about harnessing the effect for use as a speaker.

Using an ESP32 board and with a few false starts due to cheap components, he started with MIDI files and ended up with PWM frequencies. It’s an interesting journey into creating multiple PWM channels from an ESP32, and he details some of his problems along the way. The result is the set of singing light bulbs that can be seen in the video below the break, which he freely admits is probably the most awful 50 W speaker that he could have made. That however is not the point of such an experiment, and we applaud him for doing it.

For more MIDI-based tomfoolery, take a look at the PCB Tesla coil.

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3D Printing Nuclear Reactors For Fun And Profit

June 8, 2020 by 18 Comments

Over the past decades, additive manufacturing (AM, also known as 3D printing) has become increasingly common in manufacturing processes. While immensely helpful in the prototyping of new products by allowing for rapid turn-around times between design and testing, these days additive manufacturing is used more and more often in the production of everything from small production runs of custom enclosures to hard to machine components for rocket engines.

The obvious advantage of additive manufacturing is that they use generic equipment and common materials as input, without requiring expensive molds as in the case of injection molding, or extensive, wasteful machining of raw materials on a lathe, mill, and similar equipment. All of the manufacturing gets reduced to a 3D model as input, one or more input materials, and the actual device that converts the 3D model into a physical component with very limited waste.

In the nuclear power industry, these benefits haven’t gone unnoticed, which has led to 3D printed parts being developed for everything from keeping existing plants running to streamlining spent fuel reprocessing and even the printing of entire nuclear reactors.

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Raspberry Pi Plays A MIDI Tune Wherever You May Roam

June 8, 2020 by 1 Comment

MIDI controller keyboards are great because they let you control any synthesizer you plug them into. The only downside: you need a synthesizer to turn MIDI notes into actual sounds, slightly complicating some summer night campfire serenading. Not for [Geordie] though, who decided to build the nanoPi, a portable, MIDI instrument housing a Raspberry Pi.

Using a Korg nanoKEY2 USB MIDI controller as base for the device, [Geordie] took it apart and added a Raspberry Pi Zero W, a power bank to, well, power it, and a USB hub to connect a likewise added USB audio interface, as well as the controller itself. As the nanoKEY2 has a naturally slim shape, none of this would ever fit in it, so he designed and 3D printed a frame to extend its height. Rather than wiring everything up internally, he decided to route the power and data cable to the outside and connect them back to the device itself, allowing him to use both the power bank and the controller itself separately if needed.

On the software side, the Pi is running your common open source software synthesizer, Fluidsynth. To control Fluidsynth itself — for example to change the instrument — [Geordie] actually uses the Termius SSH client on his phone, allowing him also to shut down the Pi that way. While Fluidsynth’s built-in MIDI router could alternatively remap the nanoKEY2’s additional buttons, it appears the functionality is limited to messages of the same type, so the buttons’ Control Change messages couldn’t be remapped to the required Program Change messages. Well, there’s always the option to fit some extra buttons if needed. Or maybe you could do something clever in software.

As you may have noticed, the nanoPi doesn’t include any speaker — and considering its size, that’s probably for the best. So while it’s not a fully standalone instrument, it’s a nice, compact device to use with your headphones anywhere you go. And thanks to its flexible wiring, you could also attach any other USB MIDI controller to it, such as this little woodwind one, or the one that plays every pop song ever.

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A Look Behind The Canvas Of The “60 Billion Lights” Project

June 8, 2020 by 17 Comments

In May of this year, [Erich Styger] shows his project called “60 Billion Lights” off to the world.  Now he has published an update on the making of this impressive work of art. As a quick recap, “60 Billion Lights” is a canvas art piece, which has 60 dual shaft stepper motors integrated into it. Each stepper motor has forty 24-bit RGB LEDs, making for a total of 60 billion position and light combinations on the entire canvas.

With the dual shaft stepper motors, one can control the position of laser-cut acrylic rods inside each of the forty depressions that make up a unit. Each unit has its WS2812B LEDs positioned around the inside edge.

As the embedded video (after the break) shows, it can be used to create a wide variety of effects. The whole of it is driven by 15 controller boards that run FreeRTOS on an NXP LPC845 (Cortex-M0+), connected via RS-485.

In the ‘Making Of’ video (embedded after the break) and article, more details are shown of the individual components, including the dual shaft stepper motors, stepper motor PCBs, the LED ring PCBs, and countless images of the construction, painting and assembly.

If the original article gave one the impression that this was an easy project, it is this behind the scenes look that gives one a good impression of the full scale. From the countless PCBs, controller boards, wiring, programming to the assembly and testing. Not to mention the painting of the canvas itself, which is an original work.
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The Simplest Microwave Receiver

June 7, 2020 by 31 Comments

We are used to microwave receivers requiring complex chipsets and exacting PCB layouts, but as [CHZ-soft] has shown, it does not always have to be that way. With nothing more complex than a germanium point-contact diode and an oscilloscope, you can quickly, easily, and cheaply resolve microwave signals, as we are shown with a 2.4GHz wireless mouse.

Of course, there’s nothing new here, what we’re being shown is the very simplest incarnation of a crystal set. It’s a wideband device, with only the length of the wires providing any sort of resonance, but surprisingly with the addition of a very selective cavity resonator it can be turned into a useful receiver. Perhaps the most interesting take-away is that the germanium point-contact diode — once a ubiquitous component — has almost entirely disappeared. In most applications it has been supplanted by the Schottky diode, but even those usually don’t quite possess the speed in the point contact’s home ground of radio detection. This is a shame, because there are still some bench-level projects for which they are rather useful.

So if you have a point contact diode and AM radio doesn’t attract, give it a go as a microwave detector. And if the point contact diode has attracted your interest then you may want to read our piece on Rufus Turner, who brought us its archetype, the 1N34A.

Via Hacker News.

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Hackaday Links: June 7, 2020

June 7, 2020 by 7 Comments

For many of us who were in college at the time, the 1989 release of Will Wright’s classic SimCity sounded the death knell of our GPAs. Being able to create virtual worlds and then smite them with a tornado or a kaiju attack was the stuff of a procrastinator’s dreams. We always liked the industrial side of the game best, and took great pains in laying out the factory zones, power plants, and seaports. Those of a similar bent will be happy to know that Maxis, the studio behind the game, had a business simulations division, and one of their products was a complete refinery simulator the studio built for Chevron called, unsurprisingly, SimRefinery. The game, which bears a striking resemblance to SimCity, has been recovered and is now available for download, which means endless procrastination by playing virtual petrochemical engineer is only a mouse click away.

Speaking of time wasters, we stumbled upon another simulation this week that sucked away a couple of hours of productivity. As RTL-SDR.com reports, YouTuber called Information Zulu has a 24/7 live stream showing arrivals and departures at Los Angeles International Airport. That may sound boring, but the cameras used to watch the runways are virtual, and the planes are animated based on ADS-B data being scooped up by an RTL-SDR dongle. We pinged Information Zulu and asked for a rundown of the gear behind the system, but never heard back. If we do, we’ll post a full article on what we learned, because the level of detail is amazing. The arriving and departing planes sport the correct livery for the airline, the current weather conditions are shown, taxiing is shown in real time, and there’s even an audio feed from air traffic control.

If you’re looking to gain back a little of the productivity lost to the last two items, Digi-Key might be able to help with their new PCB Builder service. All you have to do is upload your gerbers and select your materials, and they’ll give you options for a bunch of different quick-turn fabrication houses. Looks mighty convenient.

Steve Mould dropped a video this week about vibration analysis. That might not sound very exciting, but the fascinating bit is how companies are now using motion amplification video techniques to show how and where industrial equipment is moving, even if those motions are too subtle to be seen by the naked eye. It’s frankly terrifying to see how pipes flex and tanks expand and contract, and how pumps and motors move relative to each other. The technique used is similar to the way a person’s pulse can be detected on a video by the subtle color change as blood rushes into capillaries. We’d love to see someone tackle a homebrew version of this so we can all see what’s going on around us.

And finally, we want to remind everyone that the Hackaday Prize is back, and that you should get your entries going. What’s new this year is the Dream Team challenges, where four worthy non-profits organizations will each assemble a three-person team to work on a specific pain-point in their process. The application deadline has been extended to June 9, and there are two $3,000 microgrants, one in June and one in July, for each team member. So look through the design briefs and see if your skills match their needs.