MIDI Association Releases Spec For TRS Jacks

August 23, 2018 by Brian Benchoff 27 Comments

The MIDI spec was released in 1983, and for more than thirty years every synthesizer, drum machine, and piece of computer hardware with MIDI has sported an enormous DIN-5 jack on the back. Why did they choose such a large connector? Well, MiniDIN connectors hadn’t even been invented yet, and today even MiniDIN connectors are rarely-seen, obsolete connectors.

In the last decade, MIDI has found its way into some very small machines. Those Pocket Operators have MIDI sync, you can control a Game Boy with MIDI using the right hardware, and the cute little Korg synths also have MIDI tucked away in there somewhere. You can’t put a DIN-5 jack on those things, leading to some weird implementations of MIDI over non-standard connectors.

Now the MIDI Association has weighed in on the situation. There’s now a spec for MIDI over 2.5mm and 3.5mm TRS jacks. In just a few short decades, you’ll be able to connect MIDI gear with an audio aux cable.

Although there are five connectors in a DIN-5 jack, most implementations use only two connectors to send and receive data. Synth manufacturers have capitalized on this fact and cheap TRS connectors to build their own implementation of MIDI using smaller connectors, sometimes with incompatable pinouts.

Now, though, there’s a standard. For TRS connectors, the tip is pin 5 on the DIN-5, the ring is pin 4, and the sleeve is pin 2. It sends and receives data to synths and drum machines from 1983, and it doesn’t use gigantic connectors.

The only caveats to the new MIDI standard is that 2.5mm TRS connectors are recommended, and that protection circuitry is strongly recommended in the case a headphone driver is inevitably connected to a MIDI device. Other than that, everything’s coming up roses, and this opens up the door to MIDI jacks that are much, much easier to source.

The Precise Science Of Whacking A Wine Glass

July 31, 2018 by Ben James 12 Comments

It’s common knowledge that tapping a wine glass produces a pitch which can be altered by adjusting the level of the tipple of choice inside. By filling twelve glasses with different amounts of liquid and tuning them to the twelve notes of the scale, it’s possible to make a one-octave instrument – though the speed and polyphony are bottle-necked by the human operator. If you think it sounds like a ripe project for automation, you’re correct: [Bitluni’s lab] has done what needed to be done, and created a MIDI instrument which plays the glasses using mallets.

Electronically it’s a simple build – some 12 V solenoids driven by MOSFETs, with an Arduino in charge. For the mechanical build, a 3D printer proved very useful, as each mallet could be made identical, ensuring a consistent tone across all glasses. Rubber covers printed in flexible filament were fitted to reduce the overtones and produce a clearer sound. [Bitluni] also utilised different types of glasses for the low and high pitches, which also helped to improve the clarity of the tone.

MIDI is of course the perfect protocol for this application; simple, lightweight and incredibly widely used, it’s the hacker’s delight for projects like this. The instrument can perform pre-programmed sequences, or be played live with a MIDI controller. Both of these are shown in the video after the break – stick around for a unique rendition of Flight Of The Bumblebee. For a more compact wine glass based music creation solution, we recommend this nifty project, which alters pitch using a water balloon raised and lowered into the glass by a servo. Continue reading “The Precise Science Of Whacking A Wine Glass” →

OpenDeck Makes Spinning Your Own MIDI Controller Easy

July 2, 2018 by Lewin Day 31 Comments

These days, MIDI controllers are just plain cool. There are a million of them out there, and they’re all dressed to the nines in flashing LEDs and sporting swag like USB MIDI interfaces and sliders that just feel right. With our italics budget running out, I should get to the point – you can make your own, and the OpenDeck platform makes it easy.

The OpenDeck board. Readily apparent is the fact that it has tons of IO.

In its most refined form, the OpenDeck is a board covered in pin headers. To these, you may connect an absolute truckload of buttons, encoders, sliders, and LEDs. The OpenDeck handles all of the inputs and outputs, while you get to have fun attaching your various gizmos to the control surface/keytar/birthday cake you happen to be building. It saves you reinventing the wheel as far as reading switches and potentiometers goes, allowing you to focus on the creative side of your project. All configuration is handled through a simple web interface.

Boards are available on Tindie, but it’s also possible to take the code and run it on various Arduinos and the like, as it’s wonderfully opensource. This gives you the power to take things to a higher level once you’re good and ready.

We’ve seen a rather cool OpenDeck build already, and if you’ve got more, you know where to reach us.

A MIDI Sequencer To Be Proud Of

June 23, 2018 by Jenny List 5 Comments

MIDI sequencers are surprisingly expensive, making them an excellent target for [RH Electronics] who has created a sixteen-step device. It supports up to eight playable parts per step, which can be either MIDI or drum triggers.

The case and front panel are built to a very high standard, and on a piece of stripboard within lies an ATmega644 which does all the MIDI work, an ATmega328 that runs the many LEDs, and an ATtiny85 that reads the front panel buttons. The whole is kept in sync by a timer on the 644 set to produce the required MIDI clock. There is an LCD display too, which carries the status and programming interface.

You can see the result in the video below the break, in which the sequencer is put through its paces alongside a tantalising glimpse of a matching synthesiser. Is this another project, or a commercial device on which Google fails us when we try to find it? Meanwhile this is certainly not the first MIDI sequencer we’ve brought you here at Hackaday, this Arduino one is another example of several also using Atmel parts.

Continue reading “A MIDI Sequencer To Be Proud Of” →

Monotron Gets All The Mods

June 9, 2018 by Adam Fabio 3 Comments

[Harry Axten] turned the diminutive Korg Monotron into a playable analog synthesizer, complete with a full-sized keyboard spanning two octaves and a MIDI interface.

Korg Introduced the Monotron analog mini-synthesizer back in 2010. They also dropped the schematics for the synth. Hackers wasted no time modifying and improving the Monotron. [Harry] incorporated several of these changes into his build. The Low-Frequency Oscillator (LFO) has been changed over to an envelope generator. The ribbon controller is gone, replaced with a CV/gate interface to sound notes.

The CV/gate interface, in turn, is connected to an ATMega328P which converts it to MIDI. MIDI data comes from one of two sources: A two-octave full-sized keyboard pulled from a scrapped MIDI controller or a MIDI connector at the back.

The user interface doesn’t stop with the keyboard. The low-cost pots on the original Monotron have been replaced with much higher quality parts on the front panel. The tuning pot is a 10-turn device, which allows for precision tuning. All the mods are mounted on a single board, which is connected to the original Monotron board.

The fruit of all hard work is an instrument that is a heck of a lot of fun to play. Check it out in the video below. Want more? You can read all about hacking about the Monotron’s bigger brother, the Monotribe.

Continue reading “Monotron Gets All The Mods” →

A Fully Open Source Raspberry Pi Synthesizer

June 8, 2018 by Tom Nardi 19 Comments

Have you ever seen something and instantly knew it was something you wanted, even though you weren’t aware it existed a few seconds ago? That’s how we felt when we received a tip about Zynthian, a fully open source (hardware and software) synthesizer. You can buy the kit online directly from the developers, or build your own from scratch using their documentation and source code. With a multitude of filters, effects, engines, and essentially unlimited upgrade potential, they’re calling it a “Swiss Army Knife of Synthesis”. We’re inclined to agree.

At the most basic level, the Zynthian is a Raspberry Pi 3 with a touch screen, a few rotary encoders, a dedicated sound card, and MIDI support. Software wise the biggest feature is arguably the real-time Linux kernel for the lowest latency possible. There’s also a custom web interface so you can control the Zynthian from another machine on the network if you want. As a matter of course, it also includes a wide array of pre-installed audio packages to experiment and create with.

Kits are offered at various prices from $420 USD for the top of the line model down to unpopulated PCBs for a few bucks. We like that they broke things down this way; allowing users of various skill (and or patience) to pay what they want. If you just want to buy the custom boards and roll your own case and Pi solution, you can do that.

If you want to go all in, you can build one entirely from scratch as well. Everything from the CAD files for the case to their custom rotary encoder library is completely open (most licensed under GPL v3) for anyone to use however they see fit. There’s even a page in the wiki for listing hardware which isn’t officially supported by the project, but remain as options for those looking to cut their own path.

Synthesizers are a fairly popular hacker project, from Google’s AI-powered version to single chip exercises in frugality. If you want to learn even more about the fine line between digital noise and music, check out this fantastic series by our very own [Elliot Williams].

[Thanks to Mynasru for the tip.]

Continue reading “A Fully Open Source Raspberry Pi Synthesizer” →

Vintage Organ Donates Parts For Two New Instruments

May 27, 2018 by Dan Maloney 8 Comments

It’s often hard to know what to do with a classic bit of electronics that’s taking up far too much of the living room for its own good. But when the thing in question is an electronic organ from the 1970s, the answer couldn’t be clearer: dissect it for its good parts and create two new instruments with them.

Judging by [Charlie Williams]’ blog posts on his Viscount Project, he’s been at this since at least 2014. The offending organ, from which the project gets its name, is a Viscount Bahia from the 1970s that had seen better days, apparently none of which included a good dusting. With careful disassembly and documentation, [Charlie] took the organ to bits. The first instrument to come from this was based on the foot pedals. A Teensy and a custom wood case turned it into a custom MIDI controller; hear it in action below. The beats controller from the organ’s keyboard was used for the second instrument. This one appears far more complex, not only for the beautiful, hand-held wooden case he built for it, but because he reused most of the original circuitry. A modern tube amp was added to produce a little distortion and stereo output from the original mono source, with the tip of the tube just peeking above the surface of the instrument. We wish there were a demo video of this one, but we’ll settle for gazing at the craftsmanship.

In a strange bit of timing, [Elliot Williams] (no relation, we assume) just posted an Ask Hackaday piece looking for help with a replacement top-octave generator for another 1970s organ. It’s got a good description of how these organs worked, if you’re in the mood to learn a little more.

Continue reading “Vintage Organ Donates Parts For Two New Instruments” →