MIDI has been a remarkably popular interface since its inception way back in 1983. Based on existing serial interfaces, and with a broad enough set of features, it remains the defacto standard for communication between musical gear. However, older gear and many modular synths simply don’t grok digital data, instead using analog control voltages to get the job done. Never fear, though – you can convert from one to the other with the goMIDI2CV.

It’s a simple device, hewn from an ATTINY microcontroller. MIDI signals are received at TTL voltage levels, and converted to output voltages by the ATTINY via use of the PWM hardware. A lowpass filter is added to remove the high-frequency content from the output signal.  A 6N138 optocoupler completes the project, to comply with the MIDI standard and ensure the device is not subject to any dangerous voltages from the hardware plugged in.

It’s a simple way to control older non-MIDI compliant hardware, and might make an old modular rig just that much more useful in the studio of today. We’ve seen similar builds before, like this combined CV and Gate converter. 

Eurorack Gets A Wireless MIDI Connection

Modular synthesizers have been around since the early 1960s, delivering huge tonal possibilities from their impressive and imposing patchbays. In 1996, the Eurorack standard was launched, and has become the go-to choice for enthusiasts new to the world of modular synthesis. [Rich Heslip] is just one such enthusiast, and has brought Bluetooth MIDI to Eurorack with his Motivation Radio module.

[Rich]’s module is built around the ESP32, which provides plenty of processing power, along with all the necessary radio hardware to communicate over Bluetooth. The unit packs plenty of connectivity into an 8HP wide panel, with four gate inputs and outputs, four CV inputs and outputs, and serial MIDI in and out.

Thanks to its Bluetooth connection, Motivation Radio makes it easy to pass note and gate data into a Eurorack setup, and can be used with the wide variety of tablet and smartphone MIDI software on offer. If you’re eager to build your own, PCB and panel designs are available courtesy of [jakplugg] and [Rich] has shared the software on Github.

Of course, if you prefer MIDI over USB, [little-scale] has the build for you. Video after the break.

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Hackaday Links: January 27, 2019

Once again, Uber found a company to build their ‘air taxis’. This time it’s Boeing. While there are no details on the Boeing bird, I’m going to propose again that Uber buy the Santa Monica airport as a hub for their air taxi program; SMO is going to be shut down anyway, and this is the funniest reality that can come from the idea of an ‘air taxi’ program.

According to ancient astronaut theorists, one of the bigger problems with full-time tech YouTubers (think Dave and Fran here) is the insistence that YouTube suggests conspiracy theory videos as a related video. If you do a video teardown on Apollo flight hardware, you’re going to fall into the same category as people who believe the moon is hollow, people who believe the moon landing was faked, and recently, flat-earthers. This is a ‘bad move’ by YouTube because the Venn diagram of people who want to watch conspiracy videos and people who want to watch teardowns is two circles. It makes community engineering hard, and you get a lot of idiots on YouTube comments. YouTube is now changing the recommendation algorithm. There are other reasons YouTube is doing this, specifically relating to videos that aren’t about weird electronics, but we’re not going to talk about that here, thx.

This week was Winter NAMM, the National Association of… music, something something. That means you can go to Anaheim and check out all the musical instrument related stuff that will be released this year. Think of it as CES, only you don’t get the flu and want to murder everyone, and it’s about guitars and synths instead of Alexas duct taped to Roombas. Here’s what it was like last year, with the tl;dr being a wall of cabs, Euroracks everywhere, and the best way to get started in the industry is to buy some old trademarks, not by actually designing something new. Speaking of, here are some Kay reissues.

So, what’s cool at NAMM this year? Let’s do guitars first. Gibson’s 2019 lineup is not dumb, a reversal of the previous twenty years; There’s a Les Paul Standard with humbuckers or P90s, and there’s a TV Junior. Fender? There’s an acoustasonic Tele that was terrible the first time around, and it’s decidedly not terrible. The Electric XII is back, finally, and it’s even cooler than the Electric Six wait never mind it has a 1 11/16th nut. There is no Tele Plus with a Honda Goldwing emblem, but we make do with what we can. The pyramids are upside-downBuy a dookie pedal.

How about some synths?  Behringer is cranking out another clone, this time an Oberheim OB-Xa. Word on the street is that a 303 is on the horizon, but the vocoder is out now. The Odyssey exists, and the SH-101 clone comes with a handle so you can keytar it.  Guitars with Raspberry Pis? Could it be? Yes, Lucern Custom Instruments is collaborating with Tracktion to put a synth in a guitar. There’s a touchscreen BioTek 2 synth installed below the bridge. It’s like something [Matt Bellamy] would play, but it’s got a Raspberry Pi.

Elektron has a new samplerOh my god, the only way to make money in the instrument industry is to buy up trademarks. Well, trademarks and signature amps and guitars. Speaking of, where’s the signature Vangelis synths?

The news that will have the biggest impact a decade from now is the announcement that MIDI 2.0 is getting ready for release. New features include auto-config with DAWs, extended resolution, and expressiveness (to stop the Western hegemony on electronic music), and backward compatibility with MIDI 1.0.

This isn’t explicitly NAMM-related, but Eurorack is now a thing and [Jan] is always coming up with some interesting synths-on-a-chip. This time, it’s a drum machine in a Eurorack format. Is it based on anything? Not really, although it would go well in any Detroit acid track. Check out the video.

An Easy Way To MIDI Sync Your Eurorack Build

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.

Mechanizing A Eurorack Sequencer

Eurorack has taken over the synthesizer community, and hundreds of people are building their own eurorack modules. [Michael Forrest] designed and built his own Eurorack sequencer module that doesn’t use weird things like capacitors and chips to store a signal. Instead, he’s doing it with stepper motors and some clever engineering.

The basic idea of a Eurorack sequencer is to somehow store a series of values and play them back repeatedly. Connect that sequence to a clock, and you get the same pattern of sounds out of your synth. This can be done digitally with a circular buffer, in the analog domain with a bunch of FETs and caps, or in this case, on a piece of paper glued to a stepper motor.

The key bit of mechanism for this build is a stepper motor with 96 steps per rotation. This is important, because the module is controlled by a clock pulse from the sequencer. Since 96 is evenly divisible by 8 and 16, that means this sequencer will play back in 4/4 time. That NEMA 17 motor with 200 steps per resolution simply won’t work in this situation. Rather, it will technically work, but it’ll be unusable.

The electronics for this build are surprisingly simple, with an Arduino taking in the clock pulse and sending the step signals to an H-driver. The motor spins a paper disk, which is read with a photoresistor and a LED. It’s simple enough to be fun, and yes, it is mounted to a proper Eurorack-sized panel. You can check out the video of this build below.

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An Englishman And 48 Gameboys Walk Into A Bar…

The original Nintendo Gameboy is perhaps one of the most revered platforms for the music known as chiptune. Primarily, artists will use the console with software like LSDJ or Nanoloop to produce their compositions. Some artists will even use two consoles when performing live. However, that’s all fairly quaint as far as [LOOK MUM NO COMPUTER] is concerned.

Back in 2016, a rig was constructed with three Gameboys. With each console having 3 oscillators and a noise channel, this gave plenty of scope. There was even a facility to detune the oscillators for a fatter sound.

Yet there remains a universal human philosophy – more is always better. In this vein, the plan is to create a monster machine consisting of 48 Gameboy consoles. This offers a somewhat maddening 144 oscillators and 48 noise channels to play with. The plan is to produce a massive synthesizer capable of producing incredibly thick, dense tones with up to six note polyphony.

The hardware side of things is at once simple and ingenious. Buttons on the consoles are connected together for remote control using ribbon cables and transistors. System clocks for the consoles are provided by a LTC1799 oscillator chip, which allows the clock to be modulated for audio effects. Initial tests with up to six Gameboys running from a single clock source have been remarkably successful.

Any mad scientist could see the genius involved in this project, and we can’t wait to see the full rig in operation. If you’re just getting started with Gameboy music, check out this primer on modding your Gameboy for hi-fi sound. Video after the break.

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With Grinning Keyboard And Sleek Design, This Synth Shows It All

Stylish! is a wearable music synthesizer that combines slick design with stylus based operation to yield a giant trucker-style belt buckle that can pump out electronic tunes. With a PCB keyboard and LED-surrounded inset speaker that resembles an eyeball over a wide grin, Stylish! certainly has a unique look to it. Other synthesizer designs may have more functions, but certainly not more style.

The unit’s stylus and PCB key interface resemble a Stylophone, but [Tim Trzepacz] has added many sound synthesis features as well as a smooth design and LED feedback, all tied together with battery power and integrated speaker and headphone outputs. It may have been originally conceived as a belt buckle, but Stylish! certainly could give conference badge designs a run for their money.

The photo shown is a render, but a prototype is underway using a milled PCB and 3D printed case. [Tim]’s Google photo gallery has some good in-progress pictures showing the prototyping process along with some testing, and his GitHub repository holds all the design files, should anyone want a closer look under the hood. Stylish! was one of the twenty finalists selected for the Musical Instrument Challenge portion of the 2018 Hackaday Prize and is therefore one of the many projects in the running for the grand prize!