To Make Reproduction Train Whistles, The Old Ways Are Best

January 21, 2019 by Donald Papp 9 Comments

Late last year, artist [Steve Messam]’s project “Whistle” involved 16 steam engine whistles around Newcastle that would fire at different parts of the day over three months. The goal of the project was bring back the distinctive sound of the train whistles which used to be fixture of daily life, and to do so as authentically as possible. [Steve] has shared details on the construction and testing of the whistles, which as it turns out was a far more complex task than one might expect. The installation made use of modern technology like Raspberry Pi and cellular data networks, but when it came to manufacturing the whistles themselves the tried and true ways were best: casting in brass before machining on a lathe to finish.

The original whistles are a peek into a different era. The bell type whistle has three major components: a large bell at the top, a cup at the base, and a central column through which steam is piped. These whistles were usually made by apprentices, as they required a range of engineering and manufacturing skills to produce correctly, but were not themselves a critical mechanical component.

In the original whistle shown here, pressurized steam comes out from within the bottom cup and exits through the thin gap (barely visible in the image, it’s very narrow) between the cup and the flat shelf-like section of the central column. That ring-shaped column of air is split by the lip of the bell above it, and the sound is created. When it comes to getting the right performance, everything matters. The pressure of the air, the size of the gap, the sharpness of the bell’s lip, the spacing between the bell and the cup, and the shape of the bell itself all play a role. As a result, while the basic design and operation of the whistles were well-understood, there was a lot of work to be done to reproduce whistles that not only operated reliably in all types of weather using compressed air instead of steam, but did so while still producing an authentic re-creation of the original sound. As [Steve] points out, “with any project that’s not been done before, you really can’t do too much testing.”

Embedded below is one such test. It’s slow-motion footage of what happens when the whistle fires after filling with rainwater. You may want to turn your speakers down for this one: locomotive whistles really were not known for their lack of volume.

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MIDI Association Announces MIDI 2.0 Prototyping

January 19, 2019 by Brian Benchoff 22 Comments

MIDI was introduced at the 1983 NAMM show as a means to connect various electronic instruments together. Since then, our favorite five-pin DIN has been stuffed into Radio Shack keyboards, MPCs, synths, eurorack modules, and DAWs. The standard basically hasn’t changed. Sure, we have MIDI SysEx messages to configure individual components of a MIDI setup, but at its core, MIDI hasn’t changed since it was designed as a current-loop serial protocol for 8-bit microcontrollers running at 1 MHz.

Now, ahead of the 2019 NAMM show, the MIDI Manufacturers Association (MMA) in conjunction with AMEI, Japan’s MIDI Association, are announcing MIDI 2.0. The new features include, “auto-configuration, new DAW/web integrations, extended resolution, increased expressiveness, and tighter timing”. It will retain backwards-compatibility with MIDI 1.0 devices.

The new initiative, like the release of the first MIDI spec, is a joint venture between manufacturers of musical instruments. The company lineup on this press release is as follows: Ableton/Cycling ’74, Art+Logic, Bome Software, Google, imitone, Native Instruments, Roland, ROLI, Steinberg, TouchKeys, and Yamaha.

This is not an official announcement of the MIDI 2.0 specification. This is the ‘prototyping’ phase, where manufacturers implement the MIDI 2.0 spec as envisioned, write some documentation, figure out what the new logo will look like, and design a self-certification process. Prototyping is expected to continue through 2019, when the final MIDI 2.0 spec will be released on the MIDI Association website.

As far as hardware hackers are concerned, there shouldn’t be any change to your existing MIDI implementation, provided you’re not doing anything new. It should be backwards compatible, after all. The new spec will allow for increased range in expression and ‘tighter’ timing, which might be an indication that the baud rate of MIDI (31,250 baud +/- 1%) may change. There’s some interesting things in store for the last old-school physical layer in existence, and we can’t wait to see what comes out of it.

The T-Pain Toy Is Now A Guitar Effect

January 9, 2019 by Lewin Day 8 Comments

T-Pain is rapper hailing from Florida, who made his name through creative use of the Autotune effect. Nobody quite does it like T-Pain to this day, but kids the world over got the chance with the release of the “I Am T-Pain” microphone, which puts effects on the user’s vocal to make them sound as fly as possible, batteries not included. In the spirit of musical exploration, [Simon] decided it would be interesting to turn the effect into a guitar pedal.

Initial plans were to wire the microphone to an input jack, and the speaker to an output jack, but things didn’t remain so simple. The toy comes with a line-in and a headphone jack already, but the wiring scheme is strange and one of the inputs can also act as an output under certain conditions. [Simon] took the kitchen sink approach, throwing a bunch of jacks at the circuit and putting it all in a pedal case with some knobs to twiddle some parameters.

The final result is a warbly, lo-fi vibrato when a guitar signal is fed in. It’s quite different from how the original toy sounds, but recalls us somewhat of the Anti-nautilus pedal when used in conjunction with a looper. Video after the break. Continue reading “The T-Pain Toy Is Now A Guitar Effect” →

An Easy Way To MIDI Sync Your Eurorack Build

January 3, 2019 by Lewin Day No comments

Eurorack synthesizer builds are known for a lot of things; simplicity isn’t necessarily one of them. However, not everything on a modular synthesizer build has to be inordinately complicated, a mess of wires, or difficult to understand. [little-scale] has built a neat and tidy module that might just find a place in your setup – the Chromatic Drum Gate Sync. The handy little device is based on a Teensy, and uses its USB MIDI libraries to make synchronizing hardware a snap.

The device has 12 channels, each responding to a single MIDI note. A note on message is used to set a gate high, and a note off message to set it low again. This allows very fine grained control of gates in a modular setup. The device can also output a variety of sync signals controlled by the USB MIDI clock – useful for keeping your modular rack in time with other digitally controlled synths.

It’s a build that espouses [little-scale]’s usual aesthetic – clean and tidy, with a focus on compactness. All the required details to build your own are available on Github.

We’ve seen the collision of [little-scale] and Teensy hardware before – with this rig playing 8 SEGA soundchips in unison.

Turning LEGO Blocks Into Music With OpenCV

December 30, 2018 by Donald Papp 2 Comments

We’re not sure what it is, but something about LEGO and music go together like milk and cookies when it comes to DIY musical projects. [Paul Wallace]’s Lego Music project is a sequencer that uses the colorful plastic pieces to build and control sound, but there’s a twist. The blocks aren’t snapped onto anything; the system is entirely visual. A computer running OpenCV uses a webcam to watch the arrangement of blocks, and overlays them onto a virtual grid where the positions of the pieces are used as inputs for the sequencer. The Y axis represents pitch, and the X axis represents time.

Embedded below are two videos. The first demonstrates how the music changes based on which blocks are placed, and where. The second is a view from the software’s perspective, and shows how the vision system processes the video by picking out the colored blocks, then using their positions to change different values which has an effect on the composition as a whole.

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Adaptive Infotainment Plays Tunes To Match Your Dangerous Driving

December 29, 2018 by Bryan Cockfield 23 Comments

Part of the fun of watching action movies is imagining yourself as the main character, always going on exciting adventures and, of course, being accompanied by the perfect soundtrack to score the excitement and drama of your life. While having an orchestra follow you around might not always be practical, [P1kachu] at least figured out how to get some musical orchestration to sync up with how he drives his car, Fast-and-Furious style.

The idea is pretty straightforward: when [P1kachu] drives his car calmly and slowly, the music that the infotainment system plays is cool and reserved. But when he drops the hammer, the music changes to something more aggressive and in line with the new driving style. While first iterations of his project used the CAN bus, he moved to Japan and bought an old Subaru that doesn’t have CAN. The new project works on something similar called Subaru Select Monitor v1 (SSM1), but still gets the job done pretty well.

The hardware uses an Asus Tinkerboard and a Raspberry Pi with the 7″ screen, and a shield that can interface with CAN (and later with SSM1). The new music is selected by sensing pedal position, allowing him to more easily trigger the aggressive mode that his previous iterations did. Those were done using vehicle speed as a trigger, which proved to be ineffective at producing the desired results. Of course, there are many other things that you can do with CAN bus besides switching up the music in your car.

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Freeforming The Atari Punk Console

December 29, 2018 by Roger Cheng 20 Comments

This stunning piece of art is [Emily Velasco’s] take on the Atari Punk Console. It’s a freeform circuit that synthesizes sound using 555 timers. The circuit has been around for a long time, but her fabrication is completely new and simply incredible!

This isn’t [Emily’s] first rodeo. She previously built the mini CRT sculpture project seen to the left in the image above. Its centerpiece is a tiny CRT from an old video camera viewfinder, and it is fairly common for the driver circuit to understand composite video. And unlike CRTs, small video cameras with composite video output are easily available today for not much money. Together they bring a piece of 1980s-era video equipment into the modern selfie age. The cubic frame holding everything together is also the ground plane, but its main purpose is to give us an unimpeded view. We can admire the detail on this CRT and its accompanying circuitry representing 1982 state of the art in miniaturized consumer electronics. (And yes, high voltage components are safely insulated. Just don’t poke your finger under anything.)

With the experience gained from building that electrically simple brass frame, [Emily] then stepped up the difficulty for her follow-up project. It started with a sound synthesizer circuit built around a pair of 555 timers, popularized in the 1980s and nicknamed the Atari Punk Console. Since APC is a popular circuit found in several other Hackaday-featured projects, [Emily] decided she needed to add something else to stand out. Thus in addition to building her circuit in three-dimensional brass, two photocells were incorporated to give it rudimentary vision into its environment. Stimulus for this now light-sensitive APC were provided in the form of a RGB LED. One with a self-contained circuit to cycle through various colors and blinking patterns.

These two projects neatly bookend the range of roles brass rods can take in your own creations. From a simple frame that stays out of the way to being the central nervous system. While our Circuit Sculpture Contest judges may put emphasis the latter, both are equally valid ways to present something that is aesthetic in addition to being functional. Brass, copper, and wood are a refreshing change of pace from our standard materials of 3D-printed plastic and FR4 PCB. Go forth and explore what you can do!

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