The Hacklet #7 – MIDI

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This week’s Hacklet is all about Hackaday.io projects which use MIDI, or Musical Instrument Digital Interface for the uninitiated. MIDI was designed from the ground up as an open communications standard for musical instruments. Nearly every major instrument company participated in the design of the standard. MIDI was first demonstrated in January of 1983, with the communications standard document following in August. Hackers, makers, and musicians immediately ran with it, using MIDI to do things the designers never dreamed of.

SAMSUNG[Robert’s] 9×9 Pixel Muon Detector/Hodoscope  is a great example of this. [Robert] is using 18 Geiger Muller Tubes to detect cosmic particles, specifically muons. The tubes are stacked in two rows which allows him to use coincidence detection. Rather than just plot some graphs or calculate impact probabilities, [Robert] hacked a Korg Nanokey 2 MIDI controller to output MIDI over USB messages corresponding to the detected muons. Check out his video to see a sample of the music of the universe!

 

diyMPCNext up is [Michele’s] DIY MPC style MIDI controller. [Michele] needed a simple low-cost drum controller that wouldn’t wake his neighbors. He loved Akai MPC controllers, so he rolled his own. [Michele] investigated force sensitive resistors but found they were very expensive. At a cost of $8 USD each, his resistors alone would be nearly the cost of a low-end MPC!  [Michele] created his own sensitive pads using a sandwich of copper tape and 3M Velostat conductive sheets. An HCF4067 routes all the analog lines to a single pin of Teensy 3.0, which then converts the analog resistor outputs to MIDI messages.

pic-midi-1vo[Johan] loves his analog synths, and wanted them to be able to talk MIDI too. He built MIDI2VC, a circuit which converts MIDI to 1V/Octave (similar to  CV/Gate). 1V/Octave is an analog control system used in some early synthesizers, as well as many modern analog creations. Pitches are assigned voltages, and as the name implies, each octave is 1 volt. A4 on the keyboard is represented by 4 volts, while A5 is 5 volts. [Johan] used a Microchip PIC16LF1823 to receive and convert the MIDI signals. The PIC outputs I2C data to an MCP4725 DAC which drives the analog side of the house.

eldanceLong before DMX512 came on the scene, hackers were controlling lights via MIDI. [Artis] continues this with El Dance, a wireless system for controlling electroluminescent wire worn by dancers. Similar in function to  [Akiba’s] EL wire system, [Artis] took a lower cost route and used the venerable NRF24L01 radio module. He added an antenna which gives the modules a range of about 30 meters. The computer running the dance routine’s music sees the transmitter side of the link as a MIDI instrument. Standard note on and off commands activate the EL wire strings.

midi-vibeOur final hack comes from [Jen] who built a MIDI Vibrator Inductor Synth. [Jen] performs in an experimental music band called My Wife, with instruments as varied as violins and sewing machines. [Jen] must be a fan of Van Halen’s Poundcake as she’s using a similar technique, with a MIDI twist. An Arduino converts MIDI notes to analog values, which are sent to a motor controller board. The motor controller uses PWM to drive a vibrator motor at the frequency of the note being played. Like all DC motors, the vibrator puts out a ton of electromagnetic noise, which is easily picked up by [Jen’s] electric bass.

That’s it for this week’s Hacklet! Tune in next week for more projects from Hackday.io!

 

MIDI And Vintage FM Synthesis

FM

Before the days when computers could play and record audio that far surpassed the quality of CDs, sound cards were very, very cool. Most audio chips from the 80s, from the Commodore SID is pretty much a synth on a chip, but you can also find similar setups in ancient ISA sound cards. [Emilio] pulled one of these cards with an ADLIB OPL2 chip on it, and used a PIC micro to create his very own FM synthesis synth (IT, translatatron, although Google is screwing up the formatting).

The Yamaha YM3812 chip, otherwise known as the OPL2, was a fairly complete synthesizer in a very tiny package using FM synthesis for some very unique sounds. Once [Emilio] had the PIC sending commands to the sound chip, he added MIDI support, allowing him to play this vintage ‘synth on a chip’ with a keyboard instead of a tracker.

Judging from the video below, it sounds great, and that’s with [Emilio] mashing the keys for a simple demo.

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Tempo Keeping Drummer Leaves Viking Ship, Now Inspires Pedallers

Bike Controlled Drum Machine

[Serdef] wrote in to tell us about a project he has recently created. It’s a drum beat generator that changes tempo depending on how fast you pedal your bike. This flies directly in the face of using music to keep your pedal timing consistent and up to speed.

The project started out with a tap-tempo drum rhythm pedal that [Serdef] had previously built. This device will generate a drum beat at a tempo corosponding with the time between 2 input signals. This type of device allows someone, say a guitarist, to quickly and easily specify the speed of the drumbeat that they are playing along with.

With the meat and potatoes of the project already figured out, the next part was to make the speed of the bike trigger the tempo of the drum beat. For the signal input, a magnet mounted on the wheel triggers a reed switch mounted on the bike fork once per wheel revolution. This is the same method of information gathering that a bicycle speedometer/odometer uses.

The business part of this project includes an Arduino that measures the speed of the wheel via the magnetic switch, adjusts the speed of the drum beat, and then sends the drum beat to a synthesizer via MIDI protocol. The synthesizer converts the MIDI signal into drum sounds amplified through a powered speaker that the rider can hear. The entire system is powered by a 9v battery and housed in a project box strapped to the bike’s handlebars.

All of the design files and Arduino code are available via [Serdef’s] excellent write up on hackaday.io in case you’re interested in making one for yourself.

C64 MIDI and Flash Cart

KerberosThe SID chip inside the Commodore 64 and 128 is arguably still the gold standard for chip tunes, and the C64 itself still a decent computer for MIDI sequencing. [Frank Buss] realized most of the MIDI cartridges for the Commodore computers are either out of production or severely limited, so he set out to create his own.

Unlike the few Commodore MIDI cartridges that are available, [Frank]’s Kerberos has MIDI In, Out, and Thru, controlled by the 6850 ACIA chip, just like the old 80s interfaces. This allows the Kerberos to interface with the old Sequential Circuits, Passport, and Datel software. He’s offering the Kerberos cart up on a crowdfunding site, so if you’d like to grab your own, have at it.

Because the Kerberos is also a Flash cart, it also ships with some of this software; [Frank] got permission from Steinberg to install their Pro 16 software with the Kerberos.  SID Wizard is also pre-loaded on the cart, along with a few other fabulous trackers and sequencers. Of course, there’s no requirement for the Flash portion of the cart to only host MIDI and synth software. You can always upload a few games to the cart over a MIDI interface. Video of the Kerberos below.

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Rock Out With Your Ribbon Controller Bass

Ribbon-Bass

[Brendan Byrne] stripped this instrument down to basics and built himself a ribbon controller bass guitar. Details are still a bit sparse  on his website, but there are plenty of detailed pictures on his flickr stream. [Brendan] built his bass as part the Future of Guitar Design Course at Parsons the New School for Design. His goal was to create an experience in which playing the instrument and altering parameters of effects are triggered by the same gestures. He’s definitely succeeded in that effort.

Basically, the bass is a four channel ribbon controller. The frets were removed to make way for four graphite strips. [Brendan] followed [Iain’s] excellent tutorial to create his own graphite strips using soft artist’s pencils. The ribbons essentially become potentiometers, which are then read by a teensy. [Brendan] expanded the instrument’s sonic palette by adding several buttons and potentiometers mapped to MIDI control codes. He even included a triple axis accelerometer so every movement of the bass can be mapped. The MIDI data is sent to a PC running commercial music software. Analog sound comes from a piezo pickup placed under the bridge of the bass.

The results are pretty awesome. While we can’t say [Brendan’s] demo was music to our ears, we definitely see the musical possibilities of this kind of instrument.

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The Tannin DIY MIDI Controller

tannin-ctlr

[Shantea] needed a DJ controller. While there are commercial controllers out there, none of them fit what he was looking for. He solved the problem by building the Tannin DIY MIDI controller. Tannin features 19 buttons, 16 potentiometers, and 4 LEDs. Buttons can send different MIDI messages for short presses and long presses. Pots can send 6 note on/off messages as well as MIDI control messages depending on their position. The LEDs blink in beat with the MIDI in clock. Everything is programmable and can be mapped thousands of different ways. The heart of the system is an Arduino Nano. [Shantea] used the hairless-midi library to convert MIDI to serial. The Arduino interfaces to a PC via serial over USB. On the host PC side, he ran loopbe30 to create a virtual MIDI cable to Traktor, his DJ software.

We love a build that looks just as good on the inside as on the outside, and Tannin doesn’t fail to impress in this respect. The frame is MDF, and the control panel is laser etched plastic on 3mm of Plexiglass. We really like Tannin’s flavone flair. Inside the case, wiring is kept organized and neat by zip ties and strips of wood below the button grid. [Shantea] had some noise issues connecting pots to flying wires, so he used a custom printed circuit board with a ground plane to gang the pots into 2 banks of 8. The results are something any controllerist would be proud of. Click past the break to see Tannin in action.

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Musician On A Budget MIDI Bass Pedals

bass_pedal1

Organ pedal boards have been around forever — they’re an easy way to multitask while playing the piano, organ, or even the guitar. [Ville] plays the electric guitar and wanted to give bass pedals a shot — the only problem is, the commercial versions are pretty pricey. So he decided to make his own temporary solution using an old MIDI keyboard he had lying around.

The beauty of this hack is it’s completely non-destructive — although you might find you like it so much you won’t want to take it apart! [Ville] started by marking out spacer keys using green cardboard. He then grouped together other sets of keys using tape and polystyrene sheets, which he recycled from a plastic waste bin. He then marked off each set of keys with the range of notes to program into the MIDI receiver — on a 49 key keyboard you get just a bit more than an octave of bass pedal keys! It’ll certainly do until you get your hands on a proper organ pedal unit.

From there it was just a matter of re-mapping the keys on the software end of things, and disabling the other unused keys. He offers a few different methods of doing this, including using VST plugins, and Pure Data — to which he’s provided a patch he made to simplify the process.

To see it in action, stick around after the break and hear [Ville] play One Hour Backwards on electric guitar.

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